Advanced treatment of WWTP effluent with filtration leading to a pretreatment technique for membrane filtration

摘要

In 2000 the European Union introduced the Water Framework Directive (WFD). The aim of thenWFD is having an ecological and chemical balance for all surface waters in Europe in 2015.nThe European Commission identified 33 priority substances and their maximum allowablenconcentrations, FHI-values (Fraunhofer Institute), which are specified in the Annex of the WFD.nThe objective of this research is to achieve the removal of suspended solids, nitrogen and totalnphosphorus together with priority substances. All these substances will be removed in one filterncalled a “One Step Total Effluent Polishing filter” i.e. 1-STEPw filter. For this purpose a filter pilotnplant was tested at the WWTP Horstermeer. The results show that the filter can fulfil the targetnvalues in the filtrate water for total nitrogen (2.2mg Ntotal/L) and total phosphorus (0.15mgnPtotal/L). The majority of the priority (hazardous) substances in the WWTP effluent are alreadynbelow the detection limit. Due to the low concentration ranges, the results on the removal ofnmedicine and pesticides are only indicative. A decreasing tendency in the removal efficiency isnshown for all measured compounds. The average specific ultrafiltration resistance (SUR) valuendecrease of the filter is 55% and the final value is always below 5·1012nm22n. This indicates thatnthe filtrate water of the filter is very well filterable and can be used as ultrafiltration feedwater.