Displaying publications 221 - 240 of 3986 in total

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  1. Mechanistic insight of α-mangostin encapsulation in 2-hydroxypropyl-β-cyclodextrin for solubility enhancement
    Muchtaridi M, Triwahyuningtyas D, Muhammad Fakih T, Megantara S, Choi SB
    J Biomol Struct Dyn, 2024 Apr;42(6):3223-3232.
    PMID: 37286382 DOI: 10.1080/07391102.2023.2214237
    α-Mangostin is the most abundant compound contained in the mangostin (Garcinia mangostana L.) plant which have been developed and proven to have many promising pharmacological effects. However, the low water solubility of α-mangostin causes limitations in its development in clinical purpose. To increase the solubility of a compound, a method currently being developed is to make drug inclusion complexes using cyclodextrins. This research aimed to use in silico techniques namely molecular docking study and molecular dynamics simulation to explore the molecular mechanism and stability of the encapsulation of α-mangostin using cyclodextrins. Two types of cyclodextrins were used including β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin docked against α-mangostin. From the molecular docking results, it shows that the α-mangostin complex with 2-hydroxypropyl-β-cyclodextrin provides the lowest binding energy value of -7.99 Kcal/mol compared to β-cyclodextrin value of -6.14 Kcal/mol. The α-mangostin complex with 2-hydroxypropyl-β-cyclodextrin also showed good stability based on molecular dynamics simulation during 100 ns. From molecular motion, RDF, Rg, SASA, density, total energy analyzes, this complex shows increased solubility in water and provided good stability. This indicates that the encapsulation of α-mangostin with 2-hydroxypropyl-β-cyclodextrin can increase the solubility of the α-mangostin.Communicated by Ramaswamy H. Sarma.
    Matched MeSH terms: Water/chemistry
  2. Fulltext Utilization of microbial fuel cells as a dual approach for landfill leachate treatment and power production: a review
    Ishaq A, Said MIM, Azman SB, Dandajeh AA, Lemar GS, Jagun ZT
    Environ Sci Pollut Res Int, 2024 Jun;31(29):41683-41733.
    PMID: 38012494 DOI: 10.1007/s11356-023-30841-w
    Landfill leachate, which is a complicated organic sewage water, presents substantial dangers to human health and the environment if not properly handled. Electrochemical technology has arisen as a promising strategy for effectively mitigating contaminants in landfill leachate. In this comprehensive review, we explore various theoretical and practical aspects of methods for treating landfill leachate. This exploration includes examining their performance, mechanisms, applications, associated challenges, existing issues, and potential strategies for enhancement, particularly in terms of cost-effectiveness. In addition, this critique provides a comparative investigation between these treatment approaches and the utilization of diverse kinds of microbial fuel cells (MFCs) in terms of their effectiveness in treating landfill leachate and generating power. The examination of these technologies also extends to their use in diverse global contexts, providing insights into operational parameters and regional variations. This extensive assessment serves the primary goal of assisting researchers in understanding the optimal methods for treating landfill leachate and comparing them to different types of MFCs. It offers a valuable resource for the large-scale design and implementation of processes that ensure both the safe treatment of landfill leachate and the generation of electricity. The review not only provides an overview of the current state of landfill leachate treatment but also identifies key challenges and sets the stage for future research directions, ultimately contributing to more sustainable and effective solutions in the management of this critical environmental issue.
    Matched MeSH terms: Water Pollutants, Chemical*
  3. Fulltext Assessment on urban lakes along the coastal region of Miri, NW Borneo: implication for hydrochemistry, water quality, and pollution risk
    Nyambar INA, Mohan Viswanathan P
    Environ Sci Pollut Res Int, 2024 Jun;31(29):41306-41328.
    PMID: 36650369 DOI: 10.1007/s11356-023-25172-9
    The main purpose of this study is to assess the urban lake water quality along the coastal region of Miri City, Sarawak, East Malaysia. This study concentrates on the hydrochemical characteristics and the mechanisms controlling the suitability of the lakes for domestic, irrigation, and industrial purposes. A total of 15 lake water samples were collected and analysed for physical parameters, major ions, nutrients, BOD, COD, and heavy metals. The results show that Lakes 6, 7, and 8 commonly exceeded the National Drinking Water Quality Standards (NDWQS) limits, particularly in physical parameters and major ions. The cation dominance was Na+  > Mg2+  > K+  > Ca2+, while the anion dominance was Cl-  > HCO3-  > SO42-. It is inferred that lake 8 was affected by the seawater intrusion through the inlet flow, resulting in an excess concentration of ions present in that lake. The concentrations of heavy metals in these lakes were considerably low, indicating that most of them were from the geogenic source. Most of the lakes were NaCl water type and the main controlling mechanism were weathering and ionic exchange processes, with anthropogenic impacts. Based on the calculated Water Quality Index (WQI) according to the National Water Quality Standards (NWQS), all lakes were suitable for irrigation use (class IV), while most of these lakes fell under the "polluted" index. Apart from that, based on the National Lake Water Quality Standards (NLWQS), all lakes were classified under category D, indicating that the lakes must be kept in good condition. According to the irrigation quality indices, lakes 1, 2, 3, 4, and 5 were the most suitable for irrigation purposes. As for metal pollution indices (HPI and HEI), lakes 1, 2, 3, 4, 5, and 15 were considered safe with low pollution status. From the multivariate statistical analysis, it is deduced that both anthropogenic and geogenic impacts mostly influenced the quality of these lake waters. The outcome of this study will help the policymakers under the national water department in sustainable management of water resources in this region.
    Matched MeSH terms: Water Quality*
  4. Expressing banana transcription factor MaERFVII3 in Arabidopsis confers enhanced waterlogging tolerance and root growth
    Teoh EY, Teo CH, Baharum NA, Tan BC
    PeerJ, 2024;12:e17285.
    PMID: 38708359 DOI: 10.7717/peerj.17285
    BACKGROUND: Waterlogging poses a significant threat to plant growth and yield worldwide. Identifying the genes responsible for mitigating waterlogging stress is crucial. Ethylene-responsive factors (ERFs) are transcriptional regulators that respond to various biotic and abiotic stresses in plants. However, their roles and involvement in responding to waterlogging stress remain largely unexplored. Hence, this study aimed to elucidate the role of ERFs in enhancing banana plant resilience to waterlogging.

    METHODS: We hypothesized that introducing a group VII ERF transcription factor in Arabidopsis could enhance waterlogging stress tolerance. To test this hypothesis, we isolated MaERFVII3 from banana roots, where it exhibited a significant induction in response to waterlogging stress. The isolated MaERFVII3 was introduced into Arabidopsis plants for functional gene studies.

    RESULTS: Compared with wild-type plants, the MaERFVII3-expressing Arabidopsis showed increased survival and biomass under waterlogging stress. Furthermore, the abundance of transcripts related to waterlogging and hypoxia response showed an elevation in transgenic plants but a decrease in wild-type and empty vector plants when exposed to waterlogging stress. Our results demonstrate the significant contribution of MaERFVII3 to waterlogging tolerance in Arabidopsis, providing baseline data for further exploration and potentially contributing to crop improvement programs.

    Matched MeSH terms: Water/metabolism
  5. Ultrasonic-assisted synthesis of CaCu3Ti4O12/reduced graphene oxide composites for enhanced photocatalytic degradation of pharmaceutical products: Ibuprofen and Ciprofloxacin
    Ahmadipour M, Ardani MR, Sarafbidabad M, Missaoui N, Satgunam M, Singh R, et al.
    Environ Sci Pollut Res Int, 2024 Apr;31(19):27770-27788.
    PMID: 38514592 DOI: 10.1007/s11356-024-32977-9
    The objective of this research is to create a highly effective approach for eliminating pollutants from the environment through the process of photocatalytic degradation. The study centers around the production of composites consisting of CaCu3Ti4O12 (CCTO) and reduced graphene oxide (rGO) using an ultrasonic-assisted method, with a focus on their capacity to degrade ibuprofen (IBF) and ciprofloxacin (CIP) via photodegradation. The impact of rGO on the structure, morphology, and optical properties of CCTO was inspected using XRD, FTIR, Raman, FESEM, XPS, BET, and UV-Vis. Morphology characterization showed that rGO particles were dispersed within the CCTO matrix without any specific chemical interaction between CCTO and C in the rGO. The BET analysis revealed that with increasing the amount of rGO in the composite, the specific surface area significantly increased compared to the CCTO standalone. Besides, increasing rGO resulted in a reduction in the optical bandgap energy to around 2.09 eV, makes it highly promising photocatalyst for environmental applications. The photodegradation of IBF and CIP was monitored using visible light irradiation. The results revealed that both components were degraded above 97% after 60 min. The photocatalyst showed an excellent reusability performance with a slight decrease after five runs to 93% photodegradation efficiency.
    Matched MeSH terms: Water Pollutants, Chemical/chemistry
  6. A new insight for real-time wastewater quality prediction using hybridized kernel-based extreme learning machines with advanced optimization algorithms
    Alavi J, Ewees AA, Ansari S, Shahid S, Yaseen ZM
    Environ Sci Pollut Res Int, 2022 Mar;29(14):20496-20516.
    PMID: 34741267 DOI: 10.1007/s11356-021-17190-2
    Accurate prediction of inlet chemical oxygen demand (COD) is vital for better planning and management of wastewater treatment plants. The COD values at the inlet follow a complex nonstationary pattern, making its prediction challenging. This study compared the performance of several novel machine learning models developed through hybridizing kernel-based extreme learning machines (KELMs) with intelligent optimization algorithms for the reliable prediction of real-time COD values. The combined time-series learning method and consumer behaviours, estimated from water-use data (hour/day), were used as the supplementary inputs of the hybrid KELM models. Comparison of model performances for different input combinations revealed the best performance using up to 2-day lag values of COD with the other wastewater properties. The results also showed the best performance of the KELM-salp swarm algorithm (SSA) model among all the hybrid models with a minimum root mean square error of 0.058 and mean absolute error of 0.044.
    Matched MeSH terms: Waste Water*
  7. Fulltext Assessment of drinking water quality using Water Quality Index and synthetic pollution index in urban areas of mega city Lahore: a GIS-based approach
    Latif M, Nasir N, Nawaz R, Nasim I, Sultan K, Irshad MA, et al.
    Sci Rep, 2024 Jun 11;14(1):13416.
    PMID: 38862670 DOI: 10.1038/s41598-024-63296-1
    The aim of the present study was to assess the drinking water quality in the selected urban areas of Lahore and to comprehend the public health status by addressing the basic drinking water quality parameters. Total 50 tap water samples were collected from groundwater in the two selected areas of district Lahore i.e., Gulshan-e-Ravi (site 1) and Samanabad (site 2). Water samples were analyzed in the laboratory to elucidate physico-chemical parameters including pH, turbidity, temperature, total dissolved solids (TDS), electrical conductivity (EC), dissolved oxygen (DO), total hardness, magnesium hardness, and calcium hardness. These physico-chemical parameters were used to examine the Water Quality Index (WQI) and Synthetic Pollution Index (SPI) in order to characterize the water quality. Results of th selected physico-chemical parameters were compared with World Health Organization (WHO) guidelines to determine the quality of drinking water. A GIS-based approach was used for mapping water quality, WQI, and SPI. Results of the present study revealed that the average value of temperature, pH, and DO of both study sites were within the WHO guidelines of 23.5 °C, 7.7, and 6.9 mg/L, respectively. The TDS level of site 1 was 192.56 mg/L (within WHO guidelines) and whereas, in site 2 it was found 612.84 mg/L (higher than WHO guidelines), respectively. Calcium hardness of site 1 and site 2 was observed within the range from 25.04 to 65.732 mg/L but, magnesium hardness values were higher than WHO guidelines. The major reason for poor water quality is old, worn-out water supply pipelines and improper waste disposal in the selected areas. The average WQI was found as 59.66 for site 1 and 77.30 for site 2. Results showed that the quality of the water was classified as "poor" for site 1 and "very poor " for site 2. There is a need to address the problem of poor water quality and also raise the public awareness about the quality of drinking water and its associated health impacts.
    Matched MeSH terms: Water Pollutants, Chemical/analysis; Water Pollution/analysis; Water Supply/standards; Water Quality*
  8. Innovative solutions for the removal of emerging microplastics from water by utilizing advanced techniques
    Noornama, Abidin MNZ, Abu Bakar NK, Hashim NA
    Mar Pollut Bull, 2024 Sep;206:116752.
    PMID: 39053257 DOI: 10.1016/j.marpolbul.2024.116752
    Microplastic pollution is one of the most pressing global environmental problems due to its harmful effects on living organisms and ecosystems. To address this issue, researchers have explored several techniques to successfully eliminate microplastics from water sources. Chemical coagulation, electrocoagulation, magnetic extraction, adsorption, photocatalytic degradation, and biodegradation are some of the recognized techniques used for the removal of microplastics from water. In addition, membrane-based techniques encompass processes propelled by pressure or potential, along with sophisticated membrane technologies like the dynamic membrane and the membrane bioreactor. Recently, researchers have been developing advanced membranes composed of metal-organic frameworks, MXene, zeolites, carbon nanomaterials, metals, and metal oxides to remove microplastics. This paper aims to analyze the effectiveness, advantages, and drawbacks of each method to provide insights into their application for reducing microplastic pollution.
    Matched MeSH terms: Water Purification/methods
  9. Fulltext Pickering emulsion stabilized by palm-pressed fiber cellulose nanocrystal extracted by acid hydrolysis-assisted high pressure homogenization
    Ng SW, Chong WT, Soo YT, Tang TK, Ab Karim NA, Phuah ET, et al.
    PLoS One, 2022;17(8):e0271512.
    PMID: 36044467 DOI: 10.1371/journal.pone.0271512
    Palm pressed fibre (PPF) is a lignocellulose biomass generated from palm oil mill that is rich in cellulose. The present work aimed to combine acid hydrolysis followed by high-pressure homogenisation (HPH) to produce nanocrystal cellulose (CNC) with enhanced physicochemical properties from PPF. PPF was alkaline treated, bleached, acid hydrolysed and homogenised under high pressure condition to prepare CNC. The effects of homogenisation pressure (10, 30, 50, 70 MPa) and cycles (1, 3, 5, 7) on the particle size, zeta potential and rheological properties of CNC produced were investigated. HPH was capable of producing CNC with better stability. Results revealed that utilizing 1 cycle of homogenisation at a pressure of 50 MPa resulted in CNC with the smallest dimension, highest aspect ratio, moderate viscosity and exceptionally high zeta potential. Subsequently, 0.15% (CNC 0.15 -PE) and 0.30% (CNC 0.30 -PE) of CNC was used to stabilise oil-in-water emulsions and their stability was evaluated against different pH, temperature and ionic strength. All the CNC-stabilised emulsions demonstrated good thermal stability. CNC 0.30 -PE exhibited larger droplets but higher stability than CNC 0.15 -PE. In short, CNC with gel like structure has a promising potential to serve as a natural Pickering emulsifier to stabilise oil-in-water emulsion in various food applications.
    Matched MeSH terms: Water/chemistry
  10. Fulltext Assessment of microplastics in highland rock salts of Northern Borneo
    Mohan Viswanathan P, Mishra A, Singam DR, John J
    J Environ Manage, 2024 Sep;368:122207.
    PMID: 39180824 DOI: 10.1016/j.jenvman.2024.122207
    Mountain salts produced from the highland region in NE Sarawak have a market value and also provide basic income to the communities. During the salt-making process, microplastics (MPs) may enter into commercial table salts from various sources, which has not been explored yet. Hence, the current research investigates the presence of MPs in the rock salts produced from the highland saline water in two different locations (L1 and L2) in NE Sarawak. Among the brine water and rock salt samples analysed, the highest concentrations of MPs were detected from the salt samples. It has been revealed that both the water and salt samples have the highest concentration of MPs occurring within the size range of 1-1000 μm. Transparent MPs are the most common colour observed in both salt and water samples, followed by white, blue, red, and black. The most prevalent shapes of MPs are fibers, which account for almost 47% in water samples and 87% in salt samples. Based on the ATR-FTIR study, polyethylene (PE) is the most prevalent polymer observed in salt samples, followed by polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET). In water samples, PP is the most dominating polymer, followed by PE and PS. Through SEM microphotographs, fiber-type MPs have smooth surfaces, fragment-type MPs have rough edges, and sheet-type MPs have layered surfaces. EDX analysis revealed that carbon (C) and oxygen (O) are the most abundant elements, followed by aluminium (Al) and sodium (Na) in MPs. Based on the results, it is inferred that the MPs in the rock salts are mainly sourced from the different stages of salt-making production. This preliminary study shed light on the presence and characteristics of MPs in rock salts in this region. The research outcomes could support sustainable management plans to improve the salt quality and enhance the market value.
    Matched MeSH terms: Water Pollutants, Chemical/analysis
  11. Feasibility assessment of a stepped solar still integrated with hexagram fin: an experimental and numerical approach toward sustainability
    Chinnasamy S, Balasubramanian K, Sampathkumar A, Babu PK, Satchi CS
    Environ Sci Pollut Res Int, 2024 Sep;31(41):53973-53992.
    PMID: 37971583 DOI: 10.1007/s11356-023-30726-y
    Effective utilization and conservation of freshwater is a global concern due to the rapid population growth and industrial usage. To address this challenge, various approaches have been developed and implemented to convert brackish water into freshwater and meet the global water demand. This study introduces hexagram-shaped aluminum fins attached to a powder-coated basin to improve the freshwater production rate of stepped solar still. The experiment involved testing the modified stepped solar still (MSSS) equipped with hexagram fins and the conventional stepped solar still (CSSS) without hexagram fins during summer days at the Sathyamangalam location (11.49° N, 77.27° E). A mathematical model was used to analyze the performance of the solar stills, and the simulation results were validated by comparing CSSS and MSSS in terms of their freshwater production. The results indicate that the productivity of CSSS increased by 40% using hexagram fins, and the MSSS with hexagram fins produced a maximum of 4.45 l/m2 of fresh water daily. The annual performance of MSSS and CSSS in the experimental location reveals a 12.6% reduction in the payback period of the solar still due to the presence of fins. The study recommends using fins in solar stills in hot climates for efficient and cost-effective water desalination applications to achieve sustainable development objectives while reducing carbon emissions.
    Matched MeSH terms: Fresh Water*
  12. Performance assessment of pilot horizontal sub-surface flow constructed wetlands for removal of diesel from wastewater by Scirpus grossus
    Al-Baldawi IA, Sheikh Abdullah SR, Anuar N, Suja F, Idris M
    Water Sci Technol, 2013;68(10):2271-8.
    PMID: 24292478 DOI: 10.2166/wst.2013.484
    One of the appropriate development technology options for the treatment of wastewater contaminated with diesel is constructed wetlands (CWs). Throughout 72 days of exposure, sampling was carried out for monitoring of physical parameters, plant growth and the efficiency of total petroleum hydrocarbon (TPH) removal, as an indication for diesel contamination, to assess the pilot-scale performance. Four pilot CWs with a horizontal sub-surface flow system were applied using the bulrush of Scirpus grossus. The CWs were loaded with different diesel concentrations of 0, 0.1, 0.2 and 0.25% (Vdiesel/Vwater). The TPH removal efficiencies were 82, 71, and 67% at the end of 72 days for diesel concentrations of 0.1, 0.2, and 0.25% respectively. In addition, the high removal efficiency of total suspended solids and chemical oxygen demand (COD) were 100 and 75.4% respectively, for a diesel concentration of 0.1%. It was concluded that S. grossus is a potential plant that can be used in a well-operated CW for restoring 0.1% diesel-contaminated water.
    Matched MeSH terms: Water Pollutants, Chemical/isolation & purification*; Water Purification*; Water Quality
  13. Fulltext Spatial variability of metals in surface water and sediment in the langat river and geochemical factors that influence their water-sediment interactions
    Lim WY, Aris AZ, Zakaria MP
    ScientificWorldJournal, 2012;2012:652150.
    PMID: 22919346 DOI: 10.1100/2012/652150
    This paper determines the controlling factors that influence the metals' behavior water-sediment interaction facies and distribution of elemental content ((75)As, (111)Cd, (59)Co, (52)Cr, (60)Ni, and (208)Pb) in water and sediment samples in order to assess the metal pollution status in the Langat River. A total of 90 water and sediment samples were collected simultaneously in triplicate at 30 sampling stations. Selected metals were analyzed using ICP-MS, and the metals' concentration varied among stations. Metal concentrations of water ranged between 0.08-24.71 μg/L for As, <0.01-0.53 μg/L for Cd, 0.06-6.22 μg/L for Co, 0.32-4.67 μg/L for Cr, 0.80-24.72 μg/L for Ni, and <0.005-6.99 μg/L for Pb. Meanwhile, for sediment, it ranged between 4.47-30.04 mg/kg for As, 0.02-0.18 mg/kg for Cd, 0.87-4.66 mg/kg for Co, 4.31-29.04 mg/kg for Cr, 2.33-8.25 mg/kg for Ni and 5.57-55.71 mg/kg for Pb. The average concentration of studied metals in the water was lower than the Malaysian National Standard for Drinking Water Quality proposed by the Ministry of Health. The average concentration for As in sediment was exceeding ISQG standards as proposed by the Canadian Sediment Quality Guidelines. Statistical analyses revealed that certain metals (As, Co, Ni, and Pb) were generally influenced by pH and conductivity. These results are important when making crucial decisions in determining potential hazardous levels of these metals toward humans.
    Matched MeSH terms: Fresh Water/chemistry*; Water Pollutants, Chemical/analysis*; Water Quality
  14. Assessment of metals distribution and microbial contamination at selected lake waters in and around Miri City, East Malaysia
    Prasanna MV, Nagarajan R, Chidambaram S, Elayaraja A
    Bull Environ Contam Toxicol, 2012 Sep;89(3):507-11.
    PMID: 22684361 DOI: 10.1007/s00128-012-0698-4
    A baseline study was carried out to assess the metal concentrations and microbial contamination at selected Lake waters in and around Miri City, East Malaysia. Sixteen surface water samples were collected at specific Lakes in the environs of major settlement areas and recreational centers in Miri City. The Physico-chemical parameters [pH, Electrical Conductivity (EC) and Dissolved Oxygen (DO)], metals (Fe, Mn, Cu, Cd, Ni and Zn) and Escherichia coli (E. coli) were analysed. The concentrations of Fe, Mn and Ni have been found to be above the permissible limits of drinking water quality standards. The metals data have also been used for the calculation of heavy metal pollution index. Higher values of E. coli indicate microbial contamination in the Lake waters.
    Matched MeSH terms: Water Microbiology; Water Pollutants, Chemical/analysis*; Water Supply*
  15. Oil droplets and solid particles removal using circular separator with inclined coalescence mediums: comparison between co-current and counter-current flow
    Ngu LH, Law PL, Wong KK, Yusof AA
    Water Sci Technol, 2010;62(5):1129-35.
    PMID: 20818055 DOI: 10.2166/wst.2010.407
    This research investigated the effects of co- and counter-current flow patterns on oil-water-solid separation efficiencies of a circular separator with inclined coalescence mediums. Oil-water-solid separations were tested at different influent concentrations and flowrates. Removal efficiencies increased as influent flowrate decreased, and their correlationship can be represented by power equations. These equations were used to predict the required flowrate, Q(ss50), for a given influent suspended solids concentration C(iss) to achieve the desired effluent suspended solids concentration, C(ess) of 50 mg/L, to meet environmental discharge requirements. The circular separator with counter-current flow was found to attend removal efficiencies relatively higher as compared to the co-current flow. As compared with co-current flow, counter-current flow Q(ss50) was approximately 1.65 times higher than co-current flow. It also recorded 13.16% higher oil removal at influent oil concentration, C(io) of 100 mg/L, and approximately 5.89% higher TSS removal at all influent flowrates. Counter-current flow's better removal performances were due to its higher coalescing area and constant interval between coalescence plate layers.
    Matched MeSH terms: Water Movements; Water Pollutants, Chemical/chemistry*; Water Purification/methods*
  16. Optimization of coagulation-flocculation process for pulp and paper mill effluent by response surface methodological analysis
    Ahmad AL, Wong SS, Teng TT, Zuhairi A
    J Hazard Mater, 2007 Jun 25;145(1-2):162-8.
    PMID: 17161910
    Coagulation-flocculation is a proven technique for the treatment of high suspended solids wastewater. In this study, the central composite face-centered design (CCFD) and response surface methodology (RSM) have been applied to optimize two most important operating variables: coagulant dosage and pH, in the coagulation-flocculation process of pulp and paper mill wastewater treatment. The treated wastewater with high total suspended solids (TSS) removal, low SVI (sludge volume index) and high water recovery are the main objectives to be achieved through the coagulation-flocculation process. The effect of interactions between coagulant dosage and pH on the TSS removal and SVI are significant, whereas there is no interaction between coagulant dosage and water recovery. Quadratic models have been developed for the response variables, i.e. TSS removal, SVI and water recovery based on the high coefficient of determination (R(2)) value of >0.99 obtained from the analysis of variances (ANOVA). The optimum conditions for coagulant dosage and pH are 1045mgL(-1) and 6.75, respectively, where 99% of TSS removal, SVI of 37mLg(-1) and 82% of water recovery can be obtained.
    Matched MeSH terms: Water Pollutants, Chemical/analysis*; Water Purification/methods*; Water Purification/standards
  17. Runoff quality and pollution loadings from a tropical urban catchment
    Yusop Z, Tan LW, Ujang Z, Mohamed M, Nasir KA
    Water Sci Technol, 2005;52(9):125-32.
    PMID: 16445181
    Runoff quality draining from 17.14 km2 urban catchment in Johor Bahru, Malaysia, was analysed. The land-use consists of residential (30.3%), agricultural (27.3%), open space (27.9%), industrial (8.1%) and commercial (6.4%) areas. Three storm events were sampled in detail. These storms produced stormflow between 0.84 mm and 27.82 mm, and peakflow from 2.19 m3/s to 42.36 m3/s. Water quality showed marked variation during storms especially for TSS, BOD and COD with maximum concentrations of 778 mg/l, 135 mg/l and 358 mg/l, respectively. Concentrations of TOC, DOC, NH3-N, Fe and level of colour were also high. In general, the river quality is badly polluted and falls in Class V based on the Malaysian Interim National Water Quality Standards. Event Mean Concentrations (EMC) for various parameters varied considerably between storms. The largest storm produced higher EMC for TSS, NO3-N and SS whereas the smaller storms tend to register higher EMC for BOD, COD, NH3-N, TOC, Ca, K, Mg, Fe and Zn. Such variations could be explained in terms of pollutant availability and the effects of flushing and dilution. Based on a three-month average recurrence interval (ARI) of rainfall, the estimated event loadings (ton/ha) of TSS, BOD, COD, TOC, NH3-N and NO3-N were 0.055, 0.016, 0.012, 0.039, 0.010, 0.0007 and 0.0002, respectively. Heavy metals present in trace quantities. Storms with 3 months ARI could capture about 70% of the total annual loads of major pollutants.
    Matched MeSH terms: Water Movements; Water Pollutants/analysis*; Water Supply/standards*
  18. Quantification of leachate discharged to groundwater using the water balance method and the hydrologic evaluation of landfill performance (HELP) model
    Alslaibi TM, Abustan I, Mogheir YK, Afifi S
    Waste Manag Res, 2013 Jan;31(1):50-9.
    PMID: 23148014 DOI: 10.1177/0734242X12465462
    Landfills are a source of groundwater pollution in Gaza Strip. This study focused on Deir Al Balah landfill, which is a unique sanitary landfill site in Gaza Strip (i.e., it has a lining system and a leachate recirculation system). The objective of this article is to assess the generated leachate quantity and percolation to the groundwater aquifer at a specific site, using the approaches of (i) the hydrologic evaluation of landfill performance model (HELP) and (ii) the water balance method (WBM). The results show that when using the HELP model, the average volume of leachate discharged from Deir Al Balah landfill during the period 1997 to 2007 was around, 6800 m3/year. Meanwhile, the average volume of leachate percolated through the clay layer was 550 m3/year, which represents around 8% of the generated leachate. Meanwhile, the WBM indicated that the average volume of leachate discharged from Deir Al Balah landfill during the same period was around 7660 m3/year--about half of which comes from the moisture content of the waste, while the remainder comes from the infiltration of precipitation and re-circulated leachate. Therefore, the estimated quantity of leachate to groundwater by these two methods was very close. However, compared with the measured leachate quantity, these results were overestimated and indicated a dangerous threat to the groundwater aquifer, as there was no separation between municipal, hazardous and industrial wastes, in the area.
    Matched MeSH terms: Water Pollutants/analysis*; Water Pollutants, Chemical/analysis; Water Pollutants, Chemical/chemistry*
  19. Ozonation of ofloxacin in water: by-products, degradation pathway and ecotoxicity assessment
    Tay KS, Madehi N
    Sci Total Environ, 2015 Jul 1;520:23-31.
    PMID: 25791053 DOI: 10.1016/j.scitotenv.2015.03.033
    Application of ozonation in water treatment involves complex oxidation pathways that could lead to the formation of various by-products, some of which may be harmful to living organisms. In this work, ozonation by-products of ofloxacin (OFX), a frequently detected pharmaceutical pollutant in the environment, were identified and their ecotoxicity was estimated using the Ecological Structure Activity Relationships (ECOSAR) computer program. In order to examine the role of ozone (O3) and hydroxyl radicals (∙OH) in the degradation of ofloxacin, ozonation was performed at pH2, 7 and 12. In this study, 12 new structures have been proposed for the ozonation by-products detected during the ozonation of ofloxacin. According to the identified ozonation by-products, O3 and ∙OH were found to react with ofloxacin during ozonation. The reaction between ofloxacin and O3 proceeded via hydroxylation and breakdown of heterocyclic ring with unsaturated double-bond. The reaction between ofloxacin and ·OH generated various by-products derived from the breakdown of heterocyclic ring. Ecotoxicity assessment indicated that ozonation of OFX could yield by-products of greater toxicity compared with parent compounds.
    Matched MeSH terms: Water Pollutants, Chemical/toxicity; Water Pollutants, Chemical/chemistry*; Water Purification/methods*
  20. Removal of iron and manganese by artificial destratification in a tropical climate (Upper Layang Reservoir, Malaysia)
    Ismail R, Kassim MA, Inman M, Baharim NH, Azman S
    Water Sci Technol, 2002;46(9):179-83.
    PMID: 12448467
    Environmental monitoring was carried out at Upper Layang Reservoir situated in Masai, Johor, Malaysia. The study shows that thermal stratification and natural mixing of the water column do exist in the reservoir and the level of stratification varies at different times of the year. Artificial destratification via diffused air aeration techniques was employed at the reservoir for two months. The results show that thermal stratification was eliminated after a week of continuous aeration. The concentrations of iron and to a lesser extent manganese in the water column was also reduced during the aeration period.
    Matched MeSH terms: Water Movements; Water Supply*; Water Purification/methods*
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