Macrophyte waste stabilization ponds: An option for municipal wastewater treatment

Abstract

The objective of this research is to evaluate the performance of macrophyte waste stabilization pond system for municipal wastewater collected from Taxila (Pakistan). A model of macrophyte waste stabilization pond system was operated for six trials with each trials comprising different detention times that is 3, 5, 7 and 10 days, respectively. For the treatment, locally available macrophyte (water hyacinth) was used. To evaluate the performance of macrophyte waste stabilization pond, BOD5, TDS, TSS, COD, faecal coliform and Nitrogen for the effluent from pond model were measured at each detention time of every trial after ensuring steady state conditions. The influent values of same parameters have been measured at the start of each trial as the wastewater sample was collected from the municipal sewer. The average reduction of effluent value of each parameter varies from 30 to 48%, that is BOD5 (48%), TDS (31%), TSS (30%), COD (42%), faecal coliform (45%), and Nitrogen (40%). The mechanisms of pollutant removal in this system include both aerobic and anaerobic microbiological conversions, sorption, sedimentation, volatilization and chemical transformations. There is currently no macrophyte wastewater waste stabilization pond system under study/practice in many of the developing countries; therefore, for the promotion of macrophyte based waste stabilization system detailed pilot scale studies should be conducted for municipal sewage under local environmental conditions to explore the treatment efficiency of the system. Also, it is necessary that macrophyte system be used as treatment facility for wastewater because their performance is comparable to conventional wastewater treatment plants and since the system has very low operation and maintenance costs. Key words: BOD5, Eicchornia crassipes, macrophytes, municipal sewage, water hyacinth, wastewater treatment.