Modelling solar enhanced waste stabilization pond

Abstract

Abstract Solar enhanced waste stabilization pond (SEWSP) was modeled in this research. In the analysis, SEWSPs of varying sizes, made of metallic tanks with inlet and outlet valves and solar reflectors, were constructed to increase the incident solar intensity. Wastewater samples collected from the inlet and outlet of the SEWSPs were examined for physico-chemical and biological characteristics for a period of twelve (12) months. The parameters examined were temperature, pH, detention time, total suspended solids, dissolved oxygen, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), algae count, faecal coliforms and E. coli. The efficiencies of the SEWSPs with respect to these parameters fluctuated with depth, location of reflectors and variation in width. The SEWSP with a width of 0.2 m whose reflector was installed at the outlet position gave the highest treatment efficiency. The conventional model was modified to account for solar irradiation. The faecal bacteria removal was significantly higher in the enhanced pond than in the conventional pond at 0.10 level of significance. The verification of the conventional model gave a good correlation of r = 0.882 between the measured and calculated Ne/No with a low standard error of s = 0.010, while the irradiated pond gave a correlation and standard error of r = 0.959 and s = 0.012 respectively. The research revealed that with the incorporation of solar radiation in WSPs, a length/ width/depth ratio of 1:0.2:0.2 can be used in the design of SEWSPs for maximum treatment efficiency.