Siemens Expands ENR Product Line With The Centrol Filter System With Denitrification Enhancement

Warrendale, PA — Siemens Water Technologies expands its enhanced nutrient removal (ENR) capabilities with the new Centrol Filter System with denitrification enhancement. The filter enhancement allows municipalities to reduce nitrogen in wastewater to levels suitable for discharge into receiving water bodies.

Nutrient pollution causes an unbalanced ecosystem harmful to fish and other wildlife, so communities are demanding more stringent wastewater discharge limits. The lowering of nitrogen and phosphorus levels to increase the quality of the wastewater effluent, enhanced nutrient removal is accomplished through the use of advanced wastewater technologies.

The Centrol Filter System is a well-established gravity filtration system with more than 200 installations worldwide. If the wastewater treatment process needs slight effluent improvement, advanced Centrol filter system can be added for polishing. Denitrification is accomplished with the Centrol system by modifying the filter media and backwash troughs and adding a carbon feed system to sustain the growth of heterotrophic bacteria as denitrifiers. The process is as follows: water is dosed with a carbon source as it enters the Centrol filter through a common flume and into the distributor where the flow is evenly split among the four filter cells, located around a central column. The water passes downward through the filter media, where nitrogen and suspended solids are removed. An open plenum underdrain, located below the media, collects treated effluent and directs it to a common effluent chamber, where the nitrate concentration in the effluent can be monitored. Next, the water flows over an effluent weir for further treatment or discharge.

The type of filter media selected depends on the plant's operating conditions and effluent water quality requirements. Although a range of media types and sizes may be used, a lower specific gravity media, such as anthracite, reduces the required backwashing rate. During operation, nitrogen gas is produced, which will become entrapped by the filter media and be sensed as false headloss. This gas is removed periodically by reversing the flow through the media bed for a short period. The waste collection troughs in the Centrol filter are located near the filter media to reduce the backwash waste volume required to wash out accumulated solids. Specially designed media retention baffles prevent media loss during gas removal and backwash.

Denitrification enhancement of the Centrol Filter System can also be added to existing cluster-style filter systems. Conventional layout filter systems, currently used for removing suspended solids, can be converted to remove nitrogen as well.

ENR solutions from Siemens Water Technologies are customized to a community's needs, whether it's an entirely new treatment facility or simply effluent polishing, or a combination of both. Existing wastewater equipment can be retrofitted with newer, more technologically advanced biological process solutions such as Orbal multichannel oxidation ditch or Omniflo Sequencing Batch Reactors. If the wastewater treatment process only needs slight effluent improvement, advanced filtration systems like the NxClear Denitrification filter or Centrol filter system can be added for polishing. For maximum nutrient removal, Siemens combines one of its proven biological processes with its membrane operating system to deliver its MBR system.

SOURCE: Siemens Industry, Inc. - Water Technologies