Now showing 1 - 10 of 35
  • Publication
    Synergistic Effect Between Iron and Food/Microorganism (F/M) Ratio in Biological Wastewater Treatment
    ( 2022-01-01)
    Subramaniam L.S.
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    Siripatana C.
    Biological wastewater treatment is mainly dependent on the actions of microorganisms that can be used to treat wastewater. Microorganisms will start to stick together when they degrade the organic matter in wastewater for food and flocculate to settle the pollutants. This study aimed to investigate the effect of food to microorganism (F/M) ratio and iron in a biological process using aerobic treatment. For this purpose, four aerobic tanks (A, B, C, D) were set up using activated sludge as the seed sludge, air pump as air diffuser to provide oxygen to the system, and three litres of synthetic medium as carbon source for each tank. A specific amount of iron (II) sulfate was added into tanks B, C, and D with the weight of 3 g, 6 g, and 9 g, respectively. Tank A act as a control, and no iron dosage was added. The F/M ratio for tanks A, B, C, and D were 0.8, 0.5, 0.4, and 0.3 mg BOD/mg MLVSS, respectively. The aerobic tanks were operated for 40 days in sequential batch mode and sampling was collected four times per week to observe the COD and MLVSS. This study has found that Tank D shows the best performance compared to all tanks with 84.71% COD removal efficiency and a fivefold increment of microorganism growth rate. These findings suggest that a relationship exists between the iron and F/M ratio to enhance the aerobic treatment process.
  • Publication
    Effects of magnesium ions in microbial cells adhesion of attached growth system for the enhancement of biogas production
    This research aims to improve the biogas production by employing cell immobilisation technique under thermophilic conditions. The thermophilic fermentative biogas production was carried out by immobilising the anaerobic sludge obtained from palm oil mill treatment plant on granular activated carbon (GAC) in repeated batch mode. Different concentration of magnesium ions (Mg2+) (0.25, 0.5, 0.75, 1.0 and 1.5 g/l) on biogas production was investigated at 60°C with an initial sucrose concentration of 5 g/l as feedstock. The effect of Mg2+supplementation at the initial stage of immobilisation process is important to increase the formation of biofilm in the attached growth system. This study had found that Mg2+could enhance the biogas production capacity with optimum Mg2+concentration of 0.75 g/l.
  • Publication
    Biohydrogen production from palm oil mill effluent with Moringa Oleifera seeds as support carrier in attached growth system
    ( 2020-06-10)
    Hamid W.Z.W.A.
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    Malek M.A.
    Biohydrogen production by dark fermentation is one of the attracting alternatives for renewable energy in worldwide. By employing immobilized cells, hydrogen production and cell density could be improved. This study aimed to investigate the efficiency of Moringa Oleifera Seeds (MOS) immobilized cells in enhancing the biohydrogen production using repeated batch fermentation under mesophilic condition, 37°C. The efficiency of MOS as support carrier, effect of the initial pH (5.0-7.0) and performance of raw and diluted Palm Oil Mill Effluent (POME) using MOS immobilized cells were investigated using anaerobic sludge as inoculums. The cumulative hydrogen production results were fitted into a modified Gompertz equation to find the maximum hydrogen production. MOS immobilized cells was more efficient in producing hydrogen compare to suspended cells (without MOS). The optimal pH obtained using MOS immobilized cells was found to be at pH 6 using raw POME with the maximum hydrogen production (Hm) of 122 mL, the maximum hydrogen production rate (Rm) of 39.0 mL/h, and 560 ppm of hydrogen concentration.
  • Publication
    Intermolecular degradation of aromatic compound and its derivatives via combined sequential and hybridized process
    ( 2023-03-01)
    Lau Y.Y.
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    Teng T.T.
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    Eng K.M.
    The under-treated wastewater, especially remaining carcinogenic aromatic compounds in wastewater discharge has been expansively reported, wherein the efficiency of conventional wastewater treatment is identified as the primary contributor source. Herein, the advancement of wastewater treatments has drawn much attention in recent years. In the current study, combined sequential and hybridized treatment of thermolysis and coagulation–flocculation provides a novel advancement for environmental emerging pollutant (EP) prescription. This research is mainly demonstrating the mitigation efficiency and degradation pathway of pararosaniline (PRA) hybridized and combined sequential wastewater treatment. Notably, PRA degradation dominantly via a linkage of reaction: thermal cleavage, deamination, silication and diazene reduction. Thermolysis acts as an initiator for the PRA decomposition through thermally induced bond dissociation energy (BDE) for molecular fragmentation whilst coagulation–flocculation facilitates the formation of organo-bridged silsesquioxane as the final degradation product. Different from conventional treatment, the hybridized treatment showed excellent synergistic degradability by removing 99% PRA and its EPs, followed by combined sequential treatment method with 86% reduction. Comprehensive degradation pathway breakdown of carcinogenic and hardly degradable aromatic compounds provides a new insight for wastewater treatment whereby aniline and benzene are entirely undetectable in effluent. The degradation intermediates, reaction derivatives and end products were affirmed by gas chromatography–mass spectrometry, Fourier transform infrared spectroscopy and ultraviolet–visible spectrophotometry (GC–MS, FTIR and UV–Vis). This finding provides valuable guidance in establishing efficient integrated multiple-step wastewater treatments. Graphical abstract: [Figure not available: see fulltext.].
  • Publication
    Hydrogen sulfide removal from fermentative biohydrogen process: Effect of ZSM-5 zeolite loading
    ( 2024-03-01)
    Asman M.K.A.
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    Wong Y.S.
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    Hanif M.A.
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    Hamdzah M.
    The production and consumption of biohydrogen is growing because it is a “green,” renewable energy that can be obtained in a relatively cost-effective manner through anaerobic digestion. Biohydrogen produced from biomass is a viable source of renewable energy; nevertheless, the presence of highly toxic and corrosive hydrogen sulfide (H2S) in the process can hinder the quality of biohydrogen production and limit its application in energy conversion equipment. Consequently, the goal of the research was to assess the feasibility of using ZSM-5 zeolite for H2S adsorption that function as activating agent to enhance biohydrogen quality under thermophilic conditions. The effect of ZMS-5 Zeolite loading (0.2–1.0 g) on biohydrogen production via dark fermentation from mixed fruit waste (MFW) was investigated using anaerobic sludge from a sewage treatment plant. The pH of the broth mixture was adjusted to 6.0, anaerobic conditions were created by purging it with nitrogen gas, and the temperature of the fermentative biohydrogen process was maintained at 60°C. Meanwhile, the H2S adsorption test was run at ambient temperature with flow rates (100 ml/min) and an H2S inlet concentration of 10000 ppm. The results indicate that the Z + H2S exhibit spectral lines corresponding to the S-H asymmetric stretching vibration of H2S at 2345.97 cm−1. The ideal adsorption capacity is at 0.8 g with yet, increasing the dosage amount of adsorbents, increases the time required for the adsorbent to achieve 90% saturation. The non-linear curve fitting demonstrated that the adsorption kinetics of all dosages used followed those of the Avrami kinetic model. This approach of using ZSM-5 zeolite for H2S removal provides an advantage in terms of minimizing environmental pollution and having great potential uses in industrial processes.
  • Publication
    Transformation from biofiltration unit to hybrid constructed wetland-microbial fuel cell: Improvement of wastewater treatment performance and energy recovery
    ( 2023-05-01)
    Teoh T.P.
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    Koo C.J.
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    Tan S.M.
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    Yap K.L.
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    This study aimed to compare the performance of biofiltration, constructed wetland, and constructed wetland microbial fuel cell (CW-MFC). The transformation from a biofiltration unit to a hybrid CW-MFC was demonstrated with the advantages of improvement of wastewater treatment while generating electricity simultaneously. The introduction of plants to the upper region of the bioreactor enhanced the DO level by 0.8 mg/L, ammonium removal by 5 %, and COD removal by 1 %. The integration of electrodes and external circuits stimulated the degradation rate of organic matter in the anodic region (1 % without aeration and 3 % with aeration) and produced 5.13 mW/m3 of maximum power density. Artificial aeration improved the nitrification efficiency by 38 % and further removed the residual COD to an efficiency of 99 %. The maximum power density was also increased by 3.2 times (16.71 mW/m3) with the aid of aeration. In treating higher organic loading wastewater (3M), the maximum power density showed a significant increment to 78.01 mW/m3 (4.6-fold) and the COD removal efficiency was 98 %. The ohmic overpotential dominated the proportion of total loss (67-91 %), which could be ascribed to the low ionic conductivity. The reduction in activation and concentration loss contributed to the lower internal resistance with the additional aeration and higher organic loading. Overall, the transformation from biofiltration to a hybrid CW-MFC system is worthwhile since the systems quite resemble while CW-MFC could improve the wastewater treatment as well as recover energy from the treated wastewater.
  • Publication
    Kinetic model discrimination on the biogas production in thermophilic co-digestion of sugarcane vinasse and water hyacinth
    Co-digestion between sugarcane vinasse (Vn) and water hyacinth (WH) at various mixing ratios of 0:1, 1:0, 1:3, 3:1, and 1:1 was carried out under thermophilic conditions (55 °C) for 60 days. The effect of various mixing ratios on the pH changes, soluble chemical oxygen demand (sCOD) reduction, and cumulative biogas production was investigated. The first order, modified Gompertz, and logistic function kinetic models were selected to fit the experimental data. Model discrimination was conducted through the Akaike Information Criterion (AIC). The study revealed that co-digestion shows better performance compared to the mono-digestion of both substrates. Vn:WH mixing ratio 1:1 with inoculum to substrate ratio (ISR) of 0.38 g VSinoculum/g VSsubstrate is the most favorable ratio, achieving sCOD reduction efficiency and cumulative biogas production of 71.6% and 1229 mL, respectively. Model selection through AIC revealed that ratio 1:1 was best fitted to the logistic function kinetic model (R2 = 0.9897) with Ym and K values of 1232 mL and 31 mL/day, respectively.
  • Publication
    Photocatalytic Degradation of Sugarcane Vinasse Using ZnO Photocatalyst: Operating Parameters, Kinetic Studies, Phytotoxicity Assessments, and Reusability
    Abstract: Photocatalytic degradation performance is highly related to optimized operating parameters such as initial concentration, pH value, and catalyst dosage. In this study, the impact of various parameters on the photocatalytic degradation of anaerobically digested vinasse (AnVE) has been determined through decolourization and chemical oxygen demand (COD) reduction efficiency using zinc oxide (ZnO) photocatalyst. In this context, the application of photocatalytic degradation in treating sugarcane vinasse using ZnO is yet to be explored. The COD reduction efficiency and decolourization achieved 83.40% and 99.29%, respectively, under the conditions of 250 mg/L initial COD concentration, pH 10, and 2.0 g/L catalyst dosage. The phytotoxicity assessment was also conducted to determine the toxicity of AnVE before and after treatment using mung bean (Vigna radiata). The reduction of root length and the weight of mung bean indicated that the sugarcane vinasse contains enormous amounts of organic substances that affect the plant's growth. The toxicity reduction in the AnVE solution can be proved by UV–Vis absorption spectra. Furthermore, the catalyst recovery achieved 93% in the reusability test. However, the COD reduction efficiency and decolourization were reduced every cycle. It was due to the depletion of the active sites in the catalyst with the adsorption of organic molecules. Thus, it can be concluded that the photocatalytic degradation in the treatment of AnVE was effective in organic degradation, decolorization, toxicity reduction and can be reused after the recovery process. Graphical abstract: [Figure not available: see fulltext.].
  • Publication
    Influence of Glucose Supplementation on the Organic Removal and Biomass Growth in Anaerobically Digested Vinasse (AnVE) by Using Aerobic Sequencing Batch Reactor (SBR)
    This paper analyses the effect of glucose supplementation in the treatment of anaerobically digested vinasse (AnVE) through reduction performance and biomass growth by using aerobic SBR system. The result revealed that the COD and ammonium reduction with the addition of glucose supplementation (65.3 ± 6.0 and 30.0 ± 5.5%) was greater than the reactor without glucose supplementation (23.6 ± 10.8 and 18.7 ± 6.0%). This can be due to the additional glucose as the carbon source for microbe metabolism nutrients. The biomass growth in the reactor with glucose supplementation increased rapidly over time, while there was no obvious biomass growth shown in the reactor without the addition of glucose. It is because glucose supplementation increased biomass accumulation in biomass production. The increment of biomass in the reactor with glucose supplementation can be further explained by the F/M ratio and biomass yield. The F/M ratio reduced when the biomass growth increased. Thus, the biomass yield started to decrease after the operation in week 2, until it reached maximum biomass growth. Therefore, it concluded that the addition of glucose supplementation in the treatment of AnVE showed a positive effect on the removal performance and biomass growth by using aerobic SBR.
  • Publication
    Investigation of Biosand Filter (BSF) on the Treatment Performance of Industrial Latex Wastewater
    Biosand Filters (BSF) has great potential to improve the water quality. BSF is used extensively in the treatment of drinking water in rural areas because it is affordable, simple to use, and has a high removal efficiency. This study used actual latex effluent to examine the effectiveness of SBR. The growth of the biolayer in the BSF is also observed. This study analyzes consistent and stable results for COD, DO and NH4-N+. With removal performance ranging from 87 % to 99 %. DO value for BSF varied from lowest value of 1.5 mg/L to 8mg/L. Overall, the BSF was capable of producing treated water for water reclamation.