Hassimi Abu Hasan

Isotherm equilibria of Mn2+ biosorption in drinking water treatment by locally isolated Bacillus species and sewage activated sludge

Manganese (Mn(2+)) is one of the inorganic contaminant that causes problem to water treatment and water distribution due to the accumulation on water piping systems. In this study, Bacillus sp. and sewage activated sludge (SAS) were investigated as biosorbents in laboratory-scale experiments. The study showed that Bacillus sp. was a more effective biosorbent than SAS. The experimental data were fitted to the Langmuir (Langmuir-1 & Langmuir-2), Freundlich, Temkin, Dubinin-Radushkevich (D-R) and Redlich-Peterson (R-P) isotherms to obtain the characteristic parameters of each model. Mn(2+) biosorption by Bacillus sp. was found to be significantly better fitted to the Langmuir-1 isotherm than the other isotherms, while the D-R isotherm was the best fit for SAS; i.e., the χ(2) value was smaller than that for the Freundlich, Temkin, and R-P isotherms. According to the evaluation using the Langmuir-1 isotherm, the maximum biosorption capacities of Mn(2+) onto Bacillus sp. and SAS were 43.5 mg Mn(2+)/g biomass and 12.7 mg Mn(2+)/g biomass, respectively. The data fitted using the D-R isotherm showed that the Mn(2+) biosorption processes by both Bacillus sp. and SAS occurred via the chemical ion-exchange mechanism between the functional groups and Mn(2+) ion.

Effective microbes for simultaneous bio-oxidation of ammonia and manganese in biological aerated filter system

This study determined the most effective microbes acting as ammonia-oxidising (AOB) and manganese-oxidising bacteria (MnOB) for the simultaneous removal of ammonia (NH(4)(+)-N) and manganese (Mn(2+)) from water. Two conditions of mixed culture of bacteria: an acclimatised mixed culture (mixed culture: MC) in a 5-L bioreactor and biofilm attached on a plastic medium (stages of mixed culture: SMC) in a biological aerated filter were isolated and identified using Biolog MicroSystem and 16S rRNA sequencing. A screening test for determining the most effective microbe in the removal of NH(4)(+)-N and Mn(2+) was initially performed using SMC and MC, respectively, and found that Bacillus cereus was the most effective microbe for the removal of NH(4)(+)-N and Mn(2+). Moreover, the simultaneous NH(4)(+)-N and Mn(2+) removal (above 95% removal for both NH(4)(+)-N and Mn(2+)) was achieved using a biological aerated filter under various operating conditions. Thus, the strain could act as an effective microbe of AOB and a MnOB for the simultaneous removal of NH(4)(+)-N and Mn(2+).

Optimized conditions for phytoremediation of diesel by Scirpus grossus in horizontal subsurface flow constructed wetlands (HSFCWs) using response surface methodology

This study investigated the optimum conditions for total petroleum hydrocarbon (TPH) removal from diesel-contaminated water using phytoremediation treatment with Scirpus grossus. In addition, TPH removal from sand was adopted as a second response. The optimum conditions for maximum TPH removal were determined through a Box-Behnken Design. Three operational variables, i.e. diesel concentration (0.1, 0.175, 0.25% Vdiesel/Vwater), aeration rate (0, 1 and 2 L/min) and retention time (14, 43 and 72 days), were investigated by setting TPH removal and diesel concentration as the maximum, retention time within the given range, and aeration rate as the minimum. The optimum conditions were found to be a diesel concentration of 0.25% (Vdiesel/Vwater), a retention time of 63 days and no aeration with an estimated maximum TPH removal from water and sand of 76.3 and 56.5%, respectively. From a validation test of the optimum conditions, it was found that the maximum TPH removal from contaminated water and sand was 72.5 and 59%, respectively, which was a 5 and 4.4% deviation from the values given by the Box-Behnken Design, providing evidence that S. grossus is a Malaysian native plant that can be used to remediate wastewater containing hydrocarbons.

Recognition of Relevant ORP, pH, and DO Bending Points in Ammonia Removal from Drinking Water through Online BAF System

This study was undertaken to identify the relevant bending points in ORP, pH, and DO profiles in ammonia removal through online monitoring. A novelty BAF system as newl application for drinking water treatment that equipped with ORP, pH, DO and sensors was used. Two types of polluted drinking water strength (low and high strength) with various concentrations and aeration flow were treated at a fixed-time reaction of 24 h. Experiments were conducted at four track studies (TS) of TS1 ( 50 mg/L, aeration 0.3 L/min), TS2 ( = 100 mg/L, aeration 2.0 L/min), TS3 ( 100 mg/L, no aeration) and TS4 ( 10 mg/L, aeration 0.1 L/min). The results showed that the removal of was more than 95% for TS1, TS2, and TS4. From the online monitoring performances, DO elbow and ammonia valley appeared in ORP and pH profiles, respectively. Similarly, new positive plateaus were observed in DO, indicating that the nitrifiers stopped to consume the DO after was completely removed. Hence, based on the bending points, the aeration system is possible to be automatically stopped just after DO elbow and ammonia valley appears in order to save the energy consumption and to shorten the time demands for the drinking water treatment process.

Removal of ion in drinking water treatment using locally isolated heterotrophic nitrifier

ABSTRACT Batch removal treatment of from drinking water was carried using locally isolated heterotrophic nitrifier of Bacillus cereus I6. This work investigates the effect of initial concentration (5–25 mg/L), initial pH (pH 3–10) and inoculum size (0.5–3.0% v/v) on the removal of . From the isolation, screening and identification, heterotrophic B. cereus I6 (98% similarity) was the most potential degrading strain in removal. The removal was high at initial concentration of 5 mg/L (62%), initial pH of 5 (69.5%) and inoculum size of 3.0% v/v (85%). The removal decreased from 62 to 24.8% when the initial concentration was increased, while it had increased from 29 to 85% when the inoculum size was being increased. The most suitable conditions for removal by heterotrophic of B. cereus I6 was observed at an initial pH of 5.

Rawatan metilena biru dalam air sisa menggunakan Scirpus grossus

Phytoremediation is an emerging technology that should be considered for the remediation of contaminated sites because of its aesthetic advantages and long-term applicability. The possibility of Scirpus grossus for degradation of a basic dye, methylene blue (MB) was investigated. The effect of the operational parameter of different dye concentrations (0, 200, 400, 600, 800 and 1000 mg/L) was determined, and the water quality parameters namely pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total organic carbon (TOC) were monitored. The UV-Visible absorption confirmed the degradation of MB within 72 days. The removal efficiency of methylene blue dye from synthetic wastewater was determined to be in the range of 86 – 38% for all treatments at different concentrations (200 – 1000 mg/L) respectively. Furthermore, the highest removals for BOD, COD in 400 mg/L and TOC in 200 mg/L MB were 69, 58 and 63% respectively.

Statistical optimization of the phytoremediation of arsenic by Ludwigia octovalvis- in a pilot reed bed using response surface methodology (RSM) versus an artificial neural network (ANN)

ABSTRACT In this study, the removal of arsenic (As) by plant, Ludwigia octovalvis, in a pilot reed bed was optimized. A Box-Behnken design was employed including a comparative analysis of both Response Surface Methodology (RSM) and an Artificial Neural Network (ANN) for the prediction of maximum arsenic removal. The predicted optimum condition using the desirability function of both models was 39 mg kg−1 for the arsenic concentration in soil, an elapsed time of 42 days (the sampling day) and an aeration rate of 0.22 L/min, with the predicted values of arsenic removal by RSM and ANN being 72.6% and 71.4%, respectively. The validation of the predicted optimum point showed an actual arsenic removal of 70.6%. This was achieved with the deviation between the validation value and the predicted values being within 3.49% (RSM) and 1.87% (ANN). The performance evaluation of the RSM and ANN models showed that ANN performs better than RSM with a higher R2 (0.97) close to 1.0 and very small Average Absolute Deviation (AAD) (0.02) and Root Mean Square Error (RMSE) (0.004) values close to zero. Both models were appropriate for the optimization of arsenic removal with ANN demonstrating significantly higher predictive and fitting ability than RSM.

Pilot study for sewage wastewater reclamation and reuse using RO membrane: comparison of different pre-treatment systems

AbstractA pilot plant study was designed to monitor the performance of two parallel lines with a capacity of 50 m3/day using different pre-treatment technologies prior to reverse osmosis (RO) units for water reclamation from a local-based effluent treatment plant in Malaysia. Line 1 consisted of coagulation-pore controllable fiber filter (PCF) and was denoted as PCF-RO, while line 2 was sand filter-ultrafiltration (UF) and was denoted as UF-RO. The pilot plant was operated continuously everyday for three months throughout the study. In the PCF-RO line, ferric chloride was chosen as a coagulant for the system. The performance and efficiency of PCF-RO compared to UF-RO in terms of system operability, percentage reduction of parameter tested, system deterioration, and the effectiveness of ferric chloride as coagulant were investigated. The results showed that permeate quality for both systems met the WHO drinking water standard for drinking water. However, membrane performance for PCF-RO which was deteriorat...

PRELIMINARY TEST OF MINING WASTEWATER CONTAINING IRON (III) AND ALUMINIUM (III) ON Scirpus grossus IN PHYTOREMEDIATION PROCESS

Preliminary test was conducted to physically observe and determine the range of Fe and Al concentrations that Scirpus grossus can grow and survive. Pails of 3 L containing 3 kg of sand and 42 days old S. grossus were exposed to different concentrations of Fe and Al solution mixture for 21 days. The mass ratio between Fe and Al in the solution mixture was 3:1. After 21 days of exposure, the plants had shown that they could grow and survive in concentrations up to 300 mg/L Fe + 100 mg/L Al. Effect concentration (EC50)value for single Fe and Al toxicity to S. grossus was predicted between 300 mg/L Fe + 100 mg/L Al and 450 mg/L Fe + 150 mg/L Al. Therefore, it is suggested for the next study of phytotoxicity the Fe and Al concentrations range may start as low as 30 mg/L Fe + 10 mg/L Al up to 450 mg/L Fe + 150 mg/L Al.

Removal of Chemical Oxygen Demand (COD) from Domestic Wastewater Using Hybrid Reed Bed System

Hybrid reed bed systems (HRBs) have a good potential for wastewater treatment in developing countries due to its simple operation and low implementation costs. HRBs units were constructed at Bukit Putri, in UKM university campus, Malaysia, of which were planted with Scirpus grossus plants, commonly known as club-rush or bulrush (water loving plants). Generally, HRBs are classified into two categories: surface-flow and subsurface-flow. Both systems are capable of removing Chemical Oxygen Demand (COD) from different types of wastewaters. The aim of this study was to determine the percentage removal of Chemical Oxygen Demand (COD) at different concentration of domestic wastewater by using a HRB systems. This hybrid system was arranged in a serial stages consisting of a surface-flow (SF) bed, followed by a vertical-flow (VF) bed and finally by a horizontal-flow (HF) bed. In the present study, the performance of the HRB on domestic wastewater, particularly on COD, with and without plants was investigated. It is observed that the planted system with Scirpus grossus had performed better than the unplanted system. The result shows that the COD removal varied between 60 and 92%, depending on the loading rates (53-86 mg/L/day). The treatment system was operated for three months in the continuous flow process. Based on the results, it can be concluded that the HRB system ensures a more stable removal of organic pollutants (COD) from domestic wastewaters.