Asian Journal of Applied Sciences (ISSN: 2321 – 0893) Volume 02 – Issue 05, October 2014 Asian Online Journals (www.ajouronline.com ) 693 Moringa Oleifera and Strychnos Potatorum Seeds as Natural Coagulant Compared with Synthetic Common Coagulants in Treating Car Wash Wastewater: Case Study 1 R.M.S. Radin Mohamed 1 , N. Abdul Rahman 2 and A. H. Mohd Kassim 3 1 Department of Water and Environmental Engineering, Faculty of Civil and Environmental Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, BatuPahat (Johor, Malaysia) Email: maya {at} uthm.edu.my 2 Department of Water and Environmental Engineering, Faculty of Civil and Environmental Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, BatuPahat (Johor, Malaysia) 3 Department of Water and Environmental Engineering, Faculty of Civil and Environmental Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, BatuPahat (Johor, Malaysia) ABSTRACT— The present study is aimed to evaluate the efficiency of different types of coagulant; chemical (alum and ferrous sulphate) and natural coagulants Moringa Oleifera and Strychnos Potatorum for treating car wash wastewater. Car wash wastewater samples were collected at Radin Car Wash Parit Raja (geographical coordinates: 1° 52' 0" North, 103° 7' 0" East) during weekdays and weekends in 10 weeks sampling regimes. The coagulants were used to treat car wash effluent and were evaluated with respect to pH, chemical oxygen demand (COD), phosphorus, total suspended solids (TSS) and turbidity.The mixing started with rapid mixing of higher revolutions per minute (rpm) for 10 minutes and followed by the slow mixing at the lowest rpm for 30 minutes. The rotation speed was adjusted while carrying out the test to determine the optimum settling time. The coagulant was finally allowed to settle for 60 minutes. The experiments were started by obtaining the optimum fresh coagulants concentration and initial pH value of the car wash wastewater. The removal efficiency of both natural coagulants was more effective compared to chemical coagulants with low dosage, 40-80mg/L. Moringa Oleifera (94%-Turbidity, 60%-COD, 81%-Phosphorus) and Strychnos Potatorum (97%-Turbidity, 54%-COD, 82%-Phosphorus). Hence, the use of natural coagulants are apparently a better option as they provide better treatment and safe to environment, and the cost is cheaper to common coagulants in water treatment. Keywords— alum, car wash wastewater, ferrous sulphate, Moringa Oleifera, Strychnos Potatorum _________________________________________________________________________________ 1. INTRODUCTION In recent years, wastewater is one of the major environmental problems arising in many densely populated and industrial areas of the world. Disposal of commercial and industry car wash wastewater can pose a significant threat to the health of our waterways, if allowed to enter the storm water system.In Korea, carwash wastewater is generated in various car washing sites at of approximately 0.5 – 1 mᵌ car per day. Such effluents contain a lot of synthetic detergents, anti-freezing agent waste, waste oils and heavy metals and can cause a range of problems if they are not treated properly (Jiang et al., 2005). In Korea, on-site community sewage treatment systems are designed to treat household wastewater. However, these systems do not provide adequate treatment for the types of contaminants found in commercial and industrial car wash wastewater. The mean removal efficiencies for different parameters oil and grease, chemical oxygen demand (COD) and total suspended solids (TSS) were as high as 80, 74 and 88 % respectively, but these values were not enough to comply with the requirements for discharge in the sewage system (Fall et al., 2007). The car wash operational controls are essential to ensure that there is no on-site disposal of hazardous waste. In Malaysia, water pollution is commonly contributed from residential wastewater (bath, laundry, sinks and kitchen) (Mohamed et al., 2013a; Chan and Mohamed, 2013; Mohamed et al., 2014a) and car wash wastewater where in most suburban areas were disconnected from the sewerage network. Increased water pollution increases the risks of respiratory, cardiovascular and neurological diseases, and affects people of all ages, from newborn children to the aged (Christine, 2010). Vehicle washing, in simple terms, involves cleaning the exterior and in some cases, the interior of motor vehicles. The use of detergents in many cleaning purposes may contain phosphates (Mohamed et al., 2014a,