HUBER Dissolved Air Flotation Plants HDF & HDF S

WASTE WATER Solutions

Effective and efficient wastewater purification and treatment for municipal and industrial applications

HUBERDissolved Air Flotation PlantsHDF & HDF S

➤➤➤ General informationProcess water is needed in many production processes asa solvent, for production of material, or for cleaningpurposes. Water is recirculated and reused for economicaland environmental reasons. Grease, oil, fat, floating andsuspended solids, settling material, and dissolvedcomponents need to be separated to provide good anduniform water quality. Recovery of valuable product fromthe water may be another additional objective. Where used process water is discharged as wastewater,extensive pre-treatment is often required to preventproblematic substances (e.g. heavy metals, HC, AOX, etc.)from entering the sewer system and thus ensure theirfunctionality in order to reduce surcharges and fees andthus the operating costs.Conventional gravity clarifiers are often incapable toachieve sufficient pre-treatment for the reliablecompliance with effluent standards or for extensivereduction of the contaminant load upstream ofsubsequent treatment stages. Various types of flotation processes have been developedfor such separation requirements, whereof dissolved airflotation with pressure water recirculation has provenmost effective.The use of a multistage rotary pump for recycle watersaturation with air eliminates the need for costly pressuretanks with high maintenance requirements.

HUBER Dissolved Air Flotation Plant HDF units are usedfor a wide variety of industrial and municipal applications, such as:➤ Slaughterhouses➤ Meat processing and packing➤ Fish processing➤ Dairies➤ Convenience food production➤ Gastronomy➤ Disposal companies➤ Soap works➤ Land remediation➤ Chemical industry➤ Petrochemical industry➤ Iron and steel industry➤ Leather & textile industry➤ Cosmetics industry➤ Galvanizing, electroplating➤ Municipal wastewater treatment➤ Activated sludge separation➤ Phosphate aftertreatment plants➤ Rendering plants

WASTE WATER Solutions

➤➤➤ Functional description of the HUBER Dissolved Air Flotation Plant HDFThe (waste) water to be treated enters the flotation plantvia the tube feeder a and is directly mixed with thereleased pressure water (white water). The micro bubbles(20 - 80 µm dia.) generated when the pressure is suddenlyreleased are brought into close contact with the suspendedmaterial in a tube feeder (special pipe-in-pipe system) n.The gas bubbles attach to the surface of solids. Due totheir increased buoyancy, the light aggregates of solidsand air bubbles float to the water surface. The blendedinfluent flows upward into the tank of the dissolved airflotation unit where it is evenly distributed over the totaltank width. The laminar flow conditions ensure optimumphase separation.The solids/gas flocs rise to the water surface where theyform a scum (or flotate) layer that is skimmed off into theflotate hopper c by a scraper b. The scraper joists withtheir special design dewater the flotate additionally. Theflotate is either collected in a container or by an eccentricscrew pump delivered to further treatment stages (e.g.sludge dewatering with HUBER Screw Press Q-PRESS) o.The non-clogging lamella separator e increases theeffective clarifier area, for maximum hydraulic loads on asmall footprint. While the water flows down through thegaps between the inclined lamella plates, buoying flocsrise a short distance and attach at the lower surface ofthe upper lamella and dense particles sink a short

distance to the upper surface of the lower lamella. Thelamellae retain thin layers until they are grown into thickand compact layers that finally detach from the surfaceand slide quickly up or down along the lamella surface.Detached light aggregates slide up and rise to the watersurface where they form a floating scum layer. Heavy sludge aggregates slide and sink down to the bottom of the tank into the sediment hopper f from where they areeither removed by an eccentric screw pump or gravitydischarged by means of a pneumatically controlled valve.The clarified waterwater flows behind the baffle plate gto an effluent box h from where the water falls over aheight-adjustable weir into the clarified water outlet i.Up to 30 % of the effluent is recirculated for the generationof pressure water. A multi-stage centrifugal pump jgenerates a pressure of about 6 bar. In this process, air isintroduced into the pump impeller housing and intensivelymixed with the water. This pressurized water flowsthrough the pressurized water line l to the pressurerelief valve of the tank.There, the micro bubbles with a diameter of 20 to 80microns are generated through pressure relief m toambient pressure. In the tube feeder n, the microbubbles thoroughly blend with the influent to be treatedso that all solids get in close contact with a sufficientnumber of micro bubbles.

➤➤➤ HUBER Dissolved Air Flotation Plant HDF for advanced (waste)water treatment

scum (flotate) hopperUb

Ua

Uc

Ue

Uf

Ug

Ui

Uj

Ul

Um

Un

Uo

chain scraper for scum (flotate) skimming

effluent weir

effluent box for thesupply of pressure water

centrifugalpump

air supply

wastewater

tube feeder pipe-in-pipe system for non-clogging

distribution of micro bubbles

pressure release valvefor generation of

micro-bubbles

pressurized water line sediment hopperremoval of settled sludge by an eccentric screw pump, or alternatively pneumatically controlled valve

lamella separatorfor improved separation efficiency

to sludge thickening / dewateringe.g. HUBER Screw Press Q-PRESS

effluent channel

Uh

➤➤➤ HUBER Dissolved Air Flotation Plant HDF S for the treatment of heavily polluted wastewater

In addition to the compact HUBER Dissolved Air FlotationPlant HDF with a separation zone of more than one metre,there is a flat flotation system with a reduced separationzone but larger water surface, the HUBER Dissolved AirFlotation Plant HDF S. The letter ‘S’ stands for sludge, asthe plant is able to separate very voluminous and highlycontaminated wastewater and sludge in a defined way.Maximum performance is ensured by a very large watersurface for reliable flotation and a flow-optimised designof the tank. The contact zone between wastewater andsaturated water is followed by a defined flow over theentire width of the tank. The sludge particles can thus rise to the water surface as required. There, they areadditionally thickened with special scraper joists and thenremoved with a chain scraper in the direction opposite tothe direction of the flow. Remaining sediment and heavymaterials are automatically discharged via several funnel-

shaped sediment outlets. The efficiency of the saturationsystem is greatly increased in these plants in order tomeet the requirements caused by higher wastewaterloads.The main field of application of the HUBER Dissolved AirFlotation Plant HDF S is heavily polluted industrialwastewater and the separation of activated sludge asrelief or alternatively as replacement for a secondaryclarifier.

HUBER Dissolved Air Flotation Plant HDF S installed for activated sludge separation

WASTE WATER Solutions

➤➤➤ Installation of the flotation system in container as a quick and locally flexible solution from 50 to 2000 m³/d

Site expansion or changes in production often result inincreased wastewater volumes for industrial companies.Rapid solutions without the need for major constructionwork are required here. For this reason, pre-treatment ofwastewater in pre-assembled containers is a good option.These plants are completely assembled in the factory,including pipeline construction and cabling. They are thendelivered and commissioned as turnkey systems. Theinterfaces are thus reduced to a minimum and the planttechnology can start operation directly.

The user’s benefits➤ Possibility of relocation

due to operational changes➤ Reduced planning costs due to

fixed container dimensions➤ Quick execution due to a high

degree of prefabrication of the plant

Installation in container construction up to 80m³/h as a fast and mobile solution

➤➤➤ Increased separation efficiency through chemical pre-treatment

➤➤➤ Increased separation efficiency through chemical treatment stage➤ Individual project-specific tube flocculator for optimal

chemicals dosing➤ Ideal admixture of chemicals due to a flow-optimised

design

➤ Compact unit directly beside the HUBER Dissolved AirFlotation Plant HDFF

➤ Accommodating individual preferences for sampling /dosing points / measurement instrumentation

➤➤➤ HUBER Chemicals Dosing DIGIT-DOSEChemicals dosing is optimal if the flotation systemconstantly achieves the required performance withoutoverdosing of chemicals and unnecessarily increasingoperating costs.In practice, it proves to be difficult to adjust the chemicalsdose due to varying volumes and freights.Large-dimensioned mixing and balancing tanks arebeneficial but can frequently not be installed due to lackof space. Besides, the investments costs are high for thetanks and the accessory equipment required, such ascirculation pumps and aeration systems forhomogenisation.The innovative HUBER Chemicals Dosing DIGIT-DOSEallows optimal dosing of the chemicals even with smallmixing and balancing tanks. The specially developedsystem uses a combination of several measuring

principles and constantly determines the optimalchemicals dose in real time.Chemicals consumption, and therefore also operatingcosts, are reduced to a minimum. Additional positiveeffects can be seen in the volume of flotate sludgegenerated.The production of hydroxide sludge resulting fromoverdosing of precipitants is effectively avoided. The further utilisation and disposal of the flotate sludgegenerated is a main cost factor of flotation plants.Furthermore, DIGIT-DOSE makes life easier for theoperating staff as the system adjusts automatically tovarying wastewater parameters without the need for anymanual intervention.

Flotation:Addition of micro bubbles for flotation of the micro flocs, mechanicalremoval of the concentrated sludge layer and separation of the solids-freeclear water phase

Flocculation:Generation of large and strong flocs by polymer addition

Neutralisation:Neutralisation of the wastewater mixture through addition of neutralisers,automatic pH regulation

Precipitation:Transformation of dissolved pollutants into removable solids

WASTE WATER Solutions

➤➤➤ DIGIT-DOSE applications➤ Slaughterhouses and meat processing industry➤ Dairies and cheese dairies➤ Food companies➤ Tanneries➤ Animal rendering plants➤ Pre-treatment by flotation in general➤ Suitable also for retrofitting existing HUBER HDF

installations!

➤➤➤ DIGIT-DOSE system benefits➤ Up to 30% reduction in chemicals consumption➤ Support and relief for operating staff➤ Up to 20% reduced flotate sludge volumes➤ Integrated automatic cleaning of the measuring

equipment used

➤ Low investments costs and space requirements formixing and balancing tanks

➤ Return on investment within few months

Saving potential in chemicals dosing

◼ COD inlet load◼ Precipitant consumption with

load-dependent dosing◼ Precipitant consumption with

constant dosing

COD

inle

t loa

d [m

g/l]

Prec

ipita

nt c

onsu

mpt

ion

[l/m

3 ]

4000

3500

3000

2500

2000

1500

1000

500

0

4,5

4

3,5

3

2,5

2

1,5

1

0,5

0

5

Wastewater flow variation during the day in an industrial company

WASTE WATER Solutions

HUBER SEIndustriepark Erasbach A1 · D-92334 BerchingPhone: +49 -84 62 -201 -0 · Fax: +49 -84 62 -201 [email protected] · Internet: www.huber.de

Subject to technical modification0,0 / 9 – 4.2021 – 4.2005

HUBER Dissolved Air Flotation Plant HDF

➤➤➤ System approachWe provide complete systems for mechanical-physical water treatment by combining the HUBERDissolved Air Flotation Plant HDF with other HUBERcomponents.➤ Chemical pre-treatment by precipitation,

neutralization and flocculation in a tube reactor toimprove separation efficiencies, and even removesome dissolved pollutants

➤ Mechanical pre-treatment with HUBER Micro Strainer ROTAMAT® Ro 9, HUBER Rotary Drum Fine Screen ROTAMAT® Ro 2, orHUBER Complete Plant ROTAMAT® Ro 5

➤ Treatment of the removed scum and sediment with:HUBER Disc Thickener S-DISC,HUBER Screw Press S-PRESS or Q-PRESS®

➤ Complete wastewater treatment: additional biologicaltreatment with HUBER Membrane System accordingto the MBR process

➤➤➤ Process safety through pilot testing in the laboratory and large-scale tests

For a realistic feasibility assessment, wastewater samplescan be analysed in advance in HUBER’s own laboratory toobtain first reference data to estimate consumptionvalues. It is also possible to organise pilot tests on thecustomer’s site with a tank-mounted HUBER Dissolved Air

Flotation Plant HDF 0.5 including the required peripheralequipment. Do not hesitate to contact us.

Laboratory test Mobile pilot unit of a HUBER Dissolved Air Flotation PlantHDF