Dyeing and printing wastewater treatment using fly-ash coated with chitosan

Printing and dyeing industry is a considerable source of environmental contamination. In this study treatment of printing and dyeing wastewater with a new type of sewage treatment agent, fly-ash coated with chitosan particles (FCCP), was examined. The effects of pH, stirring time, sedimentation time and temperature on color, COD, turbidity and NH₃-N removal were determined. The optimum dosage of FCCP and the influence of individual factors on removal efficiency were tested. The optimum parameters determined using the L₁₆(4⁵) orthogonal experiment were as follows: FCCP (weight ratio of chitosan to fly-ash 1:6) dosage, 4 g·L⁻¹; temperature, 35°C; pH, 4. The stirring time and sedimentation time were 20 min and 5 h, respectively. Under these optimum conditions, the color, COD and NH₃-N removal ratios were 97%, 80% and 75%, respectively.     

Research on heavy metals in Ruditapes philippinarum and soda industry wastes

Heavy metals pollution in Jiaozhou Bay was studied inRuditapes. philippinarum, a bioindicator of seawater pollution. Heavy metals in soda industry wastes “white mud” were also studied. Comparison of microwave digestion method with general digestion method revealed that microwave digestion is superior to general digestion in precision, recovery, digestion speed and efficiency, etc. Cd concentration in HongdaoR. philippinarum samples exceeded the national standard by 0.046 mg/kg, that of Yinghai sample by 0.02 mg/kg, and that of Hongshiya sample by 0.22 mg/kg. Sample Pb concentration in Hongshiya was found to exceed the national standard by 0.02 mg/kg. However the heavy metals concentration inR. philippinarum near the Qingdao Alkaline Factory was complied with the standard. This was proved byPenaeus chinensis culture experiment. Therefore, the possible contamination source may come from other land areas. This study is supported by Project 973 (NO.2002CB 412402), and key project of the Chinese Academy of Sciences (Grant NO.KJCX315W-215).     

Land reform and the new elite: Exclusion of the poor from communal land in Namaqualand, South Africa

The reserves and homelands across South Africa share a common history of policy interventions resulting in sedentarization, villagization and formalization of communal land use. In Namaqualand, such interventions culminated in the 1980s with attempts by the state and local vested interests to privatize the commons in the three largest Namaqualand reserves, including Leliefontein. This proposed privatization, although ostensibly aimed at averting land degradation and modernizing agricultural production, was as much about the apartheid state's broader strategy of co-option, and served to further long standing processes of class formation in the coloured communal areas of Namaqualand. In the post-apartheid period land reform has expanded the communal land-base in Namaqualand by over 25%. In spite of this, the management of the new commons in Leliefontein has many of the characteristics of land management policies imposed during apartheid. As a result, the new commons have effectively been arrogated by the same category of people who would have benefited under past privatization initiatives.This paper examines how the interests of a local elite have gained exclusive access to the new commonage farms. This has come about despite the government's commonage policy which privileges access by poorer, disadvantaged communal farmers. This case study uncovers the dynamic complexity of community driven land reform especially in relation to the roles of rural elites and their relationship to government institutions.     

生物流化床处理废水的研究进展

生物流化床技术是普通活性污泥法和生物膜法相结合的废水生化处理技术.通过对近年国内外生物流化床技术的研究和应用现状的分析,文中从生物流化床类型、特性入手,对生物流化床技术的应用前景进行展望.     

辽河油田污水回注适宜性研究

分别从地层地质条件,地下水有机指标化验,地下水多年水质变化规律,氚的同位素分析等方面研究了污水回注对地下淡水是否造成影响;并在此基础上建立了污水回注适宜性综合评价模型,对研究区进行了适宜性评价.     

糖蜜酒精废液中钾测定方法的研究

采用四苯硼钠溶液滴定电导-测量法,对糖蜜酒精废液中钾的测定方法进行了研究。该法简便快速,测定周期仅需20m in左右,所需试剂种类和用量少,准确度和精密度与四苯硼钾重量法相当。     

Reconstitution des apports en éléments traces métalliques et bilan de leur migration dans un Luvisol sableux soumis à 100 ans d'irrigation massive par des eaux usées brutes

Raw wastewaters were massively spread on sandy luvisols near Paris from 1899 to 2002, leading to high trace metals (TM) pollution of soils. Mass balance calculations were performed on a soil profile to assess vertical migration of TM. The contamination was estimated by subtracting the natural pedo-geochemical background of the horizons. TM inputs were estimated using Cr as an invariant. It is shown that Pb and Cr remained in the surface horizon, while Ni, Cd, Cu and Zn migrated downward, being more or less trapped depending on the physicochemical properties of the horizons. To cite this article: C. Dère et al., C. R. Geoscience 338 (2006).     

A study on the treatment of antifouling paint waste from shipyard

A study on the treatment of antifouling paint waste from shipyards, including sandblast waste and ship hull washing wastewater, was performed. The sandblast waste could be effectively detoxified by heat treatment, and the efficiency was affected by the temperature of the heating vessel and treatment time. The removal efficiency of total organotin compounds from the sandblast waste was over 99% at 1000 °C and treatment for 1 h. For the treatment of ship hull washing wastewater by the solvent extraction, ship diesel was a good solvent for the tributyltin (TBT) extraction, and the proper amount of solvent was about 10 mL for TBT extraction from 1 L of wastewater. The extraction efficiency of TBT was significantly affected by the agitation intensity. The TBT in the wash wastewater was rapidly extracted within 1 h. The level of the TBT residual in the wastewater extracted for 1 h was 2.8 μg L⁻¹, and this was further decreased to 0.8 after 5 h extraction.     

GT-铁氧体法处理含铬废水实验研究

通过实验研究,确定了ＧＴ－铁氧体法处理电镀含铬废水的各种工艺条件,按照该工艺提供的工艺参数处理电镀含铬废水,可以使处理后的排水中的铬含量达到排放标准。     

单斜与六方磁黄铁矿处理含Cr(VI)废水过程中pH值变化规律

与六方磁黄铁矿相比,单斜磁黄铁矿Fe缺位较普遍。在初始pH值分别为3.40～9.66和3.47～9.66较宽范围内,利用单斜磁黄铁矿和六方磁黄铁矿处理含Cr(VI) 废水,当反应达到充分平衡时,废水的pH值分别变化在3.61～4.47和5.39～6.57范围内。六方磁黄铁矿除Cr(VI)效果明显不及单斜磁黄铁矿,但被氧化的六方磁黄铁矿除Cr(VI)效率有所 提高。电化学分析表明,在酸性介质中处理的反应过程为H+的消耗过程,而在碱性介质中 则为OH 的消耗过程。根据pH值的这一变化规律,可自行调节处理过程中水质的酸性变化 ,能节省传统工艺中需要加碱以中和处理后酸性水的环节,具有一定的实际应用价值。