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There is increasing concern to determine an alternative coagulant for treating industrial effluent with minimal environmental impact and operational cost. In this study, iron (II) sulphate heptahydrate (FeSO4·7H2O) waste, an industrial byproduct from a titanium oxide processing industry, was used as a coagulant for the removal of ammonia (NH3), chemical oxygen demand (COD), biochemical oxygen demand (BOD), and suspended solid (SS) from secondary rubber processing effluent (SRPE). The highest percentage removal of BOD, COD, SS, and NH3 achieved was approximately 97%, 99%, 98%, and 95%, respectively, at pH 5.0, coagulant dose of 1 g/L, coagulation time of 60 min, sedimentation time of 60 min, and at an elevated temperature of 70 °C. The best described adsorption isotherm model was found to be the Brunauer–Emmett–Teller (BET) model, indicated that the FeSO4·7H2O adsorption took placed on the surface of iron hydroxide precipitates with multilayer formation and random distribution. The kinetics analysis showed that the adsorption mechanism was well fitted with the pseudo-second-order kinetic model. The findings of the present study show that the FeSO4·7H2O waste has the potential to be used as a coagulant for the treatment of industrial effluents, including the secondary rubber processing effluent.

In order to minimize the adverse impacts of palm oil mill effluent (POME) towards the environment and to cope with the stress associated with water scarcity, membrane technology has been employed to reclaim water from POME. This study investigated the performance and fouling propensity of membranes in treating tertiary POME with the aim to recycle and reuse the reclaimed water as boiler feed water. Three types of membranes (NF270, BW30, and XLE) were used and their performances were evaluated based on the removal of chemical oxygen demand (COD), color, turbidity, total dissolved solid, phosphorus, and conductivity. All parameters were significantly reduced through XLE and BW30 membrane filtration processes in which the permeate was complied with the boiler feed water standard, except NF270 membrane where the COD value exceeded the allowable limit. High permeation drag of NF270 and rougher surface of XLE membranes resulted in the accumulation of foulant on the membrane surfaces which eventually reduced the permeate flux, whereas BW30 membrane was encountered for lower fouling propensity due to its low permeation rate. Hence, BW30 was deemed as the best candidate for water reclamation due to its low fouling propensity and because the production of permeate complied with boiler feed water standard.

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