Control of toxic or carcinogenic disinfection byproduct (DBP) formation in drinking water is critical in an effort to improve drinking water safety and safeguard public health, due to the elevation of dissolved organic matter in source water. In this study, the oxidation by ferrous iron (Fe2+) and hydrogen peroxide (H2O2) reactions was investigated to assess its efficacy for reducing the DBP forming potentials of four trihalomethanes (THMs) and five haloacetic acids (HAAs) that are currently regulated by the United States Environmental Protection Agency. Results indicated that the oxidation efficacy was dependent on pH, concentrations of Fe2+ or H2O2 added, and initial dissolved organic carbon (DOC) (Resorcinol used as a model compound) level in simulated source waters. Under pH 5.0 and initial 2 mg C/L conditions, the treatment using 0.25 mM of Fe2+ and H2O2 was able to achieve the reductions of 94% THMs and 77% HAAs forming potentials after 90 min reaction. Furthermore, the treatment would also lead to 30% and 36% decreases in DOC and chemical oxygen demand, respectively. More importantly, the oxidation reactions showed the similar reduction efficiency for the DBP forming potentials in the presence of Escherichia coli and resulted in the effective E. coli disinfection in drinking water. pH was identified as one of the most important parameters affecting the efficacy for DBP control. This research demonstrated that the oxidative treatment by the Fe2+-H2O2 reactions would effectively mitigate DBP formation through oxidative removal of DOC and achieve drinking water disinfection simultaneously as well, which could be potentially applied, as a cost-effective and environmental-safe drinking water treatment technology, to small water systems in rural communities with elevated Fe2+ and slightly acidic source water.

为探究文山州烟区中高肥力植烟土壤的适宜施氮量,本研究采用'云87'为试验材料,以当地常规施氮量(90kg/hm2)为对照设置了不同的氮肥减施水平,研究了不同氮肥水平对烤烟生长发育及产量和质量的影响.试验结果表明,施氮量减少10％处理对烤烟农艺性状影响不显著,施氮量减少30％处理的烤烟茎围显著低于常规施氮量(对照),施氮量减少20％处理的烤烟叶长显著低于常规施氮量(对照);施氮量减少10％处理的烤烟单位产量与产值最高,但与对照没有显著差异;随着施氮量的减少,烤烟烟碱含量有明显下降趋势,烤烟总糖和还原糖呈现出先升高后降低的趋势,烟叶化学成分协调性以施氮量减少10％处理最优;施氮量减少10％处理的烤烟烟叶感官评吸质量最高.因此,综合烤烟生长发育、经济性状和内在质量情况,文山州中高肥力植烟土壤的施氮量以减少10％比较合理.本研究为确定文山州中高肥力植烟土壤的适宜施氮量提供理论依据.

Soil lead (Pb) is well known as a threat to human health and ecosystem. Although relatively insoluble, lead bullets in shooting range soil can be readily released into soluble forms through natural weathering processes and thus pose significant human and environmental risks. In this study, laboratory experiments were conducted to investigate if the Pb bullets in shooting range soil can be stabilized through surface coating of phosphate-based materials. Results indicated that FePO4 or AlPO4 coatings, insoluble metal phosphates, have been successfully formed on the surface of the Pb bullets. The EPA Toxicity Characteristic Leaching Procedure (TCLP) test showed that FePO4 or AlPO4 surface coating would effectively reduce the Pb solubility or leachability of the bullets. The surface coating under pH of <5.5 for 7 days could achieve 92–100% reduction, with 85–98% by FePO4 coating and 77–98% by AlPO4 coating as compared with the non-coating. Leachable Pb concentration in the contaminated shooting range soil was reduced by 85–98% or 77–98% as a result of the FePO4 or AlPO4 solution treatment. This study demonstrated that the FePO4 or AlPO4–based surface coating on lead bullets can effectively inhibit the Pb weathering and significantly reduce the Pb release from soil through in situ chemical stabilization, which could be potentially applicable as a cost-effective and environmental-sound technology for the remediation of Pb-contaminated shooting range soil.

The influence of soil acidification on forms and bioavailability of heavy metals in soils has not been understood well. In this study, two types of Cu polluted soils collected from Daye, Hubei(yellow brown soil)and Shouguang, Shandong(alluvial soil)were used to examine the changes of forms and availability of soil Cu under three different acidification treatments, i.e. direct acidification--sulfuric acid(T1), fertilizer acidification--ammonium sulfate(T2)and simulated acid rain(T3). Acidification treatments decreased the biomass of Brassica ol-eracea L., but increased the shoot Cu concentrations(P<0.05). In alluvial soil, the maximum concentration of the shoot Cu was 1.43 times as much as the minimum, and 1.50 times in yellow brown soil. Soil exchangeable Cu increased significantly with increasing acidification. Com-pared with the control, 0.1 mol·L-1 MgCl2-exchangeable Cu was up to 10.7%, an increment of 451.5%, in the alluvial soil;while it was up to 12.07%, an increase of 418%in the yellow brown soil. Significant positive correlation was observed between soil exchangeable Cu and the shoot Cu of Brassica oleracea L. with correlation coefficient above 0.80. However, soil exchangeable Cu had a significant negative linear correlation with soil pH [lg(EXC)=-alg(pH)+b], with the slope of-0.314~-0.352.The increase of soil Cu bioavailability by soil acidifica-tion followed the order:T3﹥T2﹥T1, showing that the bioavailability of heavy metals would be greater in soils acidified by acid rain than in those by fertilizers and industrial wastewater.

Development of high-efficient and environment-friendly amendments and their potential application in remediating polluted soils and waters have received a considerable attention in the last decade. With the fast development of environmental molecular material science and engineering, the application of nano-scale materials in remediating polluted soils and waters has gained even more attention in recent times. The unique characteristics of enhanced huge planar surfaces of nano-particles are expected to enable and increase interface reactions. Such reactions include surface and specific adsorption of heavy metallic ions and organic pollutants by asorbents, strengthened oxidation-reduction reactions on planar surfaces, etc. It is predicted that nano-scale amendments will increasingly be important in remediating polluted soils and waters. This review therefore highlights current research on application of nano-scale amendments on remediation of polluted soils and waters. Various perspectives of nano-particles with regard to environmental cleaning and potential environmental and health impacts associated with the nano-particle application are also presented. The work thus provides vital information for the future development of this field of science.

The presence of phosphorus (P) and lead (Pb) in soil can lead to the formation of highly insoluble minerals of Pb 5 (PO 4) 3 X (where X can be Cl-,OH-,F-,etc.).Hence low-cost phosphate-containing materials utilization was proposed as the best management practice (BMP) for remediation of Pb-polluted soils.Current studies involving in-situ remediation of Pb-polluted soils via phosphorus-compounds are reviewed in this paper.Key factors controlling pyromorphite formation kinetic,solution optimal pH and P/Pb molarity ratio,etc.are discussed in detail.Meanwhile,prospective studies are also discussed with the view to providing further information on remediation practices and their efficiencies in dealing with Pb-polluted soils.

There are some difficulties to treat high concentration anaerobic digestion effluent from swine wastewater treatment plant.In this study,the treatment efficiencies of lime coagulation and anaerobic lagoon were measured.In lime treatment experiment,two dosoges of lime coagulation were 1 and 5g/L respectively,the sedimentation time was 1,2,3,4,5 and 6h.In the same term,the measurements of removal efficiency of anae- robic lagoon were made at twice per day and(i.e,six measurement episodes)72h measurement episode.The re- sult showed that average COD removal of lime coagulation treatment was 57.8% when the dosage of lime was 5g/ L with 5h sedimentation time.The removal efficiency was better than lg/L dosage and anaerobic lagoon.The NH_4~+—N removal of lime coagulation treatment was lower than the removal efficiency of anaerobic lagoon.The capital construction investment of the lime coagulation may be low because of short retention time and required volume,so it is a possible process for high concentration anaerobic digestion effluent before second grade or ad- vanced treatment.

Static chambers were used to investigate greenhouse gas(GHG)leakage and emissions from different treatment units of the wastewater treatment facilities on swine farms in winter.Results showed that leakage flux of GHG from anaerobic tank was 5823.19 mg·m~(-2)·h~(-1)CO_2 equivalent,and the GHG emission fluxes from the primary and secondary aerobic ponds were 607.75 and 8.61mg·m~(-2)·h~(-1)CO_2 equivalent,respectively. Wastewater was mainly treated via anaerobic processing,therefore,N_2O emission was extremely low and could be neglected.