Treatability Study of Partially Stabilized Leachate by Composite Coagulant (Prehydrolyzed Iron and Tapioca Flour)

Abstract

Treatment of leachate before discharge is crucial to ensure the safety of the environment. Application of coagulation-flocculation in reducing pollutant from leachate was proven to be effective. However the use of chemical coagulant will indirectly affect the health of living organisms. To reduce the affect, substitution of the chemical coagulant with natural material can be used. Natural coagulant on leachate treatment was not as effective as chemical coagulant. However, the benefits of natural polymer as coagulants aids had been proven previously. Combination of chemical and natural coagulant as composite coagulant is able to simplify the process and offers many benefits. The aim of this study was to investigate the applicability of composite coagulant made from combination of prehydrolyzed iron (PHI) and tapioca flour (TF) on partially stabilized leachate and was evaluated through percentage removals of suspended solids (SS), colour, chemical oxygen demand (COD) and ammonia. A series of coagulation-flocculation jar test were carried out by considering the effect of dose and pH. Results indicated that at pH 5 and dose 0.2 g/L Fe, the percentage removals of SS, colour, COD and ammonia were 98%, 96%, 60% and 11%, respectively. The results demonstrated that PHITF can be a potential coagulant for the treatment of partially stabilized leachate.

Application of Dual Coagulant (Alum + Barley) in Removing Colour from Leachate

“…Lower removals are recorded at alkaline condition for all the coagulant tested as shown in Fig. 2.This instances was in good agreement with the previous finding [9]. The results above indicate that dual coagulant and single alum performed better in acidic condition.…”

“…Thus, addition of barley improved the coagulation process. Barley as coagulant aid, produce better strength of floc and increased the weight of the floc and finally increased the colour removal ability [4]. In comparison with Alum 3 g/L+barley and barley 1.6 g/L+alum, alum 3 g/L+barley is better as higher colour removals are recorded.…”

“…One of the main factors that affect coagulation effectiveness is coagulant type. Coagulant used consists of chemical (alum, ferric chloride, poly aluminium chloride) and natural (moringa oleifera, starch, cactus, guar gam) coagulant [4]. It is well known that chemical coagulant is better than natural coagulant.…”

“…Thus, there's a need in finding less expensive and less health effect coagulant. Application of dual coagulant made from natural and chemical coagulant is able to reduce the dose of chemical and reduce the toxicological effect [4]. Successful application of combination coagulant made from natural and chemical coagulant for leachate treatment were proven by Ong, Ramli, Kamaluddin, and Zin et al, [6][7][8][9].…”

“…Barley grain contains starch, fat and fibre components [11]. The starch in barley indicates good coagulant properties and known as natural polymer coagulant [4]. This natural polymer coagulant contains mixture of amylose and amylopectin [12].…”