Teaguebuck2014

51 times. Environmental implications suggest that sulfite pretreatment could save sludge treatment costs by 1.06 $/PE/y and reduce CO2-equivalent emissions by 5.19 kg CO2/PE/y, demonstrating its potential as a cost-effective and carbon-neutral technology for sludge management.Phosphogypsum (PG) is an industry solid waste produced from phosphoric acid manufacture. To reduce environmental pollution of the PG, H2C2O4 was employed to purify it, which then can be used for cement production. The optimal concentration of H2C2O4 for PG purification was determined. In addition, differential thermal analysis (DTA), X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence (XRF) were used to determine the removal of phosphate impurity in PG. The effects of purified PG on cement hydration and the environmental implications were also investigated. The results demonstrate that H2C2O4 can remove the intercrystalline phosphate impurities by destroying the part of the crystal structure of gypsum. With the best treatment concentration of 1% H2C2O4, 77.7% of phosphate impurity (as P2O5) was removed from PG, which subsequently shortened the final setting time down to 220 min and successfully met the national standard (GB 175-1999). ICG-001 Portland cement prepared by the 1% H2C2O4 treated PG possessed a comparable 3d compressive strength of 20.8 MPa and a 28d compressive strength of 44.6 MPa. It is concluded that PG purified by 1% H2C2O4 treatment can be used for cement production. Meanwhile, this H2C2O4 treatment can effectively reduce the environmental pollution from PG and offer a sustainable method for the utilization of PG.Conventional assessment of soil environmental quality commonly focuses on soil heavy metals (HMs), neglecting the HMs in agricultural products. To response this shortcoming, a comprehensive assessment combining both soil environmental quality and agricultural product security for evaluating soil HM impact is urgently required. This comprehensive assessment incorporates not only the HM contents in soil and agricultural product but also soil environmental quality standards, soil elemental background values, and safety standards for HMs in agricultural products. In this study, it was applied to evaluate the potential risk of HMs in soil-crop systems (i.e., soil-vegetable, soil-maize, soil-rice, and soil-wheat systems) along the Yangtze River in Nanjing, Jiangsu Province, Southeast China. Furthermore, 114Cd/110Cd isotope ratio analysis was used to identify the specific contamination sources. The mean concentrations of Cd, As, Hg, Pb, Cu, Zn, and Cr in the surface soils (0-20 cm) were 0.26, 11.07, 0.09, 32.63, 38.57, and 107.92 mg kg-1, respectively, exceeding the corresponding soil background values. Fertilizer and atmospheric deposition were the major anthropogenic sources of HM contamination in crop-growing soils. In addition to the crop type, soil pH and organic matter also influenced the transfer of HMs from soils to the edible parts of crops. Results of comprehensive assessment revealed that approximately 11.1% of paired soil-crop sites were multi-contaminated by HMs, among which paddy soils had the highest potential risk of HMs followed by maize soils, vegetable soils, and wheat soils. To evaluate the potential risk of HMs in arable land, this study provides a novel, scientific and reliable approach via integrating soil environmental quality and agricultural product security.Risk-based approaches are used to define performance standards for water and wastewater treatment to meet health-based targets and to ensure safe and reliable water quality for desired end use. In this study, a screening level QMRA for a non-membrane based indirect potable reuse (IPR) system utilizing the sequential managed aquifer recharge technology (SMART) concept was conducted. Ambient removals of norovirus, Campylobacter and Cryptosporidium in advanced water treatment (AWT) steps were combined in a probabilistic QMRA utilizing Bayesian networks constructed in Netica. Results revealed that all pathogens complied with disease burden at the 95th percentile, and according to the assumptions taken about pathogen removal, Cryptosporidium was the pathogen with the greatest risk. Through systematic sensitivity analysis, targeted scenario analysis, and backwards inferencing, critical control points for each pathogen were determined, demonstrating the usefulness of Bayesian networks as a diagnostic tool in quantifying risk of water reuse treatment scenarios.The desalination of seawater is perceived as one of the most viable processes to fulfill the mounting demand for freshwater. Despite enormous economic, social, and health benefits offered by desalination, there are several concerns regarding its prospective environmental impacts (EIs). The objective of this work is to critically evaluate the potential EIs of seawater desalination, and assess the prospects of greener desalination. The EIs of desalination on marine environment, land, groundwater, and air quality was systematically reviewed. An attempt has been made to analyze the actuality of these so-called impacts with reference to evidence from real desalination plants. The mitigative measures to counterbalance these unfavorable impacts are critically appraised. Furthermore, the brine management technologies for the disposal of reject stream, the recovery of precious materials and water, and the production of useful chemicals are also reviewed. Current challenges to minimize the adverse impacts of desalination and prospects of sustainable greener desalination to overwhelm global water scarcities are also discussed. The current desalination approaches have moderate and minor negative EIs. However, with proper mitigation and utilization of modern technologies, these impacts can be lessened. Furthermore, by employing various modern techniques, reject brine can be utilized for several useful applications while reducing its adverse impacts simultaneously. Recent advancements in desalination technologies have also offered many alternative approaches that provide a roadmap towards greener desalination. This review article will be beneficial for all the stakeholders in the desalination industry.