Saudi Journal of Civil Engineering (SJCE) | Volume-4;-Issue-03
Original Research Article
May 28, 2020
The Effectiveness of Hydrated Lime as a Flocculating Agent in Water Treatment
Awodiji, C. T. G, Nwachukwu, A. N, Onyechere, C. I, Iyidiobi, R. G, Nwabueze, B. J
Page Numbers : 30-37
DOI : 10.36348/sjce.2020.v04i03.001
The efficacy of hydrated lime (HL) as a flocculating agent in water treatment was studied in this work. Two water samples were used. Sample A was obtained from domestic sewage from Hostel A at the Federal University of Technology Owerri. While, sample B was sourced from storm water runoff from drains in Eziobodo Town, Owerri, Nigeria. The samples were treated separately using HL and sodium hydroxide (NaOH) as flocculants respectively. Alum (Al2SO4)3 was used as the coagulating agent for all samples. The jar test was adopted. Treated samples were analyzed for pH, color and turbidity. It was noted that addition of HL and NaOH in all samples increased the pH of the water. pH values for sample A and B were 2.7 and 4.1 before treatment and increased to values between 6.9 to 7.2 after treatment. The use of alum and HL in treating both samples of water led to better color quality than using alum and NaOH. Sample B water treated with HL had lesser color quality than those of sample A. The best color quality of 1.0 PCU happened when treating sample A water using 25mg/l alum and 43.8mg/l HL. Treatment of sample B using alum and NaOH did not improve turbidity. Rather, a maximum increase of 1.8% was observed at 25mg/l alum and 17.0mg/l NaOH dosage. The use of alum and HL showed a remarkable improvement in turbidity. Best value of 3.12NTU was measured at 25mg/l alum and 43.8mg/l HL dosage. Treatment of sample A with alum and HL gave better turbidity values when compared to sample B. Removal efficiencies of 95% and 90% for both samples were observed respectively. In conclusion, HL can be effectively used as a flocculating agent in treating water when applied in the right proportion.