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171.
两类混凝剂处理公厕水冲物的初步研究 总被引:1,自引:0,他引:1
本文采用无机凝聚剂、有机絮凝剂和有机-无机混凝剂对公共厕所水冲物进行了固液分离研究.条件实验表明,供试的无机凝聚剂中,铁盐对水冲物的混凝速度最快,絮凝体相对于铝盐紧实,而铝盐的絮凝体大于铁盐;有机絮凝剂对供试水冲物的混凝效果随着PAM分子量的增加,效果增强.从处理后的水质看,铝盐普遍优于铁盐.与无机凝聚剂混合使用,能显著加快铝盐的分离,使处理后的絮凝体沉淀体积变小,湿渣的含水量降低2~3倍.气浮处理后的清液,其各项主要水质指标均达到国家污水综合排放二级标准(GB 8978-1996). 相似文献
172.
DUAN Guang-ming ZHAO Jing-zhu LIU Guo-hu KE Bing XIAO Han WU Gang DENG Hong-bing 《环境科学学报(英文版)》2004,16(2):308-315
This paper assess the eco-environmental benefits that may come from the middle route project of China‘s South-North Water Transfer Scheme(SNWT) with principles and methods of eco-economics and planning reports of SNWT‘s middle route project. Some benefits were calculated in monetary units. To make sure that the results can be comparable with normal monetary indices, concrete assessment objects and the parameters are prudently selected according to the major characteristics of the project and its water import region. Primary assessment revealed that in different project construction stages, the benefit could be more than 13.07 billion RMB Yuan in 2010 and 19.79 billion RMB Yuan in 2030, respectively. The monetary value tends to increase with social-economic development. To realize these potential benefits, however, calls for more endeavors. 相似文献
173.
174.
Changes of Land Use and of Ecosystem Service Values in Sanjiang Plain, Northeast China 总被引:6,自引:0,他引:6
Wang Z Zhang B Zhang S Li X Liu D Song K Li J Li F Duan H 《Environmental monitoring and assessment》2006,112(1-3):69-91
Agricultural activities, especially reclamation, are considered major threats to the wetland ecosystems in Sanjiang Plain,
the largest concentrated area of the freshwater wetlands in China. In the past decades, the area of the cultivated land and
its grain production have been increased at the cost of wetlands shrinkage. The large-scale land reclamation severely affected
the ecosystems in this region. However, such effects at the regional scale are seldom evaluated quantitatively. We used three
datasets of LANDSAT MSS and/or TM imagery to estimate the area changes and the transition of land use types from 1980 to 2000.
We also valued changes in ecosystem services delivered by each land category using value coefficients published by Costanza
et al. [Nature 387, 1997, 253–260]. Sensitivity analysis suggested that these estimates were relatively robust. Finally, the contribution
of various ecosystem functions was ranked to the overall value of the ecosystem services in this study. According to our estimates,
the total annual ecosystem service values in Sanjiang Plain have declined by about 40% between 1980 and 2000 ($156284–182572.18
million in total over 20 years). This substantial decline is largely attributed to the 53.4% loss of wetlands. For individual
ecosystem functions, waste treatment, water supply and disturbance regulation account for more than 60% to the total ecological
values. During those two decades, the contribution of disturbance regulation, cultural and recreation decreased, while the
contribution of water regulation, nutrient cycling, food production, raw materials and climate regulation increased during
the same period. We also put forward a few proposals concerning the future land use policy formulation and sustainable ecosystems.
They are adjusting the ‘food first’ agricultural policy, establishing more nature reserves for wetlands, creating systems
for the rational use of water, harnessing the degraded cultivated land and encouraging eco-tourism. 相似文献
175.
岩体裂隙面的形貌特征直接影响其渗流特性,为了分析二者的相关关系,采用劈裂法制备了单裂隙砂岩试样,进行了裂隙面扫描分析和渗流试验,基于分形维数在定量表达不规则曲线形貌特征方面的优势,提出了考虑裂隙面形貌各向异性特征的分形维数计算方法。研究结果表明:(1)基于矩阵理论的裂隙面综合分形维数,相当于用矩阵网格去覆盖整个裂隙面,可以较好地反映裂隙面的整体形貌特征;(2)裂隙面的形貌特征对其渗流特性影响显著,随着裂隙面综合分形维数逐渐增大,裂隙岩体的渗透系数逐渐减小,而且侧向应力越大,渗透系数的减小趋势越明显;(3)分析建立了裂隙岩样渗透系数kf与裂隙面综合分形维数■的相关关系,验证分析表明,该公式计算得到的裂隙岩样渗透系数与试验结果吻合较好。相关研究成果可为裂隙岩体渗流特性分析提供参考。 相似文献
176.
177.
活性污泥胞外聚合物提取方法优化 总被引:4,自引:1,他引:3
试验对比了不同离子交换树脂(CER)含量和pH条件下胞外聚合物(EPS)的提取效果差异。结果表明,EPS各组分提取浓度均随离子交换树脂用量增加而增加,但各组分趋势不同。TOC的最佳树脂剂量为100 g CER/g VSS,而蛋白质、多糖和DNA的最佳树脂剂量约为70 g CER/g VSS。pH值对TOC、DNA和多糖的提取浓度影响较小,但对蛋白质影响比较大。各提取条件下,EPS各组分提取浓度随时间的变化过程可以分为平稳增长期、快速增长期及稳定期。 相似文献
178.
转炉渣诱导磷酸钙结晶法去除和回收废水中磷的研究 总被引:1,自引:0,他引:1
以转炉渣为晶种材料,利用批次结晶沉淀实验,研究不同的反应条件对诱导磷酸钙结晶法去除和回收废水中磷的影响。结果表明,最优反应条件为:pH=9.5,Ca/P摩尔比2∶1,转炉渣用量1.7 g/L,反应时间3 h,在此条件下,碳酸根对反应的影响甚小,对养猪场废水和污泥浓缩池上清液的处理,最高去除率分别达到95.36%和96.54%;转炉渣循环利用10次,回收磷的效果仍然很好。运用扫描电子显微镜(SEM)、X射线能谱仪(EDS)和X射线衍射仪(XRD)等测试手段对在最优工艺条件下重复使用10次的转炉渣进行了表征,证明回收的磷主要以羟基磷灰石(HAP)形态存在。 相似文献
179.
鼠李糖脂对剩余污泥中铜和镍的去除 总被引:5,自引:0,他引:5
采用批次淋洗的方法研究了鼠李糖脂浓度、pH、淋洗时间、提取次数以及重金属形态对剩余污泥中Cu和Ni去除效果的影响。结果表明,随着鼠李糖脂浓度的增加,2种重金属的去除率增加,且鼠李糖脂在碱性条件下对Cu和Ni的去除效果较好,最高去除率可分别高达80.77%和46.74%;随着振荡时间和提取次数的增加,Cu和Ni的去除率随之增加,并明显高于去离子水的提取;对污泥重金属形态进行分析发现,鼠李糖脂能有效去除酸提取态的Cu和Ni。研究结论可为剩余污泥的资源化而产生重金属安全隐患问题提供解决的参考方案和奠定理论基础。 相似文献
180.
Recycling of electrolytic manganese solid waste in autoclaved bricks preparation in China 总被引:1,自引:0,他引:1
China has played a dominant role in global electrolytic manganese metal (EMM) production, accounting for over 98 % of the total world capacity since 2008. However, with the rapid development of the EMM industry and depletion of mineral ores, electrolytic manganese solid waste (EMSW) is piling up, so more large-scale landfills are needed. The environmental problems generated by EMSW pose severe threats to soil and ground water, and have become the hot issues in society. The aim is to consume and recycle EMSW, and the primary route is to make autoclaved bricks. However, less attention has been given to the procedure and strength-forming mechanism of EMSW bricks, not to mention the production line of the brick. On the basis of physical and chemical property analysis, the pretreatment process of EMSW was indispensable to solidify/stabilize the heavy metals, such as Mn, Zn, Cd, Pb, etc.. This paper expatiated on the procedure of making EMSW autoclaved bricks, analyzed in detail the strength formed by different cementitious materials with cement properties, and introduced the practical engineering of EMSW autoclaved bricks. The results showed that the pretreatment process with quicklime was effective in solidifying/stabilizing the heavy metals. The compressive strength of EMSW bricks reached 10.05 MPa when quicklime 9 % (w/w) added. Cement may be an ideal cementitious material to create EMSW bricks of high strength in experiments and on the production line. Quicklime and cement used simultaneously produced a lower strength than that when adding cement alone because the gypsum from EMSW and an alkali could generate deleterious effects, e.g., expansion or burst. In the production line of EMSW bricks, an appropriate mix proportion to make high-quality autoclaved bricks was determined: EMSW 30–40 %, cement 10–20 %, and aggregates 40–60 %. The low content of heavy metals tested by toxicity leaching may deduce that the EMSW autoclaved bricks have low environmental risk. However, long-term environmental risk evaluation will be needed, requiring more tests and leaching modeling. Employing EMSW to make high-quality autoclaved bricks may be a promising waste-to-resource strategy. 相似文献