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J Environ Sci Health A Tox Hazard Subst Environ Eng [journal]
- Partial nitrification for nitrogen removal from sanitary landfill leachate. [JOURNAL ARTICLE]
- J Environ Sci Health A Tox Hazard Subst Environ Eng 2014 Sep 19; 49(11):1331-1340.
Biological nitrogen removal using nitrite as a shortcut has recently been proposed for the treatment of high strength landfill leachate. The aim of this study was to assess the application of the SHARON (Single reactor High activity Ammonium Removal Over Nitrite) process for the partial nitrification of leachate generated in old landfills. Particular attention was given to the start-up phase of the process. This study demonstrated that partial nitrification can be obtained when treating raw leachate after biomass acclimation. Only a fraction (50-70%) of the ammonia present in the leachate can be oxidised due to a limited amount of alkalinity available. Stable nitritation was obtained by applying a hydraulic retention time (HRT) of 4-5 d, which is higher than the values proposed for the effluent of anaerobic digesters. This higher HRT could probably be allowed by the high concentration of free ammonia present in the leachate, which could severely inhibit the growth of nitrite-oxidising bacteria.
- The occurrence of Naegleria fowleri in recreational waters in Arizona. [JOURNAL ARTICLE]
- J Environ Sci Health A Tox Hazard Subst Environ Eng 2014 Sep 19; 49(11):1322-1330.
Naegleria fowleri is a free-living amoeba found in waters in warmer regions that causes primary amoebic meningoencephalitis, a rare but almost universally fatal disease. The goal of this project was to assess the occurrence of N. fowleri and other thermophilic amoebae in 33 recreational surface waters across Arizona to determine if their presence could be correlated with seasonal or other environmental factors. First, 1-L grab samples were collected over two years and analyzed using polymerase chain reaction and amoebae viability. Seasonality was observed, with N. fowleri and thermophilic amoebae (20% and 30%, respectively) being detected more often in the winter and spring combined than in the summer and fall combined (7.9% and 9.5%, respectively). The spring and fall both had an average temperature of 18°C, yet had different occurrence data (18.2% versus 5.9% for N. fowleri, respectively; 27.3% versus 0% for viable amoebae, respectively). These results are in stark contrast to previous studies in which N. fowleri has been found almost exclusively during warmer months. Over the two-year study, N. fowleri was detected in six and thermophilic amoebae in eight of the 33 recreational water bodies. Five of these were lakes near Phoenix that tested positive for N. fowleri and thermophilic amoebae over multiple seasons. These lakes differed significantly (P ≤ 0.05) from the other 28 surface waters, with a lower average temperature in the spring, a higher temperature in the fall, a higher pH and turbidity in the summer, and a lower electro-conductivity in the spring. They also had lower Escherichia coli and heterotrophic bacteria levels during colder months. Future N. fowleri monitoring in Arizona should focus on these five lakes to further elucidate the factors that contribute to the low occurrence of this amoeba in the summer or which might explain why these lakes appear to be reservoirs for the organism.
- A model for methane production in sewers. [JOURNAL ARTICLE]
- J Environ Sci Health A Tox Hazard Subst Environ Eng 2014 Sep 19; 49(11):1316-1321.
Most sewers in developing countries are combined sewers which receive stormwater and effluent from septic tanks or cesspools of households and buildings. Although the wastewater strength in these sewers is usually lower than those in developed countries, due to improper construction and maintenance, the hydraulic retention time (HRT) could be relatively long and resulting considerable greenhouse gas (GHG) production. This study proposed an empirical model to predict the quantity of methane production in gravity-flow sewers based on relevant parameters such as surface area to volume ratio (A/V) of sewer, hydraulic retention time (HRT) and wastewater temperature. The model was developed from field survey data of gravity-flow sewers located in a peri-urban area, central Thailand and validated with field data of a sewer system of the Gold Coast area, Queensland, Australia. Application of this model to improve construction and maintenance of gravity-flow sewers to minimize GHG production and reduce global warming is presented.
- Chemical fractionation of Cu, Zn, Cd, Cr, and Pb in sewage sludge amended soils at the end of 65-d sorghum-sudan grass growth. [JOURNAL ARTICLE]
- J Environ Sci Health A Tox Hazard Subst Environ Eng 2014 Sep 19; 49(11):1304-1315.
Heavy metals are potentially toxic to human life and the environment. Metal toxicity depends on chemical associations in soil. Understanding the chemical association of trace elements in soils amended with biosolids is very important since it determines their availability within rhizosphere and mobility beyond the rhizosphere. A sequential extraction method was used to determine the various chemical associations [labile (exchangeable + sorbed), organic, carbonates, and sulfides] of Cu, Zn, Cd, Cr, and Pb at the end of sorghum-sudan grass growth (65d) in Candler fine sand (pH = 6.8) and in Ogeechee loamy sand (pH = 5.2) amended with wastewater treatment sludge (WWTS) obtained from two different sources at application rates of 0, 24.7, 49.4, 98.8, and 148.2 Mg ha(-1). Results of this study indicated that irrespective of the soil type, Cu, Cd, Cr, and Pb in the labile fractions (exchangeable + sorbed) were in the range of 0-3.0 mg kg(-1) and the amount for Zn was in the range of 0.2-6.6 mg kg(-1). Therefore, their availability to plants and mobility beyond rhizosphere would be substantially low unless further transformations occur from other fractions. Results also indicated that the presence of substantial amounts of trace elements studied were in sulfide (HNO3) fraction and in organic (NaOH) fraction irrespective of soil type with the exception of Pb which was mainly present as carbonate (Na2EDTA) fraction and the remaining Pb equally as sulfide (HNO3) and organic (NaOH) fractions. Furthermore, results indicated that Cd was mainly present as carbonate (Na2EDTA) fraction. Irrespective of soil type, source and rate of WWTS application, summation of quantities of various fractions of all the trace elements studied through sequential extraction procedure were 1 to 25 % lower than that of total recoverable quantities of these trace elements determined on acid digestion described by US EPA method 3050 B. It was further evident that growing sorghum sudan grass for 65-d following the application of WWTS either depleted labile fractions or shifted the solid phases containing the trace elements in soils away from those extractable with more severe reagents, such as 4M HNO3 to those extractable with milder reagents such as dilute NaOH and Na2EDTA.
- Study on an integrated process combining ozonation with ceramic ultra-filtration for decentralized supply of drinking water. [JOURNAL ARTICLE]
- J Environ Sci Health A Tox Hazard Subst Environ Eng 2014 Sep 19; 49(11):1296-1303.
An integrated process was specifically developed for the decentralized supply of drinking water from micro-polluted surface water in the rural areas of China. The treatment process combined ozonation with ceramic ultra-filtration (UF), coagulation for pre-treatment and granular activated carbon filtration. A flat-sheet ceramic membrane was used with a cut-off of 60 nm and the measurement of 254 mm (length) × 240 mm (width) × 6 mm (thickness). Ozonation and ceramic UF was set up whthin one reactor. The experimental results showed that the removal efficiencies of the dissolved organic carbon (DOC) and the formation potential of trihalomethanes (THMs), haloacetic acids (HAAs) and ammonia were 80%, 76%, 70% and 90%, respectively; that the turbidity of the product water was below 0.2 NTU and the particle count number (particles larger than 2 μm) was less than 50 counts per mL. The result also showed that all the pathogenic microorganisms were retained by the ceramic and that UF. Ozonation played a critical role in the control of membrane fouling and the removal of contaminants. Exactly, the membrane fouling can be controlled in situ with 3 mg L(-1) ozone at the permeate flux of 80 L m(-2) h(-1), yet the required dosage of ozone was dependent on the quality of the raw water. Therefore, this study is able to provide a highly compacted system for decentralized supply of high-quality drinking water in terms of both chemical and microbiological safety for the rural areas in China.
- Bioremediation from wastewater and extracellular synthesis of copper nanoparticles by the fungus Trichoderma koningiopsis. [JOURNAL ARTICLE]
- J Environ Sci Health A Tox Hazard Subst Environ Eng 2014 Sep 19; 49(11):1286-1295.
This is the first study describing the rapid extracellular production of copper nanoparticles by dead biomass of Trichoderma koningiopsis. The production and uptake of copper nanoparticles by dead biomass of Trichoderma koningiopsis were characterized by investigating physicochemical factors, equilibrium concentrations and biosorption kinetics, combined with scanning electron microscopy (SEM), energy dispersive X-ray (EDS), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). A successful route for the metallic copper nanoparticles synthesis was achieved, and followed a Langmuir isotherm where a high biosorption capacity was observed, 21.1 mg g(-1). The kinetic analysis showed that copper biosorption followed a pseudo-second-order model. The nanoparticles mainly exhibited a spherical shape, with an average size of 87.5 nm, and were synthesized extracellularly. The presence of proteins as stabilizing agents of the nanoparticles was demonstrated. The extracellular biosynthesis and uptake of copper nanoparticles using dead fungal biomass is a low-cost green processes, and bioremediation of impacted local.
- Biomarker responses to sewage pollution in freshwater mussels (Diplodon chilensis) transplanted to a Patagonian river. [JOURNAL ARTICLE]
- J Environ Sci Health A Tox Hazard Subst Environ Eng 2014 Sep 19; 49(11):1276-1285.
Field and laboratory experiments were combined to evaluate biomarker responses of Diplodon chilensis to sewage pollution. Mussels from an unpolluted area in Lacar lake (S0) were caged at a reference site (S1) and at two sites with increasing sewage pollution (S2, S3) in Pocahullo river (all in Argentina). After 1 month, gill (g) glutathione S-transferase (GST) and catalase (CAT) activities, and lipid peroxidation (TBARS) were found to be significantly elevated in S3, gGST being positively correlated with fecal bacteria (FC) concentration. Digestive gland (dg) enzyme activities were depressed and dgTBARS were increased in all transplanted mussels. After 3 mo, most variables returned to control levels in S1 mussels except for dgCAT and dgTBARS. After seven months, GST and CAT activities of S0 and S3 mussels were evaluated in the laboratory, before and after acute exposure (8 h) to high fecal bacteria concentration ([FC] in S3x 2). gGST increased in both groups, while dgGST responded only in S3 mussels. gCAT and dgCAT activities were similarly increased by acute exposure in both groups. Our results suggest that gGST and gCAT are suitable biomarkers for high FC pollution regardless of previous exposure history. In addition, we show that dgCAT is sensitive to the acute increase in FC load, both in naive and long-term exposed individuals, while dgGST becomes responsive after long-term acclimatization.
- Removal of organic matters and nitrogenous pollutants simultaneously from two different wastewaters using biocathode microbial fuel cell. [Journal Article]
- J Environ Sci Health A Tox Hazard Subst Environ Eng 2014 Sep 19; 49(11):1265-75.
In this study, a dual chamber MFC was constructed for simultaneous removal of organic matter and nitrogenous pollutants and bioelectricity generation from synthetic and complex industrial wastewaters and it was operated in batch and continuous mode. When the cell potential was stable after 16 days of batch mode operation, the MFC was converted to continuous mode (from batch mode) and operated for 125 days with different organic loading rates (OLR) and ammonia loading rates (ALR) and fixed hydraulic retention time (HRT) of 40 h. The OLR of 1.49 kg COD m(-3) d(-1) and ALR of 0.58 kg NH3(-) m(-3) d(-1), for anodic and cathodic chambers, respectively, gave the best results. The highest value of cell potential on these OLRs was 310 mV with current density of 85.11 mA m(-2), power density of 26.38 mW m(-2) and volumetric power density of 192.20 mW m(-3). During this period, COD reduction was 78-83% in the anodic chamber and the ammonia reduction was 36-38%. After stable operation with synthetic wastewater one case study was performed with complex industrial wastewater. Continuous mode operation was performed at two different OLR and HRT with a constant ALR. A stable power density and volumetric power density of 23.56 mW m(-2) and 112.50 mW m(-3), respectively were achieved after 24 days of continuous operation at an OLR of 0.35 kg COD/m(3) day with an ALR of 0.43 kg NH3(-) m(-3) day(-1) and corresponding HRT of 68 h. A maximum of 89% COD removal and 40% removal of ammonia was obtained after 50 days. A stable voltage of 300 mV was obtained across 1000 Ω resistance. These findings suggest that BMFC can be used for the treatment of industrial wastewater, with carbon removal in anodic chamber and electricity generation.
- Advanced treatment of cephalosporin pharmaceutical wastewater by nano-coated electrode and perforated electrode. [Journal Article]
- J Environ Sci Health A Tox Hazard Subst Environ Eng 2014 Sep 19; 49(11):1258-64.
The objective of this study was to investigate the degradation of nonbiodegradable organic pollutants in biologically cephalosporin pharmaceutical wastewater using different electrodes such as non-nano-scale electrode (traditional coated), nano-scale (nano-coated) electrode, and perforated electrode after biotreatment. The traditional coated electrode plate, nano-coated electrode plate, and two different perforated titanium dioxide (TiO2) electrode plates with an average pore size of 10 μm and 20 μm were chosen as the anode. The results demonstrated that traditional coated electrode, nano-scale electrode, and perforated electrode could effectively remove nonbiodegradable organic pollutants from pharmaceutical wastewater. The perforated electrode with an average pore size of 10 μm exhibited the best degradation effect with a 90 % decrease in the chemical oxygen demand (COD) (COD content reduced from 320 mg L(-1) to 32 mg L(-1)). During catalytic degradation, the electrical conductivity of pharmaceutical wastewater increased and the pH increased and finally reached equilibrium. It was also found that the perforated TiO2 electrode produced relatively large amounts of dissolved oxygen during the catalytic oxidation process, reaching above 4 mg L(-1), whereas the nano-coated electrode produced little dissolved oxygen. The biotoxicities of all wastewater samples increased firstly then decreased slightly during the electrical catalytic oxidation, but the final biotoxicities were all higher than initial ones.
- Lead isotope ratios in bone ash of blesbok (Damaliscus pygargus phillipsi): A means of screening for the accumulation of contaminants from uraniferous rocks. [JOURNAL ARTICLE]
- J Environ Sci Health A Tox Hazard Subst Environ Eng 2014 Sep 19; 49(11):1251-1257.
This study was done to determine whether blesbok (Damaliscus pygargus phillipsi) from the Krugersdorp Game Reserve (KGR) in Gauteng Province, South Africa have higher concentrations of (238)U and higher (206)Pb/(204)Pb and (207)Pb/(204)Pb ratios in their bone ash than blesbok from a nearby control reserve that is not exposed to mine water and has no outcrops of uraniferous rocks. Eight blesbok females from the KGR and seven from the control site, all killed with a brain shot, were used. A Thermo X-series 2 quadrupole ICPMS was used to measure the concentrations of (238)U and lead and a Nu Instruments NuPlasma HR MC-ICP-MS to measure the lead isotope ratios in the tibial ash from each animal. KGR blesbok had higher mean concentrations of (238)U (P = 0.02) and ratios of (206)Pb/(204)Pb and (207)Pb/(204)Pb (P < 0.00001) than the control blesbok. The probability of rejecting the false null hypothesis of no difference in the (206)Pb/(204)Pb or (207)Pb/(204)Pb ratios between KGR and control reserve animals (the power of the test) was 0.999. The blesbok from the KGR accumulated contaminants from an uraniferous environment. The (206)Pb/(204)Pb and (207)Pb/(204)Pb ratios in tibial ash proved effective in confirming accumulation of contaminants from uraniferous rocks.