A. Rawlings, et. al. International Journal of Engineering Research and Applications www.ijera.com ISSN: 2248-9622, Vol. 12, Issue 4, (Series-III) April 2022, pp. 26-35 www.ijera.com DOI: 10.9790/9622-1204032635 26 | Page Performance of Cyperusesculentusand Glycine max Seeds as Natural Coagulant for Domestic Wastewater Treatment A. Rawlings a ⃰ and S. Seghosime b a ⃰ Department of Civil Engineering, Faculty of Engineering, University of Benin, Benin City, Nigeria. b Department of Civil Engineering, School of Engineering, Auchi Polytechnic, Auchi, Nigeria. ABSTRACT Increased discharges of untreated wastewater to the environment have resulted in degrading water quality, endangering human health and ecosystems, contributing to water scarcity and constraining sustainable economic development. Hence, there is need for adequate wastewater treatment in order to improve water quality and promote a healthy environment. Chemical coagulants are already being used for treatment, but their enormous cost, human and environmental hazard associated with their use has necessitated the need for searching natural coagulants for wastewater treatment. In this study, laboratory scale studies using jar test experiments were carried out on sullage wastewater to analyse the performance of Cyperusesculentus (Tigernut) and Glycine max (Soybean) seeds as natural coagulant on domestic wastewater treatment. Results indicated that the seed extracts (singularly or in combination with alum) have a noticeable effect on all the parameters considered. Treatment with tigernut and soybean seed extracts (Singularly) gave 96.08% and 87.71% turbidity reduction efficiencies, 76.52% and 77.21% COD reduction efficiencies, 7.72mg/l and 6.37mg/l phosphate, 4.08mg/l and 3.98mg/l Nitrate. These values were comparable to those of alum. The pH of the treated water remains largely unaffected due to the buffering capacity of the seed extracts. Results further revealed that the combination of tigernut seed extract and alum solution gave the overall best results with all the parameters within WHO acceptable limit for both drinking water and effluent discharge except for pH. However, result of pH suggested that few chemicals will be required for pH adjustment. It was deduced from the study that the performance of the seed extracts (singularly or in combination with alum) are satisfactory, thus they have coagulating capabilities and are suitable for domestic wastewater treatment. Keywords: Natural Coagulant, Cyperusesculentus, Glycine max, Seed extracts, Alum, Sullage, Coagulation. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 09-04-2022 Date of Acceptance: 26-04-2022 --------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION Water is considered as a basic need of life.Freshwater is essential for healthy lives and environment. Yet this resource is limited in supply, as more than half of the available 0.3% freshwater [1, 2]has already been used [2]. The small fraction available is under serious threat due to factors like over exploitation, poor management and ecological degradation [3, 4]. Population growth and economic development have greatly influenced the increased demand for portable water [5] as well as anthropogenic activities which has increased generation of wastewater and its overall pollution load [6, 7].In most developed and developing countries, the vast majority of wastewater (about 80%) is released directly to the environment without adequate treatment, with detrimental impacts on human health, economic productivity, the quality of ambient freshwater resources, and ecosystems[7, 8]. Wastewater is a critical component of the water management cycle, water after it has been used is all too often seen as a burden to be disposed of or a nuisance to be ignored. The results of this neglect are now obvious. The immediate impacts include the degradation of aquatic ecosystems and waterborne illness from contaminated freshwater supplies [7]. Untreated wastewater directly contributes to increase diarrhoea diseases, such as cholera, typhoid fever and rotavirus [8]. Diseases such as these are responsible for 297,000 deaths per year of children under five years old, or 800 children every day [9]. The highest rates of diarrhoea-attributable child deaths are experienced by the rural communities in developing countries [8]. About95% of the global wastewater is released into the environment without treatment [10]. Raw wastewater or untreated wastewatercontains solids, endocrine disrupters (chemical that interfere with hormones), inorganic nutrients, heavy metals and pathogens [8]. If an excess of nutrients (such as RESEARCH ARTICLE OPEN ACCESS