SEVAR AG has a large number of references. In the following a selection of them is presented.
|Veolia Klärschlammverwertung Deutschland GmbH||Zorbau||Germany||BD3000/16|
|Dubai Municipality||Jebel Ali||UAE||3x BD3000/12|
|Klärschlammverwertung Albstadt GmbH||Albstadt||Germany||BD3000/6|
|SEEN Technologies||Opole||Poland||2x BD3000/6|
Belt dryer Jebel Ali Dubai (UAE)
BELT DRYER 3 LINES BD 3000/12
In 2009 SEVAR was commissioned with the delivery of 3 lines of the Belt Dryer BD 3000/12 for full drying of 112000 t/a digested sewage sludge. The sewage sludge is produced by the municipal sewage plant of Dubai is designed for 1,500,000 PE.
The demand on the dried sewage sludge was to be a granular with a low formation of dust. The dried sludge is used as a fertilizer. The sludge is dried with hot gases at drying temperatures up to 130 °C. The biogas produced in the anaerobic sludge digestion on the WWTP is combusted and the hot gas is mixed with fresh air and internal recirculating air to the designed drying temperature. If there is not enough biogas available alternatively fuel oil can be used to generate the hot gas.
The sewage sludge is mechanically dewatered to approx. 22% DS with a centrifuge. After dewatering it is temporarily stored in two silos with 60 m3 volume each and distributed via screw conveyors to the three lines of the Belt Dryer. The distribution unit evenly distributes the sludge to the 3 m wide stainless steel belt. At the end of the upper belt, the drying temperature is about 130 °C and the sewage sludge is dried to a dry solids content of about 50%.
On the lower belt, which moves slower and in the opposite direction, the sludge is further dried to at least 92% DS and leaves the belt dryer via a discharge screw conveyor and further via a pneumatic transport line to the storage silo. While transportation the sewage sludge is cooled down to 50 °C.
Download reference description Jebel Ali Dubai (UAE)
Belt dryer Albstadt (DE)
BELT DRYER BD 3000/6
German city Albstadt ensures the sludge disposal of its municipal waste water treatment plant and the wastewater treatment plants in the surrounding environmentally sound and running-cost effectively. Therefore in 2012 a biomass cogeneration plant with a sludge drying plant was built on the WWTP Albstadt-Ebingen site.
In 2009 SEVAR has received the order for the construction of a turnkey sludge drying plant with a throughput of 12,000 t/a sewage sludge (30% DS). In front of the belt dryer BD 3000/6 with six drying chambers a reception bunker with a moving fl oor and with a volume of 120 m3 for the storage of incoming municipal sewage sludge was installed. With a chain conveyor the sludge is transferred to the inlet unit of the belt dryer and evenly distributed in uniformly shaped particles over the belt width of 3 m.
The perforated belts made of stainless steel deliver the sewage sludge at a rate of about 0.2 m/min (frequency-controlled) through the dryer. The retention time of the material in the dryer varies in the range of 120-180 min according to the speed of the belt. The humid exhaust air of the belt dryer (appr. 20000 Nm3/h) is cleaned in the chemical scrubber (acidic and caustic) and further in the biofi lter (surface: 100 m2). With this technical solution no condensate occures. The up to 90% DS dried and crushed sludge is stored in a 150 m3 silo and burnt in a regional cement factory as RDF (calorifi c value similar to brown coal).
Download reference description Albstadt (DE)
Belt dryer Opole (PL)
BELT DRYER 2 LINES BD 3000/6
In 2013 SEVAR has built 2 drying lines with the belt dryer BD 3000/6 with a water evaporation capacity of 2,100 kg H2O /h in the sludge treatment plant of the municipal WWTP Opole in Poland. Both dryer lines can operate independently.
Cooling water of the existing CHP with an approximate temperature of about 95 °C is used in an indirect heating system with heat exchanger to heat up the drying air to a middle temperature of 80 °C. In case of a CHP failure the warm water is produced in a natural gas boiler. In a waste heat recovery system the fresh supply air is preheated with humid exhaust air (approx. 60 °C) in a heat exchanger and thereby the exhaust air is cooled down to about 45 °C. From the drying system 5-10% of the humid air are continuously withdrawn. During after treatment humid exhaust gases (approx. 18,000 Nm3/h) pass through a wet scrubber, an acidic scrubber and a biofilter. Filtered WWTP effluent is used as a wash water. Condensates are treated in the waste water treatment plant.
Two lines dry 24,000 t/a digested sewage sludge with a dry solids content of about 25% to 90% DS. The dry sewage sludge is transferred via a screw conveyor to a roller crusher to be crushed to an 8 mm size, which is required for a thermal disposal. After drying the material is stored in a silo. In case the silo is full, a reverse operation of the screw conveyor transports the dry product to containers.
Download reference description Opole (PL)
Belt dryer Schaffhausen (CH)
BELT DRYER BD 3000/5
In 2009 WWTP Assocation Schaffhausen, Switzerland has decided to renew their Waste treatment plant KBA, Kehrichtbehandlungsanlage. In addition to the renewal of the mechanical-biological treatment of domestic and commercial, organic waste and garden waste, a sewage sludge drying plant has been built.
By the fermentation of the aqueous fractions of the waste treatment biogas is produced and converted into electricity by a CHP unit. The cooling water (95/75 °C) of CHP gas engine (600 kWel) is used for the indirect heating of the belt dryer through series of internal heat exchangers to fully dry the municipal sludge up to 90% DS. The exhaust gas of the CHP is converted to steam for other usage. The residual heat of the exhaust gas is used for preheating of the fresh drying air (70/50 °C).
Haarslev Industries received an order to supply a drying plant with a throughput 8000 t/a of municipal sludge at 30% dry solids content. Sludge from neighbouring WWTPs is delivered to a 40 m3 reception bunker. The belt dryer BD3000/5 with fi ve drying modules is capable to evaporate minimum 700 kg/h of water. The sludge is pumped with an eccentric screw pump to the dosing unit of the belt dryer and evenly spread over the 3 m wide belt. The dried sewage sludge which has a granular shape is fi nally transported via a screw conveyor, stored in containers and later incinerated in a regional cement factory. The humid exhaust air of the belt dryer is cleaned passing through a chemical scrubber. The plant does not produce any condensate.
Download reference description Schaffhausen (CH)
Belt dryer Locminé (FR)
Belt dryer BD 3000/7
The Liger (Locminé innovation management of renewable energies), which emerged from a project, is a local energy center. Unique in Europe, it is the fi rst site to combine two green energy sources: Methanization of wood to produce electricity, heat, green fuel and fertilizer.
In 2015 SEVAR was awarded the contract for the construction of a turnkey fermentation residue drying plant with a throughput of 12,700 t/a fermentation residue. The wet product (25% TR) from two centrifuges is fed to the belt dryer BD 3000/7 with seven drying chambers via pumps. The distributor of the feed unit distributes the product evenly over the 3 m wide belt.
The perforated stainless steel conveyor belt transports the fermentation residue at a speed of approx. 0.2 m / min. (variable frequency) through the dryer. The dwell time of the sludge in the dryer varies from 120-180 min, depending on the belt speed.
The humid air leaving the belt dryer (approx. 20,000 Nm3/h) is cooled in the condenser before it is chemically treated (acidic and basic) and then fed to the biofi lter. The dried and shredded dry material with 85% dry matter is transported and stored in troughs via a screw distribution system.
Download reference description Locminé (FR)
Belt dryer KTA Zorbau (DE)
BELT DRYER BD 3000/16
At the Zorbau waste incineration plant, after the turbine, part of the steam is used to dry digested or stabilised dewatered sludge produced during the treatment of municipal waste water. A fully automated sewage sludge drying plant (KTA) with a belt dryer BD 3000/16 with 16 drying chambers was installed for this purpose.
The sludge is transported by the LAV (Landwirtschaftliches Verarbeitungszentrum Makranstädt) from various storage facilities and stored in one of the two inground bunkers. The fresh sludge is fed to back-mixing via hydraulically operated moving fl oors and a chain conveyor. The back-mixing takes place with already dried material in a double-shaft mixer with a DS content > 30 %. Uniformly shaped sludge strands with increased surface area after passing the distribution unit and roller press are evenly distributed onto the upper belt. After drying to 90% DS, the sludge is homogenized to 4 mm grain size in a roller mill.
The hot air required for drying is generated in the mixing chambers by heat exchangers supplied with steam. Fresh supply air is introduced through manually adjustable dampers. The circulating air fans of the mixing chamber convey the drying air into the process chamber perpendicularly to the transport direction of the sludge layer. The hot air cools down during the process and absorbs the evaporated water. The loaded air is discharged from the process chamber via exhaust air channels. The supply air of the dryer is preheated with steam condensate from the process.
Download reference description KTA Zorbau (DE)
BELT DRYER BD 3000/11
Purpose of adding the drying plant was reducing the sludge volumes and makes sludge disposal safer and easier. Therefore, US EPA Class A Rule 503 guidelines are fulfi lled by selecting the thermal drying process.
Stabilised sewage sludge is mechanically dewatered to min. 17% to 20% DS in centrifuges and pumped to the drying plant, where it is mixed in the mixer with a part of a dried sludge and conditioned to a better consistency and a higher DS% content.
The sludge is slowly dried in a hot air stream at temperatures up to 130 °C for more than an hour. The distribution unit evenly distributes the sludge onto the 3 m wide stainless-steel belt. At the end of the upper belt, the drying temperature is about 130 °C and the sewage sludge is dried to a dry solids content of about 50%. On the lower belt, which moves slower and in the opposite direction, the sludge is further dried to at least 90% dry solids content. The dried sludge passes a drum mill and a diverter. The diverter separates the sludge stream into a part for backmixing with fresh dewatered sludge and another part which is screened to remove dust and discharged to the storage. Hot gases are generated by a natural gas burner mixed with recirculated hot gases. In this way odours are kept in the recirculation loop, excess air fl ow is directed to the biofi lters, while dried sludge is free from pathogens.
Download reference description Whanganui (NZ)