The Natural Vegetation Responses to the Groundwater Change Resulting from Ecological Water Conveyances to the Lower Tarim River

This paper takes the ecological water conveyance project (EWCP) that transfers water from the Bosten Lake, to Daxihaizi Reservoir, and finally to the Taitema Lake as a case study to analyze the dynamic change of the groundwater depth, the vegetation responses to the elevation of the groundwater depth as well as the relationship between the groundwater depth and the natural vegetation. The results from many years’ monitoring in field indicate: (1) the groundwater depth has been elevating gradually with the increase in the times of watering and the elevation range has been expanding continuously in the lower reaches of Tarim River. Correspondingly, the natural vegetation has a favorable response to the elevation of the groundwater depth. The change of the natural vegetation has accordance with that of the groundwater depth. Such facts not only show that groundwater is a key factor to the growth of the native vegetation but also prove it is feasible that the degraded ecosystem can be restored and protected by the EWCP; (2) the results of analysis of the spatial-temporal response of the natural vegetation to watering reveals that the beneficial influence of the EWCP on the ecosystem in the lower Tarim River is a long-term process; (3) in terms of the function and structure of ecosystem after watering in the lower reaches of Tarim River, the EWCP does not still reach the goal of ecological restoration at a large spatial scale at present. Based on such monitoring results, some countermeasures and suggestions for the future restoration strategy are proposed so as to provide a theoretical basis for restoring and protecting the ecosystem in Tarim River, and meanwhile it can also provide some scientific references for implementing the similar ecological projects in other areas.     

Genotoxicity assessment of soils from wastewater irrigation areas and bioremediation sites using the Vicia faba root tip micronucleus assay

Genotoxicity potential of soils taken from wastewater irrigation areas and bioremediation sites was assessed using the Vicia faba root tip micronucleus assay. Twenty five soils were tested, of which 8 were uncontaminated soils and taken as the control to examine the influence of soil properties; 6 soils were obtained from paddy rice fields with a history of long-term wastewater irrigation; 6 soils were obtained from bioremediation sites to examine effects of bioremediation; and 5 PAH-contaminated soils were used to examine methodological effects between direct soil exposure and exposure to aqueous soil extracts on micronuclei (MN) frequency ( per thousand) in the V. faba root tips. Results indicate that soil properties had no significant influences on MN frequencies (p > 0.05) when soil pH varied between 3.4 to 7.6 and organic carbon between 0.4% and 18.6%. The MN frequency measured in these control soils ranged from 1.6 per thousand to 5.8 per thousand. MN frequencies in soils from wastewater irrigation areas showed 2- to 48-fold increase as compared with the control. Soils from bioremediation sites showed a mixed picture: MN frequencies in some soils decreased after bioremediation, possibly due to detoxification; whereas in other cases remediated soils induced higher MN frequencies, suggesting that genotoxic substances might be produced during bioremediation. Exposure to aqueous soil extracts gave a higher MN frequency than direct exposure in 3 soils. However, the opposite was observed in the other two soils, suggesting that both exposure routes should be tested in case of negative results from one route. Data obtained from this study indicate that the MN assay is a sensitive assay suitable for evaluating genotoxicity of soils.     

Mineralization of C.I. Reactive Yellow 84 in aqueous solution by sonolytic ozonation

The operational parameters and mechanism of mineralization of C.I. Reactive Yellow 84 (RY84), one of the azo dyes, in aqueous solution were investigated using sonolytic ozonation (US/O(3) oxidation). Of the pseudo-first-order degradation rate constants of TOC reduction, 9.0 x 10(-4), 7.3 x 10(-3) and 1.8 x 10(-2)min(-1) were observed with US, O3, and a combination of US and O3, respectively. These results illustrate that ozonation combined with sonolysis for removal of TOC is more efficient than ozonation alone or ultrasonic irradiation alone without considering the operating costs. With the initial pH value at 10.0, the ozone dose at 4.5 g h(-1), the energy density of ultrasound at 176 W l(-1), and the initial concentration of RY84 at 100 mg l(-1), the extent of mineralization measured as TOC loss was maximized. The variation of the concentrations of related ions (oxalate, formate, acetate, NO3(-), NO2(-), NH4(+), Cl(-), and SO4(2-)) during the reaction process was monitored. Other organic intermediates detected by GC/MS were N-methyleneaniline, phthalic acid, 4-hydroxyphthalic acid, isocyanatobenzene, aniline, 4-iminocyclohexa-2,5-dien-1-one, butene diacid and urea. Based on these findings, a tentative degradation pathway was proposed.     

基于现场实测的炒菜类餐饮废气排放及静电净化效率评测

为了解静电净化技术对炒菜类餐饮废气的净化效果及随运行时间的变化,该研究选取一家典型餐饮企业对炒菜灶头进行废气净化改造,不定期现场跟踪检测净化设备使用前后颗粒物、非甲烷总烃(NMHC)和VOCs组分的浓度变化。结果表明,定期清洗维护状态下,静电净化设备对颗粒物净化效率变化范围为55.7%～97.3%,平均净化效率为85.9%,净化后平均排放浓度降至4.0 mg/m³,颗粒物净化效率稳定且达标;静电净化设备对NMHC的净化效率不稳定,总体净化效率低于25%,净化后NMHC的平均排放浓度为26.0 mg/m³,仍超过排放标准,其不是去除餐饮NMHC的有效手段,需要加装其他NMHC净化设备;在组分净化效率方面,各组分的净化效率变化和差异很大,这可能与餐饮企业排放过程风速湿度波动大,产生的污染物浓度组分不稳定以及静电净化器工作过程高压电源产生的臭氧等有关,需要进一步研究。     

气相色谱法测定水和土壤中苯醚甲环唑的残留量

研究并建立了气相色谱法测定水和土壤中苯醚甲环唑残留量的分析方法。实验结果表明：水中添加苯醚甲环唑的含量为0．005～0．500mg／kg时,平均回收率为97．9％～100．5％,相对标准偏差小于6．7％;土壤中添加苯醚甲环唑的含量为0．005～0．500mg／kg时,平均回收率为95．7％～109．5％,相对标准偏差小于7．5％。将该法用于水和土壤残留实验,土壤试样在拖药后10～88d进行采样分析,其残留消解动态回归方程为y=0．8803e^-0.0122x,相关系数为-0．915,消解半衰期为56．8d;水试样在施药后0～21d进行采样分析,其残留消解动态回归方程为y=0．2624e^-0.2539x,相关系数为-0．899,消解半衰期为2．7d。     

三江平原农田夜间呼吸的涡度相关法和箱法观测比对

2004年和2005年作物生长季,分别在三江平原水田和旱田,利用涡度相关法(EC)和暗箱-气相色谱法(DC-GC)开展了夜间生态系统呼吸比对实验.结果表明,湍流交换充分时2种方法观测数据没有显著性差异,并在选取更高摩擦风速下EC数据后,二者数据一致性得到进一步提高;EC观测的夜间呼吸与箱法模型的结果差异显著(p＜0.001),并因为EC数据本身巨大的变异性而与箱法模型结果的线性相关很弱(水稻田:R2=0.06;大豆地:R2=0.23),但在较长时间域内合计数据则可以明显地提高两者的线性相关(水稻田:R2=0.16;大豆地:R2=0.75).无论是与DC-GC观测数据比较,还是与其模型结果比较,EC观测的夜间呼吸都比DC-GC法低4%～30%,并且低估程度随季节变化而变化,在生长初期和晚期低估程度最小,而在生长旺期低估程度最大.     

混凝试验搅拌器的研制

影响混凝效果的因素众多,混凝沉淀烧杯试验是进行水的混合、絮凝、沉淀工艺研究、设计和生产指导的最有效方法之一,阐述了智能型混凝试验搅拌器的设计原理和技术性能.     

pH值和碳氮比对亚硝酸型反硝化影响的研究

利用序批式反应器中长期驯化好的以亚硝酸盐为主要基质的纯种污泥,做锥形瓶实验,分别研究pH和碳氮比对亚硝酸型反硝化的影响。结果表明,亚硝酸型反硝化适宜的pH范围在7.7～8.6,最佳pH值在8.2左右;碳氮比（C/N）大于1.94,可实现连续稳定的脱氮效果,起始亚硝氮比基质降解速率随C/N的增加而增加,大于3.11速率几乎不再增加,通过动力学分析,得出该实验条件下C/N的饱和常数Ks为9.36。     

好氧高效过滤分离生物流化床的试验研究

在分析、研究内循环三相生物流化床反应器(ITBFB)效能影响因素的基础上,提出了轻质滤料过滤与ITBFB相耦合技术原理,设计出好氧高效分离生物流化床复合反应器.应用新型反应器进行生活污水中试试验的结果表明,在复合反应器HRT较短为1.1 h时,SCOD和SS去除率分别达60%和96%;在滤层厚度为30 cm,过滤速度为4.24 m/h时,复合反应器的出水悬浮物可保证16 h达标排放.     

SBR系统中活性污泥内源呼吸速率的研究

在SBR污水处理系统中应用呼吸速率测定仪对活性污泥的呼吸速率进行测定,探讨了污泥浓度和温度对内源呼吸速率的影响.对大量的比内源呼吸速率数据进行处理后发现,在混合液温度基本不变的基础上,内源呼吸速率与污泥浓度变化趋势一致,即比内源呼吸速率与污泥浓度无关;而温度对比内源呼吸速率的影响十分显著.这些结论为呼吸速率成为SBR工艺的控制参数提供了基础.