Constructed wetland - The Serbian experience

Abstract

Constructed Wetland System (CWS) in the Gložan settlement is the first such system for wastewater treatment constructed in Vojvodina (Serbia), aimed at treating local municipal wastewaters. The common reed (Phragmites australis (Cav.) Trin. ex Steud.), naturally growing on the CWS location, is used as biofiltering vegetation. The CWS efficiency was monitored based on the water balance, removal of suspended matter, reduction of the amount of organic matter, removal of nitrogen compounds and total phosphorus, bioaccumulation of nutrients in the plant organs, as well as via the number of coliform bacteria. The water balance of the CWS indicates that water is always present. The system appeared to be capable to remove 94% of suspended matter, while the decrease in organic matter, expressed via biological oxygen demand (BOD5), in the investigation period has been 80.9%. The efficiency of removal of nitrogen compounds ranged from 47.3% for nitrates, 47.5% for ammonium, to 78.3% nitrites, while the efficiency of total phosphorus removal was 29.1%. The results of microbiological analyses confirmed the sanitary safety of the effluent. The results of the chemical composition of the reed confirmed the bioaccumulation of nutrients in the plant organs. Best results were achieved at the end of the growing period (autumn).