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Maschinen- und Anlagenbau

Dear reader,

Please feel invited with thisHUBER REPORT issue to visitour IFAT stand in hall A 2, No.339/432, where we will of coursepresent innovative products andprovide according information.The IFAT is also a welcomeopportunity for us to personallydiscuss your demands, require-ments for new developments,product improvement and trends.We are especially looking for-ward to such exchange of infor-mation.

The IFAT is certainly an interna-tional meeting point and t h eexhibition the world is looking atand visitors from all over theworld will travel to. So we willhave the chance to present our-selves to our international guests,too, and analyze their specificrequirements to be able to deve-lop and offer the suitable produc-ts individually tailored for eachtarget country.

The IFAT is in this sense animportant event which gives usthe possibility to question especi-ally the export chances of ourproducts, open up new ways andestablish contacts. ThoughHUBER is meanwhile represen-ted in 44 countries by subsi-diaries, own and representative

offices, we have to be goal-direc-ted orientating us to the very spe-cific demand of the countries ifwe want to be successful there.

We are already today realizingthis by considering the individualconditions of different countries,developing products, systemsand processes in close cooperati-on with universities in Germanywhich are especially suitable forexport territories. This has alsobeen considered with our pro-ducts and ideas for decentralizedwastewater treatment we will bepresenting. They take up a trendwhich is increasingly developingespecially in emerging countries.Decentralized sewage treatmentallows for efficient wastewaterconditioning at relatively lowcost and for reuse of waterresources.

We would be very pleased to wel-come you on our IFAT stand.You will find there a presentationof our new products and perfor-mances, especially in the field ofservice and industrial wastewatertreatment. On the other hand, theinformation we will receive fromyou in personal discussions willhelp us to further improve newproducts and services. That iswhy we are especially lookingforward to your visit!

Yours sincerely,

Hans G. Huber

Centralized Sewage Treatment – A Worldwide Solution?

Content:Centralized Sewage Treatment /5

Mechanical Preliminary Treatmentwith HUBER Machines Page 2/3

There is only one name for grit washing: HUBER Page 4

WAP/SL Screenings Wash Press –A Synonym For Best Results Page 4

New: High Pressure Screenings Wash Press Page 4

The Whole World Of Sludge Treatment Page 6/7

HUBER Septic Sludge Treatment in Kuching/Sarawak Page 8

KLEIN – The Sludge Treatment Specialist Page 9

Sewage Sludge Screening EliminatesOperating Problems Page 9

Low-Temperature Drying:KLEIN Recirculating Air Sludge Dryer Page 10

Application of the CONTIFLOW ® Sandfilter (CFSF) Page 11

HUBER Service: A Customer Designed ProductProduct-Related Service to the Customer'sOptimal Benefit Page 11

RoK 1 Storm Screen Excels at Wigan, UK Page 12

Today's situation of sewage

treatment

Already in 3800 BC, faeces togetherwith wash water and storm water hadbeen discharged from households inone channel. The most famous evi-dence for the old tradition of waste-water discharge is the "cloaca maxi-ma" in Rome which was built in the5th century BC.

One has tried ever since then to dis-pose of this unpleasant material bydischarging the wastewater. In con-trast to the time of the Romans, thewastewater today contains muchmore nutrients and pollutants, due tothe significantly higher population

density, which need to be separated

in view of their harmful impact on

the environment. We have therefore

hold on to the old "Roman concept"

of combined discharge of all water

flows, completing it with a modern

centralized sewage treatment plant.

The wastewater flows that are intro-

duced into a centralized sewage

treatment plant consist of:

● Faeces with a high organic carb-

on concentration

● Yellow water (urine) with a high

nitrogen and frequently also

medicine concentration

● Potable water for transportation

of faeces

● Wash water from showers, wash-ing machines, dishwashers

● Process and cleaning water from different industries

● Storm water (in combinedsystems) with greatly varyingloads, dependent on the chargearea

With regard to the estimated 2.4 bil-lion people (WHO) in Asia, Africa,South America but also Europe whoare not having access to orderly sani-tation facilities, the question ariseswhether the described way of waste-water treatment is the appropriateand useful method for all people orwhether there could be found intelli-gent, reasonable and modern alter-native concepts which do not requireexpensive sewer systems.

Roughly estimated, the costs for lay-ing only one meter DN 800 sewer isexactly the same as for connectingone inhabitant to a decentralizedsewage treatment plant (assumed400 E per p.e.).

In countries and areas where there isno orderly wastewater disposal exi-sting today, new technologies arerequired which are able to improvefast, at low cost and efficiently thesituation of the people living thereand their environment. If the princi-ples presented below are taken intoaccount, the preferable solutionseems to be decentralized sewagetreatment, i.e. treatment of thewastewater at source.

Direct benefitDesign and construction of sewersystems usually takes up a time ofseveral years. Since a centralizedsewage treatment plant is naturallyuseless without the sewer system,the benefit starts to set in only afterquite a time lag.

Decentralized plants start cleaningthe wastewater immediately afterdelivery, which takes only few weeksfor standardized products. Such aconstruction provides a direct andimmediate benefit.

Reasonable costs with an imme-diate effect

To be continued on page 5

International R E P O R T

Page 1

Mechanical Preliminary Tr

with HUBER MachCOARSE SCREEN: HUBER CLIMBMAX ® Climbing Screen

Bar spacing: 100 - 10 mmChannel width: 600 - 2500 mmChannel depth: up to 10 m

Separation of coarse material from big flows

● In front of sewage treatment plants to protect finescreens

● In front of pumping stations and intake structures asa protective system

● For screening of combined water in sewer systems

FINE SCREEN: ROTAMAT ® Fine Screen Ro 1

Bar spacing: 6 mm and 10 mmChannel width: 600 - 3000 mm

Separation, washing, compacting and transport ofscreenings

● Combined in one unit

● High separation capacity

● Forced cleaning of the screen basket

● Well suitable for septic sludge treatment


Cost-effective separation and transport ofscreenings

● In front of sewage treatment plants

● Flexible installation possibilities

● Compact design

● Low head loss

FINE SCREEN: STEP SCREEN® Vertical


Cost-effective separation and transport ofscreenings

● Flexible installation

● Compact design

● Deep channel installations

● High discharge height

● Low head loss

FINE SCREEN: ROTAMAT ® Micro Stra

FINE SCREEN: ROTAMAT ® Drum Filte

FINEST SCREEN: ROTAMAT ® Membr

FINE SCREEN: STEP SCREEN® Flexible

FINE SCREEN: ROTAMAT ® Wedge Se

reatment

hinesainer Ro 9

Bar spacing: 6 - 0.5 mm

Channel width: 300 / 400 / 500 / 700 mm



● Excellent quality for low price

● For small and medium size sewage treatment plants

Bar spacing: 6 - 0.5 mmChannel width: 600 - 3000 mm



● Maximum separation capacities

● Best suitable for grit-containing combined water

● Eliminates the necessity for preliminary clarification

Throughput capacity: up to 5 l/sec

Separation and compaction of screenings

Separation of grit

● In front of small sewage treatment plants

● In front of pond plants and hydrophyte treatmentplants

● In front of hotel sewage treatment plants

er Screen Ro 13

Bar spacing: 6 - 0.5 mmChannel width: 600 - 3000 mm

Separation, washing, transport and compaction ofscreenings

● Especially suitable for in-line installations

● As a pre-treatment for grit washing

● Compact design

● Completely encased system to eliminate spraywater, aerosol, odors

rane Screen

Mesh size: 1.0 - 0.2 mmChannel width: 600 - 3000 mm

Separation, washing, transport and compaction ofscreenings

● Especially suitable in front of membrane bioreactors

● Removal of fibrous material and hairs

SCREENING AND GRIT SEPARATION: ROTAMAT ® Complete Plant Ro 5



Separation, dewatering and transport of grit

Separation and transport of grease

● Turn-key system for mechanical preliminarytreatment

● With optional aeration

● Compact design

● Low expense for construction work

SCREENING AND GRIT SEPARATION: ROTAMAT ® Complete Plant Ro 5 / K




Separation and transport of floating material

● Turn-key system for mechanical preliminarytreatment with minimum space demand

● Increased separation surface due to lamella units,but small dimensions




Separation and transport of floating material

● Subsequent to screenings removal

● Increased separation surface due to the separatorcone, but small dimensions

● With optional aeration

● Compact stainless steel design




● Complete system for mechanical preliminarytreatment with minimum space demand

● Increased separation surface but small dimensions


GRIT SEPARATION: ROTAMAT ® Circular Grit Trap HRSF

SCREENING AND GRIT SEPARATION: ROTAMAT ® Complete Plant Ro 5 / C

SCREENING AND GRIT SEPARATION: ROTAMAT ® Mini Complete Plant MiniCoP

ection Screen Ro 2

There is only one name for grit washing: HUBERThe RoSF Grit Treatment Systems underline their leading position

New: High PressureScreenings Wash Press- Washing of screenings and simulta-neous dewatering with high pressureConventional high pressure unitsoften achieve only poor dry sub-stance contents (DS) when proces-sing municipal screenings withoutprior washing. The viscosity of fae-ces, grease and sludge, which arealways contained in the screenings,does not allow built-up of higherpressure in the press (see fig. 1). Itis absolutely necessary therefore tohave the screenings washed beforein order to achieve high DS contents.This conventional way of scree-nings treatment causes often veryhigh investment, maintenance andspare parts costs.

The new WAP high pressure washpress (/WAP/HP) is a successfulsymbiosis between the well-provenhigh pressure component of theROTAMAT® wash press type

Ro4/HP and the WAP wash press.Screenings washing takes place inthe wash zone, like in the WAP,which is located in the conveyorpipe. The washed screenings arethen conveyed into the high pressurecone where intensive pressing takesplace.

The intelligent technique in the highpressure cone allows to react withinseconds to possibly occurring mate-rial changes in the screenings, i.e.the machine operates permanentlyat the highest pressure in the presszone and achieves therefore conti-nuously excellent DS contents bet-ween 50 and 60%, as the first refe-rence plants show!

By Wolfgang Branner

Fig. 1 left: screeings before washing; right: washed screeings

WAP/SL Screenings Wash Press – A Synonym For Best ResultsMeasurements confirm the washout degree of >95%One of the big water authorities inEngland had tested the WAP/SL for6 months. The experienced resultswere deciding for the followingframework agreement.

The quality requirements for washedscreenings are very high in England,demanding very good washoutdegrees and dry substance contents(DS). Both sizes together give aquality factor (QF) which explainsthe biological oxygen demand(BOD5) per g DS. A small QFstands for effective screenings was-hing (low BOD5) and high DS con-tent. The QF required in England is

< 20 mg BOD5 / g DS! But opera-tional reliability and easy mainten-ance are just as important since

many sewage treatment plants inEngland are operated from telecon-trol stations.

Summary:

The six months testing phase hasimpressively shown the innovativebenefits of the WAP/SL.

A) The very low QF in the washedscreenings proves how intensivewashing and pressing is by theWAP/SL. The QF reduction of >95% related to screenings underlinesthat on the one hand plenty of carbonwas washed back into the sewagetreatment plant and on the otherhand much less screenings had to beremoved due to the increased DS.

B) No great difficulties occurredduring the full test period and noconsiderable wear was noticeddespite continuous operation of theplant (24 h/d).

By Wolfgang BrannerThe WAP/SL during its six months test operation

Some Test Results

COANDA Grit Washing PlantDo you remember IFAT 1999? Thatwas when we presented HUBER asthe market leader with about 300sold COANDA Grit Washing Plantunits RoSF4. Now as the next IFATis coming up, we can proudly report600 worldwide COANDA GritWashing Plant installations. This

high number of references provesimpressively that the patentedCOANDA Grit Washing Plant isnot only nationally but also interna-tionally the state-of-the-art techno-logy for washing of contaminatedgrit from sewage treatment plants!With an annual export share inexcess of 50% the Grit Washing

Plant has been firmly established inEurope, USA and even Australiaand sets also there the standards forgrit washing, as it has done in Ger-many for years already. The COAN-DA Grit Washing Plant has beenfully accepted by the relatively con-servative mechanical wastewatertreatment sector as a new innovative

process technology and has beco-me an essential component at theheadworks! Combining reliablegrit separation and upflow washingin the fluidized bed, the COANDAGrit Washing Plant offers the func-tion of a grit classifier and at thesame time reduces the organicmaterial concentration in the grit tobelow 3%. Handling of up to 30mm mineral grain size is no pro-blem for the COANDA Grit Was-hing Plant and ensures the maxi-mum yield of mineral fraction. Ofcourse, the HUBER COANDAGrit Washing Plant, which had gota new outfit in 2000, has to gainacceptance in the market, compe-ting against cheap would-be gritwashing plants and copies. Fortun-ately, operators no longer seem toaccept delivery of a "black box"which frequently turns out to beunable to achieve the required sepa-ration efficiency and guaranteedloss on ignition!

Complete Grit Treatment SystemsThe situtation in Germany is asfollows: Since introduction of anew regulation in 1993, any resi-dential waste not complying withthe criteria specified in this regula-tion have to be thermally pre-trea-ted in a waste incineration plant.After expiry of a transitional period

until May 2005, the only waste allo-wed to landfills will be unreactivewaste. The same time limit appliesto untreated residential waste thathas by now frequently been dispo-sed to landfills, so that disposalcosts for grit from sewer systems,sink pits and refuse will dramatical-ly rise. By adding other processmodules, the COANDA Grit Was-hing Plant can be completed to a fullGrit Treatment System RoSF5,which typically consists of a feedarrangement and storage tank, coar-se material separation and grit was-hing. The RoSF5 system ensureseasy economical and ecological tre-atment of refuse grit, grit fromsewer systems and sink pits andeven highly contaminated oil grit.The first grit recycling system hadbeen started up in 1995 already.Meanwhile, almost 50 installationswith different components are ope-rated all over Europe. Dependent onthe specific requirements, the gritrecycling plants are equipped withan optional separate water conditio-ning plant which ensures recoveryof mineral material without anyadditional water demand.If you wish to obtain informationwhere to find a near COANDA GritWashing Plant or Grit TreatmentSystem installation, contact us!

By Wolfgang Branner

HUBER ROTAMAT“ COANDA Grit Washing Plant RoSF4

Continuation of page 1

Centralized Sewage Treatment – A Worldwide Solution?

Up to 90% of the investments for thecomplete sewage treatment facilityare consumed by the sewer systemand have to be made during the con-struction phase but do not achieveany benefit at that time.

The investment and operationalcosts of decentralized plants, how-ever, are low and calculable anddirectly coupled with the requestedeffect.

Autonomy

Centralized sewage treatmentenhances careless handling of theown wastewater, which results inever rising expenses for wastewaterthat contains increasingly difficult totreat components.

Decentralized systems prevent suchcarelessness, as the consequences ofwrong handling have an immediateand directly visible effect for theoperator.

Individual flow treatment

In a sewer system, the describedtypes of wastewater are combined,which makes their treatment expen-sive and complicated.

Individual flow treatment in decen-tralized systems is the reasonablealternative. Greywater can be condi-tioned to service water by means ofrelatively simple technical methods,faeces and kitchen waste can be usedenergetically and material recoveredfrom industrial wastewater. Decen-tralized systems also provide thepossibility to collect pollutants in asmall and concentrated flow andtreat this flow individually.

Technical limitation

In many areas of the world buildingof a sewer system is generallyimpossible as

● The load-bearing capacity of the

foundation soil is insufficient or

shows tectonic activity.

● The infrastructure of urban areas

of evolved mega cities is too den-

se.

● The individual households in

rural areas are too far apart.

● The falling slope is insufficient

to transport the waste water to

the sewage treatment works.

● The solids concentration and

thus viscosity of the waste water

is too high to be flowable (caused

by small wash water amounts

and/or introduction of waste

food).

● Extreme rain intensity occurs

which cannot be handled (e.g.

monsoon).

A possibility for sewage treatment insuch cases is provided by decentrali-zed systems only.

Decentralized systems

In view of all the reasons mentionedbefore, it is most useful to adjust ourtechnologies such that they can beintegrated into the concept of decen-tralized wastewater treatment.

We are working hard to develop pro-duct designs which are able to givealso those areas in the world a per-spective for an environment worthliving in and for clean potable water

and hygienic conditions, that do atthis time not seem to have any chan-ce, due to financial reasons, to reachthe standard of industrial nations.We are rather sure to provide thosecountries the chance to make it evenbetter.

Described below are some alternati-ves how to achieve a direct and sig-

nificant improvement for people andtheir environment by applying theconcept of decentralized sewagetreatment.

Septic sludge treatment

In many countries the preconditionfor a short-term solution of the sewa-ge problem is the specific collectionof faeces and yellow water in multi-compartment septic tanks. Suchseptic tanks with preceding percola-tion channels can be made even bythe inhabitants themselves. Themulti-chamber tanks retain the fae-ces, which represent the main loadof dangerous germs and oxygen-consuming compounds. The retai-ned faeces have to be pumped off

regularly and treated as shown infigure 1.

In a following step, the effluent fromthe multi-chamber tank can additio-nally be treated by means of a simplebiological system, such as rotatingbiological contactors. To collect theeffluents of several tanks, such asystem demands small channels,which are for example created with aplow. The sludge produced by thisclarification process can be collectedby trucks together with the faeces.

Fine screening of wastewater

Another treatment concept collectsthe wastewater from several dwel-ling units and separates the solids bymeans of a fine screen. A COD eli-mination of up to 60% can be achie-ved, which can be further improvedby using additives. The residualmaterial is composted or fermented,dependent on the amount.

Of course, the screened wastewatercan later be further clarified in a bio-logical treatment stage withoutmaking fine screening superfluous.

Integrated sanitation concepts

Integrated sanitation concepts areconcepts with nearly completely

independent water supply and dispo-sal within a sanitary unit. The wateris treated and reused according to itspollution rate. Such concepts willhardly be applicable in newly indu-strializing and developing countriesin the foreseeable future but rather inlarge hotels or industrial parks.

The central point of the concept isseparation of grey from black water,which can quite easily be achieved,even subsequently, by means ofappropriate house lines. After preli-minary clarification in a small scree-ning plant the greywater from sho-wers and wash-basins is fed into anultrafiltration plant to remove hairsand grit. Since the water has then alow lye and surfactants concentrati-on and does not contain any fungi,

bacteria or viruses, it can be used inwashing machines and as cleaningwater.

Faeces are collected together withyellow water and both separated byfine screening. As the contact timeof both flows within the houseinstallation is very short, the solidshardly dissolve in the liquid phase sothat screening is efficiently separa-ting faeces and yellow water. Theultrafilt rated greywater may be usedas flush water for toilets. The appli-cation of vacuum toilets is also pos-sible.

The screened faeces are compostedor fermented, whereas the yellowwater is treated in a membranceactivated sludge process togetherwith the washing machine water andcleaning water. The clarified anddisinfected wastewater is suitable tobe used for irrigation.

Such a concept saves a considerableamount of valuable potable water.Especially in countries where pota-ble water recovery means a consider-able technical and financial expense,any measure must be taken to usewater as often as possible.

Also other clarification concepts areconceivable, which could consists ofSBBR fixed bed reactors, rotatingbiological contactors or chemical-physical treatment and screening.The selection of the optimal processchain depends on the specific limit-ing conditions and requirements.

Summary

Decentralized treatment of waste-water is in many cases – whether inGermany, Europe or newly indu-strializing and developing countries– an economical, ecologically rea-sonable or technically required mea-sure. The systems and processespresented hereunder have been sel-ected as examples and must indivi-dually be adjusted to the specificlegal, financial and prevailing struc-tural conditions. Whether municipalor industrial concepts for decentrali-zed wastewater treatment – HUBERis a competent partner for any requi-rement. Additionally, customers canas always count on HUBER also ifthey need equipment for centralizedsewage treatment plants.

If you wish to obtain more detailedinformation about the HUBER con-cepts and products for decentralizedsewage treatment, do not hesitate tocontact us or visit the HUBER standat IFAT 2002 in Munich (hall A2,stand 339).

Hans Huber, Dr. Oliver Christ

Fig. 1: Treatment concept for faeces from decentralized multi-compartment septic tanks

Fig. 2: Diagram of an integrated sanitation concept

The Whole World O

The product:

The Sludge Screening Plant serves formechanical treatment of sludge, consisting in aROTAMAT® Fine Screen or Micro Strainerinstalled in a tank. As the sludge flows into thetank and through the screen, any undesiredmaterial is separated. While a screw conveyorwith integrated screenings press removes theseparated screenings from the tank, they aredewatered and reduced in volume prior to beingdischarged into a skip.

The complete clarification process takes placein a closed system, which eliminates odorannoyance.

The screenings are additionally washed. Thepress liquor flows back into the wastewaterstream, the obtained screenings are clean andsuitable for disposal at landfills. The pressliquor of the liquid phase with a high BOD loadis passed on into the sewage treatment plant forfurther treatment.

The sturdy and efficient Sludge ScreeningPlant achieves without problems a maximumthroughput capacity in excess of 300 m3/h andis available with 3 to 12 mm bar spacing.The plant has well proven its capability innumerous installations, even with grit andstones, and is the best-selling machine of itstype worldwide.

Some of the benefits:

● High separation efficiency

● Low head loss

● Screening, transport and dewateringcombined in one unit

● Sturdy, low-maintenance stainless steeldesign

Sludge Screening:ROTAMAT® Sludge Screening Plant RoS 1

The product:

The STRAINPRESS® is a horizontal pipe-shaped continuous coarse material separatorwhich consists of inlet and driving zone,screening and press zone and finally adischarge section with pressure cone andpressure cone adjusting system.

Feeding is by a pump which presses themedium through the screening zone andforwards it via the outlet pipe to further processsteps. The coarse material retained on thescreen surface is transported to the press zoneby the screw which serves as a removal unit. Inthe press zone, the material is dewatered tospadable condition prior to being discharged.The motor speed, screen perforation andgeometrical design of the discharge section canbe adjusted to all different media. The coarsematerial is separated continuously underpressure, periodical cleaning of the screeningzone by backwashing is not required.Screening is achieved with 0.35 to 10 mmperforation.


● Continuous sludge screening

● Coarse material dewatering and solidsremoval combined in one unit

● Retrofitting into pipe lines is possible withoutadditional storage tanks and conveying unitsas the STRAINPRESS® is a closed system(in-line installation with minimum spacedemand).

● Self-cleaning screen surface and re-adjustable sieve cleaning screw

● Reliable operation and constant dewateringresults due to automatic performancecontrol and pressure cone adjustingmechanism

Sludge Screening:STRAINPRESS® SP

The product:

The KLEIN Drain Belt excels for its simpleprocess, easy operability and minimum wear.The sludge is fed onto the filter belt whichrotates at approx. 15 m/min and separates bygravity the water previously set free byflocculation. Separation is assisted by pillowblocks which repeatedly restack the filter cakeand create in this way new drainage ways forthe free water. Hardly any mechanical stress isexerted on the sludge as it is transported on thefilter belt, which results also in a low polymerconsumption.

The belt velocity can be controlled by frequencyconverter and can be adjusted to suit specificrequirements. Filtrate is used for belt cleaning.

The KLEIN Drain Belt achieves withoutproblems throughput capacities of up to80 m3/h per unit and has a patented forced-guided belt so that any belt drift is definitelyavoided.

Sludge ThDra

The product:

The ROTAMAT® Screw Thickener serves forthickening of different types of municipal sludgeand separation of fibers in industrialapplications.

After addition of polymer, the sludge flows intothe wedge wire drum of the Screw Thickenerwhere it is pre-dewatered. The high degree ofadmission of the drum prevents re-dilution ofthe thickened sludge. The free water passesthrough the wedge wire into the outer wall of thethickener from where it is discharged by gravity.The polypropylene brushes mounted on thescrew flights clean the wedge wire from inside.The time-controlled spray nozzle systemensures a free filtrate outlet.

The thick sludge is by pump delivered to furthertreatment. An intermediate storage tank for thethick sludge provides also in this section for aclosed integrated system.

With the three available different model sizes,capacities of up to 100 m3/h can be achievedwith one unit.


● Compact and closed design, minimumspace demand

● Inclined installation with discharge on top

● Controllable solids concentration between5 % and 12 % DR

● Corrosion and wear resistant stainless steelconstruction

● Flexibly applicable, also as a mobile unit

Sludge Thickening:ROTAMAT® Screw Thickener RoS 2

The product:

The ROTAMAT® Screw Press serves for sludgedewatering and solids separation of small flowrates and has well proven its capability for manyyears, especially in paper and food industries.

The Screw Press excels for its closed designand easy operability. Its very low connect loadmakes it one of the most economical machinesfor sludge treatment on small sewage treatmentplants.

The sludge is fed directly into the screenbasket, from where the screw conveyortransports the material at low speed (approx.2 - 3 rpm) towards the discharge on top of theplant. While the decreasing screw pitch anddrum diameter continuously increase thepressure on the sludge, a pneumatic cylinderon the discharge controls the counter pressureand thus the dewatering efficiency of the ScrewPress. The wedge wire cylinder is cleaned by awashing system which can be operated withused water. The small wedge wire spacingguarantees an excellent filtrate quality.

With the three available different model sizes,capacities of up to 20 m3/h can be achieved


● Compact and closed design, minimumspace demand

● High efficiency despite low operating andmaintenance costs and reduced operatorattention

● Fully automatic continuous operationrequires only minimal attendance

● Best quality for low price

● Corrosion and wear resistant stainless steelconstruction


Sludge Dewatering:ROTAMAT® Screw Press RoS 3

The product:

The KLEIN Belt Filter Press is one of the best-selling sludge dewatering machines worldwide.The first KLEIN belt press had been developedin 1960 and was continuously further developedand optimized. The latest development is theKLEIN Bogenpress which consists of fourdewatering zones:

1. High-performance predewatering zone:The sludge that has been conditioned withpolymer is thickened under gravity.Additional pillow blocks repeatedly restackthe filter cake to achieve a rapid solid/liquidsseparation. More than 50 % of the watercontained in the sludge is separated in thiszone.

2. Wedge zone: In this predewatering zone thefilter belts slowly converge like a wedge andensure in this way a very gentle and regularbuild-up of pressure in the filter cake.

3. Curve zone: The filter cake, which is lyingbetween the two filter belts, passes over aperforated curved plate, the radius of whichis decreasing over its length to achieve aregular and continuous pressure increase,which is slow and gentle enough to compact

Sludge DeBoge

Of Sludge Treatment

The KLEIN Drain Belt can be combined withthe KLEIN Bogenpress to achieve an improvedBogenpress capacity of up to 80 m3/h, with thesame base area and only one-time addition ofpolymer.


● Reduced mechanical stress minimizespolymer consumption

● Clear filtrate due to gentle flock treatment

● High separation efficiency: approx. 98 %

hickening:ain Belt DB

The product:

The KLEIN Twin Belts are based on the sameprocess technology as the KLEIN Drain Beltsand excel also for their simplicity, easyoperability and minimum wear. In contrast to theDrain Belt, the KLEIN Twin Belt consists of twofilter belts with separate drives, which arearranged one above the other. The upper filterbelt is running at increased speed and theKLEIN Twin Belt is able to virtually double thethroughput compared to that of the Drain Belt.

The belt velocity can be controlled by means ofa frequency converter to suit individualrequirements. Filtrate is used for belt cleaning.

The KLEIN Twin Belt achieves withoutproblems a capacity of up to 150 m3/h per unitand has also the patented forced-guided beltwhich prevents any belt drift.


● Reduced mechanical stress minimizespolymer consumption

● Clear filtrate due to gentle sludge treatment

● High separation efficiency: approx. 98 %

Sludge Thickening:Twin Belt TB

The product:

The ROTAMAT® Disc Thickener is an inclined,slowly rotating filter disc construction. Thefiltration unit consists in a circular micro filterwith constant mesh. The filter disc is self-sealing and installed into a closed stainlesssteel tank, it divides the tank into a thickeningand a filtrate collection zone. The pre-flocculated sludge flows from the reaction tankonto the filter disc surface. The slightlyflocculated sludge settles on the filter, thefiltrate water is collected in the filtrate collectionzone and leaves the tank through the outlet.

An additional scraping device is fitted to thedisc surface to support discharge. The inclinedarrangement of the entire system ensures thatonly highly thickened solids are discharged asthick sludge.

Cleaning of the filter disc is discontinuous bymeans of a spray nozzle bar, which guaranteesthat no solids will be washed into the filtrate.Such discontinuous cleaning leads toenormous water savings, permanent operationof the cleaning system is unnecessary.

The standard conception is for cleaning withfiltrate. As a result of this system, the solidsload in the filtrate is extremely low.


● Sludge volume reduction by up to 90% ofthe initial volume

● Reliable, compact and closed completesystem

● Adjustable and controllable high sludgeoutlet concentration

● Clean filtrate – Minimized return load ontothe sewage treatment plant

● Long life and corrosion-resistance

● Minimal mechanical stress on the sludgeflock reduces polymer consumption

Sludge Thickening:ROTAMAT® Disc Thickener RoS 2 S

the sludge to such an extent that it can beexposed to highest pressures in thefollowing shear and press zone.

4. Shear and press zone: Several press rolls(6 - 10) intensify the pressure on the cakecontinuously as their diameter is decreasingand exert a shearing effect on the sludgedue to the permanent change of direction.

The Bogenpress is applicable for throughputsup to 25 m3/h, and for up to 100 m3/h whencombined with the BS Combi unit (withpreceding Drain Belt).


● High efficiency

● Economical unit, high quality standard

● Any machine components in contact withthe medium are of stainless steel

● Oversized, trebly sealed self-aligning rollerbearings

ewatering:enpress BS

The product:

ROTAMAT® Decanter Centrifuges are a newdevelopment of HUBER Technology. They arepreferably designed for high-performancedewatering of municipal sewage sludge but arealso suitable for industrial applications.

The high-quality stainless steel rotors allow fora slim and yet sturdy design with a reducedweight of the rotating mass compared toconventional designs. Components which areexposed to increased wear are equipped with ahigh-quality and easy to replace wearprotection.

The drum and screw conveyor bearings havebeen designed for a long life and minimummaintenance.

The frame and machine cover are noiseprotecting.

The main drive arrangement provides forspace-saving and flexible installation, whichmakes the machine especially suitable formobile installations.

The available centrifuge sizes cover throughputcapacities from 8.0 to 50.0 m3/h.


● Corrosion and wear resistant stainless steeldesign

● Frame and cover with integrated noiseprotection

● Well-proven hydraulic worm drive


● Fully automatic operation requiring onlyminimum operator attention

● Maximum operational reliability due toon-line control of machine parameters

Sludge Dewatering:ROTAMAT® Centrifuge RoD

The product:

The KLEIN Recirculation Air Sludge Dryer is acost-effective and technologically simpleevaporative dryer operating at lowtemperatures. Additional process stages arenot required, especially vapor and exhaust airtreatment are unnecessary (dust, odor andpollutants).

Dust production is extremely reduced as nomechanical stress is exerted on the sludgeduring the drying process so that measures ordevices for explosion protection are notrequired.

The Recirculation Air Sludge Dryer is a modulardesign, one module being sufficient for up to750 kg/h vaporization capacity, whichcorresponds to approx. 120,000 p.e. Theenergy required is 0.3 - 1 kWh/kgH2O,dependent on the climatic conditions.

The KLEIN Recirculation Air Sludge Dryer canbe operated with different types of alternativeenergy, such as any type of exhaust air, solarenergy or simply fuel. Especially solar energy isof significant importance with regard to energy-saving operation.

The Sludge Dryer is made of stainless steel,due to condensation. Energy supply isautomatically controlled on the basis of theambient and exhaust air moisture andtemperature. KLEIN Recirculation Air SludgeDryers operate automatically and require onlyminimal attendance.


● Energy-saving evaporative drying

● Use of available exhaust heat

● Modular design for easy system expansion

● No vapor and exhaust air treatment requireddue to low temperatures

Sludge Drying:Recirculation Air Sludge Dryer

HUBER Septic Sludge Treatment in Kuching/SarawakKuching with 350,000 inhabitants,is located on Borneo, Malaysia,about 200 km north of the equator.The city uses mainly the system ofcesspools to which the individualhouseholds are connected.

The septic sludge settles in the ces-spools while the supernatant liquoris discharged through a sewersystem directly into the recipient.

Since they did not have an evacuati-on concept for the 77,000 cesspoolsin Kuching until a few months ago,

overflow of the pools was inevitableand the septic sludge made its waydirectly into the recipient, which ledto significant hygienic and healthproblems for the population livingon the Kuching river.

To manage the problem, they beganin 1998 to plan a central septic slud-

ge treatment plant which was finallyput into operation in March 2000and has been working without pro-blems since that time.

The HUBER ROTAMAT® productssupplied contributed a lot to the

short construction time and efficientand trouble-free treatment of theseptic sludge. The ROTAMAT®

machines handle the major part ofmechanical treatment.

Main part of the plant are the well-proven HUBER ROTAMAT® Slud-

ge Acceptance Plant Ro3 and SludgeDewatering Plant RoS3.

The septic sludge is delivered by tan-kers and fed into the Sludge Accep-tance Plant. The integrated FineScreen Ro1 removes the coarsematerial which is discharged into anintermediate storage tank, from

which it is fed into the ROTAMAT®

Sludge Dewatering Plant by addingcoagulant agent. Most of the solidsare separated from the sewage/slud-ge mixture by this two-stage treat-ment system which is a mere mecha-nical system. The two treatment sta-ges achieve a reduction of the CODconcentration by up to 90% and ofthe phosphorus concentration byapprox. 80%. These results allowproblem-free treatment of the sludgein a conventional subsequent biolo-gical treatment stage.

Details of mechanical treatment:

The septic sludge is delivered by tan-kers to three parallel installations ofSludge Acceptance Plants Ro3.3with integrated grit trap and stored inthe following intermediate storagetank, from where four parallel Slud-ge Dewatering Plants RoS3, size 2,are fed, adding polymer. The totalplant is designed for a capacity of350 m3/day.

Inside the Ro3.3 the sludge flowsthrough the integrated ROTAMAT®

Fine Screen Ro1 which is a well-pro-ven screen that is ideal for this appli-cation due to its wear-resistant andsturdy design.

Af ter removal of the coarse material(> 10 mm) the sludge flows into theintegrated grit trap which separatesgravel and grit particles.

After mechanical treatment thesludge is pumped into storage tankswhich have stirrers integrated to pro-duce a homogeneous sludge that issuitable for dewatering.

Polymer is added and the septicsludge pumped into the SludgeDewatering Plant RoS3. A slowlyrotating conveying and compactingscrew (1-8 rpm) integrated in theRoS3 removes the sludge that hasbeen separated by a wedge wiredrum and dewaters it in the course ofthe process. Due to this principle ofslow rotation the forces acting on thestructure are considerably reducedand a special foundation or supportis unnecessary. Also wear of themachine is reduced to a minimumand maintenance work virtually eli-minated. The energy demand is verylow (approx. 2 kW per main driveper machine).

The results are impressive: Sewagesludge with an average solids con-centration of 3% is dewatered to aDS concentration of approx. 40%.The removal rate in the filtrate waterlies at approx. 95% and can beincreased to up to 99% by using a fil-trate return pump.

As the dewatering rate is high, addi-tion of lime after the dewateringplant can be minimized and is onlyrequired for disinfection.

The totally closed design of allHUBER plants minimizes annoyingodors. The special climatic conditi-ons required modification of indivi-dual plant components. The control

panels for example were equippedwith cooling systems to ensure pro-blem-free plant operation in such adry area. This is another projectwhich proves impressively that

HUBER is able to supply high-effi-ciency plants at a competitive price.Since this technology is furthermore

easy to apply, and has been applied,to other processes as well (e.g. treat-ment of manure from animal farmsetc.), we received an extraordinarilypositive feedback from many inte-

rested customers already within thefirst months after plant start-up.Similar plants will soon be realizedin cooperation with our partners inMalaysia and will certainly under-

line the capability and adjustability ofthe well-proven HUBER technology.By Franz Heindl

Map of Sarawak

Tanker delivering septic sludge into the HUBER ROTAMAT® SludgeAcceptance Plant Ro 3.3

Complete mechanical preliminary treatment: removal of screenings andgrit by the HUBER ROTAMAT® plant

Complete plant model

HUBER ROTAMAT® Sludge Acceptance Plant with integratedgrit separation Sludge dewatering up to 40 % DS with HUBER ROTAMAT® RoS3

The Sludge Treatment Specialist

– Innovative Technology from the leading specialist – The first belt filter press was develo-ped by KLEIN, Niederfischbach in1960. Whereas sewage sludge hadbefore been "dewatered" mainly bystoring the sludge for weeks on slud-ge drying beds, the new develop-ment provided for the first time thepossibility to dewater sewage sludgein a continuous process to obtainspadeable and transportable materi-al. The new belt filter press began itsimmediate triumphant progress atfirst in Germany and later all over theworld. KLEIN has continuouslydeveloped the system from the oncesimple and low-performance machi-nes to high-efficiency systemswhich could assure their position onthe market against other systems,such as centrifuge, screw press andchamber filter press, and are still in aleading position in a lot of countries.

Belt filter presses are today availablefrom numerous suppliers world-wide, which are finally all based onthe original from KLEIN. Never-theless, KLEIN is still the leading

supplier with more than 4000 unitssold worldwide.

In 1985 a new idea was borne:KLEIN established a sludge thicke-ning machine for biological excesssludge. Since the amount of lightexcess sludge with a low solids con-centration was rising as biologicaltreatment methods were improved,KLEIN engineers developed the pre-dewatering drum of their belt filterpress to a special reactor for suchdifficult to thicken light-weightexcess sludge. That developmentwas revolutionary. The special reac-tor was a conical basket covered by afilter cloth that rotated over the lon-gitudinal axis at approx. 10 rpm andseparated the water set free by priorflocculation. It was in this way pos-sible to continuously thicken biolo-gical excess sludge from approx.0.5% DS to 5-7% and reduce thevolume to less than 10%. 1000 m3

excess sludge left approx. 10 m3

which required further treatment.

This system once developed andestablished by KLEIN is today state-

of-the-art technology and it isimpossible to imagine sludge treat-ment today without this system.

The sieve drums were meanwhilereplaced by high-performance beltthickeners which are able to thickenup to 150 m3/h excess sludge. Withmore than 800 sludge thickeningunits sold, KLEIN is ahead of thefield also on this sector.

In 1990 KLEIN put the so-called"Air-O-Dry" process on the market.This cost-effective and technicallysimple drying process for sewagesludge is especially designed forsmall and medium-size sewage tre-atment plants. Compared to otherknown thermal systems the Air-O-Dry process offers special advanta-ges as it operates in the low-tempera-ture range, which ensures especiallyeconomical, eco-friendly and relia-ble treatment of municipal and indu-strial sewage sludge. The process isan open process which uses the moi-sture absorption potential of theambient air and is able to ensure eco-nomical operation under cold or

moist weather conditions by recir-culation of air. As the temperatureof the drying air is low (approx.40°C), no detrimental vapors areproduced and the exhaust air can bedischarged without additional treat-ment. The KLEIN Air-O-Drysystem dries pre-dewatered sludgefrom belt filter presses, centrifugesor chamber filter presses to up to90% DS.

Drying is managed by easy-to-oper-ate belt conveyor dryers that require

only minimum maintenance. Theirenergy demand is only half the con-sumption of thermal dryers.

With nearly 20 sludge drying unitssold to municipal and industrialsewage treatment plants KLEIN isamong the leading suppliers also inthis field.

HUBER will continue to be innova-tive on the KLEIN products.

By Manfred Dörner

Fig. 2: HUBER-KLEIN Belt Filter Press for sludge dewatering

Sewage Sludge Screening Eliminates Operating Problems

Clogged channels in the heat exchangers

Coarse Material Separator STRAINPRESS®

Untreated screenings in the primarysludge at the STW Berlin-Waß-mannsdorf caused tremendous ope-rating problems, which could com-pletely be eliminated by screeningthe primary sludge with theSTRAINPRESS®. The continuouscoarse material separator is an enc-losed air-tight in-line system inte-grated in a suction pipe line thatseparates coarse material from theliquid and dewaters and dischargesit in one operation. The STW Waßmannsdorf has beenupgraded to handle a future flow of230,000 m3/day instead of the cur-rent 140,000 m3/day. Four travelingscreens were installed in the STW’s

inlet but the 8 mm perforated platesegments were not able to preventfibrous material like hair from pas-sing into and settling in the prelimi-nary and secondary clarificationunits. As part of the mixed sludgethey clogged the heat exchangersand settled on the inflow edge of theplates in front of the sludge digestor.As a result, each of the four heatexchangers had to be opened andcleaned once a week, which is diffi-cult, time-consuming and offensivesmelling work. Installation of twoSP4 STRAINPRESS® units elimi-nated the difficulties and the pre-viously installed Mono Muncherswere no longer needed.

The STRAINPRESS® is a horizon-tal pipe-shaped machine for conti-nuous separation of solids fromsewage sludge, which consists of aninlet and drive zone, screening zone,integrated press zone and dischargearea with a pneumatic pressure-regulating cone. The liquid is pres-sed or sucked through the screeningzone. The coarse material retainedon the screen surface is transportedto the press zone by the horizontallymovable screw. Slowly increasingcompression compacts the coarsematerial to a plug. The press filtrateand the filtrate from the screeningzone are passed through an outletpipe for additional wastewater treat-

ment processes. Remote water sup-ply for screen cleaning is not requi-red.

The total mixed sludge is screenedimmediately before the heat exchan-gers. The fibrous material and hairare separated from the sludge flowand compacted. 60 m3/hour ofmixed sludge are fed into theSTRAINPRESS® by gravity orvacuum forced through the machineby pumps behind the coarse materi-

al separators. The inlet concentrati-on of the primary sludge is between2 and 3% DR. Approximately 1ton/day of screenings with roughly a42% DR are separated as compactedscreenings. Tests have shown thatthe efficiency of the STRAIN-PRESS® is excellent. Since thestart-up in April 2000, the heatexchangers have not needed anymaintenance.

By Martin Stumpmeier

1. SUMMARY

Disposal of sludge from sewagetreatment plants and production pro-cesses has become an expensive pro-blem for a lot of plant operators.

An important step towards reduceddisposal costs is maximum reduc-tion of the sewage sludge volume.

To achieve this, sludge from a con-ventional mechanical sludge dewa-tering process is dried afterwards.

Conventional thermal drying plantsare operated at temperatures over100° C, which requires appropriateequipment and safety engineeringand available qualified staff.

Alternative simple but efficient dry-ing methods have been developedwhich work at temperatures farbelow 100° C and are economical,safe and eco-friendly.

Among them are solar dryingsystems and low-temperature dryers,such as the KLEIN Belt Dryer.

The KLEIN Air-O-Dry-System usesthe water absorbing potential ofambient air for drying of municipaland industrial sludge and products.The system offers a capacity of 50 –750 kg/h vaporication capacity withan energy demand of 0.3 – 1 kWh/kgwater.

The dry material produced at lowenergy and purchase cost is avail-able for many ways of utilization anddisposal.

2. INTRODUCTION

Different drying methods for sludgefrom sewage treatment plants orindustrial production processes haveexisted since many years which drythe sludge to a small residual watercontent.

Such processes are:

● Drying processes operated at over 100° C

● Drying processes operated at temperatures far below 100° C.

All those processes have the samepurpose:

● Reduction of sludge volume to minimize disposal costs,

● Stabilization of the sludge for long-term storage,

● Increases usability of the sludge for advanced thermal utilization processes or other ways of dis-

posal.

Processes using high temperatures(> 100° C)

● Demand appropriate material suitable for high temperatures,

● Require qualified staff that is permanently available (shift work),

● Burden the environment and workplace due to the high temp-ratures and produce polluted exhaust air and vapors.

The advantage is the high dryingefficiency and minimum spacedemand.

Drying processes which operate atlow temperatures are solar dryingprocesses and low-temperature dry-ing in a belt dryer. They excel fortheir:

● Easy operation (no additional staff qualification required),

● Reduced plant technology and safety engineering owing to the low temperatures,

● High operational reliability

● Low temperature that makes exhaust air treatment unneces-sary and does not producecondensate which would haveto be returned into the sewage treatment plant,

● Product-protecting operation,

● Possibility to use exhaust heat from other processes to saveprimary energy,

● No lengthy start-up and close-down processes that needattention.

Low-temperature drying in a beltdryer was investigated in the eightiesand realized for the first time in1989. The advantages and disadvan-tages could soon be experienced andwere considered when manufactu-ring follow-up units. The low tempe-rature process was further developedto the ambient recirculating air slud-

ge drying system to make dryingmore independent from ambientinfluences. This system was for thefirst time realized in 1998.

3. PLANTS FOR LOWTEMPERATURE DRYING

Belt dryers for ambient recirculatingair drying are equipped with two ormore belts which are positioned one

above the other and use ambient airas transport medium for the water tobe evaporated and the necessarydrying energy (indirect process).

The ambient recirculating air dryingsystem can be used for municipal orindustrial sewage sludge and forproducts that need a drying tempera-ture far below 100°C.

It is necessary to break up and pelle-tize the dewatered material to ensureefficient low-temperature drying to

● Generate a big surface for discharge of the water into the drying air.

● Achieve sufficient permeability of the sludge layer on the dryer belts to ensure a sufficient am-ount of fresh drying air is bro-ught into contact with the par-ticles.

The sludge particles are fed onto abelt in the dryer and evenly distribu-ted.

During drying the particles rest onthe belt without undergoing anymechanical stress. Such gentle treat-ment prevents further breakup ofparticles and eliminates thus the riskthat particles are discharged or dustis produced during drying.

Low-temperature drying uses thecapability of absorbing water ofambient air for the drying process.The process is therefore rather vapo-rization than evaporation of water.

The belt dryers are additionallyequipped with burners to heat thedrying air to achieve a constantlyhigh drying result. The fuel used forthe dryers is natural gas, digestergas, liquid gas or oil.

Since the energy demand for dryingdepends not only on the amount ofwater to be evaporated but also onthe moisture of the ambient air, there

are probes to measure the introducedambient air temperature to be able todetermine the quantity of heat requi-red for drying.

Depending on the weather conditi-ons there are two different operationmodes applied:

● Low-temperature drying:Drying with ambient air only

● Recirculating air drying: Dryingby recirculating drying air

During ambient air drying the recir-

culation system is closed and theventilators draw the maximal amo-unt of air through the dryer, along thedistributed sewage sludge, to achie-ve the required water evaporation.

When the weather conditions or timeof day do no longer allow such ope-ration, the ventilators are throttled,the additional air supply openingsclosed and the recirculation systemopened. The amount of fresh airflowing into the dryer is much smal-ler then and is heated prior to beingmixed with the recirculating air.

The low-temperature drying unitsthat have been installed by now are

able to evaporate water amounts of100 to 750 kg/h and achieve a finalsolids concentration of 90%. Biggeramounts of water can be handled byinstalling multi-line plants. Anotheroption is partial drying to a solidsconcentration between 30 and 85%,as required.

The dry material produced (with 80to more than 90% solids concentrati-on) can be stored outdoors over alonger period without finding any

fungal infestation, odors or increa-sed moisture.

Utilization of exhaust heat

Belt dryers with low-temperaturedrying offer the advantage that low-temperature exhaust air can be usedfor drying.

Exhaust heat has usually a tempera-ture of 60 to 90° and is either exhaustair or cooling water and offers forconventional drying plants only alimited potential for utilization.

Fig. 1: Diagram of a two-stage ambient recirculating air dryer with gas burner

Fig. 2: Two-stage ambient recirculating air dryer of a municipal sewagetreatment plant

NOVELTY: The right use of solar energyFully automatic state-of-the-art solar drying,easy to operate, offering up to 90 % dewateringefficiency.

As fossil fuels are limited, the use of renewablesources of energy such as solar energy is inevita-ble. KLEIN offers therefore its recirculating airdryer as an option with solar panels for ambientair heating. The panels are attached on the dryersides to minimize the additional space demandbut maximize energy saving.

� exhaust air� dewatered sewage sludge� breaking device� fresh air� fuel� dried sewage sludge

�

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Low-Temperature Drying: KLEIN Recirculating Air Sludge Dryer

Application of the CONTIFLOW ® Sandfilter (CFSF)

Table 1: Filtration technologies and their application in wastewater treatment

1

2

3

Filtration Technology

• Granular filtration:Surface filtration, filterlayer height up to30 cm

• Volume filtration:Filter layerheight >= 1m

• Cloth filtration

Membrane filtration, e.g.

• Reverse osmosis

• Membrane filtration

• Micro filtration

Separation of

• Ion, molecules

• Macro molecules andcolloides

• Macro molecules,colloides andtechnical emulsions

• Elimination ofsuspended solids > 10µm

• Chemical-physical effectdue to precipitation andfloccation

• Elimination of

suspended solids >

10 µm

• Chemical-physical

effect due to

precipitation and

floccation

• Biological effect

Application

HUBER Service: A Customer Designed ProductProduct-Related Service to the Customer's Optimal Benefit

Competence and Efficiency · Reliability and QualitySince the ever tightening drinkingand wastewater market today hasbecome a playground for amultitude of machine and plantmanufacturers, it is gettingincreasingly difficult for customersto make a buying decision asfrequently offers differ completley,especially in terms of prices and„promised performances.”

Supply of high-quality technologyat favorable price is one importantthing, but lasting aftersales-serviceis of at least the same importance!An increasing number of customers,espacially operating staff ofdrinking and wastewater plants,confirm the high priority of areliable and long-term service forpurchased machines!

The HUBER business unit„Service” is especially concernedabout such important immediateand long-term service by offering anextensive program together with acompetent and highly motivatedteam!

Fig. 1: Continuous contact filtration

Fig. 2: Recycling of water

Hans Huber AG manufacturesunder license of Parkson Corporati-on the CONTIFLOW® SandfilterCFSF which has proven its benefitsin hundreds of filter plants andvarious fields of application.

Filtration technology is typicallyused for separation of material fromvarious media. Physical separationof suspended material in wastewatertreatment is typically combined

with physical-chemical and/or bio-logical elimination mechanisms.Table 1 shows several filtration tech-nologies.

The most common fields of applica-tion of the CONTIFLOW® Sandfil-ter are wastewater treatment, watertreatment and recycling in the follo-wing branches:

Paper and pulp industry, food indu-stry, chemical industry, iron and

● For elimination of substances,organic pollutants and refractorymaterial which are difficult toeliminate biologically by usingadsorptive substances, such aspowders combined with coagu-lant agents. The CONTIFLOW®

Sandfilter is a continuouslybackwashed sand filter. Costs

for additional wash water andsludge liquor tanks are elimina-ted. Also the measuring andautomatic control devices aresimple compared with disconti-nuous systems.

By Dieter Hilligard

steel industry, mining, surface treat-ment industry, municipal waterworks and sewage treatment works.

The CONTIFLOW® Sandfilter canbe used for the following applicati-ons:

● As an intermediate treatmentstage in the process chain toobtain wastewater that containsas little solid material as possi-ble, e.g. prior to activated carbonabsorption, ion exchanger ormembrane filtration.

● As a final treatment stage toreduce the concentration of sus-pended material.

● As a biological intensified filtra-tion for advanced elimination oforganic substances or denitrifi-cation.

RoK1 Storm Screen Excels at Wigan, UKRoK 1 Storm Screen during trials

Screening of up to 10 m3/s combined water with 6 mm perforated plate

It is no secret that the mostsophisticated testing of stormscreens in the country, if not theworld, is conducted at NorthWest Water's Wigan WWTW, aspart of the research program ofUKWIR CSO Research Group.The ROTAMAT RoK1 Storm

Screen, which is now operationalextensively throughout the UK,took to the CSO test facility forits own trial evaluation.

Briefly, the set up at Wigan is asfollows: Raw sewage, havingbeen elevated by the works inlet

screw pumps, is interceptedupstream of the works inlet scre-ens and routed through largebore pipework, incorporatingregulating valves and an induc-tion flowmeter, to test facility.The RoK1 Storm Screen wasinstalled on a side weir within a

channel fabricated from GRPpanels. From the channel, thespill from the screen and thecontinuation flow were directedto separate chambers containingframeworks for the installationof 6 mm mesh sacks. The conti-nuation/spill flow split was regu-lated by means of a slide valve inthe continuation flow outlet pipe-work. Flowmeters are alsoinstalled in both the spill andcontinuation flow returns to theinlet works.

The construction of the screen isextremely simple and robust,consisting of a half cylinder of 6mm perforated stainless steel, inwhich a transport auger with acontinuous brush fixed to thetrailing edge of the flight is loca-ted. The auger is driven by anexplosion proof submersiblemotor/gearbox, and the flightstransport screenings captured onthe perforated plate to the down-stream end of the screen, wherethe perforations give way to asolid plate. Screenings werereturned, by means of the scree-nings discharge mechanism,back to the continuation flow.

For the duration of the trial, theRoK1 Storm Screen was opera-ted in automatic mode, i.e. run-ning intermittently from thecommencement of a spill, withthe ability of switching automa-tically to continuous operationunder maximum hydraulic/scre-enings loading conditions.

Tests were undertaken with inco-ming flows set at 30, 45, 60 and100 l/s, each withcontinuation/spill flow splits of0.1, 0.2, 0.4 and 0.6.

A final conclusion, wholly basedon the results from the trial, wasquickly reached. In terms oftotal solids, the RoK1 improvedthe solids retention of a CSOwith a high sided weir by appro-ximately 10-20% over that achie-vable without a screen. Howe-ver, more importantly when rela-ted to the NRA AMP2 (1993)requirement, "in terms of grosssolids (greater than 6 mm intwo dimensions) the RoK1allowed none to pass to spill".

www.huber.de

www.HansHuberAG.com

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