Displaying publications 61 - 73 of 73 in total

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  1. Physico-chemical removal of iron from semi-aerobic landfill leachate by limestone filter
    Aziz HA, Yusoff MS, Adlan MN, Adnan NH, Alias S
    Waste Manag, 2004;24(4):353-8.
    PMID: 15081062
    Limestone has been proven effective in removing metals from water and wastewater. A literature review indicated that limestone is capable of removing heavy metals such as Cu, Zn, Cd, Pb, Ni, Cr, Fe and Mn are through a batch process or by filtration technique. The removal capability is reported at up to 90%. However, to date most of the studies have been focused on synthetic wastewater. The present study attempts to investigate the suitability of limestone to attenuate total iron (Fe) from semi aerobic leachate at Pulau Burung Landfill Site in Penang, Malaysia. Iron was found in significant quantities at the landfill site. The study also aims to establish the Fe isotherm and breakthrough time of the proposed limestone filter for post-treatment to the migrating landfill leachate before its release to the environment. The Fe isotherms were established using a batch equilibrium test, while the breakthrough characteristics were determined using continuous flow permeating through a limestone column. The latter was used in order to simulate the continuous flow of leachate that would occur in the proposed limestone filter. The limestone media used in the experiment contain more than 90% CaCO3 with particle sizes ranging from 2 to 4 mm. Four filter columns (each 150 mm in diameter and 1000 mm depth) were installed at the landfill site. Metal loadings were kept below 0.5 kg /m3 day and the experiment was run continuously for 30 days. Initial results indicated that 90% of Fe can be removed from the leachate based on retention time of 57.8 min and surface loading of 12.2 m3/m2 day. For the batch study on the Fe isotherm, the results indicated that limestone is potentially useful as an alternative leachate treatment system at a relatively low cost.
    Matched MeSH terms: Refuse Disposal/methods*
  2. Fulltext Disposal practices of unused and expired pharmaceuticals among general public in Kabul
    Bashaar M, Thawani V, Hassali MA, Saleem F
    BMC Public Health, 2017 01 07;17(1):45.
    PMID: 28061902 DOI: 10.1186/s12889-016-3975-z
    BACKGROUND: Most of the medicine users remain unaware about the disposal of unused or expired medicines. The aim of this study was to know the disposal practices of unused and expired medicines among the general public in Kabul.

    METHODS: This was a descriptive, cross-sectional survey, conducted through face-to-face interviews using prevalidated structured questionnaire. Returned questionnaires were double-checked for accuracy. Statistical Package for Social Science (SPSS) version 23 was used for statistical analysis.

    RESULTS: Total of 301 valid questionnaires were returned with a response rate of 100% in which 73.4% men and 26.6% women participated. More than half of the respondents were university graduates. Interestingly, 83.4% of the interviewees purchased medicines on the prescription of which 47.2% were university graduates, while 14.6% purchased medicine over the counter. Among the respondents, 46.5/100 purchased antibiotics and the remaining purchased NSAIDs, anti-hypertensive and anti-diabetic medicines. Significantly, 97/100 checked the expiry date of medicine before buying. Majority (95.3%) of the respondents' stored medicines at home. 77.7% of the respondents discarded the expired medicines in household trash. Majority of respondents held government responsible for creation of awareness for proper medicine disposal. Almost entire sample (98%) felt that improper disposal of unused and expired medicines can affect the environment and health.

    CONCLUSION: Gaps exist in practices, therefore robust, safe and cost-effective pharmaceutical waste management program supported with media campaign is needed. Healthcare practitioners and community pharmacists should offer training to educate customers on standard medicine disposal practices.

    Matched MeSH terms: Refuse Disposal/methods*
  3. Toward sustainable solid waste minimization by manufacturing firms in Malaysia: strengths and weaknesses
    Mallak SK, Ishak MB, Mohamed AF, Iranmanesh M
    Environ Monit Assess, 2018 Sep 06;190(10):575.
    PMID: 30191321 DOI: 10.1007/s10661-018-6935-5
    Malaysia is facing an increasing trend in industrial solid waste generation due to industrial development. Thus, there is a paramount need in taking practical actions and measurements to move toward sustainable industrial waste management. The main aim of this study is to assess practicing solid waste minimization by manufacturing firms. Analysis showed that majority of firms (92%) dispose of their wastes rather than utilize other sustainable waste management options. Also, waste minimization methods such as segregation of wastes, on-site recycle and reuse, improved housekeeping, and equipment modification were found to have significant contribution to waste reduction (p 
    Matched MeSH terms: Refuse Disposal/methods*
  4. Study of contaminant transport at an open-tipping waste disposal site
    Ashraf MA, Yusoff I, Yusof M, Alias Y
    Environ Sci Pollut Res Int, 2013 Jul;20(7):4689-710.
    PMID: 23292199 DOI: 10.1007/s11356-012-1423-x
    Field and laboratory studies were conducted to estimate concentration of potential contaminants from landfill in the underlying groundwater, leachate, and surface water. Samples collected in the vicinity of the landfill were analyzed for physiochemical parameters, organic contaminants, and toxic heavy metals. Water quality results obtained were compared from published data and reports. The results indicate serious groundwater and surface water contamination in and around the waste disposal site. Analysis of the organic samples revealed that the site contains polychlorinated biphenyls and other organo-chlorine chemicals, principally chloro-benzenes. Although the amount of PCB concentration discovered was not extreme, their presence indicates a potentially serious environmental threat. Elevated concentrations of lead, copper, nickel, manganese, cadmium, and cobalt at the downgradient indicate that the contamination plume migrated further from the site, and the distribution of metals and metals containing wastes in the site is nonhomogeneous. These results clearly indicate that materials are poorly contained and are at risk of entering the environment. Therefore, full characterization of the dump contents and the integrity of the site are necessary to evaluate the scope of the problem and to identify suitable remediation options.
    Matched MeSH terms: Refuse Disposal/methods*
  5. Investigation of biogas production and its residue with fertilization effect from municipal waste
    Bee ST, Nithiyaa M, Sin LT, Tee TT, Rahmat AR
    Pak J Biol Sci, 2013 Oct 15;16(20):1104-12.
    PMID: 24506009
    This study was aimed to investigate the production of methane gas from three different types of food waste (vegetables waste, fruit waste and grain waste) using batch type anaerobic digestion method. The digestion process was conducted by using temperature range of 27 to 36 degrees C and pH 6.5 to 7.5 to yield an optimum condition for the digestion process. The digestion was continued for a period of two weeks with the aid of cow dung as the inoculums. It was found that the grain waste yielded the highest methane 2546 mL due to the high content of carbohydrate. At the mean time, the fruit waste produced the second highest methane gas with 2000 mL as well as the vegetable waste generated the lowest methane gas with volume of 1468 mL. The vegetable waste produced the lowest methane gas because the vegetables waste contains high fibres and cellulose walls but low in glucose amount. For the fertilization test, fruit waste demonstrated the best observation for the growth of plant due to high content of potassium and followed by vegetable waste. The least effective fertilizer was grain waste due to less content of nutrients essential for plants growth.
    Matched MeSH terms: Refuse Disposal/methods*
  6. Ammoniacal nitrogen and COD removal from semi-aerobic landfill leachate using a composite adsorbent: fixed bed column adsorption performance
    Halim AA, Aziz HA, Johari MA, Ariffin KS, Adlan MN
    J Hazard Mater, 2010 Mar 15;175(1-3):960-4.
    PMID: 19945216 DOI: 10.1016/j.jhazmat.2009.10.103
    The performance of a carbon-mineral composite adsorbent used in a fixed bed column for the removal of ammoniacal nitrogen and aggregate organic pollutant (COD), which are commonly found in landfill leachate, was evaluated. The breakthrough capacities for ammoniacal nitrogen and COD adsorption were 4.46 and 3.23 mg/g, respectively. Additionally, the optimum empty bed contact time (EBCT) was 75 min. The column efficiency for ammoniacal nitrogen and COD adsorption using fresh adsorbent was 86.4% and 92.6%, respectively, and these values increased to 90.0% and 93.7%, respectively, after the regeneration process.
    Matched MeSH terms: Refuse Disposal/methods*
  7. Application of the central composite design for condition optimization for semi-aerobic landfill leachate treatment using electrochemical oxidation
    Mohajeri S, Aziz HA, Isa MH, Zahed MA, Bashir MJ, Adlan MN
    Water Sci Technol, 2010;61(5):1257-66.
    PMID: 20220248 DOI: 10.2166/wst.2010.018
    In the present study, Electrochemical Oxidation was used to remove COD and color from semi-aerobic landfill leachate collected from Pulau Burung Landfill Site (PBLS), Penang, Malaysia. Experiments were conducted in a batch laboratory-scale system in the presence of NaCl as electrolyte and aluminum electrodes. Central composite design (CCD) under Response surface methodology (RSM) was applied to optimize the electrochemical oxidation process conditions using chemical oxygen demand (COD) and color removals as responses, and the electrolyte concentrations, current density and reaction time as control factors. Analysis of variance (ANOVA) showed good coefficient of determination (R(2)) values of >0.98, thus ensuring satisfactory fitting of the second-order regression model with the experimental data. In un-optimized condition, maximum removals for COD (48.77%) and color (58.21%) were achieved at current density 80 mA/cm(2), electrolyte concentration 3,000 mg/L and reaction time 240 min. While after optimization at current density 75 mA/cm(2), electrolyte concentration 2,000 mg/L and reaction time 218 min a maximum of 49.33 and 59.24% removals were observed for COD and color respectively.
    Matched MeSH terms: Refuse Disposal/methods*
  8. Landfill leachate treatment by an experimental subsurface flow constructed wetland in tropical climate countries
    Ujang Z, Soedjono E, Salim MR, Shutes RB
    Water Sci Technol, 2005;52(12):243-50.
    PMID: 16477992
    Municipal leachate was treated in an experimental unit of constructed wetlands of subsurface flow type. The parameters studied were organics (BOD and COD), solids and heavy metals (Zn, Ni, Cu, Cr and Pb). Using two types of emergent plants of Scirpus globulosus and Eriocaulon sexangulare, more than 80% removal was achieved for all the parameters. E. sexangulare removed organics and heavy metals better than Scirpus globulosus. A higher concentration of heavy metals in the influent did not change the removal efficiency.
    Matched MeSH terms: Refuse Disposal/methods*
  9. Bioelectricity generation in microbial fuel cell using natural microflora and isolated pure culture bacteria from anaerobic palm oil mill effluent sludge
    Nor MH, Mubarak MF, Elmi HSh, Ibrahim N, Wahab MF, Ibrahim Z
    Bioresour Technol, 2015 Aug;190:458-65.
    PMID: 25799955 DOI: 10.1016/j.biortech.2015.02.103
    A double-chambered membrane microbial fuel cell (MFC) was constructed to investigate the potential use of natural microflora anaerobic palm oil mill effluent (POME) sludge and pure culture bacteria isolated from anaerobic POME sludge as inoculum for electricity generation. Sterilized final discharge POME was used as the substrate with no addition of nutrients. MFC operation using natural microflora anaerobic POME sludge showed a maximum power density and current density of 85.11mW/m(2) and 91.12mA/m(2) respectively. Bacterial identification using 16S rRNA analysis of the pure culture isolated from the biofilm on the anode MFC was identified as Pseudomonas aeruginosa strain ZH1. The electricity generated in MFC using P. aeruginosa strain ZH1 showed maximum power density and current density of 451.26mW/m(2) and 654.90mA/m(2) respectively which were five times higher in power density and seven times higher in current density compared to that of MFC using anaerobic POME sludge.
    Matched MeSH terms: Refuse Disposal/methods
  10. Optimization and characterization of bio-oil produced by microwave assisted pyrolysis of oil palm shell waste biomass with microwave absorber
    Mushtaq F, Abdullah TA, Mat R, Ani FN
    Bioresour Technol, 2015 Aug;190:442-50.
    PMID: 25794811 DOI: 10.1016/j.biortech.2015.02.055
    In this study, solid oil palm shell (OPS) waste biomass was subjected to microwave pyrolysis conditions with uniformly distributed coconut activated carbon (CAC) microwave absorber. The effects of CAC loading (wt%), microwave power (W) and N2 flow rate (LPM) were investigated on heating profile, bio-oil yield and its composition. Response surface methodology based on central composite design was used to study the significance of process parameters on bio-oil yield. The coefficient of determination (R(2)) for the bio-oil yield is 0.89017 indicating 89.017% of data variability is accounted to the model. The largest effect on bio-oil yield is from linear and quadratic terms of N2 flow rate. The phenol content in bio-oil is 32.24-58.09% GC-MS area. The bio-oil also contain 1,1-dimethyl hydrazine of 10.54-21.20% GC-MS area. The presence of phenol and 1,1-dimethyl hydrazine implies that the microwave pyrolysis of OPS with carbon absorber has the potential to produce valuable fuel products.
    Matched MeSH terms: Refuse Disposal/methods*
  11. Physicochemical profile of microbial-assisted composting on empty fruit bunches of oil palm trees
    Lim LY, Bong CP, Chua LS, Lee CT
    Environ Sci Pollut Res Int, 2015 Dec;22(24):19814-22.
    PMID: 26286798 DOI: 10.1007/s11356-015-5156-5
    This study was carried out to investigate the physicochemical properties of compost from oil palm empty fruit bunches (EFB) inoculated with effective microorganisms (EM∙1™). The duration of microbial-assisted composting was shorter (∼7 days) than control samples (2 months) in a laboratory scale (2 kg) experiment. The temperature profile of EFB compost fluctuated between 26 and 52 °C without the presence of consistent thermophilic phase. The pH of compost changed from weak acidic (pH ∼5) to mild alkaline (pH ∼8) because of the formation of nitrogenous ions such as ammonium (NH4 (+)), nitrite (NO2 (-)), and nitrate (NO3 (-)) from organic substances during mineralization. The pH of the microbial-treated compost was less than 8.5 which is important to prevent the loss of nitrogen as ammonia gas in a strong alkaline condition. Similarly, carbon mineralization could be determined by measuring CO2 emission. The microbial-treated compost could maintain longer period (∼13 days) of high CO2 emission resulted from high microbial activity and reached the threshold value (120 mg CO2-C kg(-1) day(-1)) for compost maturity earlier (7 days). Microbial-treated compost slightly improved the content of minerals such as Mg, K, Ca, and B, as well as key metabolite, 5-aminolevulinic acid for plant growth at the maturity stage of compost. Graphical Abstract Microbial-assisted composting on empty fruit bunches.
    Matched MeSH terms: Refuse Disposal/methods*
  12. Sustainable reuse of rice residues as feedstocks in vermicomposting for organic fertilizer production
    Shak KP, Wu TY, Lim SL, Lee CA
    Environ Sci Pollut Res Int, 2014 Jan;21(2):1349-59.
    PMID: 23900949 DOI: 10.1007/s11356-013-1995-0
    Over the past decade, rice (Oryza sativa or Oryza glaberrima) cultivation has increased in many rice-growing countries due to the increasing export demand and population growth and led to a copious amount of rice residues, consisting mainly of rice straw (RS) and rice husk (RH), being generated during and after harvesting. In this study, Eudrilus eugeniae was used to decompose rice residues alone and rice residues amended with cow dung (CD) for bio-transformation of wastes into organic fertilizer. Generally, the final vermicomposts showed increases in macronutrients, namely, calcium (11.4-34.2%), magnesium (1.3-40.8%), phosphorus (1.2-57.3%), and potassium (1.1-345.6%) and a decrease in C/N ratio (26.8-80.0%) as well as increases in heavy metal content for iron (17-108%), copper (14-120%), and manganese (6-60%) after 60 days of vermicomposting. RS as a feedstock was observed to support healthier growth and reproduction of earthworms as compared to RH, with maximum adult worm biomass of 0.66 g/worm (RS) at 60 days, 31 cocoons (1RS:2CD), and 23 hatchlings (1RS:1CD). Vermicomposting of RS yielded better results than RH among all of the treatments investigated. RS that was mixed with two parts of CD (1RS:2CD) showed the best combination of nutrient results as well as the growth of E. eugeniae. In conclusion, vermicomposting could be used as a green technology to bio-convert rice residues into nutrient-rich organic fertilizers if the residues are mixed with CD in the appropriate ratio.
    Matched MeSH terms: Refuse Disposal/methods*
  13. Enhanced growth of lactobacilli in soymilk upon immobilization on agrowastes
    Teh SS, Ahmad R, Wan-Abdullah WN, Liong MT
    J Food Sci, 2010 Apr;75(3):M155-64.
    PMID: 20492305 DOI: 10.1111/j.1750-3841.2010.01538.x
    Cell immobilization is an alternative to microencapsulation for the maintenance of cells in a liquid medium. The objective of this study was to evaluate the effects of agrowastes from durian (Durio zibethinus), cempedak (Artocarpus champeden), and mangosteen (Garcinia mangostana) as immobilizers for lactobacilli grown in soymilk. Rinds from the agrowastes were separated from the skin, dried, and ground (150 microm) to form powders and used as immobilizers. Scanning electron microscopy revealed that lactobacilli cells were attached and bound to the surface of the immobilizers. Immobilized cells of Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733, and L. bulgaricus FTCC 0411 were inoculated into soymilk, stored at room temperature (25 degrees C) and growth properties were evaluated over 168 h. Soymilk inoculated with nonimmobilized cells was used as the control. Utilization of substrates, concentrations of lactic and acetic acids, and changes in pH were evaluated in soymilk over 186 h. Immobilized lactobacilli showed significantly better growth (P < 0.05) compared to the control, accompanied by higher production of lactic and acetic acids in soymilk. Soymilk containing immobilized cells showed greater reduction of soy sugars such as stachyose, raffinose, sucrose, fructose, and glucose compared to the control (P < 0.05).
    Matched MeSH terms: Refuse Disposal/methods
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