Displaying publications 1 - 20 of 60 in total

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  1. Anaerobic treatment of ultrasound pretreated palm oil mill effluent (POME): microbial diversity and enhancement of biogas production
    Isa MH, Bashir MJK, Wong LP
    Environ Sci Pollut Res Int, 2022 Jun;29(29):44779-44793.
    PMID: 35138542 DOI: 10.1007/s11356-022-19022-3
    In this study, palm oil mill effluent (POME) treated by ultrasonication at optimum conditions (sonication power: 0.88 W/mL, sonication duration: 16.2 min and total solids: 6% w/v) obtained from a previous study was anaerobically digested at different hydraulic retention times (HRTs). The reactor biomass was subjected to metagenomic study to investigate the impact on the anaerobic community dynamics. Experiments were conducted in two 5 L continuously stirred fill-and-draw reactors R1 and R2 operated at 30 ± 2 °C. Reactor R1 serving as control reactor was fed with unsonicated POME with HRT of 15 and 20 days (R1-15 and R1-20), whereas reactor R2 was fed with sonicated POME with the same HRTs (R2-15 and R2-20). The most distinct archaea community shift was observed among Methanosaeta (R1-15: 26.6%, R2-15: 34.4%) and Methanobacterium (R1-15: 7.4%, R2-15: 3.2%). The genus Methanosaeta was identified from all reactors with the highest abundance from the reactors R2. Mean daily biogas production was 6.79 L from R2-15 and 4.5 L from R1-15, with relative methane gas abundance of 85% and 73%, respectively. Knowledge of anaerobic community dynamics allows process optimization for maximum biogas production.
    Matched MeSH terms: Sewage/microbiology
  2. Fulltext Genome-Centric Metagenomic Insights into the Impact of Alkaline/Acid and Thermal Sludge Pretreatment on the Microbiome in Digestion Sludge
    Liang Z, Shi J, Wang C, Li J, Liang D, Yong EL, et al.
    Appl Environ Microbiol, 2020 11 10;86(23).
    PMID: 32948522 DOI: 10.1128/AEM.01920-20
    Pretreatment of waste-activated sludge (WAS) is an effective way to destabilize sludge floc structure and release organic matter for improving sludge digestion efficiency. Nonetheless, information on the impact of WAS pretreatment on digestion sludge microbiomes, as well as mechanistic insights into how sludge pretreatment improves digestion performance, remains elusive. In this study, a genome-centric metagenomic approach was employed to investigate the digestion sludge microbiome in four sludge digesters with different types of feeding sludge: WAS pretreated with 0.25 mol/liter alkaline/acid (APAD), WAS pretreated with 0.8 mol/liter alkaline/acid (HS-APAD), thermally pretreated WAS (thermal-AD), and fresh WAS (control-AD). We retrieved 254 metagenome-assembled genomes (MAGs) to identify the key functional populations involved in the methanogenic digestion process. These MAGs span 28 phyla, including 69 yet-to-be-cultivated lineages, and 30 novel lineages were characterized with metabolic potential associated with hydrolysis and fermentation. Interestingly, functional populations involving carbohydrate digestion were enriched in APAD and HS-APAD, while lineages related to protein and lipid fermentation were enriched in thermal-AD, corroborating the idea that different substrates are released from alkaline/acid and thermal pretreatments. Among the major functional populations (i.e., fermenters, syntrophic acetogens, and methanogens), significant correlations between genome sizes and abundance of the fermenters were observed, particularly in APAD and HS-APAD, which had improved digestion performance.IMPORTANCE Wastewater treatment generates large amounts of waste-activated sludge (WAS), which consists mainly of recalcitrant microbial cells and particulate organic matter. Though WAS pretreatment is an effective way to release sludge organic matter for subsequent digestion, detailed information on the impact of the sludge pretreatment on the digestion sludge microbiome remains scarce. Our study provides unprecedented genome-centric metagenomic insights into how WAS pretreatments change the digestion sludge microbiomes, as well as their metabolic networks. Moreover, digestion sludge microbiomes could be a unique source for exploring microbial dark matter. These results may inform future optimization of methanogenic sludge digestion and resource recovery.
    Matched MeSH terms: Sewage/microbiology*
  3. An efficient oxic-anoxic process for treating low COD/N tropical wastewater: Startup, optimization and nitrifying community structure
    How SW, Nittami T, Ngoh GC, Curtis TP, Chua ASM
    Chemosphere, 2020 Nov;259:127444.
    PMID: 32640378 DOI: 10.1016/j.chemosphere.2020.127444
    In this study, we assessed and optimized a low-dissolved-oxygen oxic-anoxic (low-DO OA) process to achieve a low-cost and sustainable solution for wastewater treatment systems in the developing tropical countries treating low chemical oxygen demand-to-nitrogen ratio (COD/N) wastewater. The low-DO OA process attained complete ammonia removal and the effluent nitrate nitrogen (NO3-N) was below 0.3 mg/L. The recommended hydraulic retention time and sludge retention time (SRT) were 16 h and 20 days, respectively. The 16S rRNA sequencing data revealed that long SRT (20 days) encouraged the growth of nitrite-oxidizing bacteria (NOB) affiliated with "Candidatus Nitrospira defluvii". Comammox made up 10-20% of the Nitrospira community. NOB and comammox related to Nitrospira were enriched at long SRT (20 days) to achieve good low-DO nitrification performance. The low-DO OA process was efficient and has simpler design than conventional processes, which are keys for sustainable wastewater treatment systems in the developing countries treating low COD/N wastewater.
    Matched MeSH terms: Sewage/microbiology
  4. Fulltext Simultaneous biological nitrification and desulfurization treatment of ammonium and sulfide-rich wastewater: Effectiveness of a sequential batch operation
    Sekine M, Akizuki S, Kishi M, Kurosawa N, Toda T
    Chemosphere, 2020 Apr;244:125381.
    PMID: 31805460 DOI: 10.1016/j.chemosphere.2019.125381
    Sulfide inhibition to nitrifying bacteria has prevented the integration of digestate nitrification and biogas desulfurization to simplify anaerobic digestion systems. In this study, liquid digestate with NaHS solution was treated using nitrifying sludge in a sequential-batch reactor with a long fill period, with an ammonium loading rate of 293 mg-N L-1 d-1 and a stepwise increase in the sulfide loading rate from 0 to 32, 64, 128, and 256 mg-S L-1 d-1. Batch bioassays and microbial community analysis were also conducted with reactor sludge under each sulfide loading rate to quantify the microbial acclimatization to sulfide. In the reactor, sulfide was completely removed. Complete nitrification was maintained up to a sulfide load of 128 mg-S L-1 d-1, which is higher than that in previous reports and sufficient for biogas treatment. In the batch bioassays, the sulfide tolerance of NH4+ oxidizing activity (the 50% inhibitory sulfide concentration) increased fourfold over time with the compositional shift of nitrifying bacteria to Nitrosomonas nitrosa and Nitrobacter spp. However, the sulfur removal rate of the sludge slightly decreased, although the abundance of the sulfur-oxidizing bacteria Hyphomicrobium increased by 30%. Therefore, nitrifying sludge was probably acclimatized to sulfide not by the increasing sulfide removal rate but rather by the increasing nitrifying bacteria, which have high sulfide tolerance. Successful simultaneous nitrification and desulfurization were achieved using a sequential-batch reactor with a long fill period, which was effective in facilitating the present acclimatization.
    Matched MeSH terms: Sewage/microbiology
  5. Impacts of morphological-controlled ZnO nanoarchitectures on aerobic microbial communities during real wastewater treatment in an aerobic-photocatalytic system
    Chang JS, Chong MN, Poh PE, Ocon JD, Md Zoqratt MZH, Lee SM
    Environ Pollut, 2020 Apr;259:113867.
    PMID: 31896479 DOI: 10.1016/j.envpol.2019.113867
    This study aimed to evaluate the impacts of morphological-controlled ZnO nanoarchitectures on aerobic microbial communities during real wastewater treatment in an aerobic-photocatalytic system. Results showed that the antibacterial properties of ZnO nanoarchitectures were significantly more overwhelming than their photocatalytic properties. The inhibition of microbial activities in activated sludge by ZnO nanoarchitectures entailed an adverse effect on wastewater treatment efficiency. Subsequently, the 16S sequencing analysis were conducted to examine the impacts of ZnO nanoarchitectures on aerobic microbial communities, and found the significantly lower microbial diversity and species richness in activated sludge treated with 1D-ZnO nanorods as compared to other ZnO nanoarchitectures. Additionally, 1D-ZnO nanorods reduced the highest proportion of Proteobacteria phylum in activated sludge due to its higher proportion of active polar surfaces that facilitates Zn2+ ions dissolution. Pearson correlation coefficients showed that the experimental data obtained from COD removal efficiency and bacterial log reduction were statistically significant (p-value 
    Matched MeSH terms: Sewage/microbiology
  6. Could bacteriophages isolated from the sewage be the solution to methicillin-resistant Staphylococcus aureus?
    Tan CS, Aqiludeen NA, Tan R, Gowbei A, Mijen AB, Santhana Raj L, et al.
    Med J Malaysia, 2020 03;75(2):110-116.
    PMID: 32281590
    INTRODUCTIONS: The emergence of multidrug-resistant bacteria such as Methicillin-Resistant Staphylococcus aureus (MRSA) complicates the treatment of the simplest infection. Although glycopeptides such as vancomycin still proves to be effective in treating MRSA infections, the emergence of vancomycin-resistant strains limits the long term use of this antibiotic. Bacteriophages are ubiquitous bacterial viruses which is capable of infecting and killing bacteria including its antibiotic-resistant strains. Bactericidal bacteriophages use mechanisms that is distinct from antibiotics and is not affected by the antibioticresistant phenotypes.

    OBJECTIVES: The study was undertaken to evaluate the possibility to isolate bacteriolytic bacteriophages against S.aureus from raw sewage water and examine their efficacy as antimicrobial agents in vitro.

    METHODS: Bacteriophages were isolated from the raw sewage using the agar overlay method. Isolated bacteriophages were plaque purified to obtain homogenous bacteriophage isolates. The host range of the bacteriophages was determined using the spot test assay against the 25 MRSA and 36 MSSA isolates obtained from the Sarawak General Hospital. Staphylococcus saprophyticus, Staphylococcus sciuri and Staphylococcus xylosus were included as non-SA controls. The identity of the bacteriophages was identified via Transmission Electron Microscopy and genomic size analysis. Their stability at different pH and temperature were elucidated.

    RESULTS: A total of 10 lytic bacteriophages infecting S.aureus were isolated and two of them namely ΦNUSA-1 and ΦNUSA-10 from the family of Myoviridae and Siphoviridae respectively exhibited exceptionally broad host range against >80% of MRSA and MSSA tested. Both bacteriophages were specific to S.aureus and stable at both physiologic pH and temperature.

    CONCLUSION: This study demonstrated the abundance of S.aureus specific bacteriophages in raw sewage. Their high virulence against both MSSA and MRSA is an excellent antimicrobial characteristic which can be exploited for bacteriophage therapy against MRSA.

    Matched MeSH terms: Sewage/microbiology*
  7. Fulltext Performance of wild-Serbian Ganoderma lucidum mycelium in treating synthetic sewage loading using batch bioreactor
    Mohd Hanafiah Z, Wan Mohtar WHM, Abu Hasan H, Jensen HS, Klaus A, Wan-Mohtar WAAQI
    Sci Rep, 2019 11 06;9(1):16109.
    PMID: 31695087 DOI: 10.1038/s41598-019-52493-y
    The fluctuation of domestic wastewater characteristic inhibits the current conventional microbial-based treatment. The bioremediation fungi has received attention and reported to be an effective alternative to treat industrial wastewater. Similar efficient performance is envisaged for domestic wastewater whereby assessed performance of fungi for varying carbon-to-nitrogen ratios in domestic wastewater is crucial. Thus, the performance of pre-grown wild-Serbian Ganoderma lucidum mycelial pellets (GLMPs) was evaluated on four different synthetic domestic wastewaters under different conditions of initial pH (pH 4, 5, and 7) and chemical oxygen demand (COD) to nitrogen (COD/N) ratio of 3.6:1, 7.1:1, 14.2:1, and 17.8:1 (C3.6N1, C7.1N1, C14.2N1, and C17.8N1). The COD/N ratios with a constant concentration of ammonia-nitrogen (NH3-N) were chosen on the basis of the urban domestic wastewater characteristics sampled at the inlet basin of a sewage treatment plant (STP). The parameters of pH, COD, and NH3-N were measured periodically during the experiment. The wild-Serbian GLMPs efficiently removed the pollutants from the synthetic sewage. The COD/N ratio of C17.8N1 wastewater had the best COD and NH3-N removal, as compared to the lower COD/N ratio, and the shortest treatment time was obtained in an acidic environment at pH 4. The highest percentage for COD and NH3-N removal achieved was 96.0% and 93.2%, respectively. The results proved that the mycelium of GLMP has high potential in treating domestic wastewater, particularly at high organic content as a naturally sustainable bioremediation system.
    Matched MeSH terms: Sewage/microbiology*
  8. Fulltext Dynamics of Microbial Populations Responsible for Biodegradation during the Full-Scale Treatment of Palm Oil Mill Effluent
    Mohd-Nor D, Ramli N, Sharuddin SS, Hassan MA, Mustapha NA, Ariffin H, et al.
    Microbes Environ, 2019 Jun 27;34(2):121-128.
    PMID: 30905894 DOI: 10.1264/jsme2.ME18104
    Despite efforts to address the composition of the microbial community during the anaerobic treatment of palm oil mill effluent (POME), its composition in relation to biodegradation in the full-scale treatment system has not yet been extensively examined. Therefore, a thorough analysis of bacterial and archaeal communities was performed in the present study using MiSeq sequencing at the different stages of the POME treatment, which comprised anaerobic as well as facultative anaerobic and aerobic processes, including the mixed raw effluent (MRE), mixing pond, holding tank, and final discharge phases. Based on the results obtained, the following biodegradation processes were suggested to occur at the different treatment stages: (1) Lactobacillaceae (35.9%) dominated the first stage, which contributed to high lactic acid production; (2) the higher population of Clostridiaceae in the mixing pond (47.7%) and Prevotellaceae in the holding tank (49.7%) promoted acetic acid production; (3) the aceticlastic methanogen Methanosaetaceae (0.6-0.8%) played a role in acetic acid degradation in the open digester and closed reactor for methane generation; (4) Syntrophomonas (21.5-29.2%) appeared to be involved in the degradation of fatty acids and acetic acid by syntrophic cooperation with the hydrogenotrophic methanogen, Methanobacteriaceae (0.6-1.3%); and (5) the phenols and alcohols detected in the early phases, but not in the final discharge phase, indicated the successful degradation of lignocellulosic materials. The present results contribute to a better understanding of the biodegradation mechanisms involved in the different stages of the full-scale treatment of POME.
    Matched MeSH terms: Sewage/microbiology*
  9. Auto-flocculation through cultivation of Chlorella vulgaris in seafood wastewater discharge: Influence of culture conditions on microalgae growth and nutrient removal
    Nguyen TDP, Tran TNT, Le TVA, Nguyen Phan TX, Show PL, Chia SR
    J Biosci Bioeng, 2019 Apr;127(4):492-498.
    PMID: 30416001 DOI: 10.1016/j.jbiosc.2018.09.004
    Nowadays, the pretreatment of wastewater prior to discharge is very important in various industries as the wastewater without any treatment contains high organic pollution loads that would pollute the receiving waterbody and potentially cause eutrophication and oxygen depletion to aquatic life. The reuse of seafood wastewater discharge in microalgae cultivation offers beneficial purposes such as reduced processing cost for wastewater treatment, replenishing ground water basin as well as financial savings for microalgae cultivation. In this paper, the cultivation of Chlorella vulgaris with an initial concentration of 0.01 ± 0.001 g⋅L-1 using seafood sewage discharge under sunlight and fluorescent illumination was investigated in laboratory-scale without adjusting mineral nutrients and pH. The ability of nutrient removal under different lighting conditions, the metabolism of C. vulgaris and new medium as well as the occurrence of auto-flocculation of microalgae biomass were evaluated for 14 days. The results showed that different illumination sources did not influence the microalgae growth, chemical oxygen demand (COD) and biochemical oxygen demand (BOD) significantly. However, the total nitrogen (total-N) and total phosphorus (total-P) contents of microalgae were sensitive to the illumination mode. The amount of COD, BOD, total-N and total-P were decreased by 88%, 81%, 95%, and 83% under sunlight mode and 81%, 74%, 79%, and 72% under fluorescent illumination, respectively. Furthermore, microalgae were auto-flocculated at the final days of cultivation with maximum biomass concentration of 0.49 ± 0.01 g⋅L-1, and the pH value had increased to pH 9.8 ± 0.1 under sunlight illumination.
    Matched MeSH terms: Sewage/microbiology
  10. Fulltext Global monitoring of antimicrobial resistance based on metagenomics analyses of urban sewage
    Hendriksen RS, Munk P, Njage P, van Bunnik B, McNally L, Lukjancenko O, et al.
    Nat Commun, 2019 03 08;10(1):1124.
    PMID: 30850636 DOI: 10.1038/s41467-019-08853-3
    Antimicrobial resistance (AMR) is a serious threat to global public health, but obtaining representative data on AMR for healthy human populations is difficult. Here, we use metagenomic analysis of untreated sewage to characterize the bacterial resistome from 79 sites in 60 countries. We find systematic differences in abundance and diversity of AMR genes between Europe/North-America/Oceania and Africa/Asia/South-America. Antimicrobial use data and bacterial taxonomy only explains a minor part of the AMR variation that we observe. We find no evidence for cross-selection between antimicrobial classes, or for effect of air travel between sites. However, AMR gene abundance strongly correlates with socio-economic, health and environmental factors, which we use to predict AMR gene abundances in all countries in the world. Our findings suggest that global AMR gene diversity and abundance vary by region, and that improving sanitation and health could potentially limit the global burden of AMR. We propose metagenomic analysis of sewage as an ethically acceptable and economically feasible approach for continuous global surveillance and prediction of AMR.
    Matched MeSH terms: Sewage/microbiology*
  11. Nitrite pre-treatment of dewatered sludge for microbial fuel cell application
    Ruslan AR, Vadivelu VM
    J Environ Sci (China), 2019 Mar;77:148-155.
    PMID: 30573078 DOI: 10.1016/j.jes.2018.06.023
    The effect of pre-treatment of dewatered sludge using different nitrite concentrations and pH for microbial fuel cell (MFC) application was investigated. The results show that the addition of nitrite was feasible to increase the solubilization rate of the sludge and may reduce mass transfer limitation at the anode. This helped the MFC to reach higher voltage and to generate more power. The higher free nitrous acid (FNA) concentration under the acidic condition helped to increase sludge solubilization. However, under an alkaline condition, during which the FNA concentration was relatively low, the solubilization of the sludge was higher. The highest voltage and power density produced was 390 mV and 153 mW/m2, respectively, with the addition of nitrite at 100 mg-N/L and pH 9. Furthermore, it was found that elevated levels of FNA could inhibit electrogenic bacteria thus reducing power generation.
    Matched MeSH terms: Sewage/microbiology*
  12. Production of bio-hydrogen from dairy wastewater using pretreated landfill leachate sludge as an inoculum
    Wong YM, Show PL, Wu TY, Leong HY, Ibrahim S, Juan JC
    J Biosci Bioeng, 2019 Feb;127(2):150-159.
    PMID: 30224189 DOI: 10.1016/j.jbiosc.2018.07.012
    Bio-hydrogen production from wastewater using sludge as inoculum is a sustainable approach for energy production. This study investigated the influence of initial pH and temperature on bio-hydrogen production from dairy wastewater using pretreated landfill leachate sludge (LLS) as an inoculum. The maximum yield of 113.2 ± 2.9 mmol H2/g chemical oxygen demand (COD) (12.8 ± 0.3 mmol H2/g carbohydrates) was obtained at initial pH 6 and 37 °C. The main products of volatile fatty acids were acetate and butyrate with the ratio of acetate:butyrate was 0.4. At optimum condition, Gibb's free energy was estimated at -40 kJ/mol, whereas the activation enthalpy and entropy were 65 kJ/mol and 0.128 kJ/mol/l, respectively. These thermodynamic quantities suggest that bio-hydrogen production from dairy wastewater using pretreated LLS as inoculum was effective and efficient. In addition, genomic and bioinformatics analyses were performed in this study.
    Matched MeSH terms: Sewage/microbiology*
  13. Low-dissolved-oxygen nitrification in tropical sewage: an investigation on potential, performance and functional microbial community
    How SW, Lim SY, Lim PB, Aris AM, Ngoh GC, Curtis TP, et al.
    Water Sci Technol, 2018 May;77(9-10):2274-2283.
    PMID: 29757179 DOI: 10.2166/wst.2018.143
    Intensive aeration for nitrification is a major energy consumer in sewage treatment plants (STPs). Low-dissolved-oxygen (low-DO) nitrification has the potential to lower the aeration demand. However, the applicability of low-DO nitrification in the tropical climate is not well-understood. In this study, the potential of low-DO nitrification in tropical setting was first examined using batch kinetic experiments. Subsequently, the performance of low-DO nitrification was investigated in a laboratory-scale sequential batch reactor (SBR) for 42 days using real tropical sewage. The batch kinetic experiments showed that the seed sludge has a relatively high oxygen affinity. Thus, the rate of nitrification was not significantly reduced at low DO concentrations (0.5 mg/L). During the operation of the low-DO nitrification SBR, 90% of NH4-N was removed. The active low-DO nitrification was mainly attributed to the limited biodegradable organics in the sewage. Fluorescence in-situ hybridisation and 16S rRNA amplicon sequencing revealed the nitrifiers were related to Nitrospira genus and Nitrosomonadaceae family. Phylogenetic analysis suggests 47% of the operational taxonomic units in Nitrospira genus are closely related to a comammox bacteria. This study has demonstrated active low-DO nitrification in tropical setting, which is a more sustainable process that could significantly reduce the energy footprint of STPs.
    Matched MeSH terms: Sewage/microbiology*
  14. Evaluating new bio-hydrogen producers: Clostridium perfringens strain JJC, Clostridium bifermentans strain WYM and Clostridium sp. strain Ade.TY
    Wong YM, Wu TY, Ling TC, Show PL, Lee SY, Chang JS, et al.
    J Biosci Bioeng, 2018 May;125(5):590-598.
    PMID: 29352712 DOI: 10.1016/j.jbiosc.2017.12.012
    Three newly discovered H2 producing bacteria namely Clostridium perfringens strain JJC, Clostridium bifermentans strain WYM and Clostridium sp. strain Ade.TY originated from landfill leachate sludge have demonstrated highly efficient H2 production. The maximum H2 production attained from these isolates are in the descending order of strain C. perfringens strain JJC > C. bifermentans strain WYM > Clostridium sp. strain Ade.TY with yield of 4.68 ± 0.12, 3.29 ± 0.11, and 2.87 ± 0.10 mol H2/mol glucose, respectively. The result has broken the conventional theoretical yield of 4 mol H2/mol glucose. These isolates were thermodynamically favourable with Gibbs free energy between -33 and -35 kJ/mol (under process conditions: pH 6, 37 °C and 5 g/L glucose). All three isolates favour butyrate pathway for H2 production with the ratio of acetate and butyrate of 0.77, 0.65 and 0.80 for strain JJC, WYM and Ade.TY, respectively. This study reported provides a new insight on the potential of unique bacteria in H2 production.
    Matched MeSH terms: Sewage/microbiology
  15. Enhancement of anaerobic digestibility of waste activated sludge using photo-Fenton pretreatment
    Heng GC, Isa MH, Lim JW, Ho YC, Zinatizadeh AAL
    Environ Sci Pollut Res Int, 2017 Dec;24(35):27113-27124.
    PMID: 28963706 DOI: 10.1007/s11356-017-0287-5
    Biological treatments, such as activated sludge process, are common methods to treat municipal and industrial wastewaters. However, they produce huge amounts of waste activated sludge (WAS). The excess sludge treatment and disposal are a challenge for wastewater treatment plants due to economic, environmental, and regulatory factors. In this study, photo-Fenton pretreatment (oxidation using hydrogen peroxide and iron catalyst aided with UV light) was optimized using response surface methodology (RSM) and central composite design (CCD) to determine the effects of three operating parameters (H2O2 dosage, H2O2/Fe2+ molar ratio, and irradiation time) on disintegration and dewaterability of WAS. MLVSS removal, capillary suction time (CST) reduction, sCOD, and EPS were obtained as 70%, 25%, 12,000 mg/L, and 500 mg/L, respectively, at the optimal conditions, i.e., 725 g H2O2/kg TS, H2O2/Fe2+ molar ratio 80, and irradiation time 40 min. Two batch-fed completely mixed mesophilic anaerobic digesters were then operated at 15-day solid retention time (SRT) and 37 ± 0.5 °C to compare the digestibility of untreated and photo-Fenton pretreated sludge in terms of volatile solids (VS) reduction, COD removal, and biogas production at steady-state operations. Photo-Fenton pretreatment followed by anaerobic digestion of WAS was very effective and yielded 75.7% total VS reduction, 81.5% COD removal, and 0.29-0.31 m3/kg VSfed·d biogas production rate, compared to 40.7% total VS solid reduction, 54.7% COD removal, and 0.12-0.17 m3/kg VSfed·d biogas production rate for control. Thus, photo-Fenton can be a useful pretreatment step in sludge management.
    Matched MeSH terms: Sewage/microbiology
  16. Novel multifunctional plant growth-promoting bacteria in co-compost of palm oil industry waste
    Chin CFS, Furuya Y, Zainudin MHM, Ramli N, Hassan MA, Tashiro Y, et al.
    J Biosci Bioeng, 2017 Nov;124(5):506-513.
    PMID: 28736147 DOI: 10.1016/j.jbiosc.2017.05.016
    Previously, a unique co-compost produced by composting empty fruit bunch with anaerobic sludge from palm oil mill effluent, which contributed to establishing a zero-emission industry in Malaysia. Little was known about the bacterial functions during the composting process and fertilization capacity of this co-compost. We isolated 100 strains from the co-compost on 7 types of enumeration media and screened 25 strains using in vitro tests for 12 traits, grouping them according to three functions: plant growth promoting (fixation of nitrogen; solubilization of phosphorus, potassium, and silicate; production of 3-indoleacetic acid, ammonia, and siderophore), biocontrolling (production of chitinase and anti-Ganoderma activity), and composting (degradation of lignin, xylan, and cellulose). Using 16S rRNA gene sequence analysis, 25 strains with strong or multi-functional traits were found belong to the genera Bacillus, Paenibacillus, Citrobacter, Enterobacter, and Kosakonia. Furthermore, several strains of Citrobacter sedlakii exhibited a plant growth-stimulation in vivo komatsuna plant cultivation test. In addition, we isolated several multifunctional strains; Bacillus tequilensis CE4 (biocontrolling and composting), Enterobacter cloacae subsp. dissolvens B3 (plant growth promoting and biocontrolling), and C. sedlakii CESi7 (plant growth promoting and composting). Some bacteria in the co-compost play significant roles during the composting process and plant cultivation after fertilization, and some multifunctional strains have potential for use in accelerating the biodegradation of lignocellulosic biomass, protecting against Ganoderma boninense infection, and increasing the yield of palm oil.
    Matched MeSH terms: Sewage/microbiology
  17. Bacterial community shift for monitoring the co-composting of oil palm empty fruit bunch and palm oil mill effluent anaerobic sludge
    Zainudin MHM, Ramli N, Hassan MA, Shirai Y, Tashiro K, Sakai K, et al.
    J Ind Microbiol Biotechnol, 2017 06;44(6):869-877.
    PMID: 28197796 DOI: 10.1007/s10295-017-1916-1
    A recently developed rapid co-composting of oil palm empty fruit bunch (OPEFB) and palm oil mill effluent (POME) anaerobic sludge is beginning to attract attention from the palm oil industry in managing the disposal of these wastes. However, a deeper understanding of microbial diversity is required for the sustainable practice of the co-compositing process. In this study, an in-depth assessment of bacterial community succession at different stages of the pilot scale co-composting of OPEFB-POME anaerobic sludge was performed using 454-pyrosequencing, which was then correlated with the changes of physicochemical properties including temperature, oxygen level and moisture content. Approximately 58,122 of 16S rRNA gene amplicons with more than 500 operational taxonomy units (OTUs) were obtained. Alpha diversity and principal component analysis (PCoA) indicated that bacterial diversity and distributions were most influenced by the physicochemical properties of the co-composting stages, which showed remarkable shifts of dominant species throughout the process. Species related to Devosia yakushimensis and Desemzia incerta are shown to emerge as dominant bacteria in the thermophilic stage, while Planococcus rifietoensis correlated best with the later stage of co-composting. This study proved the bacterial community shifts in the co-composting stages corresponded with the changes of the physicochemical properties, and may, therefore, be useful in monitoring the progress of co-composting and compost maturity.
    Matched MeSH terms: Sewage/microbiology*
  18. Effect of biological and coagulation pre-treatments to control organic and biofouling potential components of ultrafiltration membrane in the treatment of lake water
    Pramanik BK, Kajol A, Suja F, Md Zain S
    Environ Technol, 2017 Mar;38(5):579-587.
    PMID: 27315513 DOI: 10.1080/09593330.2016.1202330
    Biological aerated filter (BAF), sand filtration (SF), alum and Moringa oleifera coagulation were investigated as a pre-treatment for reducing the organic and biofouling potential component of an ultrafiltration (UF) membrane in the treatment of lake water. The carbohydrate content was mainly responsible for reversible fouling of the UF membrane compared to protein or dissolved organic carbon (DOC) content. All pre-treatment could effectively reduce these contents and led to improve the UF filterability. Both BAF and SF markedly led to improvement in flux than coagulation processes, and alum gave greater flux than M. oleifera. This was attributed to the effective removal and/or breakdown of high molecular weight (MW) organics by biofilters. BAF led to greater improvement in flux than SF, due to greater breakdown of high MW organics, and this was also confirmed by the attenuated total reflection-Fourier transform infrared spectroscopy analysis. Coagulation processes were ineffective in removing biofouling potential components, whereas both biofilters were very effective as shown by the reduction of low MW organics, biodegradable dissolved organic carbon and assimilable organic carbon contents. This study demonstrated the potential of biological pre-treatments for reducing organic and biofouling potential component and thus improving flux for the UF of lake water treatment.
    Matched MeSH terms: Sewage/microbiology
  19. 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: Sewage/microbiology*
  20. Fulltext Anaerobic Treatment of Palm Oil Mill Effluent in Pilot-Scale Anaerobic EGSB Reactor
    Wang J, Mahmood Q, Qiu JP, Li YS, Chang YS, Li XD
    Biomed Res Int, 2015;2015:398028.
    PMID: 26167485 DOI: 10.1155/2015/398028
    Large volumes of untreated palm oil mill effluent (POME) pose threat to aquatic environment due to the presence of very high organic content. The present investigation involved two pilot-scale anaerobic expanded granular sludge bed (EGSB) reactors, continuously operated for 1 year to treat POME. Setting HRT at 9.8 d, the anaerobic EGSB reactors reduced COD from 71179 mg/L to 12341 mg/L and recycled half of sludge by a dissolved air flotation (DAF). The average effluent COD was 3587 mg/L with the consistent COD removal efficiency of 94.89%. Adding cationic polymer (PAM) dose of 30 mg/L to DAF unit and recycling its half of sludge caused granulation of anaerobic sludge. Bacilli and small coccid bacteria were the dominant microbial species of the reactor. The reactor produced 27.65 m(3) of biogas per m(3) of POME which was utilized for electricity generation.
    Matched MeSH terms: Sewage/microbiology*
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