Ecological Effectiveness of Constructed Wetlands in Treating Oil Refinery Wastewater
Wastewater produced from the oil refinery contains high concentrations of organic and inorganic pollutants; therefore it cannot be discharged directly into river without any treatment. The main objective of the research was to quantify the effect of different filter media on the treatment performance of vertical flow wetlands in the prevailing climate of Pakistan. Phragmites karka were planted in large containers as a vertical flow wetland to evaluate their efficiencies in the purification of refinery wastewater and their growth in wetlands fed with oil refinery wastewater. The results from a ten-month treatment showed that the purifying efficiency of constructed wetlands for oil-refined wastewater was low at the beginning but it improved gradually with the growth of plants and biofilm. Thus, a gravel-filled wetland and a organic compost filled wetland were operated identically with primarily treated refinery wastewater at a hydraulic loading rate of 0.100md−1, intermittently. Both of the wetland cells were planted with Phragmites karka. According to the first year results, average removal efficiencies for the compost and gravel wetland cells were as follows: total suspended solids (TSS) (78%), chemical oxygen demand (COD) (83%), biological oxygen demand (BOD) (73%), oil and grease (O & G) (54%) and total nitrogen (TN) (34%). The treatment performances of the compost filled wetland were better than that of the gravel-filled wetland in terms of removal of COD and BOD. Since this study was a pioneer for implementation of vertical flow constructed wetlands in Pakistan using local sources, it has proved that this eco-technology could also be used effectively for water quality enhancement in Pakistan.
Keywords: Vertical Flow Constructed Wetland, Refinery Wastewater, Treatment, COD Removal, Gravel, Compost
Masud Aslam Muhammad
Doctoral Researcher, Institute of Environmental Sciences & Engineering, National University of Sciences & Technology, Rawalpindi
Mr. Masud has worked on the water and air quality monitoring, wastewater chemistry and microbiology, designing safety management program for processing industry, developed mathematical models that can be used for the designing of constructed wetlands for treatment of industrial wastewater. Mr. Masud has also conducted an audit of the tannery sector worked as a EMS ISO-14001 Lead Auditor in collaboration with Cleaner Production Program, Sialkot(CPP).
Previously he worked as a Research Associate for, Asianics International, on the World Bank Project “Country Water Resources Assistance Strategy”. He was mainly entrusted to prepare and review the research papers titled “Role of Large Dams in the Basin” and “Agricultural Modernization through Better Water Management”.
Major areas of responsibilities include, project conception, project planning, scheduling and monitoring activities of the project, setting up and running the program.