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Rising trend of solid waste production particularly in town and city areas has caused numerous environmental pollutions. Population growth, economic and lifestyle patterns are the factors that lead to the alarming rate of solid waste production. Landfilling is widely used for disposal of wastes due to its low operation and maintenance costs. However, leachate discharged from landfill could be a problem to surface and groundwater if it is not adequately treated. So, the investigation of the transportation and transformation phenomena of micro pollutants along the river receiving discharge from landfill leachate is mandatory. This study is carried out to investigate the water quality as well as to detect the presence of endocrine disrupting compounds (EDCs) along Kinta river in Peninsular Malaysia. Water quality parameters i.e. biological oxygen demand, chemical oxygen demand, ammoniacal nitrogen, total suspended solids, dissolved oxygen and pH were recorded to calculate the water quality index (WQI). The identification of EDCs was carried out using gas chromatography–mass spectrometry analysis. Water quality index result showed that the status of the river in both months fall under good and medium status where it requires intensive/conventional treatment for consumable and drinking purposes. None of the EDCs was detected in any of the samples analysed in the present study. It is believed that the information gained are useful and beneficial for decision making authority.

Produced water (PW) is the abundant by-product of oil and gas industries. It contains several organic pollutants and needs proper treatment before its discharge. This study investigated the effectiveness of Ferrate (VI) (Fe6+) oxidation for remediation of the organic compounds produced water. A series of batch experiments were performed by ferrate oxidation method. A glass beaker of 1000 ml as reactor covered with aluminum foil was used to protect from sunlight. Produced water sample of 300 ml and a pre-decided amount of Fe6+ was added to initiate the oxidation process. All experiments were performed at constant magnetic stirrer speed of 200 rpm at room temperature. The Fe6+ dosage of 1-25 mg/l, pH 1-7, and contact time 5-90 minutes were used to determine the effectiveness of Fe6+ for organic compounds degradation. The COD removal was increased with the increase in Fe6+ dosage and contact time. The maximum COD removal was achieved with Fe6+ dosage up to 15 mg/l; further any increase in Fe6+ dosage decreased the COD removal. The same trend was observed for pH, COD removal was increased until pH 5 beyond that COD removal was decreased. Maximum 55% of COD removal was attained under optimum conditions such as pH, Fe6+ dosage, and contact time were 5, 15mg/l and 50mins respectively. The results indicate that Ferrate (VI) oxidation is a promising method for the degradation of organic compounds in produced water.

The objective of this work was to investigate the effect of ultrasound irradiation on palm oil mill effluent (POME) treatment. The experiment was statistically designed by response surface methodology (RSM) based on central composite design (CCD) to evaluate individual and interactive effects of operational independent variables including ultrasonication amplitude, ultrasonication time and total solids concentration. The treatment performance was assessed by three dependent variables, viz., particle size reduction, total suspended solid reduction and organic solubilisation improvement. Experimental results showed that ultrasonication irradiation has positive effect on POME treatment. The optimum operation condition suggested by RSM were ultrasonication amplitude of 50%, ultrasonication duration of 18.94 mins and total solids concentration of 6.47% with expected organic disintegration results as 47.7% particle size reduction, 18.9% of solid reduction and 31.5% of solubilisation improvement.

The capacity of microorganisms to remove heavy metal from wastewater has been a subject of diverse interest. Whereas some heavy metals are essential for effective microbial activity, some heavy metals could be toxic to the microorganisms at concentrations higher than their minimal inhibitory limit. The kinetics of Zn2+ removal from aqueous solution was evaluated in terms of substrate removal rate for two identical suspended and immobilized bioreactors. The suspended growth bioreactor was used as a control system (CS) and contains only biomass. The immobilized bioreactor (IB) contains both biomass and microwave incinerated rice husk ash (MIRHA). The bioreactors were operated at a fixed HRT of 29.1 hours, whereas Zn2+ influent concentration was varied in the range of 0.5, 1, 2, 5, 10 and 15 mg/L. At steady state conditions, the results show that Zn2+ removal was in the range of 72, 75, 72.5, 68.2, 70.3 and 58.7% for CS, whereas it was in the range of 88, 90, 83, 88.6, 86.2 and 83.7% for IB. The substrate removal rate was found as 1.1856 g/L.d for CS and 4.2693 g/L.d for IB. The results clearly show that Zn2+ removal was more favorable in IB, indicating that the performance of the bioreactor was enhanced by the addition of MIRHA.

In this study, activated carbon was developed from sugarcane bagasse and its effectiveness in adsorbing lead (Pb2+) ions from synthetic aqueous solution was examined. Sugarcane bagasse activated carbon (SCBA) was developed in a tube furnace at a temperature of 900 °C, a heating rate of 10 °C/min, residence time of 3 hours, and at a nitrogen flow rate of 100 mL/min. Batch adsorption experiments were carried out to investigate the effects of pH and SCBA dosages on the adsorption process. The batch adsorption test showed that extent of Pb2+ adsorption by SCBA was dependent upon pH and SCBA dosage. The optimum pH for Pb2+ adsorption was found to be at pH 5.0. Maximum Pb2+ removal efficiency obtained from the batch studies was 87.3 % at SCBA dosage of 10 g/L. Equilibrium adsorption data was described by Langmuir model with a coefficient of determination (R2) of 0.9508. Maximum adsorption capacity according to Langmuir model was evaluated to be 23.4 mg/g. The adsorption capacity of the SCBA was compared with that of other plant-based adsorbents. SCBA is an effective adsorbent for the removal of Pb2+ from aqueous solution.

Municipal and industrial wastewater treatment plants produce large amounts of sludge. This excess sludge is an inevitable drawback inherent to the activated sludge process. In this study, the waste activated sludge was obtained from the campus wastewater treatment plant at Universiti Teknologi PETRONAS (UTP), Malaysia. Fenton pretreatment was optimized by using the response surface methodology (RSM) to study the effects of three operating conditions including the dosage of H2O2 (g H2O2/kg TS), the molar ratio of H2O2/Fe2+ and reaction time. The optimum operating variables to achieve MLVSS removal 65%, CST reduction 28%, sCOD 11000 mg/L and EPS 500 mg/L were: 1000 g H2O2/kg TS, H2O2/Fe2+ molar ratio 70 and reaction time 45 min. Fenton process was proved to be able to enhance the sludge disintegration and dewaterability.