Volume No. 4 Issue No.: 2 Page No.: 297-309 Oct.-Dec 2009

 

EVALUATION OF EFFICACY IN THE TREATMENT OF DOMESTIC WASTEWATER BY DIFFERENT AQUATIC MACROPHYTES

 

S. Wijetunga*, D.H.U. Sandamali and K.D.N. Weerasinghe

Department of Agricultural Engineering, Faculty of Agriculture,
University of Ruhuna, Kamburupitiya, (SRI LANKA)

 

Received on : July 29, 2009

 

ABSTRACT

 

The use of phytoremediation is an emerging technology as an environmentally friendly and a low cost technology for the treatment of different kind of wastewaters. Application of phytoremediation techniques for the treatment of domestic wastewater was inadequately reported. Therefore the objective of this study was to evaluate the locally available wetland plants for the possible application of the treatment of domestic wastewater. Four different aquatic macrophytes, Ipomoea aquatica, Limnocharis flava, Monochoria vaginalis and Colocasia spp were evaluated for the treatment of domestic wastewater generated from student’S cafeteria in the University. The root dipping technique was practiced for the study. Seventy five liter Styrofoam boxes were used and experiment was arranged according to the Randomized Complete Block Design (RCBD). The water quality parameters such as Chemical Oxygen Demand(COD), Total Solids(TS), Total Suspended Solids(TSS), Total Kjeldahl Nitrogen(TKN), Orthophosphate, Electrical Conductivity(EC) and pH were monitored to evaluate the treatment efficiency of different plants and the fresh weight gain of the plants were also determined at the end. The average COD removal efficiency, 68.39% was the highest in the system of Limnocharis flava, while lowest 36.77% was observed in the Colocasia sp. system. TS, TSS, TKN, removal efficiencies were highest in the treatment system of Limnocharis flava, while TDS is removed efficiently by Ipomoea aquatica. During the study period pH was initially increased from 5.5 to 6.5 at the 6th day and it was constant until the end of the study in all aquatic plant systems and control units. The highest weight gain was observed in the Limnocharis flava and Ipomoea aquatica. According to the results Limnocharis flava is the most suitable plant for the treatment of domestic wastewater. Nevertheless, Ipomoea aquatic was also considerably removed different pollutants present in the domestic wastewater. Colocasia sp. did not show any progress in the treatment of pollutants in the study wastewater. Therefore, the treatment system with Limnocharis flava and Ipomoea aquatic could be recommended for the removal of pollutants present in the domestic wastewater as an effective, environmental friendly and low cost treatment system.

 

Keywords : Phytoremediation, Aquatic Macrophytes, Wastewater Treatment, Domestic Wastewater

 

 

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