Parkson implements phosphorous removal system at membrane bioreactor plant in Korea
01 November 2012
Parkson has implemented an energy-efficient phosphorous removal system at a membrane bioreactor plant in South Korea to help achieve some of the tightest standards for phosphorous removal in the world. The installation at the wastewater treatment plant is the first of its kind to pair an MBR system with the new DynaSand® EcoWash™ sand filtration technology, which offers huge energy savings over traditional sand filters.
The installation in Korea consists of 10 DynaSand® EcoWash™ filters, divided into two cells which process the flow from two separate membrane bioreactor units. Unlike traditional filters that operate on a continuous backwashing schedule, the EcoWash™ design relies on intermittent backwashing to achieve high quality filtrates with minimal energy use.
This wastewater treatment plant posed a unique setting for the DynaSand®, because the membrane bioreactor system produces a very low level of suspended solids which makes phosphorous precipitation and flocculation more difficult. Another challenge was the alkalinity of the effluent water, which limits the amount of chemical addition to meet the minimum pH limit of 6. Despite these challenges, the DynaSand® EcoWash™ can successfully maintain adequate flocculation and remove phosphorous to the required level of less than 0.3 mg/l with a Poly Aluminum Chloride (PAC) addition, while meeting the pH requirements. Notably, the DynaSand® achieves these results without the benefit of additional residence time or equipment between the chemical addition and the filters. The chemical is injected in the feed pipe, passing through a static mixer, and into the filters where flocculation and separation occur.
The design at the plant also includes a Lamella® gravity plate settler to treat reject water from the DynaSand® to further reduce the overall reject flow from the filter system.
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