Section 02

Sanitary wastewater and sewerage systems SASC-S-02

SASC-S-02

SANITARY WASTEWATER AND SEWERAGE SYSTEMS This Section contains the operation and maintenance requirements for the treatment and disposal of sanitary and industrial wastewaters in Saudi Aramco. NOTE: All sub-sections should be read in conjunction with the applicable Saudi Aramco Engineering Standards and any referenced documents listed at the end of this Code Section. ACRONYMS AND DEFINITIONS

ACRONYMS

EPD Environmental Protection Department HMA Hazardous Material Advisor LPD Loss Prevention Department MEPA Meteorology & Environmental Protection Administration MSO Material Supply Organization OM Operating Manual PCBs Polychlorinated Biphenyls RCSHF Reclamation Chemicals Storage and Handling Facility SAES Saudi Aramco Engineering Standard SAMSO Saudi Aramco Medical Services Organization SO Storehouse Operations TCLP Toxicity Characteristic Leaching Procedure TEL Tetraethyl Lead DEFINITIONS

Acidity: Quantitative capacity of aqueous solutions to react with hydroxide ions to a designated pH. Measured by titration, with a standard solution of a base to a specified end point. Usually expressed as milligrams per liter of calcium carbonate. Activated Carbon: Carbon activated by high-temperature heating with steam or carbon dioxide, producing an internal porous particle structure. Total surface area of granular activated carbon is estimated to be 1,000m2/gm. Alkalinity: Capacity of water to neutralize acids, imparted by the waters content of carbonates, bicarbonates, hydroxides, and occasionally borates, silicates, and phosphates. Expressed in milligrams per liter of equivalent calcium carbonate. Anaerobic Waste Treatment: Waste stabilization brought about by the action of microorganisms in the absence of air or elemental oxygen. Usually refers to waste treatment by methane fermentation. Approved Facility: Any waste management facility approved by EPD. Backwash: Process by which water is forced through a filtration bed in the direction opposite to the normal flow (usually upward). During backwashing, the granular bed expands, allowing material previously filtered out to be washed away. Bioassay: Assay method using a change in biological activity as a qualitative or quantitative means of analyzing the response of biota to industrial wastes and other wastewaters. Viable organisms, such as live fish or daphnia, are used as test organisms. Biochemical Oxygen Demand (BOD): Measure of the concentration of organic impurities in wastewater. The amount of oxygen required by bacteria while stabilizing organic matter under aerobic

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conditions, expressed in milligrams per liter, is determined entirely by the availability of material in the wastewaters to be used as biological food and by the amount of oxygen utilized by the microorganisms during oxidation. Biological Oxidation: Process in which living organisms in the presence of oxygen convert the organic matter contained in wastewater into a more stable or mineral form. Buffer: Any combination of chemicals used to stabilize the pH or alkalinities of solutions. Chlorination: Application of chlorine to water or wastewater, generally for the purpose of disinfections, but frequently for accomplishing other biological or chemical results. Chlorine Contact Chamber: Detention basin in which a liquid containing diffused chlorine is held for a sufficient time to achieve a desired degree of disinfection. Chlorine Demand: Difference between the amounts of chlorine added to the wastewater and the amount of residual chlorine remaining at the end of a specific contact time. The chlorine demand for given water varies with the amount of chlorine applied, time of contact, temperature, pH, and nature and amount of impurities in the water. Clarification: Any process or combination of processes to reduce the concentration of suspended matter in a liquid. Coagulation: Process by which chemicals (coagulants) are added to an aqueous system, to render finely divided, dispersed matter with slow or negligible settling velocities into more rapidly settling aggregates. The coagulants neutralize forces that cause dispersed particles to repel each other. Comminution: Process of cutting and screening solids contained in wastewater flow before it enters the pumps or other units in the treatment plant. Denitrification: Chemically bound oxygen in nitrate or nitrate ions stripped away by microorganisms, producing nitrogen gas, which can cause floc to rise in the final sedimentation process. An effective method of removing nitrogen from wastewater. Detention Time: Average period of time a fluid element is retained in a basin or tank before discharge. Dual Media Filtration: Filtration process that uses a bed composed of two distinctly different granular substances (such as anthracite coal and sand), as opposed to conventional filtration through sand only. Electrical Conductivity: Reciprocal of the resistance in ohms measured between opposite faces of a centimeter cube of an aqueous solution at a specified temperature. Expressed as microhms per centimeter in degrees Celsius. Food to Microorganism Ratio (F/M): Aeration tank loading parameter. Food may be expressed in pounds BOD added per day to the aeration tank; microorganisms may be expressed as mixed liquor volatile suspended solids (MLVSS) in the aeration tank. Freeboard: Vertical distance from the top of a tank, basin, column, or wash trough (in the case of sand filters) to the surfaces of its contents. Grease Skimmer: Device for removing floating grease or scum from the surface of wastewater in a tank. Grit Chamber: Detention chamber or an enlargement of a sewer, designed to reduce the velocity of flow of the liquid, to permit the separation of mineral from organic solids by differential sedimentation.

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Hardness: Characteristic of water imparted by salts of calcium, magnesium, and iron (such as bicarbonates, carbonates, sulfates, chlorides, and nitrates), which causes curdling of soap, deposition of scale in boilers, damage in some industrial processes, and sometimes objectionable taste. It may be determined by a standard laboratory procedure or computed from the amounts of calcium, magnesium, iron, aluminum, manganese, barium, strontium, and zinc, and is expressed as equivalent calcium carbonate. Hydraulic loading: Quantity of flow passing though a column or packed bed, expressed in the units of volume per unit time per unit area; e.g., ga./min/ft2 (m3/m2.s). Influent: Wastewater or other liquid (raw or partially treated) flowing into a reservoir, basin, treatment process, or treatment plant. Landfarming: A controlled disposal process that uses naturally occurring bacteria to biodegrade non-leaded oily sludges in soil. Leaded Oily Sludge: Any oily sludges, whether solid or semi-solid, collected from leaded gasoline and tetraethyl lead tanks and vessels containing 100 mg/Kg total lead or greater. Chemical Oxygen Demand (COD): Measure of the oxygen-consuming capacity of inorganic and organic matter present in water or wastewater, expressed as the amount of oxygen consumed from a chemical oxidant in a specific test. It does not differentiate between stable and unstable organic matter and thus, does not necessarily correlate with biochemical oxygen demand. Mixed Liquor Suspended Solid (MLSS): Concentration of suspended solids carried in the aeration basin of an activated sludge process. Mixed Liquor: Mixture of activated sludge and wastewater undergoing activated sludge treatment in the aeration tank. Neutralization: Reaction of acid or alkali with the opposite reagent until the concentrations of hydrogen and hydroxyl ions in the solution are approximately equal. Nitrification: Conversion of nitrogenous matter to nitrates. Non-Leaded Oily Sludge: Any oily sludge, whether solid or semi-solid, containing less than 100 mg/Kg total lead. Non-Settleable Sludge: Suspended matter that does not settle or float to the surface of water in a period of 1 hour. Organic Nitrogen: Nitrogen combined in organic molecules, such as protein, amines, and amino acids. Oxidation Pond or Lagoon: Basin used for retention of wastewater before final disposal, in which biological oxidation of organic material is affected by natural or artificially accelerated transfer of oxygen to the water from air. Oxidation: Addition of oxygen to a compound. More generally, any reaction involving the loss of electrons from an atom. Oxygen Uptake Rate: Amount of oxygen utilized by an activated sludge system during a specific time period. Parshall Plume: Calibrated device developed by Ralph Parshall for measuring the flow of liquid in an open conduit, which consists essentially of a contracting length, a throat, and an expanding length. A sill, over which the flow passes at critical depth, is located at the throat. The upper and lower heads are individually measured at a definite distance from the sill. The lower head need not be measured

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unless the sill is submerged more than about 67 percent. Physical-Chemical Treatment: (PCT) Plant Treatment sequence in which physical and chemical processes are used to the exclusion of explicitly biological process (including incidental biological treatment obtained on filter media or absorptive surfaces). In this sense, a PCT scheme is a substitute for conventional biological treatment. A PCT scheme following an existing biological plant may, by contrast, be termed simply a tertiary plant, although it is also a PCT in a general sense. Polyelectrolyte: Chemicals consisting of high molecular weight molecules with many reactive groups situated along the length of the chain. Polyelectrolytes react with the fine particles in the waste and assist in bringing them together into larger and heavier masses for settling. Primary Settling Tank: First settling tank for the removal of settleable solids through which wastewater is passed in a treatment works. Primary Treatment: 1) First (sometimes only) major treatment in a wastewater treatment works, usually sedimentation; or 2) removal of a substantial amount of suspended matter, but little or no colloidal and dissolved matter. Raw Sludge: Settled sludge promptly removed from sedimentation tanks before decomposition has much advanced. Frequently referred to as undigested sludge. Recirculation Rate: Rate of return of part of the effluent from a treatment process to the incoming flow. Sanitary Sewer: Sewer that carries liquid and water-carried human waste from residences, commercial buildings, industrial plants, and institutions, together with minor quantities of storm, surface, and groundwater(s) that are not admitted intentionally. Significant quantities of industrial wastewater are not carried in sanitary sewers. Screen: Device with openings, generally of uniform size, used to retain or remove suspended or floating solids in flowing water or wastewater and to prevent them from entering an intake or passing a given point in a conduit. The screening element may consist of parallel bars, rods, wires, grating, wire mesh, or perforated plate; the openings may be of any shape, although they are usually circular or rectangular. Also a device used to segregate granular material, such as sand, crushed rock, and soil, into various sizes. Secondary Settling Tank: Tank through which effluent from some prior treatment process flows for the purpose of removing settleable solids. Secondary Wastewater Treatment: Treatment of wastewater by biological methods after primary treatment by sedimentation. Sedimentation: Process of subsidence and deposition of suspended matter carried by water, wastewater, or other liquids, by gravity. Usually accomplished by reducing the velocity of the liquid to below the point at which it can transport the suspended material. Also called settling. Skimming Tank: Tank so designed that floating matter will rise and remain on the surface of the wastewater until removed, while the liquid discharges continuously under certain walls or scum baffles. Sludge Age: In the activated sludge process, a measure of the length of time (expressed in days) a particle of suspended solids has been undergoing aeration. Usually computed by dividing the weight of the suspended solids in the aeration tank by the daily addition of new suspended solids having their origin in the raw waste. Sludge Volume Index (SVI): Numerical expression of the settling characteristics of activated sludge. The ratio of the volume in milliliters of sludge settled from a 1,000-ml sample in 30 minutes to the

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concentration of mixed liquor in milligrams per liter multiplied by 1,000. Stabilization Pond: Type of oxidation pond in which biological oxidation of organic matter is effected by natural or artificially accelerated transfer of oxygen to the water from air.

Submerged Weir: Weir that, when in use, results in the water level on the downstream side rising to an elevation equal to or higher than, the weir crest. The rate of discharge is affected by the tailwater. Also called drowned weir.

Suspended Solid: Solids that float on the surface of, or are in suspension in, water, wastewater, or other liquids, and that are largely removable by laboratory filtering. Also the quantity of material removed from wastewater in a laboratory test, as prescribed in Standard Methods for the Examination of Water and Wastewater and referred to as non-filterable residue. Total Organic Carbon (TOC): Measure of the amount of organic material in a water sample, expressed in milligrams per liter of carbon. Measured by Beckman carbonaceous analyzer or other instrument in which the organic compounds are catalytically oxidized to CO2 and measured by an infrared detector. Frequently applied to wastewaters. Turbidity: Condition in water or wastewater caused by the presence of suspended matter, resulting in the scattering and absorption of light rays. Measure of fine suspended matter in liquids. Analytical quantity, usually expressed in Jackson turbidity units (Jtu) or Nephelometric turbidity units (NTUs), determined by measurements of light diffraction. Turbulent Flow: Flow of a liquid past an object so that the velocity at any fixed point in the fluid varies irregularly. Type of fluid flow in which there is an unsteady motion of the particles and the motion at a fixed point varies in no definite manner. Sometimes called eddy or sinuous flow.

1 ENGINEERING DESIGN

Wastewater shall be treated and disposed of by processes that meet the design requirements in SAES-A-104 Wastewater Treatment, Reuse, and Disposal. Copies of the preliminary and detailed engineering reports, design drawings, and specifications prepared in accordance with SAES-A-104 shall be submitted to the Manager, Environmental Protection Department, (EPD) for review and approval.

2 PROTECTION OF WATER SUPPLIES

2.1 Minimum Separation Distances

2.1.1 Minimum horizontal separation distances between sewerage components and water systems shall be as indicated in Table 1.

2.1.2 Sewer line crossing with potable water lines shall comply with the requirements of

SAES-S-010, Sanitary Sewers.

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TABLE 1 Minimum Horizontal Separation Distances

Minimum Distance To Be Maintained From: Water Wells m(ft)

Water Lines m(ft)

Sewer Lines Septic Tank/Grease Traps Disposal Field Seepage Pit Areas Irrigated with Reclaimed Wastewater Reclaimed Water Line Sewage Treatment Plants (onshore) Sewage Lift Stations (onshore)

15 (50) 15 (50) 30 (100) 45 (150) 150 (500) 15 (50) 150 (500) 90 (300)

3a(10) 3 (10) 3 (10) 3 (10) 15b(50) 3a(10)

a -In the event that these separation distances can not be met, see SAES-S-010. b - This buffer zone applies to spray irrigation areas only.

2.2 Water Supply and Prevention of Cross Connections

2.2.1 Water Supply: An adequate supply of potable water under pressure that complies with requirements described in SASC-S-01 shall be provided for sanitary and drinking purposes, use in the laboratory, and for general cleaning duties around the plant. The design and construction of all plumbing shall comply with the requirements of the Saudi Aramco Plumbing Code, SAES-S-060. Where it is not possible to provide potable water from a public water supply, separate water well may be provided. The location, design, construction and quality of water obtained from the well shall comply with SASC-S-01. Since the plant operators and visitors will use this water supply for sanitary and drinking purposes, it shall be plumbed as outlined above.

2.2.2 Prevention of Cross Connections: Cross connecting the potable water supply with

any non-potable or other water supply of questionable quality is prohibited. The use of water in a wastewater treatment plant is a necessity, but special precautions are required to protect the potable water supply. In this regard, two separate water systems must be provided which are not physically connected in any way; i.e., a plant potable water system and a plant non-potable water system.

2.2.2.1 Backflow Prevention: Atmospheric vacuum breakers shall be installed for

all potable water wash down hoses. Reduced pressure backflow devices (RPBDs) or air gap and break tank shall be installed on all potable water lines serving wastewater lift stations and wastewater treatment plants unless a totally separate non-potable water system using reclaimed water is installed for all cleaning requirements and chemical make-up water requirements. The RPBD should be installed with adequate space to facilitate maintenance and testing. Adequate clearance from the floor, ceiling, and walls must be provided to facilitate the removal of the relief valve. An RPBD shall not be installed in a pit below ground level. The RPBD must be inspected regularly for indication of failure.

2.2.2.2 Separate Non-Potable Water System: Where water from a separate

potable water supply is used to provide make-up water to the non-potable water system, then the potable water must be discharged to a break tank with an air gap of at least 15 centimeters (6 inches) above the maximum water level, or the overflow outlet of the tank, whichever is higher.

2.2.2.3 Separate Non-Potable Water System Using Reclaimed Wastewater: If

break tank shall not be required between the source of reclaimed wastewater and the wastewater treatment plant.

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2.2.2.4 Non-potable water systems shall be properly color-coded as identified in Table 2 of SAES-A-104.

2.2.2.5 All outlets from a non-potable water system shall be posted with permanent

signs and logos (artist's drawing), in Arabic and English, indicating that the water is non-potable and is not safe for drinking.

3 WASTEWATER PUMP STATIONS

3.1 Wastewater pump stations shall not be subject to flooding. A suitable superstructure, preferably located off the right of way of streets and alleys to collect the stormwater shall be provided. The station shall be readily accessible.

3.2 Pump systems shall be designed to handle unexpected downtime. Design of the pump

facility shall incorporate ease of maintenance and repair. The design of the pumps shall be in accordance with SAES-S-010.

3.3 Each pump station shall have at least two units of the same capacity. The capacity of

each must exceed the expected maximum wastewater flow. If more than two pumps are provided, the capacity of the pump system must be such that with one pump out of service, the capacity of the remaining pumps exceeds the expected maximum wastewater flow. Each pump shall have a separate suction.

3.4 Pneumatic ejector-type pump stations require at least two pneumatic ejectors unless

the ejector pot has been located in a dry well with all parts accessible for the repair of leaks. If the ejector pot forms the lower part of the lift, two pots shall be required.

3.5 Pumps handling raw wastewater shall be preceded by readily accessible bar racks with

clear openings not exceeding 5 centimeters (2 inches) unless pneumatic ejectors are used or special devices are installed to protect the pumps from clogging or damage. Where the size of the installation warrants, a mechanically cleaned bar screen with a grinder or comminution device shall be used. Where screens are located below ground, convenient facilities shall be provided for handling screenings.

3.6 Adequate ventilation shall be provided for all lift stations. Where the pump pit is below

the ground surface, mechanical ventilation is required and arranged to ventilate the dry well and the wet well independently. There shall be no interconnections between the wet well and the dry well ventilating systems. In pits over 4.5 meters (15 feet) deep, multiple inlets and outlets shall be used. Dampers shall not be used on exhaust or fresh air ducts and fine screens and other obstructions in the air ducts shall be avoided to prevent clogging.

3.7 There shall be no physical connection between any potable water supply and a

wastewater pump station, which under any conditions might cause contamination of the potable water supply. If a potable water supply is brought to the pump station, it must comply with conditions stipulated in SASC-S-01

3.8 Alarm systems shall be provided for all pump stations. The alarm shall be activated in

cases of power failure, pump failure, or any cause of pump station malfunction. Where a municipal facility of 24-hour attendance is not available, pump station alarms shall be telemetered. Where no such facility exists, an audiovisual device shall be installed at the station for external observation.

3.9 Force mains shall be a minimum of 10 centimeters (4 inches) in diameter. Air release

valves shall be provided on lines at all peaks in elevation.

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4 SANITARY WASTEWATER TREATMENT SYSTEMS 4.1 General

4.1.1 Industrial wastewater and stormwater run-off shall not be mixed with sanitary wastewater prior to treatment. The streams may be combined after treatment, prior to disposal.

4.1.2 Hauling of raw sewage from holding tanks will not normally be considered an

acceptable method of waste disposal unless specifically approved by Manager, EPD. 4.1.3 All outside areas shall be kept free of nuisances and safety hazards (refer to SASC-

S-18). 4.1.4 All on-shore treatment units shall be located a minimum of 150 meters (500 feet)

from any residential areas, camp areas, or office areas. 4.1.5 All treatment plants and holding ponds shall be surrounded by a Saudi Aramco Type

V Security fence. 4.1.6 Routine housekeeping of buildings and grounds shall be included in the operators

regular daily responsibilities. All buildings and equipment should be routinely cleaned. Doors, windows, walls and other areas should be kept clean, dry, and in good repair. Outside grounds should be mowed regularly with the grass clippings removed promptly. Equipment and piping should be cleaned and painted as required for appearance and identification purposes.

4.1.7 The direction of prevailing winds shall be considered when selecting the plant site. 4.1.8 Effluent quality requirements for wastewater treatment plants shall conform to

applicable requirements as outlined in: (1) Table 3 of this section; (2) SAES-A-103, Marine Wastewater Discharges; (3) SAES-A-104, Wastewater Treatment, Reuse, and Disposal; (4) Meteorology & Environmental Protection Administration Standards; (5) Jubail or Yanbu Royal Commission Standards; and (6) Al Hasa Irrigation and Drainage Authority (HIDA).

4.1.9 All municipal wastewater treatment plants shall be operated in accordance with the

latest version of Operation of Municipal Wastewater Treatment Plants published by the US Water Environmental Federation (WEF). All industrial wastewater treatment plants shall be operated in accordance with the latest versions of the applicable industrial manuals (e. g. API instructions).

4.1.10 Exceptions to Table 1 of SAES-A-104 requirements may be granted on a case-by-

case basis for sanitary wastewater that is discharged into an evaporation pond, which meets the design requirements of Standard 8.1 of SAES-A-104.

4.1.11 Sanitary sewage discharged more than 4 nautical miles from shore does not need to

be treated to meet Table 1 requirements; it shall be comminuted and disinfected prior to discharge in accordance with SAES-A-103.

4.1.12 Discharges to the land are not permitted unless written approval is obtained. 4.1.13 Sanitary wastewater sludge shall be stabilized (aerobic digestion) prior to drying in

sludge drying beds. Dried sludge shall be disposed of in an approved sanitary landfill designed as per SAES-S-007 and operated as per Section SASC-S-03.

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4.1.14 All sanitary wastewater reuse applications must be designed and installed as per SAES-A-104. Adequate control measures must be taken to prevent inappropriate


alterations in the piping that could result in cross connections with potable water. All warning signs, backflow preventors, and cross connection control measures shall be maintained as originally designed. The minimum horizontal separation distances between sewerage components and wastewater system shall be in accordance to Table 1 of this instruction.

4.1.15 For any waste or mixture of wastes not specifically mentioned in this instruction or in

the event of incidents involving wastes, the treatment and disposal method must be approved by Manager, EPD.

4.2 Preliminary Treatment

4.2.1 All sanitary wastewater treatment plants shall have bar screens, mesh screens, and/or comminutors. Bar screens shall be located upstream of the grit chambers and shall be readily accessible at all times to allow inspection and maintenance.

4.2.2 A stairway and/or ladder shall be provided for access if bar screens, mesh screens,

or comminutors are located one or more meters below or above ground level. Equipment shall be provided to transfer the screenings to ground elevation.

4.2.3 In order to provide for drainage of the screenings, manually cleaned bar screens shall

be constructed having 30 degrees to 60 degrees slope to a horizontal platform. The bar spacing shall be from 25 to 40 millimeters for manually cleaned screens. The mechanically cleaned screens shall have spacing as small as 10 millimeters.

4.2.4 An accessible platform shall be provided for the manually cleaned screening facilities.

The operators to rake screenings shall use the platform. A drainage system shall be provided for the platform.

4.2.5 Auxiliary manually cleaned screens shall be provided where mechanically operated

screening devices are used. The design shall include provisions for automatic diversion of the entire wastewater flow through the auxiliary screens if the regular units fail.

4.2.6 Grit removal equipment shall be provided for all sanitary wastewater treatment plants

and shall be located upstream of pumps and comminuting devices.

4.2.7 Equipment to wash the grit shall be provided unless the grit is handled in such a manner as to prevent odors and fly nuisance. The grit collecting chambers shall be installed with the capability to be dewatered.

4.2.8 The screenings and grit shall be stored in covered containers.

4.2.9 The screenings and the grit shall be disposed of in a sanitary landfill that is approved

by EPD

4.3 Primary Treatment

4.3.1 The waste oil and the oily sludges resulted from the operation of the separators shall be disposed of in a waste disposal facility that is approved by the Manager, EPD

4.3.2 Waste oil or wastewater containing oil shall be stored in either an above ground tank

with secondary containment or in a lined pit (or sump). The liner for the pit (or sump) shall be as a minimum 30-mil high-density polyethylene. The sump or the pit shall be constructed of reinforced concrete.

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4.3.3 Equalization shall be installed in wastewater treatment plants in order to protect the biological system from fluctuations in organics, pH, flow rates, and toxic substances.

4.3.4 Equalization tanks having a detention time of more than two hours shall have

mixers. The air shall be supplied at a rate of 1.25 to 2.0 ft3/103 gal. /min. (0.01 to 0.015 m3/min.).

4.3.5 Each sedimentation basins shall be provided with walkways with guard rails along the

perimeter. A stairway shall be installed for sedimentation basins with vertical walls terminating one or more meter above or below ground level.

4.3.6 Sedimentation basins shall be provided with scum baffles and a means for collection

and disposal of the separated scum into the sludge digester. Sedimentation basins designed for flow rates less than 100 cubic meters per day shall have hydraulic skimming provided that the scum pick-up is capable of removing scum from the entire operating surface of the sedimentation basin. Sedimentation basins designed for flow rates of 100 cubic meters per day or more shall be equipped with mechanical skimmers.

4.3.7 Sedimentation basin access platforms shall have a pressure hose and hose rack for

cleaning the effluent weirs. 4.3.8 Mechanical skimmers shall be equipped with a means to automatically clean the

weirs. Brushes or scraper blade to be attached to the end of the skimmer can be used for this service.

4.3.9 Mechanical sludge collecting equipment shall be provided for sedimentation units

with a design flow equal to or greater than 100 cubic meters per day and shall have provisions for individual inspection and sampling.

4.3.10 A smooth wall finish and a hopper bottom slope of not less than 60 degrees shall be

provided for sedimentation basins that are not equipped with mechanical sludge collecting equipment.

4.4 Secondary Treatment

4.4.1 The activated sludge process may be used where the wastewater is amenable to

biological treatment; some of the modified processes require a greater degree of attention and operating supervision. These requirements shall be considered when proposing this type of treatment.

4.4.2 Biological wastewater treatment ponds (facultative ponds) and associated equipment shall be designed to meet the wastewater disposal requirements in Table 3 of this instruction unless the wastewater will be disposed in an evaporation pond. Discharges to an evaporation pond do not need to meet the Table 3 requirements provided the treatment pond is designed and operated according to Standard 8.1.1.2 of SAES-A-104 and approval is granted by Manager, EPD.

4.4.3 Pond-based wastewater treatment shall only be used in remote areas. Consideration shall be given to such factors as prevailing winds, pond configuration, soil conditions, use of effluent, and distance to populated areas.

4.4.4 Facultative ponds shall either be preceded by facilities for primary treatment of the

raw sewage or shall include a minimum of two ponds in series. The first pond shall

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be used for solids separation and biological treatment and the second pond shall be for biological treatment only.

4.4.5 Oily wastewater shall be pretreated for removal of free oil before discharge to the

biological treatment system.

4.4.6 A tank-based activated sludge process is the preferred treatment method where the wastewater is amenable to biological treatment.

4.4.7 Extended aeration and oxidation ditches are the preferred activated sludge treatment

methods; other methods may be used as per the approval of the Manager, EPD.

4.4.8 Extended aeration is the preferred method when high effluent quality and ammonia removal is required. Extended aeration shall be used in applications where a high probability of shock loads exists.

4.4.9 The oxidation ditch may be used where treatment needs are similar to those for

extended aeration. All oxidation ditch systems shall provide final clarification and return sludge capability equal to that required for the extended aeration system. Provision shall be made to easily vary the immersion depth of the rotor for flexibility of operation.

4.4.10 If the design flow exceeds 1000 cubic meters per day (250,000 gallons per day), the

total aeration tank volume shall be divided among two or more units, each capable of independent operation.

4.4.11 Equipment for measuring return sludge, excess sludge, and air shall be provided in

activated sludge plants having a design flow of 7500 cubic meters per day or more.

4.4.12 Aeration tanks shall be constructed of reinforced concrete or steel unless approved by the Materials Engineering and Corrosion Control Division.

4.4.13 Aeration tank equipment in contact with wastewater shall be constructed of 316

stainless steel unless approved by the Materials Engineering and Corrosion Control Division.

4.4.14 Surface mechanical aerators are the preferred type of aerators for wastewater

treatment systems that treat greater than 3800 cubic meters per day. Mechanical aeration devices shall be of such capacity to provide oxygen transfer to and mixing of the vessel contents equivalent to that provided by compressed air.

4.4.15 The diffuser systems shall have devices for removing and replacing diffusers without

de-watering the tank. They shall also have non-clog diffusers for all systems using intermittent aeration.

4.4.16 The diffuser systems shall have individual diffuser header assemblies with air control

valves. The diffuser head control valves shall allow for throttling of the airflow.

4.4.17 The air diffuser system, including piping, shall be capable of delivering 150 percent of design air requirements.

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4.4.18 The blower/compressor units shall be equipped with automatic reset and restart mechanisms to place the units back in operation after periods of power outage.

4.4.19 Air filters shall provide for a flow rate of 120 percent of the design requirements.

4.4.20 The requirements for the secondary sedimentation units are the same as those for

primary sedimentation units. The secondary sedimentation units shall have dual skimmers or heavy-duty full-length skimmers.

4.5 Tertiary Treatment

4.5.1 The flocculation equipment shall be designed and operated in order to obtain

optimum floc growth, control of deposition of solids, and prevent floc destruction at peak hourly flow.

4.5.2 Polymers are to be used as flocculation aids and shall be introduced into a flash mix

tank upstream of a flocculation tank or into the flocculation zone using several alternate input points.

4.5.3 Air flotation units shall not be used to treat sanitary wastewater. If the units are used

for industrial wastewater they shall be located downstream of the gravity oil/water separators and equalization equipment.

4.6 Chemical Treatment

4.6.1 Chemical addition equipment shall be provided in cases where the pH of the

discharge is outside of the pH range in Table 3 of this instruction or in cases where conventional gravity settling or biological treatment is not able to treat the discharge to Table 1 of SAES-A-104 concentrations.

4.6.2 Chemical treatment systems shall be of multiple-unit flexibility to allow for operational

adjustments in chemical feed point locations, chemical feed rates, and use of alternative chemicals.

4.6.3 The chemical dosage required shall be the minimum necessary to bring about

optimum treatment. The choice of treatment chemical(s) shall be based upon the characteristics of the raw wastewater, the quality requirement of the final effluent and the economics of the process.

4.6.4 Coagulation feed systems shall be provided with standby feeders, adequate chemical

storage and conveyance facilities, adequate reserve chemical supply, and automatic dosage control.

4.6.5 In instances where only pH correction is needed, holding tanks and metering pumps

may be used when pH adjustment is required. Other simple pH control system with either acid or base addition can be used when gradual mixing will not provide a sufficient buffering capacity.

4.6.6 Selection of chemical feed points shall be based on the type of chemicals used, the

type of wastewater treatment process, the reaction times, and the type of components in use. There shall be flexibility in feed point location with multiple feed points.

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4.6.7 The dry chemical feeders shall be equipped with a mixing tank which is capable of providing a minimum 5-minute retention time at the peak hourly flow rate. Polyelectrolyte feed installations shall be equipped with multiple solution vessels and transfer piping.

4.6.8 Mixing of the chemicals shall be accomplished using a large diameter low speed mixer. Flash mixing shall be provided for chemicals such as polymers, metal salts and pH control chemicals. The flash mixer shall have a mean temporal velocity gradient, G (sec.), of at least 800. The detention period shall be at least 30 seconds at peak hourly flow.

4.6.9 Secondary spill containment shall be provided around all chemical feed system

components.

4.6.10 An adequate supply of treatment chemicals shall be provided at the treatment plant.

4.6.11 The liquid storage tanks and tank fill connections shall be located within a secondary spill containment structure.

4.6.12 Bag or drum storage shall be located near the solution make-up point with trolleys in

order to provide for the convenient movement of drum or bag.

4.6.13 Platforms, ladders and railings shall be provided as necessary to afford convenient and safe access to all filling connections, storage tank entry locations, and measuring devices.

4.6.14 Containment areas shall be sloped into a sump area and shall not contain floor drains

that drain into a sewer.

4.6.15 Chemical precipitation sludge shall be disposed of in a facility approved by the Manager, EPD.

4.6.16 Eye washes and safety showers shall be provided in areas where chemicals are

being handled.

4.6.17 Chemical feed equipment and storage facilities shall either be constructed of corrosion-resistant materials or have a protective coating as approved by the Materials Engineering and Corrosion Control Division.

4.7 Wastewater Filtration

4.7.1 Convenient access to the component of the filters shall be provided at the treatment

plants for cleaning and maintenance.

4.7.2 The backwash rate shall be adequate to fluidize each media layer a minimum of 20 percent.

4.7.3 Waste filter backwash waters shall be returned to the inlet of the wastewater

treatment plant. Filtered water shall be used as the source of backwash water. 4.7.4 Selection of media size shall depend on the filtration rate selected, the type of

treatment provided for the filter influent, the filter configuration and the effluent quality objectives. The manufacturers of the filters should approve the use of local sand.

4.7.5 A manual override for operating equipment and critical valves shall be provided if

automatic control is used.

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4.7.6 The distribution of the backwash air through the under drain system shall be uniform.

4.7.7 The filter shall be equipped with water troughs, a means of measurement and control of the backwash rate, equipment for indicating filter head loss, surface wash or air scouring equipment, a positive means of shutting off flow to the filter being backwashed, and filter influent and effluent sampling points.

4.7.8 Adequate pumping capacity shall be available with the largest unit out of

service, where waste backwash water is returned for treatment by pumping.

4.7.9 The rate of return of waste filter backwash water to the treatment units shall not exceed 15 percent of the design flow rate to the treatment units.

4.7.10 Filtration rates shall not exceed 110 liters per minute per square meter (3 gallons per

minute per square foot) for single media (sand) filters, 150 liters per minute per square meter for dual media filters, and 190 liters per minute per square meter for multi-media filters (based on the design flow rate applied to the filter units).

4.7.11 Intermittent sand filters shall be protected from surface wash and blowing sand. 4.7.12 Gravity or pressure type filters shall be used for wastewater filtration.

4.8 Sludge Handling

4.8.1 The sludge pipe to the beds shall terminate at least 30 centimeters (12 inches) above

the surface and be arranged so that it shall drain. Concrete splash plates for the percolation-type beds shall be provided at sludge discharge points.

4.8.2 Provision shall be made to maintain sufficient continuity of service so sludge may be

de-watered without accumulation beyond storage capacity. 4.8.3 If it is proposed to de-water or dispose of sludge by other methods, a detailed

description of the process and design data shall accompany the plans. The final quality of the de-watered sludge must be such that the disposal of the dried sludge does not create a health hazard.

4.8.4 Filtrate from de-watering units shall be returned to the process for adequate treatment.

4.9 Grease Traps

4.9.1 Grease traps shall be provided for communal kitchens catering to 10 or more

4.9.2 Grease traps should normally be located within 9 meters (30 feet) of the plumbing fixtures served to prevent congealing of the grease in the lines.

4.9.3 Grease traps shall be maintained in efficient operating condition by regular removal

of accumulated grease and sediment. 4.9.4 The minimum capacity of the grease trap shall be equal to the maximum volume of

water used in the kitchen during a mealtime period or as specified in latest edition of the Uniform Plumbing Code, whichever is greater. An estimate of 9.5 to 11.3 liters (2.5 - 3.0 gallons) of water per meal served can be used to determine the required volume.

4.9.5 Grease removed from the grease trap shall be disposed in an approved sanitary

landfill.

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4.10 Onsite Disposal Systems (Holding Tanks, Septic Tanks and Disposal Fields) 4.10.1 General

4.10.1.1 Onsite disposal systems include holding tanks, septic tanks, absorption

beds, seepage pits, and evapotranspiration beds. Onsite disposal systems are only acceptable at locations with less than 30 employees where no connection to a sanitary sewer is available, and the systems are designed per Standard 12 of SAES-A-104. The Manager, EPD, may allow facilities with greater than 30 employees conditional approval for the use of an onsite disposal system on a case-by-case basis. (Any wastewater being trucked off-site for disposal must be treated in an approved wastewater treatment plant).

4.10.1.2 All onsite disposal systems (with the exception of holding tanks) shall be

preceded by a septic tank designed in accordance with Standard 12 of SAES-A-104, Wastewater Treatment, Reuse, and Disposal.

4.10.1.3 Septic tanks with disposal to absorption beds or seepage pits are not

acceptable in areas where the ground water is within 1.5 meters (5 feet) of the surface.

4.10.1.4 Septic tanks shall be maintained in efficient operating condition by regular

removal of accumulated sediment and sludge. 4.10.1.5 Absorption beds, seepage pits, and evapotranspiration beds shall be

routinely inspected to ensure proper operation. Any evidence of surface contamination with wastewater must be investigated and the underlying cause corrected immediately.

4.10.1.6 Effluent from septic tanks contains a high level of pathogenic bacteria and

shall not be considered safe. Appropriate safety precautions such as the use of protective clothing (e.g., gloves and overalls) shall be used when contact with the tank contents is unavoidable.

4.10.1.7 Roof drains, foundation drains and drainage from other sources producing

large intermittent or constant volumes of clear water shall not be piped into the septic tank or absorption area. Such large volumes of water will stir up the contents of the tank and carry some of the solids into the outlet line; the disposal system following the septic tank will likewise become flooded or clogged, and may fail. Drainage from garage floors, or other sources of oily waste, shall also be excluded from the septic tank.

4.10.1.8 Toilet paper substitutes should not be flushed into a septic tank. Paper

towels, newspaper, wrapping paper, rags, and sticks may not decompose in the septic tank, and are likely to lead to clogging of the plumbing and disposal system.

4.10.1.9 Adequate venting is obtained through the building plumbing if the septic

tank and the plumbing are designed and installed in accordance with SAES-A-104 and SAES-S-060. A separate vent on a septic tank is not necessary.

4.10.1.10 A chart showing the location of the septic tank and disposal system should

be placed at a suitable location in the facility served by such a system. The chart should contain brief instructions as to the inspection and maintenance required. The chart should assist in acquainting operators of the necessary maintenance that septic tanks require, thus forestalling

46


failures by assuring satisfactory operation.

4.10.1.11 Abandoned septic tanks shall be filled with earth or rock.

4.10.1.12 Septage and portable toilet wastes shall be disposed of at an approved wastewater treatment system designed as per SAES-A-104.

4.10.1.13 Any facility using off-site disposal of wastewater shall maintain records that

can demonstrate that the wastewater shipments were received by the approved wastewater treatment system (Saudi Aramco 9564).

4.10.2 Percolation Tests

Percolation tests shall be performed to determine the suitability of the soil for absorption/seepage type systems. Results from the percolation tests shall be used in conjunction with the standards in SAES-A-104, Wastewater Treatment, Reuse, and Disposal to develop the design of the absorption bed or seepage pit. The Manager, EPD, must approve all percolation test procedures and results. Percolation test procedures are as follows:

4.10.2.1 Number and Location of Tests: Six or more tests shall be made in

separate test holes spaced uniformly over the proposed soil absorption field.

4.10.2.2 Type of Test Hole: Dig or bore a hole, with horizontal dimensions from 10

to 30 centimeters (4.0 to 12 inches) and vertical side to the depth of the proposed absorption trench. In order to save time, labor, and volume of water required per test, the holes can be bored with a 10 centimeters (4.0 inches) auger.

4.10.2.3 Preparation of Test Hole: Carefully scratch the bottom and sides of the

hole with a knife blade or sharp pointed instrument in order to remove any smeared soil surfaces and to provide a natural soil interface into which water may percolate. Remove all loose material from the hole. Add 5.0 centimeters (2.0 inches) of coarse sand or fine gravel to protect the bottom from scouring and sediment.

4.10.2.4 Saturation and Swelling of the Soil: It is important to distinguish between

saturation and swelling. Saturation means that the void spaces between soil particles are full of water. This can be accomplished in a short period of time. Swelling is caused by intrusion of water into the individual soil particle. Swelling is a slow process, especially in clay-type soil, and is the reason for requiring a prolonged soaking period. Carefully fill the hole with clear water to a minimum depth of 30 centimeters (12 inches) over the gravel. In most soils, it is necessary to refill the hole by supplying a surplus reservoir of water, possibly by means of an automatic siphon, to keep water in the hole for at lease 4.0 hours and preferably overnight. Determine the percolation rate 24 hours after water is first added to the hole. This procedure is to insure that the soil is given ample opportunity to swell and to approach the condition it will be in during the wettest season of the year. Thus, the test will give comparable results in the same soil, whether made in a dry or in a wet season. In sandy soils containing little or no clay, the swelling procedure is not essential.

4.10.2.5 Percolation-rate measurement: With the exception of sandy soils,

percolation-rate measurements shall be made on the day following the procedure described under item 4.10.2.4 above.

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If water remains in the test hole after the overnight swelling period, adjust the depth to approximately 15 centimeters (6.0 inches) over the gravel. From a fixed reference point measure the drop in water level over a 30-minute period. This drop is used to calculate the percolation rate. If no water remains in the hole after the overnight swelling period, add clear water to bring the depth of water in the hole to approximately 15 centimeters (6.0 inches) over the gravel. From a fixed reference point, measure the drop in water level at approximately 30-minute intervals for 4.0 hours, refilling 15 centimeters (6.0 inches) over the gravel as necessary. The drop that occurs during the final 30-minute period is used to calculate the percolation rate. The drops during prior periods provide information for possible modification of the procedure to suit local circumstances. In sandy soils or other soils in which the first 15 centimeters (6.0 inches) of water seeps away in less than 30 minutes, after the overnight swelling period, the time interval between measurements shall be taken as 10 minutes and the test run for one hour. The drop that occurs during the final 10 minutes is used to calculate the percolation rate.

4.10.3 Cleaning of Septic Tanks

Septic tanks shall be cleaned before too much sludge or scum is allowed to accumulate. If either the sludge or scum approaches too closely to the bottom of the outlet device, particles will be scoured into the disposal field and will clog the system. Eventually, when this happens, liquid may break through to the ground surface, and the wastewater may back up in the plumbing fixtures. When a disposal field is clogged in this manner, it is not only necessary to clean the tank, but it also may be necessary to construct a new disposal field.

4.10.3.1 There are wide differences in the rate that sludge and scum will

accumulate from one system to the next. Tanks should be inspected at least once a year. The depth of sludge and scum should be measured in the vicinity of the outlet baffle. The tank should be cleaned if either: a) the bottom of the scum mat is within approximately 7.5 centimeters (3.0 inches) of the bottom of the outlet device; or b) sludge comes within the limits specified in Table 2.

TABLE 2 Allowable Sludge Accumulation

Liquid Depth 75 cm (2.5ft) 90 cm (3.0 ft) 120 cm (4.0 ft) 150 cm (5.0 ft)

Liquid Capacity of Septic Tank

Distance From Bottom of Outlet to Top of Sludge Liters Gallons cm in cm in cm in cm in 2835 3400 3780 7560

750 900 1000 2000

12.5 10.0 10.0 10.0

5.0 4.0 4.0 4.0

15.0 10.0 10.0 10.0

6.0 4.0 4.0 4.0

25.0 17.5 15.0 10.0

10.0 7.0 6.0 4.0

32.52 25.0 20.0 10.0

13.0 10.0 8.0 4.0

4.10.3.2 Scum can be measured with a stick to which a weighted flap has been

hinged, or with any other suitable device. The stick is forced through the mat, the hinged flap falls into a horizontal position, and the stick is raised until resistance from the bottom of the scum is felt.

4.10.3.3 A long stick wrapped with rough, white toweling and lowered to the bottom

of the tank will show the depth of sludge and the liquid depth of the tank.

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The stick should be lowered behind the outlet device to avoid scum particles. After several minutes, if the stick is carefully removed, the sludge line can be distinguished by sludge particles adhering to the toweling.

4.10.3.4 Cleaning is usually accomplished by pumping the contents of the tank into a

tank truck. Septic tanks should not be washed or disinfected after pumping. A small residual of sludge should be left in the tank for seeding purposes. When a large septic tank is being cleaned, care shall be taken not to enter the tank until it has been thoroughly ventilated and gases have been removed to prevent explosion hazards and asphyxiation of workmen. Preferably, workmen required to enter the tank should wear self-contained breathing apparatus. If not available, a stout rope shall be tied around the workman's chest under his armpits, with the other end held above ground by another person(s) strong enough to pull him out if any gas remaining in the tank should overcome him.

4.10.3.5 The material removed may be buried in an approved sanitary landfill or,

with permission of the proper authority, emptied into a sanitary sewer system. Sludge should never be emptied into storm drains or discharged directly into any stream or watercourse. Waste shipments shall be manifested to the disposal location as per Standard 6.0 of GI 430.001.

4.10.4 Holding Tanks

4.10.4.1 Holding tanks for wastewater may only be used by facilities with less than

30 employees and no connection to a sanitary sewer is available. The Manager, EPD, must approve design drawings and specifications of holding tanks.

4.10.4.2 Holding tanks must be pumped out at intervals of sufficient frequency to

prevent overflow of the contents onto the ground adjacent to the tank. A designated representative of a camp or facility served by the tank must maintain a written record of these pumping intervals to ensure this requirement is met.

410.4.3 Any holding tanks which have overflowed, or otherwise have created an

odor or public health nuisance, must be immediately reported to EPD. 4.10.4.4 Contents removed from holding tanks must be disposed of in an approved

septage receiving facility or other approved wastewater treatment facility. The disposal contractor must provide, when requested by EPD, proof of proper disposal by submission of the Waste Manifest Form (Saudi Aramco 9564) as a requirement for continuing to provide waste disposal service at Saudi Aramco facilities

4.11 Operation and Maintenance of Sanitary Wastewater Treatment Plants

All wastewater treatment plants shall be operated and maintained in manner that: (1) risks to public health and the environment are minimized, and (2) all applicable standards are achieved. Note: that the following Section is not intended to replace a detailed operations and maintenance manual. In all cases, the original equipment manufacturers operation and maintenance instructions should be followed.

49

4.11.1 Operation and Maintenance Manuals: All plants shall provide and maintain Operation and Maintenance manuals at the site. All new plants shall submit Operation and Maintenance manuals to the Manager, EPD, for review and approval. The degree of complexity of the operation and maintenance manual shall be as required by the complexity of the wastewater treatment system. A suggested table of


contents for operation and maintenance manuals follows:

Description of Process Description of Facilities Operation and Control Laboratory Testing Records Preventive Maintenance Program References

4.11.2 No wastewater may be disposed of to the marine environment if it does not meet the

MEPA discharge requirements in Table 3 of these instructions. Discharges to evaporation ponds and other approved discharge locations must meet Table 3 of these instructions; however, the Manager, EPD, may waive specific discharge requirements on a case-by-case basis. No desert dumping of wastewater is permitted.

4.11.3 Record keeping: The maintenance of good records is essential to the efficient and

orderly operation of any treatment plant. Only by maintaining clear and concise records of operation will past experiences be of assistance in guiding future operations. Sanitary wastewater treatment plants shall be sampled per the instructions shown on Table 5 of this document. 4.11.3.1 At a minimum, the records should include the daily operators log,

laboratory reports, and maintenance activities. The daily operating log should note any unusual conditions, routine operational and maintenance activities, etc.

4.11.3.2 Sanitary wastewater treatment facilities shall maintain daily records of

influent and effluent flow rates to aid staff in ensuring that design flow rates are not exceeded and to warn of possible process upsets.

4.11.4 Wastes discharged shall at no time contain substances in concentrations toxic to

human, animal, plant or fish life. The wastes discharged shall not contain phenols, cresols, or any other substances in concentration sufficient to impart objectionable tastes, odors, or foaming to usable waters.

4.11.5 Disinfection: All wastewater treatment plants which discharge effluent or reuse

effluent on land must provide disinfection to achieve the required bacteriological effluent water quality requirements as identified in sub-section 6 of this Code Section

4.11.5.1 Chlorination facilities shall be operated to provide an effluent total residual

chlorine concentration of at least 1.0 mg/L (1.0 ppm) after a contact time of at least 30 minutes at peak hourly flow. The operator for all wastewater treatment plants shall maintain daily records of total effluent chlorine residual levels.

4.11.5.2 Other disinfection processes require approval of the Manager ,EPD. Where

other processes are proposed, the design report shall include evidence of successful disinfection under similar conditions.

4.11.6 Removal, Handling And Storage of Screenings and Grit

4.11.6.1 Screenings and grit shall be wasted, dried, and disposed of in a landfill

approved by the Manager, EPD.

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4.11.6.2 Screenings and grit that are temporarily stored on the premises shall be bagged or stored in covered containers.

4.11.6.3 Handling of screenings and grit should only be performed with appropriate

protective clothing such as gloves and coveralls. 4.11.6.4 Routinely monitor equipment such as traveling bar screens, comminutors,

etc. for proper operation. Lubricate all equipment as recommended by the original equipment manufacturer.

4.11.7 Waste Facultative Ponds

4.11.7.1 Facultative ponds shall be maintained to eliminate weeds, floating grease,

floating mats of algae and scum, etc. These materials provide harborage for insects, which can act as disease vectors. Breeding insects in the ponds can be treated with an appropriate pesticide such as Abate. Weeds can be manually removed from the dike areas or carefully sprayed with an herbicide taking care not to poison the pond. Floating materials can be removed by vacuum truck and disposed of at an approved landfill.

4.11.7.2 A minimum of 0.75 to 1.0 meter (2.5 - 3.0 feet) water depth should be

maintained in ponds to prevent rooting of plants and minimize odors. 4.11.7.3 Odors resulting from temporary overloading of a pond system may be able

to be mitigated by the addition of sodium nitrate in quantities of 11.2 grams per cubic meter (100 pound per acre). The sodium nitrate should be spread evenly across the lagoon.

4.11.7.4 Routine maintenance for permanent facultative ponds requires periodic

removals of accumulated solids, removal of floating materials, correction of bank erosion, and routine clearing of shrubs and grasses from the dike area. The Manager, EPD, shall approve disposal of dredged solids. Protective clothing such as gloves and coveralls should be worn when working with wastewater or sludge.

4.11.8 Activated Sludge Treatment Process

4.11.8.1 A well operated activated sludge system will generally be brown in color

and should have an "earthy" odor. 4.11.8.2 Maintain at least 2.0 mg/L (2.0 ppm) of dissolved oxygen under all

conditions of loading in all parts of the aeration tanks except immediately beyond the inlet. Monitor the aeration basin dissolved oxygen level daily. A dark blackish color may indicate an anaerobic condition caused by low air. Increase the air to maintain the dissolved oxygen in the appropriate range.

4.11.8.3 Maintain sufficient velocity of movement and turbulence to bring sludge

particles into intimate contact with all portions of the wastewater and to prevent deposition of solids on the tank bottom.

4.11.8.4 Inspect aeration system frequently to ensure the proper operation of

blowers or mechanical aerators. Clean blower air filters regularly. Routinely check belt tensioning and alignment. Check equipment oil levels routinely and lubricate equipment as recommended by the original equipment manufacturer. Perform all other preventive maintenance as recommended by the original equipment manufacturer.

4.11.8.5 Monitor the aeration basin total suspended solids levels daily through

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either laboratory determination of total suspended solids, through monitoring the 30 minute settled sludge volume in a one liter graduated cylinder, or with the sludge volume index (SVI). A good operating rule of thumb is to maintain enough sludge in the aeration system to record 300-500 mL for the 30-minute settled sludge volume with adjustment as necessary to cope with process upsets, presence of filamentous organisms, and other variations on a plant-by-plant basis.

4.11.8.6 Clean floating sludge and scum from the clarifier surface daily. Floating

sludge can normally be forced to settle with a water spray. Scum may have to be removed manually with a net or other skimming device. Any materials removed from the surface should be placed in the plant digester or on drying beds for dewatering with ultimate disposal to an approved landfill. Check the functioning of the return sludge system to ensure it is functioning correctly. Take corrective action as required. Routinely check oil levels of the equipment and perform preventive maintenance as recommended by the original equipment manufacturer.

4.11.9 Rotating Biological Contactors (RBC): A rotating biological contactor consists of a

series of closely spaced circular disks of polystyrene or polyvinyl chloride. The disks are partially submerged in wastewater and rotated slowly through it. All RBCs must be preceded by preliminary treatment to remove rags and other trash and primary treatment for the removal of solids and oils and greases.

4.11.9.1 Maintain preliminary and primary treatment units in good working order. 4.11.9.2 Observe and record the appearance of the biomass routinely. Note any

unusual changes in the appearance of the biomass. 4.11.9.3 Monitor and record the dissolved oxygen concentration in the first stage

routinely. Dissolved oxygen concentrations below 0.5 mg/L (0.5 ppm) in the first stage are an indicator that the facilities are overloaded.

4.11.9.4 Routinely perform all preventive maintenance as recommended by the

original equipment manufacturer. Monitor the temperature of the contactor shaft bearings. Listen for unusual noises from all rotating equipment. Check lubricant levels in all rotating equipment. Ensure chain drives are well lubricated. Check belt drives for alignment and tensioning.

4.11.9.5 Clean floating sludge and scum from the clarifier surface daily. Floating

sludge can normally be forced to settle with a water spray. Scum may have to be removed manually with a net or other skimming device. Any materials removed from the surface should be placed in the plant digester or on drying beds for dewatering with ultimate disposal to an approved landfill. Routinely check oil levels of the equipment and perform preventive maintenance as recommended by the original equipment manufacturer.

4.11.10 Aerobic Sludge Digestion: All sludge shall be stabilized prior to dewatering. A well

digested sludge will drain rapidly, dry faster, and will not generate an obnoxious odor. Operation and maintenance of aerobic sludge digestors is similar to operation of activated sludge systems.

4.11.10.1 Ensure adequate and even distribution of air to provide oxygen for solids

digestion and for solids mixing. 4.11.10.2 Maintain a minimum of 1.0 mg/L (1.0 ppm) dissolved oxygen in the

digester. 52


4.11.10.3 Concentrate digested sludge by turning off the air for approximately 4.0

hours prior to decanting supernatant back to the wastewater treatment system.

4.11.10.4 Ensure proper operation of upstream oil and grease removal equipment

such as grease traps. Excessive levels of oil and grease levels in the wastewater can cause problems in the aerobic digester and in sludge drying beds. Oil and grease are oxidized slowly and can be concentrated in the digester. Too much oil and grease in digested sludge results in a sludge with poor dewatering characteristics and which is likely to generate odors as it dries.

4.11.11 Sludge Drying Beds: - Normal Operating Procedures: Sludge drying beds are a

relatively simple method of sludge dewatering. Sludge dewatering is required prior to final disposal of digested sludge to an approved sanitary landfill.

4.11.11.1Start flow of liquid sludge into bed. Stop flow when the liquid is

approximately 20 to 30 centimeters (8 to 12 inches) deep through out the bed. Do not apply new sludge on top of a layer of dry sludge.

4.11.11.2 Inspect the beds every few days noting any odors or insect problems.

Remove any weed growth. 4.11.11.3 When sludge is dry (normally up to three weeks depending on weather and

depth of sludge) remove the sludge taking care not to damage the sand and gravel layers. Remove as little sand with the sludge as possible. Sludge can be removed by shovel or forks at a moisture content of 60 to 70 percent, but if it is allowed to dry to 40 percent moisture, it will weigh only half as much and is still easy to handle. If the sludge gets too dry (10 to 20 percent moisture) it will be dusty and will be difficult to remove because it will crumble as it is removed.

4.11.11.4 After the sludge is removed, inspect the bed, rake the surface of the sand

to level it and to remove any debris, and add make up sand if necessary. The bed is ready for the next application of sludge.

4.11.11.5 All sludge beds produce some odor when in operation; however, obnoxious

odors are generally not a problem unless the sludge being dewatered is insufficiently stabilized or there are excessive levels of oil and grease in the system. Odor control should begin at the source. Inspect the digester to ensure a minimum dissolved oxygen concentration of 1.0 mg/L (1.0 ppm). Increase the aeration if necessary. Inspect the system for signs of excessive oil and grease such as grease balls in the aeration basin and ashing (small gray floating globules of grease) in the secondary clarifier. If grease is a problem, eliminate the source of oil and grease. If operational constraints prevent the elimination of the odors at the source, chemical masking agents may be sprayed at the sludge beds or the pH of the digester contents can be raised to 12 for three hours prior to disposal to the beds. Raising the pH to 12 with sodium hydroxide or hydrated lime should inhibit the biological reactions, which are responsible for producing the odors.

4.11.11.6 Flies may be a problem in certain areas and seasons and shall be

controlled by destruction of breeding and use of traps and poisons. The fly may be controlled most effectively in the larva stage. Borax or calcium borate applied to the surface of the sludge will kill the larvae. Neither chemical is dangerous to man or to domestic animals. These chemicals

53


can be sprinkled on the sludge, especially in the cracks of the drying cake. Other chemicals sometimes used are chloride of lime and sulfate of iron. The adult fly can be killed by spraying. Fly trapping is particularly suited for outdoor conditions. A satisfactory form of trap consists of a conical, gauze-covered structure leading into a larger space in which poisoned bait is placed.

4.12 Safety

4.12.1 General:

4.12.1.1 Adequate provision must be made to protect operators and visitors from hazards. A brief outline of some of the major safety considerations is given below. Contact the Loss Prevention Department regarding detailed requirements for gas piping, and safety features of chlorine installations. See also SAES-A-104, Wastewater Treatment, Reuse, and Disposal.

4.12.1.2. Wastewater discharges must be disinfected to meet the discharge

standards as shown in MEPA, SAES-A-l03, SAES-A-104 and this document, as applicable. The hazards of disinfectants must be considered in the design.

4.12.1.3 Chlorination: Chlorination facilities shall be designed to provide at least 30

minutes at peak hourly flow. The contact structure may be a tank or a combination of tank and out fall sewer. The structure must be baffled to prevent short-circuiting. The chlorine feed equipment shall be oversized to meet emergency situations. Where other disinfection processes are proposed, the design report shall include evidence of successful disinfection under similar conditions.

4.12.2 Gas Chlorination Facilities

4.12.2.1 Detailed safety handling, storage instructions and procedures shall be

included in all operation and maintenance manuals for plants using chlorine gas.

4.12.2.2 A chlorine gas detection system with alarm shall be provided in the vicinity

of the gas storage cylinders. 4.12.2.3 A leakage test kit, consisting of ammonia, water and swab, or other

acceptable chlorine detector, shall be provided in a clearly marked location. 4.12.2.4 At least one self contained, air type, breathing apparatus which provides a

30 minute air supply, such as manufactured by Scott Aviation Company, shall be provided and hung in a conspicuous place outside the chlorination room. Larger installations must also have several canister-type masks. Air packs shall be inspected regularly to ensure proper functioning.

4.12.2.5 A mechanism for flushing the eyes with potable water shall be in close

proximity to the chlorination facility. Operation of the eyewash shall be by means of a push bar.

4.12.2.6 Gas chlorine cylinders shall be shielded from direct sunlight or from

overheating above 60 oC (140oF) from any source, either while in storage or in use.

4.12.2.7 Safety chains must be provided to hold the cylinders securely upright, both

on the scales and in storage areas.

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4.12.2.8 Leak repair kits shall be provided for the type of gas cylinder used. Kits are available for 100 and 150 pound cylinders, one-ton cylinders, and tank cars.

4.12.2.9 Operator training shall be provided annually in the proper response actions

to be followed in the event of an accidental chlorine leak. 4.12.2.10 Material Safety Data Sheets (MSDSs) or Chemical Hazard Bulletins

(CHBs) shall be posted in a conspicuous location.

4.12.2.11 A separate house or room at or above ground level must be provided exclusively for chlorination purposes. If the chlorination space is a part of a larger building, the door of the chlorination area must open to the outside of the building and must be outward-opening. The door shall have a 30 by 30 centimeters (12 by 12 inches) one-light window to allow observance of conditions in the room prior to entering.

4.12.2.12 Sufficient ventilation shall be provided to allow one complete air change in

the chlorination room every two minutes. The exhaust duct must take in air for exhausting within 30 centimeters (12 inches) of the floor level. A louvered fresh air intake must be provided to serve as a make-up air supply when the exhaust fan is operating. This intake shall be located in the ceiling or near ceiling level. The exhaust fan must be wired to automatically activate when the light is turned to the ON position. The light switch shall be located outside the room. As an additional safety factor, a pressure-type switch shall be located in the door to the chlorination room, which shall activate the exhaust fan automatically when the door is opened in case the operator fails to turn on the light switch. The exhaust outlet shall be directed away from the fresh air intake and away from other occupied areas.

4.12.3 Hypochlorination Systems

4.12.3.1 Detailed safety handling, storage instructions and procedures shall be

included in all operation and maintenance manuals. 4.12.3.2 A safety shower with an eye wash mechanism for flushing the eyes with

potable water shall be located in close proximity to the dosing facility. Operation of the eyewash shall be by means of a push bar.

4.12.3.3 Calcium hypochlorite and sodium hypochlorite are strong oxidants and

must be stored safely in a cool and dry location. 4.12.3.4 Operator training shall be provided annually in the proper response actions

to be followed in the event of an accidental hypochlorite spill. 4.12.3.5 Material Safety Data Sheets (MSDSs) or Chemical Hazard Bulletins

(CHBs) shall be posted in a conspicuous location.

4.12.4 Lifesaving Buoys and Rescue Poles shall be provided adjacent to large bodies of wastewater.

4.12.5 Sanitary Facilities and Personal Hygiene:

4.12.5.1 Sanitary facilities shall be provided at all manned wastewater treatment plants per Section SASC-S-12 Places of employment. Ensure that:

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Toilet facilities are clean and in good repair.


Hand washing and shower facilities are clean and in good repair. For permanent plants with design flows greater than 1000 cubic meters per day (264,000 gpd), a separate changing/locker room or enclosure is provided and that it is kept clean and in good repair.

4.12.5.2 Employees at wastewater plants shall wear clean protective overalls,

footwear and gloves as necessary. Employees must wash their hands regularly, particularly before smoking or eating.

5 SANITARY WASTEWATER EFFLUENT DISCHARGE & REUSE REQUIREMENTS 5.1 General Requirements

5.1.1 Toxic Wastes: The wastes discharged shall at no time contain substances in concentrations toxic to human, animal, plant or fish life.

5.1.2 Objectionable Wastes: The wastes discharged shall not contain phenols, cresols, or

any other substances in concentration sufficient to impart objectionable tastes, odors, or foaming to usable waters.

5.1.3 Maximum Allowable Limits: The minimum effluent quality standards for sanitary

wastewater discharges are presented in Table 3 (or the most recent revision of Meteorology and Environmental Protection Administration standards or the standards of the Yanbu or Jubail Royal Commission, depending upon the location of the discharge). Additional requirements for effluent reuse are presented in sub-section 5.2. EPD will monitor these standards on a monthly or quarterly basis, through effluent sample collection and analysis.

5.1.4 Discharges of untreated wastewater to the land are not permitted. Discharges of

treated wastewater to the land require written approval from the Manager, EPD. 5.1.5 The Table 3 limits do not apply to wastewater treatment systems which discharge to

properly designed, lined evaporation ponds and to onsite wastewater treatment systems. All exceptions to Table 3 requirements must receive approval from the Manager, EPD.

5.1.6 Sanitary sewage from offshore facilities that is discharged more than 4 nautical miles

from shore does not need to meet Table 3 requirements; it shall be comminuted and disinfected prior to discharge.

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TABLE 3 - Effluent Discharge Limitations (1) Jubail Royal

Commission Limit (3) Yanbu Royal Commission Limit (4)

Pollutant (2)

MEPA Limit

Maximum

Monthly Mean

Maximum

Monthly Mean

Physical -Chemical Pollutants Floatable None None None None None pH Units 6-9 6-9 6-9 6-9 6-9 Total Suspended Solids (TSS)

15 mg/L

25 mg/L

10 mg/L

15 mg/L

8 mg/L

Temperature (5) +10C - (5) (5)

Turbidity 75 NTU (6) 75 NTU 50 NTU 15 NTU 8 NTU Dissolved Oxygen - 2.0 mg/L min. - 4 mg/L min. 5 mg/L min. Salinity - - - + 2 ppt + 1 ppt Non-Organic Pollutants

mg/L (30 day mean)

mg/L

mg/L

mg/L

mg/L

Aluminum - 25 15 25 15 Ammonia (as N) 1.0 3 1 3 1 Arsenic 0.1 0.5 0.1 0.5 0.1 Barium - 2.0 1.0 2 1 Cadmium 0.02 0.05 0.01 0.05 0.01 Chlorine (residual) (7) 0.5 2.0 0.5 0.3


(4) Limits taken from Environmental Protection Manual, Royal Commission for Jubail and Yanbu/Yanbu Project, Madinat Yanbu Al-Sinaiyah, 1991.

(5) To be determined on a case-by-case basis. (6) Nephelometric Turbidity Units. Also to be determined on a case-by case basis in areas deemed by EED to be biologically

sensitive. (7) Not applicable for wastewater reuse applications or discharge into evaporation ponds. For Jubail R.C. area, this value should read

Phosphorus reported as total P (8) Not to exceed 15 mg/L in any individual discharge. (9) Most probable number

5.1.7 Reuse of treated effluent requires written approval of the Manager, EPD.

5.1.8 Appropriate advisory signs in Arabic and English shall be permanently posted at all reclaimed wastewater surface impoundments, storage tanks, irrigation areas, reclaimed water outlets, etc.

5.1.9 All reclaimed wastewater lines and appurtenances shall be clearly marked as such. 5.1.10 To preclude interchange of hoses on potable and reclaimed water lines, where hose

bibs are present on potable and reclaimed water lines, different size hose bibs shall be used.

5.1.11 Any potable water service connection shall be separated by an air gap of at least 15

cm (6 inches) and shall be approved by the Manager, EPD. 5.1.12 Tanker trucks used to haul reclaimed wastewater shall be clearly marked in Arabic

and English that the water is sewage effluent and is unsafe for drinking or washing. 5.1.13 Reclaimed wastewater shall not be ponded without the written approval of the

Manager, EPD, and other concerned Departments. 5.1.14 Irrigation of areas with unrestricted access to the public shall only be irrigated when

the facilities would not be in use by the public, such as between 9 PM and 6 AM.

5.2 Requirements Applicable to Marine Discharges of Sanitary Wastewater

Each installation shall be reviewed by EPD and other concerned organizations to determine the need for more restrictive discharge requirements than those specified in Table 3. This analysis will be based upon proximity to recreational waters or shellfish beds, quantity and quality of effluent to be discharged, depth of receiving waters, and distance from shoreline. These regulations apply to all installations discharging sanitary wastewater effluent into marine environments. Sanitary wastewater discharges shall be in accordance with the requirements of Table 3 and SAES-A-103, Marine Wastewater Discharge Standard and the most recent MEPA Environmental Protection Standards, and/or Standards of the Royal Commission.

5.2.1 Bacteriological Objectives for Recreational Waters: Recreational areas are

marine areas specifically designated by Saudi Aramco or other authorities for water contact sports (swimming, diving, etc.) or other areas used for such purpose by the general public. Within these areas the following bacteriological objectives shall be maintained throughout the water column: Samples of water from each sampling station shall have a most probable number of coliform organisms less than l, 000 per 100 milliliters (10 per milliliter) provided that no more than 20 percent of the samples at any sampling station in any 30 day period exceed 1,000 per 100 milliliters (10 per milliliter), and provided further that no single sample, when verified by a repeat sample taken within 48 hours, shall exceed 10,000 per 100 milliliters (100 per milliliter).

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5.2.2 Bacteriological Objectives for Shellfish Areas: At all areas where shellfish may be harvested for human consumption, the following bacteriological objectives shall be


maintained throughout the water column: The median total coliform concentration shall not exceed 70 per 100 milliliters, and not more than 10 percent of the samples shall exceed 230 per 100 milliliters.

5.2.3 Physical and Chemical Objectives for Water: The minimum effluent quality

requirements for marine discharges of treated sanitary wastewater are listed in Table 3. In cases of conflict between SASC-S-02 and any other recognized Standard (MEPA, Royal Commission, SAES-A-103), the most restrictive standard shall apply.

5.2.4 Principles for Management of Wastewater Discharges to Marine Environments:

Wastewater management systems that discharge into the marine environments must be designed and operated in a manner that shall maintain the indigenous marine life and preserve a healthy and diverse marine community.

5.2.4.1 Dilution: Outfalls and diffusion systems must be designed to achieve rapid

initial dilution and effective dispersion to minimize concentrations of substances not removed by treatment.

5.2.4.2 Location of Discharges: The discharge locations must be determined

after a detailed assessment of the oceanographic and biological characteristics of the location to assure that:

Pathogenic organisms and viruses are not present in areas where shellfish are harvested for human consumption or in areas used for swimming or other body-contact sports. Natural water quality conditions are not altered in areas designated as being of special biological significance. Maximum protection is provided to the marine environment.

5.2.4.3 Areas of Special Biological Significance: Waste shall be discharged a

sufficient distance and depth from areas designated as being of special biological significance to assure maintenance of natural water quality conditions in those areas.

5.2.4.4 Sludge: The discharge of municipal and industrial waste sludge or digester

supernatant directly to the ocean without further treatment, is prohibited. 5.2.4.5 Bypassing: The bypassing of untreated waste to the sea is prohibited. 5.2.4.6 Sewer Outfalls: Body-contact sports or the harvesting of shellfish shall not

be allowed in the vicinity of a sewer outfall. The restricted area shall be determined after extensive bacteriological and/or viral studies have been completed and reviewed by EPD.

5.3 Requirements Applicable to No-Discharge Systems for Sanitary Wastewater

Wastewater discharged to lined evaporation ponds shall receive primary treatment in a facultative stabilization pond at a minimum and may be exempt from meeting some of the effluent quality requirements given in Table 3 of this sub-section. Exceptions to the Table I requirements may be granted on a case-by-case basis by the Manager, EPD. Wastewater treated in an existing sanitary wastewater treatment plant prior to discharge to the pond shall receive a minimum of secondary treatment. Stabilization pond sizing shall be per the requirements of SAES-A-104. The public health impacts of other methods of disposal will be evaluated on a case-specific basis.

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5.4 Reuse of Treated Wastewater

5.4.1 General 5.4.1.1 All sanitary wastewater reuse applications must be designed and installed

as per SAES-A-104, Standard 13. 5.4.1.2 Reuse of treated effluent requires written approval of the Manager, EPD.

5.4.2 Reuse of Treated Wastewater within Family Communities

5.4.2.1 Reuse practice within Saudi Aramco family communities includes spray-

bubbler and drip irrigation of unrestricted areas such as parks, playgrounds and landscape shrubbery and spray irrigation of restricted areas (spray fields).

5.4.2.2 All wastewater to be used for irrigation in unrestricted areas shall be a well-

oxidized, tertiary treated effluent. Tertiary treatment shall mean effluent from a secondary treatment plant such as activated sludge, which has subsequently been coagulated, clarified, filtered and disinfected.

5.4.2.3 All wastewater to be used for irrigation in restricted areas shall be a well

oxidized, filtered, disinfected effluent. All restricted areas shall be provided with a Saudi Aramco Type V security fence with lockable gates. A minimum buffer zone of 2 times the diameter of the largest spray irrigation pattern shall be provided between the nearest spray gun and the perimeter fence.

5.4.2.4 Bacteriological and Viral Quality: The total coliforms as determined by

the Multiple Tube Fermentation Method (MPN) shall normally be less than 2.2 colonies per 100 ml. sample and shall not exceed 23 colonies per 100 ml. on any individual grab sample. Effluent to be reused for irrigation in unrestricted areas shall be free from enteric viruses. Facility effluent will be sampled and analyzed on a random basis, at the discretion of EPD, to ensure compliance with the enteric virus standard.

5.4.2.5 Residual Chlorine Concentration: A total chlorine residual of at least

0.50 mg/L (0.5 ppm) shall be maintained in all parts of the irrigation system at all times.

5.4.2.6 Effluent Water Quality For Unrestricted Areas: Effluent to be reused, as

irrigation water in unrestricted areas shall meet the requirements in sub-section 5.1.3 except as noted below:

BOD5 < 10 mg/L TSS < 5 mg/L Turbidity < 2.5 NTU 30 Day Avg/ 5.0 NTU Maximum Daily

5.4.2.7 Effluent Water Quality For Restricted Areas: Effluent to be reused as

irrigation water in restricted, spray

Section 02

Documents

sanitary wastewater

sewerage systems sascs

presence of oxygen

elemental oxygen

waste management facility

anaerobic waste treatment

availability of material

disposal of sanitary