Displaying publications 121 - 140 of 214 in total

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  1. Characteristics of treated effluents and their potential applications for producing concrete
    Noruzman AH, Muhammad B, Ismail M, Abdul-Majid Z
    J Environ Manage, 2012 Nov 15;110:27-32.
    PMID: 22705857 DOI: 10.1016/j.jenvman.2012.05.019
    Conservation and preservation of freshwater is increasingly becoming important as the global population grows. Presently, enormous volumes of freshwater are used to mix concrete. This paper reports experimental findings regarding the feasibility of using treated effluents as alternatives to freshwater in mixing concrete. Samples were obtained from three effluent sources: heavy industry, a palm-oil mill and domestic sewage. The effluents were discharge into public drain without danger to human health and natural environment. Chemical compositions and physical properties of the treated effluents were investigated. Fifteen compositional properties of each effluent were correlated with the requirements set out by the relevant standards. Concrete mixes were prepared using the effluents and freshwater to establish a base for control performance. The concrete samples were evaluated with regard to setting time, workability, compressive strength and permeability. The results show that except for some slight excesses in total solids and pH, the properties of the effluents satisfy the recommended disposal requirements. Two concrete samples performed well for all of the properties investigated. In fact, one sample was comparatively better in compressive strength than the normal concrete; a 9.4% increase was observed at the end of the curing period. Indeed, in addition to environmental conservation, the use of treated effluents as alternatives to freshwater for mixing concrete could save a large amount of freshwater, especially in arid zones.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  2. A review on the formation of titania nanotube photocatalysts by hydrothermal treatment
    Wong CL, Tan YN, Mohamed AR
    J Environ Manage, 2011 Jul;92(7):1669-80.
    PMID: 21450395 DOI: 10.1016/j.jenvman.2011.03.006
    Titania nanotubes are gaining prominence in photocatalysis, owing to their excellent physical and chemical properties such as high surface area, excellent photocatalytic activity, and widespread availability. They are easily produced by a simple and effective hydrothermal method under mild temperature and pressure conditions. This paper reviews and analyzes the mechanism of titania nanotube formation by hydrothermal treatment. It further examines the parameters that affect the formation of titania nanotubes, such as starting material, sonication pretreatment, hydrothermal temperature, washing process, and calcination process. Finally, the effects of the presence of dopants on the formation of titania nanotubes are analyzed.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  3. Biological treatment of anaerobically digested palm oil mill effluent (POME) using a Lab-Scale Sequencing Batch Reactor (SBR)
    Chan YJ, Chong MF, Law CL
    J Environ Manage, 2010 Aug;91(8):1738-46.
    PMID: 20430515 DOI: 10.1016/j.jenvman.2010.03.021
    The production of highly polluting palm oil mill effluent (POME) has resulted in serious environmental hazards. While anaerobic digestion is widely accepted as an effective method for the treatment of POME, anaerobic treatment of POME alone has difficulty meeting discharge limits due to the high organic strength of POME. Hence, subsequent post-treatment following aerobic treatment is vital to meet the discharge limits. The objective of the present study is to investigate the aerobic treatment of anaerobically digested POME by using a sequencing batch reactor (SBR). The SBR performance was assessed by measuring Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS) removal as well as Sludge Volume Index (SVI). The operating pH and dissolved oxygen concentrations were found to be 8.25-9.14 and 1.5-6.4 mg/L, respectively, throughout the experiment. The experimental results demonstrate that MLVSS, OLR and sludge loading rate (SLR) play a significant role in the organic removal efficiency of SBR systems and therefore, further investigation on these parameters was conducted to attain optimum SBR performance. Maximum COD (95-96%), BOD (97-98%) and TSS (98-99%) removal efficiencies were achieved at optimum OLR, SLR and MLVSS concentration ranges of 1.8-4.2 kg COD/m(3)day, 2.5-4.6 kg TSS/m(3)day and 22,000-25,000 mg/L, respectively. The effluent quality remained stable and complied with the discharge limit. At the same time, the sludge showed good settling properties with average SVI of 65. It is envisaged that the SBR process could complement the anaerobic treatment to produce final treated effluent which meets the discharge limit.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  4. Nutrient removal in a pilot and full scale constructed wetland, Putrajaya city, Malaysia
    Sim CH, Yusoff MK, Shutes B, Ho SC, Mansor M
    J Environ Manage, 2008 Jul;88(2):307-17.
    PMID: 17467147
    Putrajaya Wetlands in Malaysia, a 200ha constructed wetland system consisting of 24 cells, was created in 1997-1998 to treat surface runoff caused by development and agricultural activities from an upstream catchment before entering Putrajaya Lake (400ha). It was designed for stormwater treatment, flood control and amenity use. The water quality improvement performance of a section of the wetland cells is described. The nutrient removal performance was 82.11% for total nitrogen, 70.73% for nitrate-nitrogen and 84.32% for phosphate, respectively, along six wetland cells from Upper North UN6 to UN1 from April to December 2004. Nutrient removal in pilot scale tank systems, simulating a constructed wetland and planted with examples of common species at Putrajaya, the Common Reed Phragmites karka and Tube Sedge Lepironia articulata, and the capacity of these species to retain nutrients in above and below-ground plant biomass and substrate is reported. The uptake of nutrients by the Common Reed and Tube Sedge from the pilot tank system was 42.1% TKN; 28.9% P and 17.4% TKN; 26.1% P, respectively. The nutrient uptake efficiency of the Common Reed was higher in above-ground than in below-ground tissue. The results have implications for plant species selection in the design of constructed wetlands in Malaysia and for optimizing the performance of these systems.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  5. Comparison of the efficiencies of attached- versus suspended-growth SBR systems in the treatment of recycled paper mill wastewater
    Muhamad MH, Sheikh Abdullah SR, Abu Hasan H, Abd Rahim RA
    J Environ Manage, 2015 Nov 1;163:115-24.
    PMID: 26311084 DOI: 10.1016/j.jenvman.2015.08.012
    The complexity of residual toxic organics from biologically treated effluents of pulp and paper mills is a serious concern. To date, it has been difficult to choose the best treatment technique because each of the available options has advantages and drawbacks. In this study, two different treatment techniques using laboratory-scale aerobic sequencing batch reactors (SBRs) were tested with the same real recycled paper mill effluent to evaluate their treatment efficiencies. Two attached-growth SBRs using granular activated carbon (GAC) with and without additional biomass and a suspended-growth SBR were used in the treatment of real recycled paper mill effluent at a chemical oxygen demand (COD) level in the range of 800-1300 mg/L, a fixed hydraulic retention time of 24 h and a COD:N:P ratio of approximately 100:5:1. The efficiency of this biological treatment process was studied over a 300-day period. The six most important wastewater quality parameters, namely, chemical oxygen demand (COD), turbidity, ammonia (expressed as NH3-N), phosphorus (expressed as PO4(3)-P), colour, and suspended solids (SS), were measured to compare the different treatment techniques. It was determined that these processes were able to almost completely and simultaneously eliminate COD (99%) and turbidity (99%); the removals of NH3-N (90-100%), PO4(3)-P (66-78%), colour (63-91%), and SS (97-99%) were also sufficient. The overall performance results confirmed that an attached-growth SBR system using additional biomass on GAC is a promising configuration for wastewater treatment in terms of performance efficiency and process stability under fluctuations of organic load. Hence, this hybrid system is recommended for the treatment of pulp and paper mill effluents.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  6. Improvement of COD removal by controlling the substrate degradability during the anaerobic digestion of recalcitrant wastewater
    Kawai M, Nagao N, Kawasaki N, Imai A, Toda T
    J Environ Manage, 2016 Oct 01;181:838-846.
    PMID: 27449962 DOI: 10.1016/j.jenvman.2016.06.057
    The recalcitrant landfill leachate was anaerobically digested at various mixing ratios with labile synthetic wastewater to evaluate the degradation properties of recalcitrant wastewater. The proportion of leachate to the digestion system was increased in three equal steps, starting from 0% to 100%, and later decreased back to 0% with the same steps. The chemical oxygen demand (COD) for organic carbon and other components were calculated by analyzing the COD and dissolved organic carbon (DOC), and the removal efficiencies of COD carbon and COD others were evaluated separately. The degradation properties of COD carbon and COD others shifted owing to changing of substrate degradability, and the removal efficiencies of COD carbon and COD others were improved after supplying 100% recalcitrant wastewater. The UV absorptive property and total organic carbon (TOC) of each molecular size using high performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) with UVA and TOC detectors were also investigated, and the degradability of different molecular sizes was determined. Although the SEC system detected extracellular polymeric substances (EPS), which are produced by microbes in stressful environments, during early stages of the experiment, EPS were not detected after feeding 100% recalcitrant wastewater. These results suggest that the microbes had acclimatized to the recalcitrant wastewater degradation. The high removal rates of both COD carbon and COD others were sustained when the proportion of labile wastewater in the substrate was 33%, indicating that the effective removal of recalcitrant COD might be controlled by changing the substrate's degradability.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  7. A tannin-based agent for coagulation and flocculation of municipal wastewater: Chemical composition, performance assessment compared to Polyaluminum chloride, and application in a pilot plant
    Hameed YT, Idris A, Hussain SA, Abdullah N
    J Environ Manage, 2016 Dec 15;184(Pt 3):494-503.
    PMID: 27789092 DOI: 10.1016/j.jenvman.2016.10.033
    Chemical composition and flocculation efficiency were investigated for a commercially produced tannin - based coagulant and flocculant (Tanfloc). The results of Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive Spectroscopy (EDX) confirmed what claimed about the chemical composition of Tanfloc. For moderate polluted municipal wastewater investigated in both jar test and pilot plant, Tanfloc showed high turbidity removal efficiency of approximately 90%, while removal efficiencies of BOD5 and COD were around 60%. According to floc size distribution, Tanfloc was able to show distinct performance compared to Polyaluminum chloride (PAC). While 90% of flocs produced by Tanfloc were smaller than 144 micron, they were smaller than 96 micron for PAC. Practically, zeta potential measurement showed the cationic nature of Tanfloc and suggested coincidence of charge neutralization and another flocculation mechanism (bridging or patch flocculation). Sludge Volumetric Index (SVI) measurements were in agreement with the numbers found in the literature, and they were less than 160 mL/g. Calcium cation as flocculation aid showed significant improvement of flocculation efficiency compared to other cations. Finally Tanfloc showed competing performance compared to PAC in terms of turbidity, BOD5 and COD removal, floc size and sludge characteristics.
    Matched MeSH terms: Waste Disposal, Fluid/methods
  8. An efficient and economical treatment for batik textile wastewater containing high levels of silicate and organic pollutants using a sequential process of acidification, magnesium oxide, and palm shell-based activated carbon application
    Birgani PM, Ranjbar N, Abdullah RC, Wong KT, Lee G, Ibrahim S, et al.
    J Environ Manage, 2016 Dec 15;184(Pt 2):229-239.
    PMID: 27717677 DOI: 10.1016/j.jenvman.2016.09.066
    Considering the chemical properties of batik effluents, an efficient and economical treatment process was established to treat batik wastewater containing not only high levels of Si and chemical oxygen demand (COD), but also toxic heavy metals. After mixing the effluents obtained from the boiling and soaking steps in the batik process, acidification using concentrated hydrochloric acid (conc. HCl) was conducted to polymerize the silicate under acidic conditions. Consequently, sludge was produced and floated. XRD and FT-IR analyses showed that wax molecules were coordinated by hydrogen bonding with silica (SiO2). The acidification process removed ∼78-95% of COD and ∼45-50% of Si, depending on the pH. In the next stage, magnesium oxide (MgO) was applied to remove heavy metals completely and almost 90% of the Si in the liquid phase. During this step, about 70% of COD was removed in the hydrogel that arose as a consequence of the crosslinking characteristics of the formed nano-composite, such as magnesium silicate or montmorillonite. The hydrogel was composed mainly of waxes with polymeric properties. Then, the remaining Si (∼300 mg/L) in the wastewater combined with the effluents from the rinsing steps was further treated using 50 mg/L MgO. As a final step, palm-shell activated carbon (PSAC) was used to remove the remaining COD to 
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  9. Influence of high temperature on the performance of aerobic granular sludge in biological treatment of wastewater
    Ab Halim MH, Nor Anuar A, Abdul Jamal NS, Azmi SI, Ujang Z, Bob MM
    J Environ Manage, 2016 Dec 15;184(Pt 2):271-280.
    PMID: 27720606 DOI: 10.1016/j.jenvman.2016.09.079
    The effect of temperature on the efficiency of organics and nutrients removal during the cultivation of aerobic granular sludge (AGS) in biological treatment of synthetic wastewater was studied. With this aim, three 3 L sequencing batch reactors (SBRs) with influent loading rate of 1.6 COD g (L d)(-1) were operated at different high temperatures (30, 40 and 50 °C) for simultaneous COD, phosphate and ammonia removal at a complete cycle time of 3 h. The systems were successfully started up and progressed to steady state at different cultivation periods. The statistical comparison of COD, phosphate and ammonia for effluent from the three SBRs revealed that there was a significant difference between groups of all the working temperatures of the bioreactors. The AGS cultivated at different high temperatures also positively correlated with the accumulation of elements including carbon, oxygen, phosphorus, silicon, iron, aluminium, calcium and magnesium that played important roles in the granulation process.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  10. Modeling BOD and COD removal from Palm Oil Mill Secondary Effluent in floating wetland by Chrysopogon zizanioides (L.) using response surface methodology
    Darajeh N, Idris A, Fard Masoumi HR, Nourani A, Truong P, Sairi NA
    J Environ Manage, 2016 Oct 01;181:343-352.
    PMID: 27393941 DOI: 10.1016/j.jenvman.2016.06.060
    While the oil palm industry has been recognized for its contribution towards economic growth and rapid development, it has also contributed to environmental pollution due to the production of huge quantities of by-products from the oil extraction process. A phytoremediation technique (floating Vetiver system) was used to treat Palm Oil Mill Secondary Effluent (POMSE). A batch study using 40 L treatment tanks was carried out under different conditions and Response Surface Methodology (RSM) was applied to optimize the treatment process. A three factor central composite design (CCD) was used to predict the experimental variables (POMSE concentration, Vetiver plant density and time). An extraordinary decrease in organic matter as measured by BOD and COD (96% and 94% respectively) was recorded during the experimental duration of 4 weeks using a density of 30 Vetiver plants. The best and lowest final BOD of 2 mg/L was obtained when using 15 Vetiver plants after 13 days for low concentration POMSE (initial BOD = 50 mg/L). The next best result of BOD at 32 mg/L was obtained when using 30 Vetiver plants after 24 days for medium concentration POMSE (initial BOD = 175 mg/L). These results confirmed the validity of the model, and the experimental value was determined to be quite close to the predicted value, implying that the empirical model derived from RSM experimental design can be used to adequately describe the relationship between the independent variables and response. The study showed that the Vetiver system is an effective method of treating POMSE.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  11. Algal-bacterial aerobic granular sludge for real municipal wastewater treatment: Performance, microbial community change and feasibility of lipid recovery
    Purba LDA, Zahra SA, Yuzir A, Iwamoto K, Abdullah N, Shimizu K, et al.
    J Environ Manage, 2023 May 01;333:117374.
    PMID: 36758398 DOI: 10.1016/j.jenvman.2023.117374
    Despite various research works on algal-bacterial aerobic granular sludge for wastewater treatment and resource recovery processes, limited information is available on its application in real wastewater treatment in terms of performance, microbial community variation and resource recovery. This study investigated the performance of algal-bacterial aerobic granular sludge on real low-strength wastewater treatment in addition to the characterization of microbial community and fatty acid compositions for biodiesel production. The results demonstrated 71% COD, 77% NH4+-N and 31% phosphate removal efficiencies, respectively. In addition, all the water parameters successfully met the effluent standard A, imposed by the Department of Environment (DOE) Malaysia. Core microbiome analyses revealed important microbial groups (i.e., Haliangium ochraceum, Burkholderiales and Chitinophagaceae) in bacterial community. Meanwhile the photosynthetic microorganisms, such as Oxyphotobacteria and Trebouxiophyceae dominated the algal-bacterial aerobic granular sludge, suggesting their important roles in granulation and wastewater treatment. Up to 12.51 mg/gSS lipid content was recovered from the granules. In addition, fatty acids composition showed high percetages of C16:0 and C18:0, demonstrating high feasibility to be used for biodiesel production application indicated by the cetane number, iodine value and oxidation stability properties.
    Matched MeSH terms: Waste Disposal, Fluid/methods
  12. Production and recovery of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from biodiesel liquid waste (BLW)
    Martla M, Umsakul K, Sudesh K
    J Basic Microbiol, 2018 Nov;58(11):977-986.
    PMID: 30095175 DOI: 10.1002/jobm.201800279
    Polyhydroxyalkanoates (PHAs) has been paid great attention because of its useful thermoplastic properties and complete degradation in various natural environments. But, at industrial level, the successful commercialization of PHAs is limited by the high production cost due to the expensive carbon source and recovery processes. Pseudomonas mendocina PSU cultured for 72 h in mineral salts medium (MSM) containing 2% (v/v) biodiesel liquid waste (BLW) produced 79.7 wt% poly(3-hydroxybutyrate) (PHB) at 72 h. In addition, this strain produced 43.6 wt% poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with 8.6 HV mol% at 60 h when added with 0.3% sodium propionate. The synthesized intracellular PHA granules were recovered and purified by the recently reported biological method using mealworms. The weight average molecular weight (Mw ) and number average molecular weight (Mn ) of the biologically extracted PHA were higher than that from the chloroform extraction with comparable melting temperature (Tm ) and high purity. This study has successfully established a low-cost process to synthesize PHAs from BLW and subsequently confirmed the ability of mealworms to extract PHAs from various kinds of bacterial cells.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  13. Insights into bacterial community metatranscriptome and metabolome in river water influenced by palm oil mill effluent final discharge
    Sharuddin SS, Ramli N, Yusoff MZM, Muhammad NAN, Ho LS, Maeda T
    J Appl Microbiol, 2023 Oct 04;134(10).
    PMID: 37757470 DOI: 10.1093/jambio/lxad219
    AIMS: This study aimed to investigate the effect of palm oil mill effluent (POME) final discharge on the active bacterial composition, gene expression, and metabolite profiles in the receiving rivers to establish a foundation for identifying potential biomarkers for monitoring POME pollution in rivers.

    METHODS AND RESULTS: The POME final discharge, upstream (unpolluted by POME), and downstream (effluent receiving point) parts of the rivers from two sites were physicochemically characterized. The taxonomic and gene profiles were then evaluated using de novo metatranscriptomics, while the metabolites were detected using qualitative metabolomics. A similar bacterial community structure in the POME final discharge samples from both sites was recorded, but their composition varied. Redundancy analysis showed that several families, particularly Comamonadaceae and Burkholderiaceae [Pr(>F) = 0.028], were positively correlated with biochemical oxygen demand (BOD5) and chemical oxygen demand (COD). The results also showed significant enrichment of genes regulating various metabolisms in the POME-receiving rivers, with methane, carbon fixation pathway, and amino acids among the predominant metabolisms identified (FDR  4, and PPDE > 0.95). This was further validated through qualitative metabolomics, whereby amino acids were detected as the predominant metabolites.

    CONCLUSIONS: The results suggest that genes regulating amino acid metabolism have significant potential for developing effective biomonitoring and bioremediation strategies in river water influenced by POME final discharge, fostering a sustainable palm oil industry.

    Matched MeSH terms: Waste Disposal, Fluid/methods
  14. Treatment and biotransformation of highly polluted agro-industrial wastewater from a palm oil mill into vermicompost using earthworms
    Lim SL, Wu TY, Clarke C
    J Agric Food Chem, 2014 Jan 22;62(3):691-8.
    PMID: 24372356 DOI: 10.1021/jf404265f
    In this laboratory-scale study, earthworms were introduced as biodegraders of palm oil mill effluent (POME), which is a wastewater produced from the wet process of palm oil milling. POME was absorbed into amendments (soil or rice straw) in different ratios as feedstocks for the earthworm, Eudrilus eugeniae. The presence of earthworms led to significant increases in pH, electrical conductivity, and nutrient content but decreases in the C/N ratio (0.687-75.8%), soluble chemical oxygen demand (19.7-87.9%), and volatile solids (0.687-52.7%). However, earthworm growth was reduced in all treatments by the end of the treatment process. Rice straw was a better amendment/absorbent relative to soil, with a higher nutrient content and greater reduction in soluble chemical oxygen demand with a lower C/N ratio in the vermicompost. Among all treatments investigated, the treatment with 1 part rice straw and 3 parts POME (w/v) (RS1:3) produced the best quality vermicompost with high nutritional status.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  15. Phytoremediation of palm oil mill secondary effluent (POMSE) by Chrysopogon zizanioides (L.) using artificial neural networks
    Darajeh N, Idris A, Fard Masoumi HR, Nourani A, Truong P, Rezania S
    Int J Phytoremediation, 2017 May 04;19(5):413-424.
    PMID: 27748626 DOI: 10.1080/15226514.2016.1244159
    Artificial neural networks (ANNs) have been widely used to solve the problems because of their reliable, robust, and salient characteristics in capturing the nonlinear relationships between variables in complex systems. In this study, ANN was applied for modeling of Chemical Oxygen Demand (COD) and biodegradable organic matter (BOD) removal from palm oil mill secondary effluent (POMSE) by vetiver system. The independent variable, including POMSE concentration, vetiver slips density, and removal time, has been considered as input parameters to optimize the network, while the removal percentage of COD and BOD were selected as output. To determine the number of hidden layer nodes, the root mean squared error of testing set was minimized, and the topologies of the algorithms were compared by coefficient of determination and absolute average deviation. The comparison indicated that the quick propagation (QP) algorithm had minimum root mean squared error and absolute average deviation, and maximum coefficient of determination. The importance values of the variables was included vetiver slips density with 42.41%, time with 29.8%, and the POMSE concentration with 27.79%, which showed none of them, is negligible. Results show that the ANN has great potential ability in prediction of COD and BOD removal from POMSE with residual standard error (RSE) of less than 0.45%.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  16. Mesoporous activated carbon derived from fruit by-product by pyrolysis induced chemical activation: optimization and mechanism for fuchsin basic dye removal
    Hapiz A, Jawad AH, Alothman ZA, Wilson LD
    Int J Phytoremediation, 2024 May;26(7):1064-1075.
    PMID: 38084662 DOI: 10.1080/15226514.2023.2288904
    In this study, pineapple crown (PC) feedstock residues were utilized as a potential precursor toward producing activated carbon (PCAC) via pyrolysis induced with ZnCl2 activation. The PCAC has a surface area (457.8 m2/g) and a mesoporous structure with an average pore diameter of 3.35 nm, according to the Brunauer-Emmett-Teller estimate. The removal of cationic dye (Fuchsin basic; FB) was used for investigating the adsorption parameters of PCAC. The optimization of significant adsorption variables (A: PCAC dose (0.02-0.1 g/100 mL); B: pH (4-10); C: time (10-90); and D: initial FB concentration (10-50 mg/L) was conducted using the Box-Behnken design (BBD). The pseudo-second-order (PSO) model characterized the dye adsorption kinetic profile, whereas the Freundlich model reflected the equilibrium adsorption profile. The maximum adsorption capacity (qmax) of PCAC for FB dye was determined to be 171.5 mg/g. Numerous factors contribute to the FB dye adsorption mechanism onto the surface of PCAC, which include electrostatic attraction, H-bonding, pore diffusion, and π-π stacking. This study illustrates the utilization of PC biomass feedstock for the fabrication of PCAC and its successful application in wastewater remediation.
    Matched MeSH terms: Waste Disposal, Fluid/methods
  17. Fulltext Prospective Application of Palm Oil Mill Boiler Ash as a Biosorbent: Effect of Microwave Irradiation and Palm Oil Mill Effluent Decolorization by Adsorption
    Hamzah MH, Ahmad Asri MF, Che Man H, Mohammed A
    Int J Environ Res Public Health, 2019 09 17;16(18).
    PMID: 31533308 DOI: 10.3390/ijerph16183453
    Common conventional biological treatment methods fail to decolorize palm oil mill effluent (POME). The present study focused on using the abundant palm oil mill boiler (POMB) ashes for POME decolorization. The POMB ashes were subjected to microwave irradiation and chemical treatment using H2SO4. The resultant adsorbents were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Brunauer-Emmett-Teller (BET) analyses. The adsorption efficiency was evaluated at various pH levels (2-8.5), adsorption dosages (3-15 g) in 200 mL, and contact times (1-5 h). The microwave-irradiated POMB-retained ash recorded the highest color removal of 92.31%, for which the best conditions were pH 2, 15 g adsorbent dosage in 200 mL, and 5 h of contact time. At these best treatment conditions, the color concentration of the treated effluent was analyzed using the method proposed by the American Dye Manufacturers Institute (ADMI). The color concentration was 19.20 ADMI, which complies with the Malaysia discharge standard class A. The Freundlich isotherm model better fit the experimental data and had a high R2 of 0.9740. Based on these results, it can be deduced that microwave-irradiated POMB-retained ash has potential applications for POME decolorization via a biosorption process.
    Matched MeSH terms: Waste Disposal, Fluid/methods
  18. Fulltext The Pertinence of Microwave Irradiated Coconut Shell Bio-Sorbent for Wastewater Decolourization: Structural Morphology and Adsorption Optimization Using the Response Surface Method (RSM)
    Abdulsalam M, Che Man H, Isma Idris A, Zainal Abidin Z, Faezah Yunos K
    Int J Environ Res Public Health, 2018 10 09;15(10).
    PMID: 30304814 DOI: 10.3390/ijerph15102200
    Palm oil mill effluent contains carcinogenic coloured compounds that are difficult to separate due to their aromatic structure. Though colour treatment using adsorption processes at lower pH (<4) have been reported effectual, due to its acidity the remediated effluent poses an environmental hazard as a result. Thus, the current study focused on achieving decolourization at neutral pH by enhancing the morphology of the coconut shell activated carbon (CSAC) using N₂ as activating-agent with microwave irradiation heating. The microwave pretreated and non-pretreated CSAC were characterized using scanned electron microscopy (SEM), energy dispersive X-ray (EDX) and Brunauer-Emmett-Teller (BET) analysis. A significant modification in the porous structure with a 66.62% increase in the specific surface area was achieved after the pretreatment. The adsorption experimental matrix was developed using the central composite design to investigate the colour adsorption performance under varied pH (6⁻7), dosage (2⁻6 g) and contact time (10⁻100 min). At optimum conditions of neutral pH (7), 3.208 g dosage and contact time of 35 min, the percentage of colour removal was 96.29% with negligible differences compared with the predicted value, 95.855%. The adsorption equilibrium capacity of 1430.1 ADMI × mL/g was attained at the initial colour concentration of 2025 ADMI at 27 °C. The experimental data fitted better with the Freundlich isotherm model with R² 0.9851.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  19. Fulltext Effect of Organic Loading Rate on Anaerobic Digestion Performance of Mesophilic (UASB) Reactor Using Cattle Slaughterhouse Wastewater as Substrate
    Musa MA, Idrus S, Hasfalina CM, Daud NNN
    Int J Environ Res Public Health, 2018 10 11;15(10).
    PMID: 30314290 DOI: 10.3390/ijerph15102220
    In this study, the performance of a laboratory scale upflow anaerobic sludge blanket (UASB) reactor operating at mesophilic temperature (35 °C) was examined. Cattle slaughterhouse wastewater (CSWW) was used as the main substrate. The total and effective volumes of the reactor were 8 L and 6 L, respectively. Twelve different organic loading rates (OLR) were applied and the performance was evaluated. The chemical oxygen demand (COD) removal efficiency was more than 90% during batch study. In the continuous study, COD removal was also approximately 90% at OLR 0.4 g/L d-1 which subsequently dropped to below 50% when the loading rate increased to 15 g/L d-1. Approximately 5 L/d of biogas was obtained with high methane concentration at stages VI and XI corresponding to OLR of 2 and 10 g/L d-1, respectively. It was observed that the concentration of volatile fatty acids was low and that the alkalinity of the wastewater was sufficient to avoid acidification. Specific methane yields of 0.36 and 0.38 LCH₄/g COD added were achieved at OLR 7 and 10 g/L d-1. A hydraulic retention time (HRT) of 1 day was sufficient to remove greater than 70% of COD which correspond to 89% methane concentration. Parameters like soluble COD, NH₃-N, pH, alkalinity, total suspended solid (TSS), fats, oil, and grease were also investigated. The results show that the UASB reactor could serve as a good alternative for anaerobic treatment of CSWW and methane production.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  20. Fulltext A Comparative Study of Biogas Production from Cattle Slaughterhouse Wastewater Using Conventional and Modified Upflow Anaerobic Sludge Blanket (UASB) Reactors
    Musa MA, Idrus S, Harun MR, Tuan Mohd Marzuki TF, Abdul Wahab AM
    Int J Environ Res Public Health, 2019 12 31;17(1).
    PMID: 31906118 DOI: 10.3390/ijerph17010283
    Cattle slaughterhouses generate wastewater that is rich in organic contaminant and nutrients, which is considered as high strength wastewater with a high potential for energy recovery. Work was undertaken to evaluate the efficiency of the 12 L laboratory scale conventional and a modified upflow anaerobic sludge blanket (UASB) reactors (conventional, R1 and modified, R2), for treatment of cattle slaughterhouse wastewater (CSWW) under mesophilic condition (35 ± 1 °C). Both reactors were acclimated with synthetic wastewater for 30 days, then continuous study with real CSWW proceeds. The reactors were subjected to the same loading condition of OLR, starting from 1.75, 3, 5 10, 14, and 16 g L-1d-1, corresponding to 3.5, 6, 10, 20, 28, and 32 g COD/L at constant hydraulic retention time (HRT) of 24 h. The performance of the R1 reactor drastically dropped at OLR 10 g L-1d-1, and this significantly affected the subsequent stages. The steady-state performance of the R2 reactor under the same loading condition as the R1 reactor revealed a high COD removal efficiency of 94% and biogas and methane productions were 27 L/d and 89%. The SMP was 0.21 LCH4/gCOD added, whereas the NH3-N alkalinity ratio stood at 651 mg/L and 0.2. SEM showed that the R2 reactor was dominated by Methanosarcina bacterial species, while the R1 reactor revealed a disturb sludge with insufficient microbial biomass.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
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