Enhancement of Primary Sedimentation Using Natural Coagulants in Wastewater Treatment Plants

H. M. Hussein, Sohier Mansour, Samy Tharwat, Mina Danial

Abstract: Coagulation and flocculation are used in wastewater treatment to control the produced waste. Chemical coagulants have limited success in wastewater treatment because of their deficiency of consistency in meeting discharge requirements, high costs, handling, and disposal of huge volumes of sludge resulting from the increase of chemicals, and multiple operating problems. Instead of chemical coagulants, the natural ones can also be successfully used. Samples of wastewater were collected from the effluent of the grit removal chamber at the Belkas wastewater treatment plant, which is located in Egypt to study the enhancement of the performance of primary sedimentation. Experiments were conducted at various doses of Moringa Oleifera Seeds Powder (MOSP), Banana Peel Powder (BPP) and Mango Seeds Powder (MSP) using jar test equipment. Wastewater quality parameters were measured before and after treatment to evaluate the removal efficiency of turbidity, TSS, BOD₅, and COD. Using response surface methodology (RSM) to analyze the results of removal efficiency. Results showed that optimum operating conditions for (MOSP) at 720 mg/l and 45 min of sedimentation increased the removal efficiency of turbidity, TSS, BOD₅ and COD to 97.1 %, 99.3%, 94.67%, and 85.1% respectively. However, the optimum operating conditions for (MSP) at 480 mg/l and 45 min of sedimentation increased the removal efficiency of turbidity, TSS, BOD₅, and COD to 73.55 %, 62.57%, 59.87%, and 51.52% respectively. The optimum operating conditions for (BPP) at 105 mg/l and 45 min of sedimentation increased the removal efficiency of turbidity, TSS, BOD₅, and COD to 66.98 %, 57.93%, 58.76%, and 44.09% respectively. The removal efficiency will be reduced due to using doses of natural coagulants that exceed the optimum dose of each coagulant.