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891.
对江苏油田王龙庄污水处理站结垢机理及影响因素进行了分析研究,找出了目前防垢杀菌措施存在的不足。在此基础上,对引进变频式微电脑水处理器的先导性试验结果进行了分析。监测结果表明,其阻垢率达到83.3%以上。该处理器不仅具有很好的防垢、除垢功能,还具有很好的杀菌作用。处理后的污水中固体含量、颗粒总数、含油量、TGB、铁细菌等均有较大幅度的下降,同时还大幅度减少了药剂成本、维修费用等,投入产出比为1∶7,取得了较好的经济效益。  相似文献   
892.
随着人们环境保护意识的逐渐加强,油田采油过程中产生的大量含油污水的处理问题越来越受到人们的重视.做好这部分污水的处理,不仅可以保护好环境,而且还可以将处理后的污水回注油层,节约大量的水资源.为此,介绍一种油田污水处理的新技术--SSF(悬浮污泥过滤)污水净化处理技术.  相似文献   
893.
The prediction of the atmospheric concentration of ozoneand of other photochemical pollutants represents one of themajor scientific challenges in the study of urban airquality. To this aim, photochemical models are widelyapplied as support tools for regulatory purposes, but theirresults are known to be affected by several uncertainties,in boundary conditions, geographical and meteorologicaldata and the chemical composition of emission and ambientair as well. Also the mechanism selected to describe theurban chemistry may lead to large differences in the modelresults. In this work, the influence of ambient air composition onthe results of photochemical model has been studied using a simple Lagrangian trajectory model coupled with different chemical sub-models (CB-IV and a simplified version of EMEP). To this aim a parametric sensitivity study of ozone with respect to its precursors' concentration was performed withreference to the same meteorological conditions and by simulatingdifferent scenarios characterized by specific emitted pollutantsconcentration. Rather than analyzing sensitivity by changing initial composition, an analytical local sensitivity concept has been applied; this allowed evaluation the influence of initial concentration on the predicted ozone concentration andto discriminate between VOC-sensitive and NOx-sensitive kineticregimes. Finally, these results have been successfully comparedwith those obtained applying the concept of photochemical indicators (i.e. O3/NOy and H2O2/HNO3 ratios).  相似文献   
894.
ABSTRACT: In order to determine appropriate application rates and to ensure low pollutant levels in sewage sludge, knowing the chemical composition of sewage sludge is of great importance in a land application program. The objective of this study is to evaluate the variability of selected chemical characteristics of sewage sludge from New Jersey publicly owned treatment works (POTWs). Measurements of total Kjeldahl nitrogen (TKN), NH4+‐N, P, K+, Cd, Cu, Pb, and Zn reported by 98 facilities in the 1996 and 1997 New Jersey Sludge Quality Assurance Regulations (SQAR) reports were statistically analyzed. Sewage sludge from Category 5 POTWs (greater than 10 percent industrial input) showed higher Cd, Cu, and Pb concentrations than Category 3 and Category 4 facilities (less than 10 percent industrial input). Even though only two years of data were analyzed, there was an indication that Cd and Pb concentrations in sewage sludge are decreasing with time. The yearly mean of only a few facilities exceeded the federal pollution concentration limits (40 CFR Part 503, Table 3). Phosphorus and Cd values showed the highest variability within facilities based on the coefficient of variation. Due to the variability of sewage sludge constituents, the use of the yearly rolling mean of nutrient concentrations to determine application rates was considered inadequate. An actual analysis of the sewage sludge to be applied is more appropriate to determine application rates than historical data.  相似文献   
895.
Biomass burning associated with shifting cultivation areas from the northeastern region of India is an important source of trace gas emissions in the Southeast Asian region. In the present study, satellite data pertaining to IRS-P4 OCM data and DMSP-OLS has been used to quantify the intensity, areal extent and amount of biomass burnt in the northeastern region states at district level. Trace gas emissions have been quantified both by using IPCC based emission ratios and ground based emission ratios obtained from field based studies. Areal estimates with respect to shifting cultivation areas from IRS-P4 OCM satellite data of 4th April 2000 suggested nearly 112.99 km2 of the northeastern region of India affected due to shifting cultivation. In the study, DMSP OLS nighttime data has been used to capture the real time fires during the dry season. The results suggested high amount of fires during the March season when compared to April and May. Using the emission ratios obtained from the ground-based studies and IPCC emission ratios, the emissions for the individual non-CO2 trace gases have been computed in a GIS framework using the biomass data, combustion factors and emission ratios. Results suggested emissions of 2.063 Mt CH4, 17.94 Mt CO, 1.419 Mt N2O, and 51.28 Mt NO x and 2.643 Mt release of CH4, 3.7204 Mt CO, 0.145 Mt N2O, and 8.477 Mt NO x , respectively, from biomass burning due to shifting cultivation for the year 2000, from the northeastern region in India. The study highlights the importance of Satellite Remote sensing data and GIS in quantifying the trace gas emissions from biomass burning.  相似文献   
896.
The environmental performance of hemp based natural fiber mat thermoplastic (NMT) has been evaluated in this study by quantifying carbon storage potential and CO2 emissions and comparing the results with commercially available glass fiber composites. Non-woven mats of hemp fiber and polypropylene matrix were used to make NMT samples by film-stacking method without using any binder aid. The results showed that hemp based NMT have compatible or even better strength properties as compared to conventional flax based thermoplastics. A value of 63 MPa for flexural strength is achieved at 64% fiber content by weight. Similarly, impact energy values (84–154 J/m) are also promising. The carbon sequestration and storage by hemp crop through photosynthesis is estimated by quantifying dry biomass of fibers based on one metric ton of NMT. A value of 325 kg carbon per metric ton of hemp based composite is estimated which can be stored by the product during its useful life. An extra 22% carbon storage can be achieved by increasing the compression ratio by 13% while maintaining same flexural strength. Further, net carbon sequestration by industrial hemp crop is estimated as 0.67 ton/h/year, which is compatible to all USA urban trees and very close to naturally, regenerated forests. A comparative life cycle analysis focused on non-renewable energy consumption of natural and glass fiber composites shows that a net saving of 50 000 MJ (3 ton CO2 emissions) per ton of thermoplastic can be achieved by replacing 30% glass fiber reinforcement with 65% hemp fiber. It is further estimated that 3.07 million ton CO2 emissions (4.3% of total USA industrial emissions) and 1.19 million m3 crude oil (1.0% of total Canadian oil consumption) can be saved by substituting 50% fiber glass plastics with natural fiber composites in North American auto applications. However, to compete with glass fiber effectively, further research is needed to improve natural fiber processing, interfacial bonding and control moisture sensitivity in longer run.  相似文献   
897.
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   
898.
基于世界银行数据库1960~2020年数据,采用Mann-Kendall(MK)检验和Spearman's Rho(SR)检验,对全球219个国家及地区的CO2排放及社会经济数据进行趋势分析.结果表明:MK检验和SR检验得出一致结论,共有42个国家和1个经济体联盟实现碳达峰,46个国家处于碳达峰平台期.多数国家碳达峰时...  相似文献   
899.
推动有条件的地区率先行动是“全国一盘棋”实现双碳目标的必然选项.考虑到中国各省的差异性,研究基于碳排放空间分配测算各省达峰压力,进而从达峰压力、减排现状、经济发展、政策支持和资源禀赋这5个维度构建省域碳达峰能力评价体系,采用熵值法确定指标权重,对中国除香港、澳门、台湾和西藏以外的30个省级行政区进行碳达峰能力综合评价,基于评价结果将各省划分为5个梯队.结果表明:①海南和北京等18地的碳排放空间呈现盈余,河北和山东等8地碳排放空间呈现赤字,另有浙江、安徽、河南和湖北这4地分配所得的碳排放空间与各自实际排放量相当;②发达地区碳达峰能力普遍高于欠发达地区,其中北京和上海等地碳达峰能力尤为突出,江西和贵州等地碳达峰能力提升空间较大.最后,针对不同达峰梯队的省份,因地制宜地提出差异化达峰目标和行动建议.  相似文献   
900.
韩方红  高凡  何兵  曹燕  姚小晨 《环境科学》2024,45(6):3297-3307
土地利用变化会导致不同类型碳源和碳汇功能变化,是碳排放的关键来源.从土地利用变化的角度开展阿克苏河流域碳排放及其影响因素研究,对于促进流域山水林田湖草沙冰一体化保护修复、助力碳达峰与碳中和目标实现具有重要意义.基于1990~2020年的4期土地利用数据与同期社会经济数据,测算土地利用碳排放总量,探究土地利用碳排放时空轨迹及其影响因素.结果表明:①1990~2020年,耕地、林地、建设用地和未利用地整体呈增加趋势,草地和水域呈减少态势.土地利用类型空间变化特征主要表现为草地、未利用地转换为耕地;②1990~2020年流域净碳总排放量呈现持续上升趋势,累计增加了14.78×104 t,耕地面积增加是引起流域净碳排放量增长的关键因素;③流域土地利用碳排放量空间上呈中间高四周低的分布格局,净碳排放量显著变化区域主要分布在温宿县南部、阿克苏市、阿瓦提县及阿拉尔市;④人类活动对土地利用碳排放驱动作用最强且其影响由东部向西部逐渐增大,年均气温对土地利用碳排放影响贡献主要集中在阿克苏市东部和阿瓦提县北部,年均降雨量对温宿县北部和阿合奇县西部的抑制作用较强.  相似文献   
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