Ens 505 waste water management

BY

A.PONMALR

10-510-007

ENS 505 WASTE WATER MANAGEMENT

COMPUTERIZATION AND MONITORING OF WASTE WATER TREATMENT SYSTEM

INTRODUCTION

A Computer based software for monitoring the different treatment process.

In order to perform the activity of analyzing a variety of sampling points and type of samples depending on the objective of control.

Type of samples are 1) Treated water. 2) Raw water and waste water. 3) Sludge from sewage works. 4) Treatment reagents, etc.

DEFINITION

Polluted wastewater pumped into the Wastewater Treatment Plant goes through a complex, multi-stage treatment process that takes about 22 hours.

The treatment plant uses physical, chemical and biological processes to removed contaminants, producing a high quality discharge.

All the process are carried out by computerized system

Why Computer Aided Control andOperation?

A lot of money is being invested into measurement and monitoring systems in most process industries today and the wastewater treatment industry is no exception.

System Complexity

The operation and control of a modern process industry, such as wastewater treatment plants, is often associated with high complexity.

The vast source of disturbances, e.g. changing ambient conditions, mechanical

breakdowns, the large amount of data collected by the measurement systems.

A Dynamic conditions caused by changes in the influent wastewater.

Complex cause-effect relationships caused by the use of biological cultures, recirculations and control actions.

Automation and Control in Wastewater Treatment The Treatment plants all over the world are equipped

with data collecting systems.

These systems are used for monitoring, automatic control and as a decision base for operational strategies.

The sample values are often an average over the sampling period, during which some sensors continuously deliver values and others perhaps only once a minute.

CONT…

Some variables are controlled automatically with

controllers.

The controlled variables are

1) Oxygen level in aerated basins

2) Return and Recycling flow rates

3) Adding of chemicals

Monitoring

1. In most process industries, monitoring of the process and the process output is performed to achieve conformity with quality, safety and economic requirements imposed on the production.

2. The level of monitoring differs from various fields.

3. Pioneering efforts can be found for petrochemical and pharmaceutical industries.

4. Waste water treatment industries cannot be considered to be the most diligent and systematic users of monitoring.

Industrial waste water monitoring check list

Each facility with anaerobic wastewater treatment must monitor these parameters.

Volume of wastewater entering an anaerobic reactor or anaerobic lagoon.

Concentration of COD or BOD of wastewater entering an anaerobic reactor or lagoon.

Anaerobic wastewater or anaerobic sludge treatment processes with biogas recovery must also monitor these parameters…

Volumetric flow rate of recovered biogas.

CH4 content of recovered biogas.

Temperature

Pressure

Moisture content

CONT…

An advanced monitoring system for controlling the treatment process of wastewater containing chromium (VI) was developed by using a flow method as a chemical sensing probe.

In this system, the acquisition of monitoring information and the control of the treatment process is computer-controllable

. SEP-1701002-D

ST 203 Chrome Removal Complete System.

ENPROX 1500D

Wastewater Treatment System 15 GPM.

ENPROX 500D

Wastewater Treatment System 5 GPM.

Equipment for monitoring wastewater treatment chemicals

Remote Monitoring of Waste Water Treatment Equipment

Alarm functions enable rapid identification of abnormalities.

Reduces time required for periodic monitoring and patrolling of facilities.

Systems easy to set up, minimizing engineering man hours.

Powerful software (DAQWORX) available for remote monitoring.

Measured data can also be saved to the CX1000/CX2000 storage media for extra security.

SCADA IN WASTEWATER TREATMENT

SCADA (Supervisory Control and Data Acquisition) + HMI (Human Machine Interface)

Its an assemblage of computer and communications equipment designed to work together for the purpose of controlling a commercial process.

SCADA is usually implemented on

1) Manufacturing processes (chemical and pharmaceutical processing, food processing, and discrete manufacturing)

CONT

2) Treatment processes (wastewater treatment, municipal water treatment systems)

3) Distribution systems (gas, oil and water pipelines)

Besides control, SCADA systems also perform monitoring, data logging, alarming and diagnostic functions.

Cont…

The term SCADA also refers to centralized systems which monitor and control entire sites or complexes of systems spread out over large areas.

SCADA = CCC (Control, Cost reduction and Confidence)

Systems concepts

Most control actions are performed automatically by Remote Terminal Units ("RTUs")

or by programmable logic controllers ("PLCs").

FUNCTIONS IN SCADA

Control function

Monitoring function

Data logging function

CONTROL FUNCTION

SCADA systems are capable of running standard control algorithms like P, PI, and PID regulatory.

It is for maintaining 1. Specific levels in tanks, 2. Maintaining prescribed flow rates and 3. Maintaining processes at specific temperatures

and pressures.

Monitoring Functions

Providing an effective visual interface between the process and an operator is often the main function of the system.

Data Logging Functions

Once data has been brought into the system, the SCADA system will archive selected data into electronic records that may be recalled and reviewed at a later time.

A SCADA System usually consists of the following subsystems

1) Human Machine Interface or HMI HMS is the apparatus which presents

process data to a human operator and through which the human operator monitors and controls the process.

2) A supervisory (computer) system, gathering data on the process and sending commands to the process.

Cont…

3) Remote Terminal Units (RTUs) connecting to sensors in the process, converting sensor signals to digital data and sending digital data to the supervisory system.

4) Communication infrastructure connecting the supervisory system to the Remote Terminal Units.

A SCADA system could be programmed to

1. Monitor high and low levels in the day tanks.2. Fill them when a certain level is reached. 3. Calculate and store the volume used. 4. Monitor the level in the main feed tank. 5. Alarm when a certain level is reached to notify

purchasing.6. Plot the usage of chemicals vs time, process, or any

other parameter.

ADVANTAGES

Systems have multiple levels of security available so that screens can be locked, hidden or displayed depending on the security level.

Higher levels of authorization can change set points and timing.

Updating software is a remote operation and is easily done without a site visit.

CONT…

Once a system is running, program changes are easily made at little cost.

We can remotely monitor a system to debug or update software in real time.

The system stays running while we work.

Costs are relatively low and the new object oriented systems can be programmed rapidly.

ABS (Absorbent Bio-filter System)

ABS significantly lowers costs and increases treatment performance for rural areas.

As an alternative to village-scale on-site wastewater treatment units.

The monitoring parameters -operational conditions of the systems are

1) Oxidation Reduction Potential (ORP), 2) Water level, 3) Pump status, 4) Power supply (on / off).

CONT…

The monitoring system included measurement, control and display devices.

The dispersed nature of such on-site units has brought about the need for remote monitoring systems and integrated management with the least number of operators in a central location.

CMMS (COMPUTERIZED MAINTENANCE MANAGEMENT SYSTEM)

It is a software based information management system used to automate the maintenance process.

One major benefit of CMMS is the ability to schedule equipment and

maintenance in a way that does not interfere with use of the equipment.

St. Marys New Wastewater Treatment Plant

Flow Equalization

Equipment at the beginning of the treatment plant controls the volume of wastewater that can be processed for treatment.

During high flow conditions (> 9,000,000 gallons per day) - plant cannot treat all of the flow- electric gate- divert a portion - 2,700,000 gallon equalization basin- storage.

CONT…

The captured wastewater in the equalization basin is automatically returned to the treatment plant for treatment when system flows return to normal.

A computerized process monitoring and control system controls all aspects of flow equalization.

Wastewater Treatment Stages

1. Influent Screening & Vortex De-gritting - large and heavy inorganic material are removed.

2. Oxidation Ditch wastewater is biologically treated

to reduce biological oxygen demand and to oxidize ammonia.

The ditch is sized to accommodate the design loading without the need for separate primary settling.

A chemical is added to removed phosphorus.

CONT…

5. Plant Effluent - treated wastewater is discharged to the St. Marys River.

6. Cannibal Solids Reduction Process - solids removed or generated during treatment undergo further treatment through a cannibal solids reduction process.

CONT…

3. Final Clarifiers 1) Two peripheral feed clarifiers separate sludge from treated wastewater.

2) Clear wastewater flows to the disinfection process.

3) Sludge is returned to the oxidation ditch or wasted to the solids reduction process.

4. UV Disinfection - the energy from ultraviolet lights is utilized to reduce the pathogen content of the wastewater.

6. Solids Reduction Process

Solids separation module.

Interchange module

CONT…

1. Solids Separation Module -screens small material from the solids, and an interchange module.

2. Interchange Module -the solids are subjected to alternating periods of oxygen-available (aerobic) and oxygen-deficient (facultative) environments.

which encourages cannibalization of the microorganisms and reducing the volume of the solids.

CONT…

7. Sludge Storage - solids ultimately are wasted from the cannibal process to one of two digesters for thickening and storage.

Sludge is either applied to agricultural land as a soil conditioner (bio solids) or dewatered and disposed of in a landfill.

The Klagshamn Wastewater Treatment Plant (WWTP)

Southern parts of Malmo

The treatment process has to be monitored and adjusted

continuously through a computerized control system to ensure that the effluent requirements are fulfilled.

COMPUTERIZED MONITORING The monitoring is carried out by meters which continuously measure

the

1) Phosphorus concentration 2) Water flow and 3) Other parameters.

At the Klagshamn laboratory the water from the different stages of the treatment process is analysed.

The advantage of using meters is the opportunity to monitor, process and control the plant as changes occur.

REFERENCE: St. Marys New Wastewater Treatment Plant http://WWW.vasyd.se.

Stephan J. Sosik, CEO, scada system in waste water treatment.

S.-K. Kwun, Y.-H. Cho, J.-K. Chun, Development of monitoring system for a multiple on –site waste water treatment unit mo, American Society of Agricultural and Biological Engineers.

"http://en.wikipedia.org/wiki/SCADA"

Christian Rosen ,Monitoring Wastewater Treatment Systems, Department of Industrial Electrical Engineering and Automation.

Sam Bastawros, P.E. Nosa Irenumaagho, P.E. Ewa Gorgi, P.E., utilization of computerized maintenance management system at south side waste water treatment plant