O3/H2O2降解水中致嗅物质2-MIB的效能与机理

采用O3/H2O2工艺对水中致嗅物质二甲基异莰醇(2-methylisoborneol,2-MIB)的去除效能与机理进行了研究,探讨了H2O2与O2的投加方式、摩尔比以及溶液pH值和水质等因素对2-MIB降解的影响,并通过Gc-MS对2-MIB的氧化降解中间产物进行了分析.实验结果显示,H202能明显促进O3对水中2-MIB的氧化降解.单独臭氧氧化2Omin时2-MIB的降解率为38.7%;在同样体系中加入适量的H202后2.MIB的降解率最大能提高到89.2%,H202与O3最佳投加摩尔比为0.6左右.低浓度(0.5 mg·L-1)腐殖酸对O3/H2O2体系2.MIB的降解速率有比较明显的促进作用,高浓度的腐殖酸则会产生较明显的抑制作用;自由基捕获剂叔丁醇对O3/H2O2体系中2-MIB氧化降解具有明显的抑制作用.鉴定出2-MIB的氧化降解产物有4-羟基-1,7,7-三甲基双环[2,2,1]庚烷-2-酮、1,7,7-三甲基双环[2,2,1]庚烷-2,4-二酮、1,7,7-三甲基双环[2,2,1]庚烷-2-酮等,并对2-MIB氧化机制和降解的可能途径进行了推导.     

Water quality in rice-growing watersheds in a Mediterranean climate

Rice (Oryza sativa L.) agriculture is estimated to cover 161 million ha of land on Earth, with 10% grown in temperate regions. Currently there are strong concerns about surface water nutrient pollution, and the purpose of this study was to determine the impacts of temperate rice cultivation on nutrient dynamics at the small watershed scale. Over the course of the 2008 growing season (May through September), bi-weekly grab samples were collected from outlets of 11 agricultural subwatersheds in California. Samples were analyzed for NO₃-N, NH₄-N, PO₄-P, K, and dissolved organic nitrogen (DON) concentrations, and the average values across all subwatersheds and sampling dates were 0.22, 0.031, 0.047, 1.36, and 0.32 mg L⁻¹, respectively. Linear mixed effects analysis was used to evaluate the magnitude of relationships between nutrient concentration and flux and subwatershed characteristics (i.e. percent soil clay and organic matter, percent rice area, irrigation water reuse, subwatershed discharge, irrigated area, and time, measured as the day in the growing season). For all nutrients, flux decreased over time and increased with discharge. Concentrations of K and DON were highest at the start and end of the growing season. Concentrations of NH₄-N were near non-detect levels, with the exception of a peak in mid-July, which corresponds to when many growers top-dress rice fields with N fertilizer. Nitrate-N concentration and flux decreased with percent rice area, whereas PO₄-P concentrations increased with percent rice area, indicating that rice area should be considered in future watershed-scale studies of nutrient discharge. In all subwatersheds, the discharge loads of K were smaller than surface water input loads, while NO₃-N, NH₄-N, PO₄-P, and DON discharge loads exceeded input loads when total growing season discharge was greater than 3500-6600 m³ ha⁻¹. This implies that the management of subwatershed discharge can be used to control nutrient export from rice-growing areas.     

铅酸蓄电池生产废水治理技术应用研究

采用“氧化还原＋中和反应＋高效凝聚”工艺处理废蓄电池回收和电池制造企业生产废水。总处理水量为208m^3／d;进水水质：pH：1-2、总铅：13．5mg／L、SS：450mg／L。经该工艺处理后,废水中的总铅、pH、SS等指标均能达标排放。     

Trophic mode and organics metabolic characteristic of fungal community in swine manure composting

Fungal trophic modes and substrates utilization ability was observed in composting. Fungi had the higher diversity and more trophic types in thermophilic phase. Fungi had the higher metabolic potential in fresh swine manure and mature production. Redox potential, organics and moisture are main factors impacting fungal community. Composting reduced pathogenic fungi and enrich dung saprotroph fungi in swine manure. The succession of fungal community, trophic mode and metabolic characteristics were evaluated in 60 days composting of swine manure by high-throughput sequencing, FUNGuild and Biolog method, respectively. The result showed that the fungal community diversity reached to the highest level (76 OTUs) in the thermophilic phase of composting, then sustained decline to 15 OTUs after incubation. There were 10 fungal function groups in the raw swine manure. Pathotroph-saprotroph fungi reached to 15.91% on Day-10 but disappeared on Day-60. Dung saprotroph-undefined saprotroph fungi grown from 0.19% to 52.39% during the treatment. The fungal community had more functional groups but the lower substrate degradation rates in the thermophilic phase. The fungal communities on Day-0 and Day-60 had the highest degradation rates of amino acids and polymers, respectively. Redundancy analysis showed that ORP (49.6%), VS/Ash (45.3%) and moisture (39.2%) were the main influence factors on the succession of fungal community in the swine manure composting process.     

南京市机动车尾气污染现状调查及其对人群健康的影响

机动车尾气排是影响城市大气环境质量的重要因素，监测表明：南京市道路环境污染来重，尤其是隧道及交通繁忙的路段。通过对２２０人作问卷调查，发现机动车尾气污染已对经常接触的人群产生很大的影响。     

海水中总氮的测定方法比较研究

通过标准曲线、检出限和测定范围、方法精密度、方法准确度、实际海水样品测定结果、加标回收率、分析效率和物料消耗这几方面比较了过硫酸钾氧化法、流动注射分析法和高温氧化-化学发光检测法这3种测定海水中总氮(TN)方法的优缺点。结果表明,流动注射分析法和高温氧化-化学发光检测法的测定范围更宽,精密度、准确度更好,3种样品的加标回收率达到96.2%~101%;高温氧化-化学发光检测法分析效率高、物料消耗少、节能环保,适用于一般海水样品的批量分析,且由于测定范围大,该法也适用于TN浓度较高的海水样品的批量分析,流动注射分析法因其较低的检出限更适用于TN浓度较低的海水样品的批量分析。     

Decomposition and oxidation of sodium 3,5,6-trichloropyridin-2-ol in sub- and supercritical water

Sodium 3,5,6-trichloropyridin-2-ol (STCP) is a necessary precursor compound for the production of chlorpyrifos and triclopyr, which are extensively used as pesticide and herbicide, respectively. In the process of STCP production, however, large amount of wastewater containing STCP is discharged, which causes increasingly environmental concerns. Therefore, it is of great significance to develop a rapid and effective method for the disposal of containing STCP contaminants. In this work, the thermal decomposition of STCP in sub- and supercritical water was investigated using a continuous tubular reactor. While STCP was stable below 280 °C, it could be effectively decomposed at elevated temperature. FT-IR spectra of the decomposition products indicated that the pyridine ring structure in the STCP molecule was stable even at temperatures up to 400 °C. The decomposition reaction was mainly caused by the substitution of Cl groups in the STCP molecule with OH groups, resulting in polyhydroxylated pyridines as the major decomposition product. Moreover, high pressure favored the substitution reaction. To completely decompose STCP into non-toxic or low toxic compounds, supercritical water oxidation (SCWO) was employed to evaluate the oxidation of STCP using H₂O₂ as an oxidant. It was found that STCP could be completely oxidized to H₂O, CO₂ and corresponding inorganic ammonium salts with an oxidation rate of 99%.     

Plant uptake of radiocaesium from artificially contaminated soil monoliths covering major European soil types

Uptake of ¹³⁷Cs was measured in different agricultural plant species (beans, lettuce, barley and ryegrass) grown in 5 undisturbed soil monoliths covering major European soil types. The first cultivation was made three years after soil contamination and plants were grown during 3 successive years. The plant–soil ¹³⁷Cs transfer factors varied maximally 12-fold among soils and 35-fold among species when grown on the same soil. Single correlations between transfer factors and soil properties were found, but they varied widely with plant type and can hardly be used as a predictive tool because of the few soils used. The variation of ¹³⁷Cs concentrations in plants among soils was related to differences in soil solution ¹³⁷Cs and K concentrations, consistent with previous observations in hydroponics and pot trials. Absolute values of transfer factors could not be predicted based on a model validated for pot trials. The ¹³⁷Cs activity concentration in soil solution decreased significantly (11- to 250-fold) for most soils in the 1997–1999 period and is partly explained by decreasing K in soil solution. Transfer factors of lettuce showed both increasing and decreasing trends between 2 consecutive years depending on soil type. The trends could be explained by the variation in ¹³⁷Cs and K concentrations in soil solution. It is concluded that differences in ¹³⁷Cs transfer factors among soils and trends in transfer factors as a function of time can be explained from soil solution composition, as shown previously for pot trials, although absolute values of transfer factors could not be predicted.     

Degradation of acetic acid with sulfate radical generated by persulfate ions photolysis

The photolysis of was studied for the removal of acetic acid in aqueous solution and compared with the H₂O₂/UV system. The radicals generated from the UV irradiation of ions yield a greater mineralization of acetic acid than the OH radicals. Acetic acid is oxidized by radicals without significant formation of intermediate by-products. Increasing system pH results in the formation of OH radicals from radicals. Maximum acetic acid degradation occurred at pH 5. The results suggest that above this pH, competitive reactions with the carbon mineralized inhibit the reaction of the solute with and also OH radicals. Scavenging effects of two naturally occurring ions were tested; in contrast to ions, the presence of Cl⁻ ions enhances the efficiency of the /UV process towards the acetate removal. It is attributed to the formation of the Cl radical and its great reactivity towards acetate.