Chitosan based adsorbents have received a lot of attention for adsorption of dyes. Various modifications of this polysaccharide have been investigated to improve the adsorption properties as well as mechanical and physical characteristics of chitosan. This review paper discusses major research topics related to chitosan and its derivatives for application in the removal of dyes from water. Modification of chitosan changes the original properties of this material so that it can be more suitable for adsorption of different types of dye. Many chitosan derivatives have been obtained through chemical and physical modifications of raw chitosan that include cross-linking, grafting and impregnation of the chitosan backbone. Better understanding of these varieties and their affinity toward different types of dye can help future research to be properly oriented to address knowledge gaps in this area. This review provides better opportunity for researchers to better explore the potential of chitosan-derived adsorbents for removal of a great variety of dyes.
Matched MeSH terms: Water Purification*; Waste Water*
Clostridium sp. strain Ade.TY is potentially a new biohydrogen-producing species isolated from landfill leachate sludge. Here we present the assembly and annotation of its genome, which may provide further insights into its gene interactions for efficient biohydrogen production.
This study investigated the optimum conditions for total petroleum hydrocarbon (TPH) removal from diesel-contaminated water using phytoremediation treatment with Scirpus grossus. In addition, TPH removal from sand was adopted as a second response. The optimum conditions for maximum TPH removal were determined through a Box-Behnken Design. Three operational variables, i.e. diesel concentration (0.1, 0.175, 0.25% Vdiesel/Vwater), aeration rate (0, 1 and 2 L/min) and retention time (14, 43 and 72 days), were investigated by setting TPH removal and diesel concentration as the maximum, retention time within the given range, and aeration rate as the minimum. The optimum conditions were found to be a diesel concentration of 0.25% (Vdiesel/Vwater), a retention time of 63 days and no aeration with an estimated maximum TPH removal from water and sand of 76.3 and 56.5%, respectively. From a validation test of the optimum conditions, it was found that the maximum TPH removal from contaminated water and sand was 72.5 and 59%, respectively, which was a 5 and 4.4% deviation from the values given by the Box-Behnken Design, providing evidence that S. grossus is a Malaysian native plant that can be used to remediate wastewater containing hydrocarbons.
Matched MeSH terms: Water Pollutants, Chemical/metabolism*; Water Purification/methods
A study has been conducted to determine the composition of surfactants in runoff water in the semi-urban area of Bandar Baru Bangi, Selangor, Malaysia. Runoff samples were collected from five different locations with contrasting functional activities and the colorimetric method was used to analyze the concentrations of surfactants as methylene blue active substances (MBAS) for anionic surfactants and as disulphine blue active substances (DBAS) for cationic surfactants. The results showed that the highest surfactant concentrations of MBAS and DBAS in runoff water were recorded in the samples collected at the residential area, with the concentrations of 3.192 ± 0.727 and 0.170 ± 0.028 μmol/L, respectively. Anionic surfactants as MBAS were found to dominate the concentration of surfactants in both runoff and rainwater. The concentrations of both anionic and cationic surfactants in runoff water were recorded as being higher than in rainwater.
Matched MeSH terms: Water Pollutants, Chemical/analysis*; Water Pollution, Chemical/statistics & numerical data
Urbanization and frequent storms play important roles in increasing faecal bacteria pollution, especially for tropical urban catchments. However, only little information on the faecal bacteria levels from different land use types and the factors that influence bacteria concentrations is available. Thus, the objectives of this study were to quantify the levels and transport mechanism of faecal coliforms (FCs) from residential and commercial catchments. Stormwaters were sampled and the runoff flow rates were measured from both catchments during four storm events in Skudai, Malaysia. The samples were then analysed for FC, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS) and ammoniacal-nitrogen (NH3-N) concentrations. Intra-storm and inter-storm characteristics of FC bacteria were investigated in order to identify the level and transport pattern of FC. The commercial catchment showed significantly higher event mean concentration (EMC) of FC than the residential catchment. For the residential catchment, the highest bacterial concentrations occurred during the early part of stormwater runoff with peak concentrations usually preceding the peak flow. First flush effect was more prevalent at the residential catchment.
Matched MeSH terms: Water Microbiology*; Water Movements*
A lab-scale granular activated carbon sequencing batch biofilm reactor (GAC-SBBR), a combined adsorption and biological process, was developed to treat real wastewater from a recycled paper mill. In this study, one-consortia of mixed culture (4000-5000 mg/L) originating from recycled paper mill activated sludge from Kajang, Malaysia was acclimatized. The GAC-SBBR was fed with real wastewater taken from the same recycled paper mill, which had a high concentration of chemical oxygen demand (COD) and adsorbable organic halides (AOX). The operational duration of the GAC-SBBR was adjusted from 48 h to 24, 12 and finally 8 h to evaluate the effect of the hydraulic retention time (HRT) on the simultaneous removal of COD and AOX. The COD and AOX removals were in the range of 53-92% and 26-99%, respectively. From this study, it was observed that the longest HRT (48 h) yielded a high removal of COD and AOX, at 92% and 99%, respectively.
Matched MeSH terms: Water Pollutants, Chemical/isolation & purification*; Waste Water/chemistry*
Adsorption capacity of an agricultural waste, palm-tree fruit stones (date stones), for phenolic compounds such as phenol (Ph) and p-nitro phenol (PNPh) at different temperatures was investigated. The characteristics of such waste biomass were determined and found to have a surface area and iodine number of 495.71 m2/g and 475.88 mg/g, respectively. The effects of pH (2-12), adsorbent dose (0.6-0.8 g/L) and contact time (0-150 min) on the adsorptive removal process were studied. Maximum removal percentages of 89.95% and 92.11% were achieved for Ph and PNPh, respectively. Experimental equilibrium data for adsorption of both components were analyzed by the Langmuir, Freundlich and Tempkin isotherm models. The results show that the best fit was achieved with the Langmuir isotherm equation with maximum adsorption capacities of 132.37 and 161.44 mg/g for Ph and PNPh, respectively. The kinetic data were fitted to pseudo-first order, pseudo-second order and intraparticle diffusion models, and was found to follow closely the pseudo-second order model for both components. The calculated thermodynamic parameters, namely ΔG, ΔH, and ΔS showed that adsorption of Ph and PNPh was spontaneous and endothermic under examined conditions.
Matched MeSH terms: Water Pollutants, Chemical/metabolism*; Water Purification*
The pollution status of the downstream section of the Jakara River was investigated. Dissolved oxygen (DO), 5-day biochemical oxygen demand (BOD(5)), chemical oxygen demand (COD), suspended solids (SS), pH, conductivity, salinity, temperature, nitrogen in the form of ammonia (NH(3)), turbidity, dissolved solids (DS), total solids (TS), nitrates (NO(3)), chloride (Cl) and phosphates (PO(3-)(4)) were evaluated, using both dry and wet season samples, as a measure of variation in surface water quality in the area. The results obtained from the analyses were correlated using Pearson's correlation matrix, principal component analysis (PCA) and paired sample t-tests. Positive correlations were observed for BOD(5), NH(3), COD, and SS, turbidity, conductivity, salinity, DS, TS for dry and wet seasons, respectively. PCA was used to investigate the origin of each water quality parameter, and yielded 5 varimax factors for each of dry and wet seasons, with 70.7 % and 83.1 % total variance, respectively. A paired sample t-test confirmed that the surface water quality varies significantly between dry and wet season samples (P < 0.01). The source of pollution in the area was concluded to be of anthropogenic origin in the dry season and natural origins in the wet season.
Matched MeSH terms: Water Pollutants, Chemical/analysis*; Water Quality/standards*
This study employed three chemometric data mining techniques (factor analysis (FA), cluster analysis (CA), and discriminant analysis (DA)) to identify the latent structure of a water quality (WQ) dataset pertaining to Kinta River (Malaysia) and to classify eight WQ monitoring stations along the river into groups of similar WQ characteristics. FA identified the WQ parameters responsible for variations in Kinta River's WQ and accentuated the roles of weathering and surface runoff in determining the river's WQ. CA grouped the monitoring locations into a cluster of low levels of water pollution (the two uppermost monitoring stations) and another of relatively high levels of river pollution (the mid-, and down-stream stations). DA confirmed these clusters and produced a discriminant function which can predict the cluster membership of new and/or unknown samples. These chemometric techniques highlight the potential for reasonably reducing the number of WQVs and monitoring stations for long-term monitoring purposes.
Matched MeSH terms: Water Pollutants, Chemical/analysis*; Water Quality*
This paper examines the storm runoff quality from a commercial area in south Johor, Malaysia. Six storm events with a total of 68 storm runoff samples were analyzed. Event Mean Concentration (EMC) for all constituents analysed showed large inter-event variation. Site mean concentrations (SMC) for total suspended solids (TSS), oil and grease (O&G), biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrate-nitrogen (NO(3)-N), nitrite-nitrogen (NO(2)-N), ammonia-nitrogen (NH(3)-N), total phosphorus (Total P) and Soluble P are 261, 4.31, 74, 192, 1.5, 0.006, 1.9, 1.12 and 0.38 mg/L, respectively. The SMCs at the studied site are higher than those reported in many urban catchments. The mean baseflow concentrations were higher than the EMCs for COD, Soluble P, NH(3)-N, NO(3)-N, Total P and NO(2)-N. However, the reverse was observed for TSS and O&G. All pollutants showed the occurrence of first flush phenomenon with the highest strength was observed for TSS, COD and NH(3)-N.
Matched MeSH terms: Water Movements*; Water Pollutants, Chemical/chemistry*
Surface sediments along the south of Caspian Sea were collected to evaluate the contamination of heavy metals. The result ranged (μg/g, Fe% dw): Pb(13.06-33.48); Ni(18.01-69.63); Cd(0.62-1.5); Zn(30.11-87.88); Cu(5.86-26.37) and Fe(1.8-4%) respectively. Cadmium showed higher EF when compared to other sites. Geoaccumulation Index value for Cd in most stations was classified as moderately contaminated and moderately to strongly contaminated, as well as the average of I(geo) of Cd (1.77 ± 0.35) suggested that surface sediments of Caspian coast were moderately polluted by this metal. The result of the Pearson correlation showed that there were significant positive associations between Ni, Cd and Zn (r = 0.44-0.76; p < 0.01).
Matched MeSH terms: Fresh Water/chemistry*; Water Pollutants, Chemical/analysis*
The Bio-ecological Drainage System, or BIOECODS, is an urban drainage system located at the Engineering Campus, Universiti Sains Malaysia. It consists of a constructed wetland as a part of the urban drainage system to carry storm water in a closed system. In this closed system, the constructed wetland was designed particularly for further treatment of storm water. For the purpose of studying the water balance of the constructed wetland, data collection was carried out for two years (2007 and 2009). The results show that the constructed wetland has a consistent volume of water storage compared to the outflow for both years with correlation coefficients (R(2)) of 0.99 in 2007 and 0.86 in 2009.
Matched MeSH terms: Water Movements*; Water Purification/methods*
Removal of arsenic from aqueous solution was carried out using electrocoagulation. Experiments were conducted using mild steel sacrificial anode covering wide range in operating conditions to assess the removal efficiency. The maximum arsenic removal efficiency was recorded as 94% under optimum condition. The electrocoagulation mechanism of arsenic removal has been developed to understand the effect of applied charge and electrolyte pH on arsenic removal efficiency. Further the experimental data were tested with different adsorption isotherm model to describe the electrocoagulation process.
Matched MeSH terms: Water Pollutants, Chemical/isolation & purification*; Water Purification/methods
In this study, advanced oxidation process utilizing Fenton's reagent was investigated for degradation of malachite green (MG). The effects of different reaction parameters such as the initial MG concentration, initial pH, the initial hydrogen peroxide concentration, the initial ferrous concentration and the reaction temperature on the oxidative degradation of MG have been investigated. The optimal reacting conditions were experimentally found to be pH 3.40, initial hydrogen peroxide concentration=0.50mM and initial ferrous concentration=0.10mM for initial MG concentration of 20mg/L at 30 degrees C. Under optimal conditions, 99.25% degradation efficiency of dye in aqueous solution was achieved after 60 min of reaction.
Matched MeSH terms: Water Pollutants, Chemical/chemistry; Water Purification/methods*
The purpose of this paper are to determine the concentration of heavy metals namely cadmium (Cd), copper (Cu) and lead (Pb) in water and sediment; and to investigate the effect of sediment pH and sediment organic matter on concentration of cadmium, copper and lead in sediment at oxidation fraction. For this purpose the concentration of heavy metals were measured in water and sediments at 15 sites from Tasik Chini, Peninsular Malaysia. The sequential extraction procedure used in this study was based on defined fractions: exchangeable, acid reduction, oxidation, and residual. The concentration of heavy metals in residual fraction was higher than the other fractions. Among the non-residual fractions, the concentration of heavy metals in organic matter fraction was much higher than other fractions collected from all sampling sites. The pH of the sediment in all sites was acidic. The mean pH ranges from 4.8 to 5.5 with the higher value observed at site 15. Results of organic matter analysis showed that the percentage of organic matter present in sediment samples varies throughout the lake and all sites of sediments were relatively rich in organic matter ranging from 13.0% to 34.2%. The highest mean percentage of organic matter was measured at sampling site 15, with value of 31.78%.
Matched MeSH terms: Fresh Water/chemistry*; Water Pollutants, Chemical/analysis*
A study of the water quality changes of Chini Lake was conducted for 12 months, which began in May 2004 and ended in April 2005. Fifteen sampling stations were selected representing the open water body in the lake. A total of 14 water quality parameters were measured and Malaysian Department of Environment Water Quality Index (DOE-WQI) was calculated and classified according to the Interim National Water Quality Standard, Malaysia (INWQS). The physical and chemical variables were temperature, dissolved oxygen (DO), conductivity, pH, total dissolved solid (TDS), turbidity, chlorophyll-a, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), ammonia-N, nitrate, phosphate and sulphate. Results show that base on Malaysian WQI, the water in Chini Lake is classified as class II, which is suitable for recreational activities and allows body contact. With respect to the Interim National Water Quality Standard (INWQS), temperature was within the normal range, conductivity, TSS, nitrate, sulphate and TDS are categorized under class I. Parameters for DO, pH, turbidity, BOD, COD and ammonia-N are categorized under class II. Comparison with eutrophic status indicates that chlorophyll-a concentration in the lake was in mesotrophic condition. In general water quality in Chini Lake varied temporally and spatially, and the most affected water quality parameters were TSS, turbidity, chlorophyll-a, sulphate, DO, ammonia-N, pH and conductivity.
Matched MeSH terms: Fresh Water/chemistry*; Water Pollutants/analysis*
A study was conducted to investigate the efficiency of coagulation and flocculation processes for removing colour from a semi-aerobic landfill leachate from one of the landfill sites in Malaysia. Four types of coagulant namely aluminium (III) sulphate (alum), ferric (III) chloride, ferrous (II) sulphate and ferric (III) sulphate were studied using standard jar test apparatus. Results indicated that ferric chloride was superior to the other coagulants and removed 94% of colour at an optimum dose of 800 mg/l at pH 4. The effect of coagulant dosages on colour removal showed similar trend as for COD, turbidity and suspended solids. This suggested that colour in landfill leachate was mainly contributed by organic matters with some insoluble forms that exhibited turbidity and suspended solids readings. The results from this study suggested that ferric chloride could be a viable coagulant in managing colour problems associated with landfill leachate.
Matched MeSH terms: Water Pollutants, Chemical/chemistry*; Water Purification/methods*
Water-based cooling towers and their water supply at two hospitals in Johor were surveyed for the presence Legionella pneumophila. L. pneumophila were grown from 19 (76%) out of 25 collected water samples. One hospital cooling tower was contaminated with L. pneumophila serogroup 1.
Matched MeSH terms: Water Pollution/analysis*; Water Supply/standards
A study on physico-chemical parameters and pathogenic bacterial community was carried out at the coastal waters of Pulau Tuba island, Langkawi. The physico-chemical parameters such as temperature (27.43-28.88 degrees C), dissolved oxygen (3.79-6.49 mg l(-1)), pH (7.72-8.20), salinity (33.10-33.96 ppt), total dissolved solids (32.27-32.77 g l(-1)) and specific conductivity (49.83-51.63 mS cm(-1)) were observed. Station 3 and station 4 showed highest amount of nitrates (26.93 and 14.61 microg at N l(-1)) than station 1 (2.04 microg at N l(-1)) and station 2 (4.18 microg at N l(-1)). The highest concentration (12.4 +/- microg l(-1)) of chlorophyll a was observed in station 4 in October 2005. High phosphorus content (561 microg P l(-1)) was found in the station 2. Thirteen bacterial isolates were successfully identified using API 20E system. The highest amount of bacteria was observed at Station 4 (3400 CFU ml(-1)) and the lowest numberwas at Station 2 (890 CFU ml(-1)). Out of identified 13 Gram-negative bacterial isolates dominant species were Aeromonas hydrophila, Klebsiella oxytoca, Pseudomonas baumannii, Vibrio vulnificus, Proteus mirabilis, Providencia alcalifaciens and Serratia liquefaciens. Apart from this, oil biodegrading Pseudomonas putida were also identified. The study reveals the existing status of water quality is still conducive and the reasonably diverse with Gram-negative bacteria along the Pulau Tuba Langkawi.
Matched MeSH terms: Water Microbiology*; Water Pollutants; Water Pollution
The development of eco-friendly and efficient technologies for treating wastewater is one of the attractive research area. Phytoremediation is considered to be a possible method for the removal of pollutants present in wastewater and recognized as a better green remediation technology. Nowadays the focus is to look for a sustainable approach in developing wastewater treatment capability. Water hyacinth is one of the ancient technology that has been still used in the modern era. Although, many papers in relation to wastewater treatment using water hyacinth have been published, recently removal of organic, inorganic and heavy metal have not been reviewed extensively. The main objective of this paper is to review the possibility of using water hyacinth for the removal of pollutants present in different types of wastewater. Water hyacinth is although reported to be as one of the most problematic plants worldwide due to its uncontrollable growth in water bodies but its quest for nutrient absorption has provided way for its usage in phytoremediation, along with the combination of herbicidal control, integratated biological control and watershed management controlling nutrient supply to control its growth. Moreover as a part of solving wastewater treatment problems in urban or industrial areas using this plant, a large number of useful byproducts can be developed like animal and fish feed, power plant energy (briquette), ethanol, biogas, composting and fiber board making. In focus to the future aspects of phytoremediation, the utilization of invasive plants in pollution abatement phytotechnologies can certainly assist for their sustainable management in treating waste water.
Matched MeSH terms: Water Pollutants, Chemical/isolation & purification*; Waste Water/chemistry*