Membrane biological treatment and agricultural reuse of Mediouna wastewaters (Casablanca,Morocco) [Traitement biologique membranaire et réutilisation agricole des eaux usées de Mediouna (Casablanca,Maroc)]

Since a decade,the preservation of water resources has become a major environmental concern in morocco through the national sanitation program (nsp) that was launched in 2005. this program aims to effectively collect and treat wastewater through using efficient wastewater treatment plants (wwtps) for the reuse of treated wastewater for agricultural irrigation. in this context,the lyonnaise des eaux casablanca (lydec) installed a wastewater treatment plant in april 2013 from the mediouna locality (south east of casablanca) in order to protect the receiving environment of hassar stream,to eliminate pollution and health risks to human as well as animal populations,and finally to produce treated water for agricultural reuse.this treatment plant sized to 40,000 population equivalent (pe),with future expansion to 80,000 population equivalent,adopts modern technology for wastewater treatment combining intensive biological treatment with a membrane filtration (membrane biological reactor,mbr). this work proposes to assess the purification performance of this mbr system by reference to moroccan standards of wastewater reuse for irrigation. the results,based on monitoring conducted during the first 6 months of operation of the station ranging from april to october 2013,have shown very high returns for key physicochemical parameters. the registered abatement rate reached 90,9 % for cod,99,25 % for bod5,99,13 % for tss,95,59 % for total kjeldahl nitrogen (tkn) and 80,20 % for orthophosphate. at the same time,the level of physicochemical quality (ph,salinity,conductivity and heavy metals) and hygienic quality (fecal coliform) are found to comply with moroccan standards for irrigation waters.