Displaying publications 21 - 40 of 363 in total

Abstract:
Sort:
  1. Oil palm biomass-based adsorbents for the removal of water pollutants--a review
    Ahmad T, Rafatullah M, Ghazali A, Sulaiman O, Hashim R
    J Environ Sci Health C Environ Carcinog Ecotoxicol Rev, 2011 Jul;29(3):177-222.
    PMID: 21929380 DOI: 10.1080/10590501.2011.601847
    This article presents a review on the role of oil palm biomass (trunks, fronds, leaves, empty fruit bunches, shells, etc.) as adsorbents in the removal of water pollutants such as acid and basic dyes, heavy metals, phenolic compounds, various gaseous pollutants, and so on. Numerous studies on adsorption properties of various low-cost adsorbents, such as agricultural wastes and its based activated carbons, have been reported in recent years. Studies have shown that oil palm-based adsorbent, among the low-cost adsorbents mentioned, is the most promising adsorbent for removing water pollutants. Further, these bioadsorbents can be chemically modified for better efficiency and can undergo multiple reuses to enhance their applicability at an industrial scale. It is evident from a literature survey of more than 100 recent papers that low-cost adsorbents have demonstrated outstanding removal capabilities for various pollutants. The conclusion is been drawn from the reviewed literature, and suggestions for future research are proposed.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  2. Removal of pesticides from water and wastewater by different adsorbents: a review
    Ahmad T, Rafatullah M, Ghazali A, Sulaiman O, Hashim R, Ahmad A
    J Environ Sci Health C Environ Carcinog Ecotoxicol Rev, 2010 Oct;28(4):231-71.
    PMID: 21069614 DOI: 10.1080/10590501.2010.525782
    In this review article, the use of various low-cost adsorbents for the removal of pesticides from water and wastewater has been reviewed. Pesticides may appear as pollutants in water sources, having undesirable impacts to human health because of their toxicity, carcinogenicity, and mutagenicity or causing aesthetic problems such as taste and odors. These pesticides pollute the water stream and it can be removed very effectively using different low-cost adsorbents. It is evident from a literature survey of about 191 recently published papers that low-cost adsorbents have demonstrated outstanding removal capabilities for pesticides.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  3. Prospects of banana waste utilization in wastewater treatment: A review
    Ahmad T, Danish M
    J Environ Manage, 2018 Jan 15;206:330-348.
    PMID: 29100146 DOI: 10.1016/j.jenvman.2017.10.061
    This review article explores utilization of banana waste (fruit peels, pseudo-stem, trunks, and leaves) as precursor materials to produce an adsorbent, and its application against environmental pollutants such as heavy metals, dyes, organic pollutants, pesticides, and various other gaseous pollutants. In recent past, quite a good number of research articles have been published on the utilization of low-cost adsorbents derived from biomass wastes. The literature survey on banana waste derived adsorbents shown that due to the abundance of banana waste worldwide, it also considered as low-cost adsorbents with promising future application against various environmental pollutants. Furthermore, raw banana biomass can be chemically modified to prepare efficient adsorbent as per requirement; chemical surface functional group modification may enhance the multiple uses of the adsorbent with industrial standard. It was evident from a literature survey that banana waste derived adsorbents have significant removal efficiency against various pollutants. Most of the published articles on banana waste derived adsorbents have been discussed critically, and the conclusion is drawn based on the results reported. Some results with poorly performed experiments were also discussed and pointed out their lacking in reporting. Based on literature survey, the future research prospect on banana wastes has a significant impact on upcoming research strategy.
    Matched MeSH terms: Waste Disposal, Fluid*
  4. The use of date palm as a potential adsorbent for wastewater treatment: a review
    Ahmad T, Danish M, Rafatullah M, Ghazali A, Sulaiman O, Hashim R, et al.
    Environ Sci Pollut Res Int, 2012 Jun;19(5):1464-84.
    PMID: 22207239 DOI: 10.1007/s11356-011-0709-8
    BACKGROUND: In tropical countries, the palm tree is one of the most abundant and important trees. Date palm is a principal fruit grown in many regions of the world. It is abundant, locally available and effective material that could be used as an adsorbent for the removal of different pollutants from aqueous solution.

    REVIEW: This article presents a review on the role of date palm as adsorbents in the removal of unwanted materials such as acid and basic dyes, heavy metals, and phenolic compounds. Many studies on adsorption properties of various low cost adsorbent, such as agricultural waste and activated carbons based on agricultural waste have been reported in recent years.

    CONCLUSION: Studies have shown that date palm-based adsorbents are the most promising adsorbents for removing unwanted materials. No previous review is available where researchers can get an overview of the adsorption capacities of date palm-based adsorbent used for the adsorption of different pollutants. This review provides the recent literature demonstrating the usefulness of date palm biomass-based adsorbents in the adsorption of various pollutants.

    Matched MeSH terms: Waste Disposal, Fluid/economics; Waste Disposal, Fluid/methods*
  5. Pilot-scale removal of chromium from industrial wastewater using the ChromeBac system
    Ahmad WA, Zakaria ZA, Khasim AR, Alias MA, Ismail SM
    Bioresour Technol, 2010 Jun;101(12):4371-8.
    PMID: 20185301 DOI: 10.1016/j.biortech.2010.01.106
    The enzymatic reduction of Cr(VI) to Cr(III) by Cr(VI) resistant bacteria followed by chemical precipitation constitutes the ChromeBac system. Acinetobacter haemolyticus was immobilized onto carrier material inside a 0.2m(3) bioreactor. Neutralized electroplating wastewater with Cr(VI) concentration of 17-81 mg L(-1) was fed into the bioreactor (0.11-0.33 m(3)h(-1)). Complete Cr(VI) reduction to Cr(III) was obtained immediately after the start of bioreactor operation. Together with the flocculation, coagulation and filtration, outflow concentration of less than 0.02 mg Cr(VI)L(-1) and 1mg total CrL(-1) were always obtained. Performance of the bioreactor was not affected by fluctuations in pH (6.2-8.4), Cr(VI) (17-81 mg L(-1)), nutrient (liquid pineapple waste, 1-20%v/v) and temperature (30-38 degrees C). Standby periods of up to 10 days can be tolerated without loss in activity. A robust yet effective biotechnology to remove chromium from wastewater is thus demonstrated.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  6. Recent developments in physical, biological, chemical, and hybrid treatment techniques for removing emerging contaminants from wastewater
    Ahmed SF, Mofijur M, Nuzhat S, Chowdhury AT, Rafa N, Uddin MA, et al.
    J Hazard Mater, 2021 08 15;416:125912.
    PMID: 34492846 DOI: 10.1016/j.jhazmat.2021.125912
    Emerging contaminants (ECs) in wastewater have recently attracted the attention of researchers as they pose significant risks to human health and wildlife. This paper presents the state-of-art technologies used to remove ECs from wastewater through a comprehensive review. It also highlights the challenges faced by existing EC removal technologies in wastewater treatment plants and provides future research directions. Many treatment technologies like biological, chemical, and physical approaches have been advanced for removing various ECs. However, currently, no individual technology can effectively remove ECs, whereas hybrid systems have often been found to be more efficient. A hybrid technique of ozonation accompanied by activated carbon was found significantly effective in removing some ECs, particularly pharmaceuticals and pesticides. Despite the lack of extensive research, nanotechnology may be a promising approach as nanomaterial incorporated technologies have shown potential in removing different contaminants from wastewater. Nevertheless, most existing technologies are highly energy and resource-intensive as well as costly to maintain and operate. Besides, most proposed advanced treatment technologies are yet to be evaluated for large-scale practicality. Complemented with techno-economic feasibility studies of the treatment techniques, comprehensive research and development are therefore necessary to achieve a full and effective removal of ECs by wastewater treatment plants.
    Matched MeSH terms: Waste Disposal, Fluid
  7. Molecular characterization of anaerobic sulfur-oxidizing microbial communities in up-flow anaerobic sludge blanket reactor treating municipal sewage
    Aida AA, Hatamoto M, Yamamoto M, Ono S, Nakamura A, Takahashi M, et al.
    J Biosci Bioeng, 2014 Nov;118(5):540-5.
    PMID: 24930844 DOI: 10.1016/j.jbiosc.2014.04.011
    A novel wastewater treatment system consisting of an up-flow anaerobic sludge blanket (UASB) reactor and a down-flow hanging sponge (DHS) reactor with sulfur-redox reaction was developed for treatment of municipal sewage under low-temperature conditions. In the UASB reactor, a novel phenomenon of anaerobic sulfur oxidation occurred in the absence of oxygen, nitrite and nitrate as electron acceptors. The microorganisms involved in anaerobic sulfur oxidation have not been elucidated. Therefore, in this study, we studied the microbial communities existing in the UASB reactor that probably enhanced anaerobic sulfur oxidation. Sludge samples collected from the UASB reactor before and after sulfur oxidation were used for cloning and terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA genes of the bacterial and archaeal domains. The microbial community structures of bacteria and archaea indicated that the genus Smithella and uncultured bacteria within the phylum Caldiserica were the dominant bacteria groups. Methanosaeta spp. was the dominant group of the domain archaea. The T-RFLP analysis, which was consistent with the cloning results, also yielded characteristic fingerprints for bacterial communities, whereas the archaeal community structure yielded stable microbial community. From these results, it can be presumed that these major bacteria groups, genus Smithella and uncultured bacteria within the phylum Caldiserica, probably play an important role in sulfur oxidation in UASB reactors.
    Matched MeSH terms: Waste Disposal, Fluid
  8. Landfill leachate treatment using sub-surface flow constructed wetland by Cyperus haspan
    Akinbile CO, Yusoff MS, Ahmad Zuki AZ
    Waste Manag, 2012 Jul;32(7):1387-93.
    PMID: 22456086 DOI: 10.1016/j.wasman.2012.03.002
    Performance evaluation of pilot scale sub-surface constructed wetlands was carried out in treating leachate from Pulau Burung Sanitary Landfill (PBSL). The constructed wetland was planted with Cyperus haspan with sand and gravel used as substrate media. The experiment was operated for three weeks retention time and during the experimentation, the influent and effluent samples were tested for its pH, turbidity, color, total suspended solid (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD(5)), ammonia nitrogen (NH(3)-N), Total phosphorus (TP), total nitrogen (TN) and also for heavy metals such as iron (Fe), magnesium (Mg), manganese (Mn) and zinc (Zn) concentrations. The results showed that the constructed wetlands with C. haspan were capable of removing 7.2-12.4% of pH, 39.3-86.6% of turbidity, 63.5-86.6% of color, 59.7-98.8% of TSS, 39.2-91.8% of COD, 60.8-78.7% of BOD(5), 29.8-53.8% of NH(3)-N, 59.8-99.7% of TP, 33.8-67.0% of TN, 34.9-59.0% of Fe, 29.0-75.0% of Mg, 51.2-70.5% of Mn, and 75.9-89.4% of Zn. The significance of removal was manifested in the quality of the effluent obtained at the end of the study. High removal efficiencies in the study proved that leachate could be treated effectively using subsurface constructed wetlands with C. haspan plant.
    Matched MeSH terms: Waste Disposal, Fluid/methods
  9. Fulltext Adsorption Studies of Volatile Organic Compound (Naphthalene) from Aqueous Effluents: Chemical Activation Process Using Weak Lewis Acid, Equilibrium Kinetics and Isotherm Modelling
    Akinpelu AA, Chowdhury ZZ, Shibly SM, Faisal ANM, Badruddin IA, Rahman MM, et al.
    Int J Mol Sci, 2021 Feb 19;22(4).
    PMID: 33669883 DOI: 10.3390/ijms22042090
    This study deals with the preparation of activated carbon (CDSP) from date seed powder (DSP) by chemical activation to eliminate polyaromatic hydrocarbon-PAHs (naphthalene-C10H8) from synthetic wastewater. The chemical activation process was carried out using a weak Lewis acid of zinc acetate dihydrate salt (Zn(CH3CO2)2·2H2O). The equilibrium isotherm and kinetics analysis was carried out using DSP and CDSP samples, and their performances were compared for the removal of a volatile organic compound-naphthalene (C10H8)-from synthetic aqueous effluents or wastewater. The equilibrium isotherm data was analyzed using the linear regression model of the Langmuir, Freundlich and Temkin equations. The R2 values for the Langmuir isotherm were 0.93 and 0.99 for naphthalene (C10H8) adsorption using DSP and CDSP, respectively. CDSP showed a higher equilibrium sorption capacity (qe) of 379.64 µg/g. DSP had an equilibrium sorption capacity of 369.06 µg/g for C10H8. The rate of reaction was estimated for C10H8 adsorption using a pseudo-first order, pseudo-second order and Elovich kinetic equation. The reaction mechanism for both the sorbents (CDSP and DSP) was studied using the intraparticle diffusion model. The equilibrium data was well-fitted with the pseudo-second order kinetics model showing the chemisorption nature of the equilibrium system. CDSP showed a higher sorption performance than DSP due to its higher BET surface area and carbon content. Physiochemical characterizations of the DSP and CDSP samples were carried out using the BET surface area analysis, Fourier-scanning microscopic analysis (FSEM), energy-dispersive X-ray (EDX) analysis and Fourier-transform spectroscopic analysis (FTIR). A thermogravimetric and ultimate analysis was also carried out to determine the carbon content in both the sorbents (DSP and CDSP) here. This study confirms the potential of DSP and CDSP to remove C10H8 from lab-scale synthetic wastewater.
    Matched MeSH terms: Waste Disposal, Fluid
  10. Operational factors affecting the bioregeneration of mono-amine modified silica loaded with Acid Orange 7
    Al-Amrani WA, Lim PE, Seng CE, Ngah WS
    Water Res, 2012 Dec 1;46(19):6419-29.
    PMID: 23062787 DOI: 10.1016/j.watres.2012.09.014
    In this study, the operational factors affecting the bioregeneration of AO7-loaded MAMS particles in batch system, namely redox condition, initial acclimated biomass concentration, shaking speed and type of acclimated biomass were investigated. The results revealed that with the use of mixed culture acclimated to AO7 under anoxic/aerobic conditions, enhancement of the bioregeneration efficiency of AO7-loaded MAMS and the total removal efficiency of COD could be achieved when the bio-decolorization and bio-mineralization stages were fully aerated with dissolved oxygen above 7 mg/L. Shorter duration of bioregeneration was achieved by using relatively higher initial biomass concentration and lower shaking speed, respectively, whereas variations of biomass concentration and shaking speed did not have a pronounced effect on the bioregeneration efficiency. The duration and efficiency of bioregeneration process were greatly affected by the chemical structures of mono-azo dyes to which the biomasses were acclimated.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  11. The effect of drastic temperature changes on the performance of MBR treating municipal wastewater
    Al-Amri A, Salim MR, Aris A
    Water Sci Technol, 2011;64(7):1398-405.
    PMID: 22179635 DOI: 10.2166/wst.2011.421
    A study has been carried out to define the effect of drastic temperature changes on the performance of lab-scale hollow-fibre MBR in treating municipal wastewater at a flux of 10 L m(-2) h(-1) (LMH). The objectives of the study were to estimate the activated sludge properties, the removal efficiencies of COD and NH(3)-N and the membrane fouling tendency under critical conditions of drastic temperature changes (23, 33, 42 & 33 °C) and MLSS concentration ranged between 6,382 and 8,680 mg/L. The study exhibited that the biomass reduction, the low sludge settleability and the supernatant turbidity were results of temperature increase. The temperature increase led to increase in SMP carbohydrate and protein, and to decrease in EPS carbohydrate and protein. The BRE of COD dropped from 80% at 23 °C to 47% at 42 °C, while the FRE was relatively constant at about 90%. Both removal efficiencies of NH(3)-N trended from about 100% at 33 °C to less than 50% at 42 °C. TMP and BWP ascended critically with temperature increase up to 336 and 304 mbar respectively by the end of the experiment. The values of suspended solids (SS) and the turbidity in the final effluent were negligible. The DO in the mixed liquor was varying with temperature change, while the pH was within the range of 6.7-8.3.
    Matched MeSH terms: Waste Disposal, Fluid/methods
  12. Responses of growth of lady's fingers (Abelmoschus esculentus L.) to different treatments methods of dairy wastewater
    Al-Dulaimi RI, Ismail N, Ibrahim MH
    Ann Agric Environ Med, 2014;21(1):42-8.
    PMID: 24847548
    Water is one of the most important precious resources found on the earth, and are most often affected by anthropogenic activities and by industry. Pollution caused by human beings and industries is a serious concern throughout the world. Population growth, massive urbanization, rapid rate of industrialization and modern techniques in agriculture have accelerated water pollution and led to the gradual deterioration of its quality. A large quantity of waste water disposed of at sea or on land has caused environmental problems which have led to environmental pollution, economic losses and chemical risks caused by the wastewater, and its impact on agriculture. However, waste water which contain nutrients and organic matter has possible advantages for agricultural purposes. Therefore, the presented study was undertaken to assess the impact of Dairy Effluent (treated and untreated waste water) on seed germination, seedling growth, dry matter production and the biochemical parameters of lady's fingers (Abelmoschus esculentus L.).
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  13. Influence of pathogenic bacterial activity on growth of Scenedesmus sp. and removal of nutrients from public market wastewater
    Al-Gheethi AA, Mohamed RM, Jais NM, Efaq AN, Abd Halid A, Wurochekke AA, et al.
    J Water Health, 2017 Oct;15(5):741-756.
    PMID: 29040077 DOI: 10.2166/wh.2017.080
    The present study aims to investigate the influence of Staphylococcus aureus, Escherichia coli and Enterococcus faecalis in public market wastewater on the removal of nutrients in terms of ammonium (NH4-) and orthophosphate (PO43) using Scenedesmus sp. The removal rates of NH4- and orthophosphate PO43- and batch kinetic coefficient of Scenedesmus sp. were investigated. The phycoremediation process was carried out at ambient temperature for 6 days. The results revealed that the pathogenic bacteria exhibited survival potential in the presence of microalgae but they were reduced by 3-4 log at the end of the treatment process. The specific removal rates of NH4- and PO43- have a strong relationship with initial concentration in the public market wastewater (R2 = 0.86 and 0.80, respectively). The kinetic coefficient of NH4- removal by Scenedesmus sp. was determined as k = 4.28 mg NH4- 1 log10 cell mL-1 d-1 and km = 52.01 mg L-1 (R2 = 0.94) while the coefficient of PO43- removal was noted as k = 1.09 mg NH4- 1 log10 cell mL-1 d-1 and km = 85.56 mg L-1 (R2 = 0.92). It can be concluded that Scenedesmus sp. has high competition from indigenous bacteria in the public market wastewater to remove nutrients, with a higher coefficient of removal of NH4- than PO43.
    Matched MeSH terms: Waste Disposal, Fluid*
  14. Energy recovery and carbon/nitrogen removal from sewage and contaminated groundwater in a coupled hydrolytic-acidogenic sequencing batch reactor and denitrifying biocathode microbial fuel cell
    Al-Mamun A, Jafary T, Baawain MS, Rahman S, Choudhury MR, Tabatabaei M, et al.
    Environ Res, 2020 04;183:109273.
    PMID: 32105886 DOI: 10.1016/j.envres.2020.109273
    Developing cost-effective technology for treatment of sewage and nitrogen-containing groundwater is one of the crucial challenges of global water industries. Microbial fuel cells (MFCs) oxidize organics from sewage by exoelectrogens on anode to produce electricity while denitrifiers on cathode utilize the generated electricity to reduce nitrogen from contaminated groundwater. As the exoelectrogens are incapable of oxidizing insoluble, polymeric, and complex organics, a novel integration of an anaerobic sequencing batch reactor (ASBR) prior to the MFC simultaneously achieve hydrolytic-acidogenic conversion of complex organics, boost power recovery, and remove Carbon/Nitrogen (C/N) from the sewage and groundwater. The results obtained revealed increases in the fractions of soluble organics and volatile fatty acids in pretreated sewage by 52 ± 19% and 120 ± 40%, respectively. The optimum power and current generation with the pretreated sewage were 7.1 W m-3 and 45.88 A m-3, respectively, corresponding to 8% and 10% improvements compared to untreated sewage. Moreover, the integration of the ASBR with the biocathode MFC led to 217% higher carbon and 136% higher nitrogen removal efficiencies compared to the similar system without ASBR. The outcomes of the present study represent the promising prospects of using ASBR pretreatment and successive utilization of solubilized organics in denitrifying biocathode MFCs for simultaneous energy recovery and C/N removal from both sewage and nitrate nitrogen-contaminated groundwater.
    Matched MeSH terms: Waste Disposal, Fluid
  15. Removal of inorganic pollutants using electrocoagulation technology: A review of emerging applications and mechanisms
    Al-Raad AA, Hanafiah MM
    J Environ Manage, 2021 Dec 15;300:113696.
    PMID: 34509809 DOI: 10.1016/j.jenvman.2021.113696
    Electrocoagulation (ECoag) technique has shown considerable potential as an effective method in separating different types of pollutants (including inorganic pollutants) from various sources of water at a lower cost, and that is environmentally friendly. The EC method's performance depends on several significant parameters, including current density, reactor geometry, pH, operation time, the gap between electrodes, and agitation speed. There are some challenges related to the ECoag technique, for example, energy consumption, and electrode passivation as well as its implementation at a larger scale. This review highlights the recent studies published about ECoag capacity to remove inorganic pollutants (including salts), the emerging reactors, and the effect of reactor geometry designs. In addition, this paper highlights the integration of the ECoag technique with other advanced technologies such as microwave and ultrasonic to achieve higher removal efficiencies. This paper also presents a critical discussion of the major and minor reactions of the electrocoagulation technique with several significant operational parameters, emerging designs of the ECoag cell, operating conditions, and techno-economic analysis. Our review concluded that optimizing the operating parameters significantly enhanced the efficiency of the ECoag technique and reduced overall operating costs. Electrodes geometry has been recommended to minimize the passivation phenomenon, promote the conductivity of the cell, and reduce energy consumption. In this review, several challenges and gaps were identified, and insights for future development were discussed. We recommend that future studies investigate the effect of other emerging parameters like perforated and ball electrodes on the ECoag technique.
    Matched MeSH terms: Waste Disposal, Fluid
  16. Feasibility study of sequencing batch reactor system for upgrading wastewater treatment in Malaysia
    Al-Shididi S, Henze M, Ujang Z
    Water Sci Technol, 2003;48(11-12):327-35.
    PMID: 14753553
    The objective of this study was to assess the feasibility of the Sequencing Batch Reactor (SBR) system for implementation in Malaysia. Theoretical, field, laboratory investigations, and modelling simulations have been carried out. The results of the study indicated that the SBR system was robust, relatively cost-effective, and efficient under Malaysian conditions. However, the SBR system requires highly skilled operators and continuous monitoring. This paper also attempted to identify operating conditions for the SBR system, which optimise both the removal efficiencies and the removal rates. The removal efficiencies could reach 90-96% for COD, up to 92% for TN, and 95% for SS. An approach to estimate a full operational cycle time, to estimate the de-sludging rate, and to control the biomass in the sludge has also been developed. About 4 hours react time was obtained, as 2.25 hours of nitrification with aerated slow fill and 1.75 hour of denitrification with HAc addition as an additional carbon source. Inefficient settling was one of the problems that affect the SBR effluent quality. The settling time was one hour for achieving Standard B (effluent quality) and 2 hours for Standard A.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
  17. Statistical optimization of adsorption processes for removal of 2,4-dichlorophenol by activated carbon derived from oil palm empty fruit bunches
    Alam MZ, Muyibi SA, Toramae J
    J Environ Sci (China), 2007;19(6):674-7.
    PMID: 17969639
    The adsorption capacity of activated carbon produced from oil palm empty fruit bunches through removal of 2,4-dichlorophenol from aqueous solution was carried out in the laboratory. The activated carbon was produced by thermal activation of activation time with 30 min at 800 degrees C. The adsorption process conditions were determined with the statistical optimization followed by central composite design. A developed polynomial model for operating conditions of adsorption process indicated that the optimum conditions for maximum adsorption of phenolic compound were: agitation rate of 100 r/min, contact time of 8 h, initial adsorbate concentration of 250 mg/L and pH 4. Adsorption isotherms were conducted to evaluate biosorption process. Langmuir isotherm was more favorable (R2 = 0.93) for removal of 2,4-dichlorophenol by the activated carbon rather than Freundlich isotherm (R2 = 0.88).
    Matched MeSH terms: Waste Disposal, Fluid/methods
  18. Statistical optimization of process conditions for cellulase production by liquid state bioconversion of domestic wastewater sludge
    Alam MZ, Muyibi SA, Wahid R
    Bioresour Technol, 2008 Jul;99(11):4709-16.
    PMID: 17981027
    A two-level fractional factorial design (FFD) was used to determine the effects of six factors, i.e. substrate (domestic wastewater sludge - DWS) and co-substrate concentration (wheat flour - WF), temperature, initial pH, inoculum size and agitation rate on the production of cellulase enzyme by Trichoderma harzianum in liquid state bioconversion. On statistical analysis of the results from the experimental studies, optimum process conditions were found to be temperature 32.5 degrees C, substrate concentration (DWS) 0.75% (w/w), co-substrate (WF) concentration 2% (w/w), initial pH 5, inoculum size 2% (v/w) and agitation 175 rpm. Analysis of variance (ANOVA) showed a high coefficient of determination (R2) of 0.975. Cellulase activity reached 10.2 FPU/ml at day 3 during the fermentation process which indicated about 1.5-fold increase in production compared to the cellulase activity obtained from the results of design of experiment (6.9 FPU/ml). Biodegradation of DWS was also evaluated to verify the efficiency of the bioconversion process as a waste management method.
    Matched MeSH terms: Waste Disposal, Fluid*
  19. Biological treatment of sewage treatment plant sludge by pure bacterial culture with optimum process conditions in a stirred tank bioreactor
    Alam MZ, Muyibi SA, Jamal P
    J Environ Sci Health A Tox Hazard Subst Environ Eng, 2007 Sep;42(11):1671-9.
    PMID: 17849310
    Biological treatment of sewage treatment plant (STP) sludge by potential pure bacterial culture (Bacillus sp.) with optimum process conditions for effective biodegradation and bioseparation was carried out in the laboratory. The effective and efficient bioconversion was evaluated with the treatment of pure bacterial culture and existing microbes (uninnoculated) in sludge. The optimum process conditions i.e., temperature, 40 degrees C; pH, 6; inoculum, 5% (v/v); aeration, 1 vvm; agitation speed, 50 rpm obtained from the previous studies with chemical oxygen demand COD at 30 mgL(-1) were applied for the biological treatment of sludge. The results indicated that pure bacterial culture (Bacillus sp.) showed higher degradation and separation of treated sludge compared to treatment with the existing mixed microbes in a stirred tank bioreactor. The treated STP sludge by potential pure bacterial culture and existing microbes gave 30% and 11%; 91.2% and 59.1; 88.5% and 52.3%; 98.4% and 51.3%; 96.1% and 75.2%; 99.4% and 72.8% reduction of total suspended solids (TSS, biosolids), COD, soluble protein, turbidity, total dissolved solids (TDS) and specific resistance to filtration (SRF), respectively within 7 days of treatment. The pH was observed at 6.5 and 4 during the treatment of sludge by pure culture and existing microbes, respectively.
    Matched MeSH terms: Waste Disposal, Fluid/instrumentation; Waste Disposal, Fluid/methods*
  20. Removal of phenol by activated carbons prepared from palm oil mill effluent sludge
    Alam MZ, Muyibi SA, Mansor MF, Wahid R
    J Environ Sci (China), 2006;18(3):446-52.
    PMID: 17294638
    The study was attempted to produce activated carbons from palm oil mill effluent (POME) sludge. The adsorption capacity of the activated carbons produced was evaluated in aqueous solution of phenol. Two types of activation were followed, namely, thermal activation at 300, 500 and 800 degrees C, and physical activation at 15 degrees C (boiling treatment). A control (raw POME sludge) was used to compare the adsorption capacity of the activated carbons produced. The results indicated that the activation temperature of 800 degrees C showed maximum absorption capacity by the activated carbon (POME 800) in aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon of POME 800. It was observed that the adsorption capacity was higher at lower values of pH (2-3) and higher value of initial concentration of phenol (200-300 mg/L). The equilibrium data were fitted by the Langmuir and Freundlich adsorption isotherms. The adsorption of phenol onto the activated carbon POME 800 was studied in terms of pseudo- first and second order kinetics to predict the rate constant and equilibrium capacity with the effect of initial phenol concentrations. The rate of adsorption was found to be better correlation for the pseudo-second order kinetics compared to the first order kinetics.
    Matched MeSH terms: Waste Disposal, Fluid/methods*
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links