TREATABILITY STUDIES ON RAW WATER FROM APONMU RESERVIOR IN ILARA – MOKIN, , NIGERIA

Abstract

Adequate water supply is an important ingredient in human’s development. In this study, samples of war water were collected from Aponmu reservoir at Elizade University, Ilara – Mokin , Ondo State, Nigeria at intervals of one week for six months. These water samples were subjected to laboratory studies (Column, pH adjustment, Jar and residual chlorine tests). Laboratory analysis of flocs formation during coagulation, iron and microbes removal of chlorination process, pH adjustment and residual chlorine after treatment of the samples were conducted using standard methods in a bench scale and executed at prototype phase. Iso-concentration curves were developed from column tests to ascertain settle-ability of the flocs during treatment. The study revealed that optimum doses of coagulant and chlorination were 80 mg/l, and 10 mg/l, respectively for effective removal of iron and residual chlorine concentration of 3 mg/l. Flocs removal was 65 % of the influent flocs in the coagulated raw water at a depth of 1.2 m and at a retention time of 60 minutes. Analysis of iso-concentration curves revealed that overall flocs removal was 89 % at 60 minutes. This indicated that for a retention period of an hour 350 mg/l of flocs would be removed from the coagulated raw water. Removal of iron from the coagulated water was between 90 and 95 % of initial iron concentration of 1.42 mg/l and removal of microbes was 99.1 % at retention time of 40 minutes. It was concluded that Aponmu reservoir can be used as water source with little modification of the current facilities, but further studies are required to ascertain effects of other factors (quality of raw water, rainfall intensity, time of concentration, discharge rate) on quality of water production.