Journal of Environmental Treatment Techniques 2021, Volume 9, Issue 1, Pages: 158-163 158 Treatment of Wastewater from Pulp and Paper Mill using Coagulation and Flocculation Balpreet Kaur 1 *, Rajeev Kumar Garg 1 , Anirudh Pratap Singh 2 1 Department of Chemical Engineering, ShaheedBhagat Singh State Technical Campus, Ferozepur, Punjab, India 2 Dean, Punjab Technical University, Jalandhar, Punjab, India Received: 10/06/2020 Accepted: 21/10/2020 Published: 20/03/2021 Abstract In this work, an effluent sample from a local medium-scale paper mill has been treated using alum as a coagulant and chitosan (natural polymer) as a flocculant. Initially, the dose of alum has been optimized by adjusting the zeta potential to near zero for best coagulation results. The dose of 0.04 g/L was able to merely coagulate and unable to cause sweep flocculation of impurities. Then, at the optimised dose of 0.04 g/L various concentrations of chitosan in the range of 0.1-0.5 g/L were investigated for obtaining maximum flocculation of the suspended impurities. The physico-chemical parameters like pH, total suspended solids (TSS), chemical oxygen demand (COD), absorbance, and zeta potential were studied for comprehending the flocculation behavior. The observed results exhibited that the maximum flocculation was achieved at the chitosan concentration of 0.3 g/L. At the flocculant concentration of 0.3 g/L, 81% TSS removal and maximum 78% COD were reduced. Moreover, zeta potential value of the collected supernatant was close to zero ( –1.49 mV) which showed larger floc formation and easy settleability of the impurities. In all, it can be said that the utilization of chitosan along with alum may be a better option for the treatment of pulp and paper wastewater as well as other similar types of wastewater . Keywords: Pulp and paper mill waste water; coagulation-flocculation; chitosan; zeta potential; COD 1 Introduction 1 The environmental pollution due to the activities of small and medium-scale pulp and paper industries is multidimensional, causing serious problems not only to land fertility but also to the natural flora fauna as well as aquatic environment. The pulp and paper industry generates about 70- 120 m 3 of wastewater per metric ton of paper produced [1, 2]. Pulping is the initial step in paper making involving mechanical or chemical treatment of raw material. It is widely used for the separation of cellulose/hemi-cellulose fibers for attaining improvement in its papermaking properties [3]. Further, bleaching is carried out in multistage processes to remove the residual lignin and hence achieve whiteness and brightness in the pulp [4]. Both these steps are highly energy-intensive consuming enormous volumes of freshwater and involving usage of large quantities of chemicals which consequently affect the properties of discharged effluents [5]. Various studies authenticate the harmful and undesirable impacts of these chemicals [6-8]. These effluents have been responsible for generating color problems, algal growth, and scum formation which hamperthe aesthetic looks of the environment.Also the *Corresponding author: Balpreet Kaur, Department of Chemical Engineering, Shaheed Bhagat Singh State Technical Campus, Ferozepur, Punjab, India. Email: balpreet_kaur@yahoo.com life of aquatic beings like zooplankton and fish is adversely affected due to release of toxic chemicals. The use of cleaner technologies and incorporating modifications in the process design can potentially reduce the pollutant load from industrial wastewater. Nevertheless, waste generation cannot be completely eliminated. Therefore, alternative techniques need to be introduced which can meet the prescribed discharge limits for most affecting pollutants like COD, BOD, AOX, color, turbidity, etc. [9, 10]. In this respect, chemical coagulation and flocculation offer a promising solution to waste water treatment facilities [11]. In this technique salts of selective metals are added to wastewater which initially neutralize the charge on impurities and subsequently agglomerate them into larger flocs which can be easily removed by settling. The factors affecting the effectiveness of these techniques are the nature of coagulating agent, dose of coagulant, pH of solution, concentration, and nature of impurities present in wastewater. Generally, the pulp and paper mill effluents consist of many non-biodegradable, hydrophobic, and polar compounds specifically phenols, lignin, long-chain fatty acids, resinous acids, and aromatic compounds [12]. Almost all of these toxic compounds can be effectively removed through coagulation followed by flocculation. In the past, many synthetic flocculants e.g. (PAM, HE, PEI) for precipitation of suspended impurities of paper mill waste water have been used [13]. The precipitated products obtained after the application of these flocculants have not been fully analyzed for degradation. It is expected that the precipitates are Journal web link: http://www.jett.dormaj.com https://doi.org/10.47277/JETT/9(1)163 J. Environ. Treat. Tech. ISSN: 2309-1185