PURPOSE: Urbanization and industrialization in China has resulted in a dramatic increase in the volume of wastewater and sewage sludge produced from wastewater treatment plants. Problems associated with sewage sludge have attracted increasing attention from the public and urban planners. How to manage sludge in an economically and environmentally acceptable manner is one of the critical issues that modern societies are facing. METHODS: Sludge treatment systems consist of thickening, dewatering, and several different alternative main treatments (anaerobic digestion, aerobic digestion, drying, composting, and incineration). Agricultural application, landfill, and incineration are the principal disposal methods for sewage sludge in China. However, sewage sludge disposal in the future should focus on resource recovery, reducing environmental impacts and saving economic costs. RESULTS: The reuse of biosolids in all scenarios can be environmentally beneficial and cost-effective. Anaerobic digestion followed by land application is the preferable options due to low economic and energy costs and material reuse. CONCLUSION: It is necessary to formulate a standard suitable for the utilization of sewage sludge in China.

PURPOSE: Dechlorination of polychlorinated biphenyls (PCBs) by nanoscale zerovalent iron (NZVI) is often strongly hindered by increased pH because large amounts of H+ ions were consumed during the surface reaction. The main objective of this work was to evaluate the effect of pH control in acid on the dechlorination processes of PCBs and to compare the dechlorination efficiency between 2,4,4′-trichlorobiphenyl (2,4,4′-CB) and the extracted PCBs from the field PCBs-contaminated soil in this system. METHODS: The reaction solution pH was controlled to be weakly acid (4.90–5.10) with an automatic pH control system, in which the dechlorination of 2,4,4′-CB and extracted PCBs from a PCBs-contaminated soil by NZVI and palladized nanoscale zerovalent iron (NZVI/Pd) was investigated. RESULTS: To control the reaction solution pH to be acid actually increased the dechlorination rate of PCBs by NZVI and NZVI/Pd. The observed normalized pseudo-first-order dechlorination rate constants (k obs) of 2,4,4′-CB increased from 0.0029 min−1 (no pH control) to 0.0078 min−1 (pH control) by NZVI and from 0.0087 min−1 (no pH control) to 0.0108 min−1 (pH control) by NZVI/Pd. In the case of NZVI/Pd, the chlorines in the para position were much more easily dechlorinated than ortho position, and biphenyl was the dominating product. As the solution pH was controlled at 4.90–5.10, the dechlorination rate constants of PCB congeners extracted from soil (k obs) were 0.0027–0.0033 min−1 and 0.0080–0.0098 min−1 by NZVI and NZVI/Pd, respectively. CONCLUSIONS: To keep the reaction solution to be weakly acid markedly increased the dechlorination rate of PCBs, which may offer a novel technology in the remediation of PCBs-contaminated soil.

PURPOSE: Phytoremediation is the exploitation of plants and their rhizospheric microorganisms for pollutants treatment like textile dyes, which are toxic, carcinogenic and mutagenic from the effluent. The purpose of this work was to explore a naturally found plant and bacterial synergism to achieve an enhanced degradation of Remazol Black B dye (RBB). METHODS: In vitro cultures of Zinnia angustifolia were obtained by seed culture method. Enzymatic analysis of the plant roots and Exiguobacterium aestuarii strain ZaK cells was performed before and after decolorization of RBB. Metabolites of RBB formed after its degradation were analyzed using UV–Vis spectroscopy, high-performance liquid chromatography (HPLC), Fourier transform infrared (FTIR) and gas chromatography–mass spectrometry (GC-MS). Phytotoxicity studies were performed. RESULTS: The consortium ZE was found to be more efficient than individual plant and bacteria. Z. angustifolia roots showed significant induction in the activities of lignin peroxidase, laccase, DCIP reductase and tyrosinase during dye decolorization. E. aestuarii showed significant induction in the activities of veratryl alcohol oxidase, azo reductase and DCIP reductase. Analysis of metabolites revealed differential metabolism of RBB by plant, bacteria and consortium ZE. E. aestuarii and Z. angustifolia led to the formation of 3,6-diamino-4-hydroxynaphthalene-2-sulfonic acid, (ethylsulfonyl)benzene, and 3,4,6-trihydroxynaphthalene-2-sulfonic acid and propane-1-sulfonic acid, respectively, whereas consortium ZE produced 4-hydroxynaphthalene-2-sulfonic acid, naphthalene-2-sulfonic acid and 4-(methylsulfonyl)phenol. The phytotoxicity study revealed the nontoxic nature of the metabolites formed after dye degradation. CONCLUSION: Consortium ZE was found to be more efficient and faster in the degradation of RBB when compared to degradation by Z. angustifoila and E. aestuarii individually.

Water of good quality is one of the basic needs of human life. Worldwide, great efforts are being undertaken for an assured water supply. In this respect, one of the largest water technology projects worldwide is the Yangtze Three Gorges Dam in China. There is a need for extensive scientific and technical understanding of the challenges arising from this large hydrological engineering project. German and Chinese groups from various scientific fields are collaborating to provide knowledge for the sustainable management of the reservoir. In this project description, the Yangtze Three Gorges Dam Project, its goals and challenges, are described in brief, and the contributions of the German research projects are presented.

PURPOSE: The major aromatic constituents of petroleum products viz. benzene, toluene, and mixture of xylenes (BTX) are responsible for environmental pollution and inflict serious public concern. Therefore, BTX biodegradation potential of individual as well as formulated bacterial consortium was evaluated. This study highlighted the role of hydrogen peroxide (H2O2), nitrate, and phosphate in stimulating the biodegradation of BTX compounds under hypoxic condition. MATERIALS AND METHODS: The individual bacterium viz. Bacillus subtilis DM-04 and Pseudomonas aeruginosa M and NM strains and a consortium comprising of the above bacteria were inoculated to BTX-containing liquid medium and in soil. The bioremediation experiment was carried out for 120 h in BTX-containing liquid culture and for 90 days in BTX-contaminated soil. The kinetics of BTX degradation either in presence or absence of H2O2, nitrate, and phosphate was analyzed using biochemical and gas chromatographic (GC) technique. RESULTS: Bacterial consortium was found to be superior in degrading BTX either in soil or in liquid medium as compared to degradation of same compounds by individual strains of the consortium. The rate of BTX biodegradation was further enhanced when the liquid medium/soil was exogenously supplemented with 0.01 % (v/v) H2O2, phosphate, and nitrate. The GC analysis of BTX biodegradation (90 days post-inoculation) in soil by bacterial consortium confirmed the preferential degradation of benzene compared to m-xylene and toluene. CONCLUSIONS: It may be concluded that the bacterial consortium in the present study can degrade BTX compounds at a significantly higher rate as compared to the degradation of the same compounds by individual members of the consortium. Further, addition of H2O2 in the culture medium as an additional source of oxygen, and nitrate and phosphate as an alternative electron acceptor and macronutrient, respectively, significantly enhanced the rate of BTX biodegradation under oxygen-limited condition.

BACKGROUND: PM10 aerosol samples were simultaneously collected at two urban and one urban background sites in Fuzhou city during two sampling campaigns in summer and winter. PM10 mass concentrations and chemical compositions were determined. METHODS: Water-soluble inorganic ions (Cl−, NO 3 − , SO 4 2− , NH 4 + , K+, Na+, Ca2+, and Mg2+), carbonaceous species (elemental carbon and organic carbon), and elements (Al, Si, Mg, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, and Pb) were detected using ion chromatography, thermal/optical reflectance, and proton-induced X-ray emission methods, respectively. RESULTS: PM10 mass concentrations, as well as most of the chemical components, were significantly increased from urban background to urban sites, which were due to enhanced anthropogenic activities in urban areas. Elements, carbonaceous species, and most of the ions were more uniformly distributed at different types of sites in winter, whereas secondary ion SO 4 2− , NO 3 − , and NH 4 + showed more evident urban-background contrast in this season. The chemical mass closure indicated that mineral dust, organic matters, and sulfate were the most abundant components in PM10. The sum of individually measured components accounted for 86.9–97.7% of the total measured PM10 concentration, and the discrepancy was larger in urban area than in urban background area. CONCLUSION: According to the principal component analysis–multivariate linear regression model, mineral dust, secondary inorganic ions, sea salt, and motor vehicle were mainly responsible for the PM10 particles in Fuzhou atmosphere, and contributed 19.9%, 53.3%, 21.3%, and 5.5% of PM10, respectively.

BACKGROUND: Air samples collected on three different urban sites in East of France (Strasbourg, Besançon, and Spicheren), from April 2006 to January 2007, were characterized to measure the concentrations of polycyclic aromatic hydrocarbons (PAHs) in the particulate phase (PM10) and to examine their seasonal variation, diurnal variations, and emission sources. RESULTS: The average concentrations of ΣPAHs were 12.6, 9.5, and 8.9 ng m−3 for the Strasbourg, Besançon, and Spicheren sites, respectively. Strong seasonal variations of individual PAH concentrations were found at the three sampling sites, with higher levels in the winter that gradually decreased to the lowest levels in the summer. The diurnal variations of PAH concentrations in summer presented highest concentrations during the morning (04:00–10:00) and the evening (16:00–22:00) times, indicating the important contribution from vehicle emissions, in the three sampling sites. Furthermore, the ratio of BaP/BeP suggests that the photochemical degradation of PAHs can suppress their concentrations in the midday/afternoon (10:00–16:00), time interval of highest global irradiance. In winter, concentrations of PAH were highest during the evening (16:00–22:00) time, suggesting that domestic heating can potentially be an important source for particulate PAH, for the three sampling sites. CONCLUSION: Diagnostic ratios were used to identify potential sources of PAHs. Results showed that vehicle emissions may be the major source of PAHs, especially in summer, with a prevalent contribution of diesel engines rather than gasoline engines at the three sites studied, independently of the seasons.

INTRODUCTION: To assess the status of polycyclic aromatic hydrocarbons (PAHs) contamination in sediments from the upper reach of Huaihe River, East China, 16 surface sediment samples were collected in March 2007 and analyzed for 16 USEPA priority PAHs. RESULTS AND DISCUSSION: The results indicated that the total concentrations of 16 PAHs (∑PAHs) were 95.2–877.5 μg kg−1 dry weight (dw) with a mean value of 370.8 μg kg−1 dw for the main stream, 85.7–935.2 μg kg−1 dw with a mean concentration of 480.7 μg kg−1 dw for tributaries, and 144.8–303.2 μg kg−1 dw with an average concentration of 224.0 μg kg−1 dw for lakes. PAHs pollution was closely related to sewage input and industrial activities. Furthermore, the distribution of PAHs in sediments from the main stream indicated that the input of tributaries was an important factor for Huaihe River. In comparison to a worldwide survey of sedimentary PAHs concentrations, PAHs pollution in Huaihe River sediments was ranked as low to moderate. The dominant compounds in surface sediment samples were four-ring and five-ring PAH compounds. CONCLUSION: Selected PAH ratios suggested that PAHs mainly came from the contamination of pyrogenic processes, such as coal and biomass combustion. Risk assessment indicated that PAHs in sedimentary environment in the upper reach of Huaihe River may cause mild toxic effects but would not cause immediate biological effects.

BACKGROUND, AIM, SCOPE: Treatment of wastewater has become significant with the declining water resources. The presence of recalcitrant organics is the major issue in meeting the pollution control board norms in India. The theme of the present investigation was on partial or complete removal of pollutants or their transformation into less toxic and more biodegradable products by heterogeneous Fenton oxidation process using mesoporous activated carbon (MAC) as the catalyst. MATERIALS AND METHODS: Ferrous sulfate (FeSO4·7H2O), sulfuric acid (36 N, specific gravity 1.81, 98% purity), hydrogen peroxide (50% v/v) and all other chemicals used in this study were of analytical grade (Merck). Two reactors, each of height 50 cm and diameter 6 cm, were fabricated with PVC while one reactor was packed with MAC of mass 150 g and other without MAC served as control. RESULTS AND DISCUSSION: The oxidation process was presented with kinetic and thermodynamic constants for the removal of COD, BOD, and TOC from the wastewater. The activation energy (Ea) for homogeneous and heterogeneous Fenton oxidation processes were 44.79 and 25.89 kJ/mol, respectively. The thermodynamic parameters ΔG, ΔH, and ΔS were calculated for the oxidation processes using Van’t Hoff equation. Furthermore, the degradation of organics was confirmed through FTIR and UV–visible spectroscopy, and cyclic voltammetry. CONCLUSIONS: The heterocatalytic Fenton oxidation process efficiently increased the biodegradability index (BOD/COD) of the tannery effluent. The optimized conditions for the heterocatalytic Fenton oxidation of organics in tannery effluent were pH 3.5, reaction time–4 h, and H2O2/FeSO4·7H2O in the molar ratio of 2:1.

PURPOSE: Malachite Green (MG) is used for a variety of applications but is also known to be carcinogenic and mutagenic. In this study, a novel Micrococcus sp. (strain BD15) was observed to efficiently decolorize MG. The purposes of this study were to explore the optimal conditions for decolorization and to evaluate the potential use of this strain for MG decolorization. METHODS: Optical microscope and UV–visible analyses were carried out to determine whether the decolorization was due to biosorption or biodegradation. A Plackett–Burman design was employed to investigate the effect of various parameters on decolorization, and response surface methodology was then used to explore the optimal decolorization conditions. Kinetics analysis and antimicrobial activity tests were also performed. RESULTS: The results indicated that the decolorization by the strain was mainly due to biodegradation. Concentrations of MG, urea, and yeast extract and inoculum size had significantly positive effects on MG decolorization, while concentrations of CuCl₂ and MgCl₂, and temperature had significantly negative effects. The interaction between different parameters could significantly affect decolorization, and the optimal conditions for decolorization were 1.0 g/L urea, 0.9 g/L yeast extract, 100 mg/L MG, 0.1 g/L inoculums (dry weight), and incubation at 25.2°C. Under the optimal conditions, 96.9% of MG was removed by the strain within 1 h, which represents highly efficient microbial decolorization. Moreover, the kinetic data for decolorization fit a second-order model well, and the strain showed a good MG detoxification capability. CONCLUSION: Based on the results of this study, we propose Micrococcus sp. strain BD15 as an excellent candidate strain for MG removal from wastewater.