The developed microbial granules containing photosynthetic pigments had successfully achieved approximately 18-21% of carbon dioxide (CO2) removal in POME for one complete SBR cycle. Also, the granules had reached CO2 removal at 15-29% within 24h and removal of 25% after 5 days. Both results were inconsistent possibly due to the slow mass transfer rate of CO2 from gas to liquid as well as the simultaneous effect of CO2 production and respiration among the microbes. Furthermore, results showed the removal of CO2 from air increases proportionally with the CO2 removed in liquid. The CO2 biofixation of granules attained was approximately 0.23g/L/day for a week. Using the regression model, the removal of CO2 between liquid and gas, CO2 biofixation rate were highly correlated with the treatment time. A statistically significant relationship was obtained between CO2 concentration in liquid, biomass productivity and treatment time for the CO2 biofixation rate of the granules.
Matched MeSH terms: Water Pollution, Chemical/analysis; Water Purification/methods*
In this work, heterogeneous photocatalysis was used to treat pulp and paper mill effluent (PPME). Magnetically retrievable Fe2O3-TiO2 was fabricated by employing a solvent-free mechanochemical process under ambient conditions. Findings elucidated the successful incorporation of Fe2O3 into the TiO2 lattice. Fe2O3-TiO2 was found to be an irregular and slightly agglomerated surface morphology. In comparison to commercial P25, Fe2O3-TiO2 exhibited higher ferromagnetism and better catalyst properties with improvements in surface area (58.40 m2/g), pore volume (0.29 cm3/g), pore size (18.52 nm), and band gap (2.95 eV). Besides, reusability study revealed that Fe2O3-TiO2 was chemically stable and could be reused successively (five cycles) without significant changes in its photoactivity and intrinsic properties. Additionally, this study demonstrated the potential recovery of Fe2O3-TiO2 from an aqueous suspension by using an applied magnetic field or sedimentation. Interactive effects of photocatalytic conditions (initial effluent pH, Fe2O3-TiO2 dosage, and air flow-rate), reaction mechanism, and the presence of chemical oxidants (H2O2, BrO3-, and HOCl) during the treatment process of PPME were also investigated. Under optimal conditions (initial effluent pH = 3.88, [Fe2O3-TiO2] = 1.3 g/L, and air flow-rate = 2.28 L/min), the treatment efficiency of Fe2O3-TiO2 was 98.5% higher than the P25. Based on Langmuir-Hinshelwood kinetic model, apparent rate constants of Fe2O3-TiO2 and P25 were 9.2 × 10-3 and 2.7 × 10-3 min-1, respectively. The present study revealed not only the potential of using magnetic Fe2O3-TiO2 in PPME treatment but also demonstrated high reusability and easy separation of Fe2O3-TiO2 from the wastewater.
Matched MeSH terms: Water Purification/methods*; Waste Water*
The presence of Cs(I) ions in nuclear wastewater becomes an important issue for the reason of its high toxicity. The development of adsorbent embedded metal-based catalysts that has sufficient adsorption capacity is expected for the removal of Cs(I) ions from contaminated water. This study tested the use of maghemite, titania and combined maghemite-titania polyvinyl alcohol (PVA)-alginate beads as an adsorbent to remove Cs(I) ions from aqueous solution with the variables of pH and initial concentration using batch experiments under sunlight. The results showed that the use of combined maghemite-titania PVA-alginate beads can have an efficiency of 93.1% better than the use of either maghemite PVA-alginate beads with an efficiency of 91.8% or titania PVA-alginate beads with an efficiency of 90.1%. The experimental data for adsorption of Cs(I) ions from aqueous solution with the initial concentrations of 50, 100 and 200 mg L(-1) on the surface of combined maghemite-titania PVA-alginate beads were well fit by the pseudo-second-order and Langmuir models. The optimal adsorption of Cs(I) ions from aqueous solution by combined maghemite-titania PVA-alginate beads under sunlight occurs at pH 8 with an initial Cs(I) ion concentration of 50 mg L(-1). The combined maghemite-titania PVA-alginate beads can be recycled at least five times with a slight loss of their original properties.
Matched MeSH terms: Water Pollutants, Chemical/chemistry; Water Purification*
Chlorophyll-a concentrations (mg/l) in surface waters of Songsong Islands were mapped using an optically derived remote sensing model. Landsat TM imagery dated 8 October 2008 was used in the classification process and in situ measurements made on 19 May 2012 during spring tidal condition (HW: 2.6 m, LW: 0.9 m) served as ground truthing data. The temporal difference between data used will be useful to review the robustness of the model. Three classes of chlorophyll-a concentrations were mapped: Class 1: 10 mg/l. Considering the dynamic nature of coastal and marine waters particularly the shallow region, and the temporal difference between the Landsat TM imagery used in classification and the field data, results of chlorophyll-a mapping using the developed remote sensing model was high at 83.3%, with producer’s accuracy of 50%–100% and user’s accuracy of 80%–100%. Kappa coefficient of agreement, Kˆ , calculated was 57.1%.
Acute Gastroenteritis (AGE) is common world wide and is a major health problem. The commonest cause is from contaminated water or food. Common infective agents are Rotavirus, Staph. aureus and Bacillus cereus. There was an AGE outbreak in Ipoh City from late August till early October 2006. Epidemiological and laboratory investigations were done. Fresh stool samples were taken from symptomatic patients. Water and food sampling were also done. Descriptive analysis of the outbreak was done. A total of 170 patients, mostly between 1 - 5 years of age, were affected. The highest incidents were seen in Bercham. Fever and diarrhea were the prominent features. Two stool samples (13.3%) were positive for E.coli and rotavirus respectively. Twelve of the twenty (60%) water samples taken were contaminated with coliform and fecal matter. Twenty-one of the eighty ((26.3%) food samples taken grew either E.coli, Staph. aureus or Bacillus cereus. It was concluded that a general source was responsible for this problem. The water supply to Ipoh City and the surrounding area is the most likely source. Novovirus was suspected as the organism involved because of the self-limiting and mild nature of the illness that occurred in this outbreak.
The AGE outbreak in Kinta District in September 2006 is due to contaminated
water supply from two water treatment
Matched MeSH terms: Water; Water Pollution; Water Supply; Water Purification
This paper presents the numerical modelling techniques for the simulation of the energy conversion chain from wave to electricity in an Oscillating Water Column (OWC) equipped with a full-scaled self rectifying turbine. The performance of the OWC device has been assessed for the stand-alone power system of a typical Irish climatic wave condition. The results showed that the overall performance of the complete device depends on the level of turbine damping, which in turn depends on the wave climate, especially the significant wave height. Furthermore, turbine efficiency predicted using quasi-steady showed qualitatively favourable agreement with the experimental results.
The aqueous extract of various plants like Coriandrum sativum (AECS), Alternanthera tenella colla (AEAT), Spermacoce hispida (AESH) and Mollugo verticillata (AEMV) was studied for its hexavalent chromium (CrVI) reduction property. Even though antioxidant activity was present, AEAT, AESH and AEMV did not reduce CrVI. AECS showed rapid and dose-dependent CrVI reduction. The efficient reduction of 50 mg/L of CrVI using AECS was attained in the presence of 250 µg/mL of starting plant material, incubating the reaction mixture at pH 2, 30°C and agitation at 190 rpm. Under such conditions, about 40 mg/L of CrVI was reduced at 3 h of incubation. FT-IR analysis revealed the involvement of phenols, alcohols, alpha-hydroxy acid and flavonoids present in the AECS for the CrVI reduction. These results indicate that not all the plant extracts with rich antioxidants are capable of reducing CrVI. Using the conditions standardized in the present study, AECS reduced about 80% of CrVI present in the tannery effluent. These results signify the application of AECS as an eco-friendly method in the wastewater treatment.
Matched MeSH terms: Water Pollutants, Chemical/chemistry*; Water Purification*
Water pollution is a critical management issue, with many rivers and streams draining urban areas being polluted by the disposal of untreated solid waste and wastewater discharge, storm water and agricultural runoff. This has implications for biodiversity, and many rivers in the developing world are now considered compromised. We investigated benthic macroinvertebrate community structure and composition in relation to physico-chemical conditions of the water column and sediments. The study was conducted in an Austral catchment subject to both urban and agricultural pollutants in two different seasons. We assessed whether sediment characteristics were more important drivers of macroinvertebrate community composition than water column characteristics. We expected clear differences in macroinvertebrate community composition and in the associated community metrics due to distinct flow conditions between the two seasons. A combination of multivariate analyses (canonical correspondence analysis (CCA)) and biological indicator analysis were used to examine these patterns. Chironomidae was the most abundant family (>60%) in the upper mainstem river and stream sites. Stream sites were positively associated with CCA axis 2, being characterised by high turbidity and lower pH, salinity, phosphate concentration, channel width and canopy cover. Canopy cover, channel width, substrate embeddedness, phosphate concentration, pH, salinity and turbidity all had a significant effect on macroinvertebrate community composition. Using CCA variation partitioning, water quality was, however, a better predictor of benthic macroinvertebrate composition than sediment chemical conditions. Furthermore, our results suggest that seasonality had little effect on structuring benthic macroinvertebrate communities in this south-eastern zone of South Africa, despite clear changes in sediment chemistry. This likely reflects the relative lack of major variability in water chemistry compared to sediment chemistry between seasons and the relatively muted variability in precipitation between seasons than the more classic Austral temperate climates.
Matched MeSH terms: Water; Water Pollution; Water Quality; Waste Water
Providing safe drinking-water to human civilization is indispensable; it is one of the most cost-effective means of reducing the disease burden of diarrhea. Unfortunately, water supply quality monitoring from public water treatment plants (WTPs) is often neglected or taken for granted. To determine the produced water quality, WTPs in Sarawak, Malaysia were assessed for their protozoa removal ability. A self-administered questionnaire based on the regulations in the Drinking-water Standards for New Zealand (DWSNZ) was developed. Optional 10-liter raw water samples were collected from willing WTPs for the detection of protozoan cysts. Routine physical and microbial testing of WTP parameters were also requested for raw water quality overview. Two of the nine assessed WTPs achieved three log credits in the treatment component, one of which belonged to Peninsular Malaysia. No log credits were obtained in the other tested components for any samples. Most of the WTPs employed "Coagulation, Sedimentation, and Filtration" using rapid gravity filters without enhancement (P < 0.05). Giardia cysts were detected in raw water sources used for treatment, and the geographical location was identified as an influencing factor for raw water quality. There is an urgent requirement for active collaboration and holistic approaches to review existing water management policies and interventions. WTPs in Sarawak did not achieve the log credits required to safeguard the microbial quality of the water supplied; however, only Giardia cysts were detected in 10-liter raw water samples despite routine microbial parameter monitoring showing disturbing contamination levels.
Matched MeSH terms: Water; Water Supply; Water Purification; Water Quality
Adsorption is one of the most efficient ways to remove heavy metal from wastewater. In this study, the adsorptive removal of hexavalent chromium, Cr (VI) from aqueous solution was investigated using natural zeolite, clinoptilolite, in the form of hollow fibre ceramic membrane (HFCM). The HFCM sample was prepared using phase inversion-based extrusion technique and followed by sintering process at different sintering temperatures in the range of 900-1050 °C. The fabricated HFCM was characterised using scanning electron microscopy (SEM), contact angle, water permeability, and mechanical strength for all HFCMs sintered at different temperatures. The adsorption and filtration test of Cr (VI) were performed using an in-house water permeation set up with a dead-end cross-flow permeation test. An asymmetric structure with sponge- and finger-like structures across the cross-section of HFCM was observed using SEM. Based on the characterisation data, 1050 °C was chosen to be the best sintering temperature as the water permeability and mechanical strength of this HFCM were 29.14 L/m2∙h and 50.92 MPa, respectively. The performance of the HFCM in adsorption/filtration was 44% of Cr (VI) removal at the Cr (VI) concentration of 40 mg/L and pH 4. In addition, the mathematical model was also performed in simulating the experimental data obtained from this study. All in all, the natural zeolite-based HFCM has a potential as a single-step Cr (VI) removal by membrane adsorption for the wastewater treatment.
Matched MeSH terms: Water Pollutants, Chemical; Water Purification*; Waste Water
The objective of this study was to identify the spatial and temporal variabilities of selected nutrients in the Setiu Wetlands Lagoon (SWL), Malaysia. Water samples were collected quarterly at ten monitoring sites. This study presents results from a 10-year field investigation (2003 to 2010 and 2014 to 2015) of water quality in the SWL. For the spatial pattern, four clusters were identified with hierarchical cluster analysis. Analysis of the temporal trend shows that the high total suspended solid loading in 2010 was due to large-scale land clearing upstream of the SWL. The enrichment of ammonium after 2010 could plausibly be due to land-based aquaculture diffuse discharges. In 2005-2007, expansion of oil palm plantations within the Setiu catchment had doubled the phosphorus concentration in the SWL. The natural and anthropogenic alterations of the lagoon inlets profoundly influenced the spatial distribution patterns of nutrients in the SWL. These results suggest that intense anthropogenic disturbances close to the SWL accounted for the water quality deterioration.
Matched MeSH terms: Water Pollutants, Chemical/analysis*; Water Quality*
Knowledge related to distributions of rainfall amounts are of great importance for the design of water related structures. The greater problem facing hydrologists and engineers identifying the best distribution form for regional data. The main goal of the study is to perform regional frequency analysis of maximum daily rainfalls selected each year among daily rainfalls measured over stations in Selangor and Kuala Lumpur by using the L-moment method. Several distributions were taken into account in this study which include two-parameter normal (NOM), lognormal (LN2), three-parameter lognormal (LN3), logistic (LOG), generalized logistic (GLO), extreme value type I (EV1), generalized extreme value (GEV) and generalized Pareto (GPA) distribution. The most suitable distribution was determined according to the mean absolute deviation index (MADI), mean square deviation index (MSDI) and the L-moment ratio diagram. The result of this study showed that the GLO distribution is the most suitable distribution to fit the data of maximum daily rainfalls for stations in Selangor and Kuala Lumpur.
Fishes from five streams in Gunung Machinchang and six streams in Gunung Raya areas of Pulau Langkawi were surveyed with the aim to investigate their diversity and distribution. Fish samples were collected from 23rd to 29th November 2007. Samplings took place along the 50 m reach of each of the site using an electrofisher and scoop nets. A total of 619 individuals of fish comprising 27 species and 14 families were recorded. Sixty-six percent from the taxa listed were of the cyprinids and Puntius binotatus was the most abundant species. Carassius auratus auratus was recorded for the first time in Pulau Langkawi. Streams of the Gunung Machinchang area were dominated by secondary freshwater fish species, but in the Gunung Raya area the streams were dominated by primary freshwater fish species. The highest diversity of fish was recorded for Sg. Kubang Badak with Simpson Index Ds = 0.838 and the lowest was for Sg. Perangin with Ds = 0.450. The highest evenness index of fish species was detected for Sg. Temurun with Es = 0.684 and the lowest was for Sg. Perangin with Es = 0.299. Species overlapping between streams of the two areas was 9.6%.
Malaysia is a tropical country that is highly dependent on surface water for its raw water supply. Unfortunately, surface water is vulnerable to pollution, especially in developed and dense urban catchments. Therefore, in this study, a methodology was developed for an extensive temporal water quality index (WQI) and classification analysis, simulations of various pollutant discharge scenarios using QUAL2K software, and maps with NH3-N as the core pollutant using an integrated QUAL2K-GIS. It was found that most of the water quality stations are categorized as Class III (slightly polluted to polluted). These stations are surrounded by residential areas, industries, workshops, restaurants and wet markets that contribute to the poor water quality levels. Additionally, low WQI values were reported in 2010 owing to development and agricultural activities. However, the WQI values improved during the wet season. High concentrations of NH3-N were found in the basin, especially during dry weather conditions. Three scenarios were simulated, i.e. 10%, 50% and 70% of pollution discharge into Skudai river using a calibrated and validated QUAL2K model. Model performance was evaluated using the relative percentage difference. An inclusive graph showing the current conditions and pollution reduction scenarios with respect to the distance of Skudai river and its tributaries is developed to determine the WQI classification. Comprehensive water quality maps based on NH3-N as the core pollutant are developed using integrated QUAL2K-GIS to illustrate the overall condition of the Skudai river. High NH3-N in the Skudai River affects water treatment plant operations. Pollution control of more than 90% is required to improve the water quality classification to Class II. The methodology and analysis developed in this study can assist various stakeholders and authorities in identifying problematic areas and determining the required percentage of pollution reduction to improve the Skudai River water quality.
Matched MeSH terms: Water; Water Supply; Water Purification; Water Quality
Groundwater resources constitute the main source of clean fresh water for domestic use and it is essential for food production in the agricultural sector. Groundwater has a vital role for water supply in the Campanian Plain in Italy and hence a future sustainability of the resource is essential for the region. In the current paper novel data mining algorithms including Gaussian Process (GP) were used in a large groundwater quality database to predict nitrate (contaminant) and strontium (potential future increasing) concentrations in groundwater. The results were compared with M5P, random forest (RF) and random tree (RT) algorithms as a benchmark to test the robustness of the modeling process. The dataset includes 246 groundwater quality samples originating from different wells, municipals and agricultural. It was divided for the modeling process into two subgroups by using the 10-fold cross validation technique including 173 samples for model building (training dataset) and 73 samples for model validation (testing dataset). Different water quality variables including T, pH, EC, HCO3-, F-, Cl-, SO42-, Na+, K+, Mg2+, and Ca2+ have been used as an input to the models. At first stage, different input combinations have been constructed based on correlation coefficient and thus the optimal combination was chosen for the modeling phase. Different quantitative criteria alongside with visual comparison approach have been used for evaluating the modeling capability. Results revealed that to obtain reliable results also variables with low correlation should be considered as an input to the models together with those variables showing high correlation coefficients. According to the model evaluation criteria, GP algorithm outperforms all the other models in predicting both nitrate and strontium concentrations followed by RF, M5P and RT, respectively. Result also revealed that model's structure together with the accuracy and structure of the data can have a relevant impact on the model's results.
Matched MeSH terms: Fresh Water; Water Supply; Water Quality; Water Wells
The aim of this study was to determine the occurrence of free-living amoebae (FLA) in Peninsular Malaysia and to compare different methodologies to detect them from water samples. Water samples were collected from tap water, recreational places, water dispensers, filtered water, etc. and tested for FLA using both cultivation and polymerase chain reaction (PCR) via plating assays and centrifugation methods. Amoebae DNA was extracted using Instagene matrix and PCR was performed using genus-specific primers. Of 250 samples, 142 (56.8%) samples were positive for presence of amoebae, while 108 (43.2%) were negative. Recreational water showed higher prevalence of amoebae than tap water. PCR for the plating assays revealed the presence of Acanthamoeba in 91 (64%) samples and Naegleria in 99 (70%) of samples analysed. All samples tested were negative for B. mandrillaris. In contrast, the centrifugation method was less effective in detecting amoebae as only one sample revealed the presence of Acanthamoeba and 52 (29%) samples were positive for Naegleria. PCR assays were specific and sensitive, detecting as few as 10 cells. These findings show the vast distribution and presence of FLA in all 11 states of Peninsular Malaysia. Further studies could determine the possible presence of pathogenic species and strains of free-living amoebae in public water supplies in Malaysia.
Matched MeSH terms: Fresh Water/parasitology*; Water Supply/statistics & numerical data*
The remediation of wastewater requires treatment technologies which are robust, efficient, simple to operate and affordable such as adsorption. Lately, three-dimensional (3D) graphene based materials have attracted significant attention as effective adsorbents for wastewater treatment. The intrinsic properties of 3D graphene structure such as large surface area and interconnected porous structure can facilitate the transport of pollutants into the 3D network and provide abundant active sites for trapping the pollutants. For the synthesis of 3D graphene structure, ice-templating is commonly practiced due to its facile steps, cost effectiveness and high scalability potential. This review covers the ice-templating fabrication technique for 3D graphene based materials and their application as adsorbents in eliminating dyes and heavy metals from aqueous media. The assembly mechanisms of the ice-templating fsynthesis are comprehensively discussed. Further discussion on the fundamental principles, critical process parameters and characteristics of ice-templated 3D graphene structures is also included. A thorough review on the mechanisms for batch adsorption of dyes and heavy metals is presented based on the structures and properties of the 3D graphene materials. The review further evaluates the dynamic adsorption in packed columns and the regeneration of 3D graphene based materials.
Matched MeSH terms: Water Pollutants, Chemical/chemistry*; Water Purification/methods*
Preliminary work was carried out f o r the development of a rapid method for the detection and enumeration of enterococcal phages in natural water. Eight enterococcal phages were isolated after amplification from water obtained from 2 local ponds. These were plaque-purified and used to test the phage susceptibility of 34 strains of enterococci isolated from pristine and polluted waters. Eight strains with the widest phage susceptibility were used as hosts in a double agar layer (DAL) and a single agar layer (SAL) assay for phage enumeration without pre-assay amplification. N o phages were obtained with the DAL method with all 8 hosts. Usingthe SALmethod, 2 phages were obtained with 1 of the 2 hosts used. Phage isolation was not improved by incubation at 44.5°C. For rapid quantitative testing, the sensitivity of the assays has to be increased to enable phage isolation without the need for prior amplification. KEYWORDS: Enterococci, phage, enumeration