Phytoremediation of Sewage Effluent with Some Selected Aquatic Plants from Anaerobically Digested Biogas Plant From the Valley View University Biogas Facility, Oyibi, Accra

Abstract

Water is a resource of increasing scarcity due to continual expansion of production, increase in population and urbanization. This work was conducted to assess the quality of sewage effluent from a biogas facility at the Valley View University, Oyibi, Accra and also to investigate into the phytoremediation potential of Eichhornia crassipes (Water hyacinth), Neptunia oleracae (Water mimosa), Lemna minor (Duckweed) and Ceratophyllum desernum (Coontail) in remediating contaminants from the sewage effluent. This is in the broader interest of resource recovery (especially water) from sewage effluent which could be used for both essential and non-essential purpose. Samples of sewage effluent for phytoremediation were taken over a period of six weeks and subjected to microbiological and physico-chemical examination to assess the reductions in levels of pollutants. The studied parameters included Temperature, Hydrogen ion concentration, Turbidity, Nitrate, Nitrite, Ammonia, Phosphate, Biochemical Oxygen Demand, Total Suspended Solids, Total Coliform, Faecal Coliform and Total heterotrophic bacteria. These were used to assess the performance efficiency of the aquatic plants in reducing the polluting strength of the waste water. The data were analyzed using Microsoft excel and Statistical Package for Social Science (SPSS) software packages. One way analysis of variance (ANOVA) was ran to determine significant differences of the parameters per plant. Results from this study showed that only parameters such temperature (27.3°C), pH (7.47), BOD (38 mg/l), Turbidity (48 mg/l) and TC (348 cfu/100ml) were within EPA limits and hence sewage effluent from the Valley View University biogas facility was not satisfactory to be discharged into the environment. The study also found out that Eichhornia crassipes (Water hyacinth), Neptunia oleracea (Water mimosa), Lemna minor (duckweed) and Ceratophyllum demersum (coontail) have great removal efficiencies for contaminants from sewage effluent. The efficiency in terms of decreasing ranking were Ceratophyllum demersum > Eichhornia crassipes > Lemna minor > Neptunia oleracea. This study also determined the public awareness and the potential for acceptance, of reuse applications for the treated sewage effluent. It revealed that both women and men have concerns especially regarding the use of treated wastewater as drinking water and felt that treated wastewater reuse for applications not involving close personal contact was acceptable, due to reduced health risk concerns. An integrated approach for treatment of the sewage effluent from the Valley View University biogas facility is recommended before any reuse application.