Wet oxidation: a pre-treatment procedure for sludge

Wet oxidation process is specially effective for wastes with a high organic matter which can not be removed by conventional treatment methods. The digested and raw activated sludges of PAKMAYA yeast factory are treated by wet oxidation process. The liquid-phase organic matter concentration [as total organic carbon (TOC)] was increased by 16.5% in 10 min during the wet oxidation in the presence of Cu as catalyst and H2O2. Lenghtening the period of the wet oxidation, the TOC-concentration was increased by 66% in 120 min. The biodegradability of the sludge after wet oxidation process was also examined. A very little development in the biodegradability was observed, when wet oxidation was applied as pre-treatment to the digested sludge (5% decrease as TOC, in the presence of Cu catalyst and H2O2). However, in the case of digestion of the raw sludge after the application of wet oxidation, the biodegradability increased significantly (approximately 75%, as TOC). Moreover, wet oxidation improved the ability of settling of sludge solids, as well as enhancing the treatment efficiency. Finally, the volume of settled solids was decreased by 80% in the presence of Cu and H2O2. NH3+-N, NO2(-)-N and NO3(-)-N concentrations in the supernatant decreased with the wet oxidation. pH value of the sludge increased from 6.6 to 7.8-8.0. Since stable sludge was taken from the digester where the nitrification process was progressing, a decrease in the nitrite concentration, with an increase in nitrate was observed in the digestion continuing after the wet oxidation pre-treatment. However, in the raw activated sludge, there was a nitrite formation only in the non-pretreated sludge.     

白色污染及其防治技术的思考

在分析白色污染产生的背景及其对环境危害的基础上,就其处理技术,包括分离、再生处理和再资源化等技术进行了讨论,提出了应该综合治理白色污染的措施和方案。     

南充生态经济系统的能值分析与可持续发展研究

本文利用美国生态学家H．T.Odum的能值分析理论和方法对南充生态经济系统的能量流动进行定量的分析。简要介绍了南充自然、社会、经济等方面的概况，结合南充的基础数据，应用能值理论计算出1994～2003年南充生态经济系统的能值评估表及能值指标趋势分析。在计算南充的人均能值使用量（EPC），电力占有率（FEE），环境负荷率（ELR），能值投入率（EIR），净能值产出率（EYR），能值货币比率（EDR），能值使用强度（ED），人口承载力（PCC），废物能值比率（WER），能值自给率（ES），可持续发展指数（ESI）基础上，运用南充的各项指标与其它国家和地区进行了横向和纵向的分析。结果表明：南充的生态经济系统是比较脆弱的，从发展过程来看还没有进入工业积累阶段，仍然属于农业大市。所以加强第二、第三产业的发展是南充经济发展的重要出路。     

Similarities and differences in adsorption mechanism of dichlorvos and pymetrozine insecticides with coconut fiber biowaste sorbent

Abstract

In this study, the similarities and differences of the adsorption mechanisms between dichlorvos and pymetrozine and coconut fiber biowaste sorbent (CF-BWS) were investigated. CF-BWS was produced using the slow pyrolysis process at 600?°C for 4?h. HCl acid modification was used to improve the specific surface area. The properties of CF-BWS were analyzed by SEM, FT-IR, BET, and pHpzc. The adsorption kinetics of dichlorvos and pymetrozine on the CF-BWS were well explained by the pseudo-second-order model. The adsorption isotherms for both insecticides were followed the Langmuir isotherm. The difference in molecular structures and surface chemistry caused the difference in adsorption mechanisms of both insecticides. The pore-filling and the hydrophobic interactions were the key mechanisms for both insecticide adsorptions. However, the π–π electron donor–acceptor interaction played the major role in the pymetrozine adsorption but hardly impacted on the adsorption of dichlorvos. The hydrogen bonding mechanism was pronounced in the pymetrozine adsorption, but it had little influence on the dichlorvos adsorption. The CF-BWS is exhibited as an excellent material for the removal of both pollutants and has high potential to be used further as the adsorbent in water treatment process.     

环境—经济系统下工业“三废”排放的预测和控制对策

我国现阶段的环境问题应放在环境－经济系统下进行考察和解决。结合环境－经济系统，系统分析环境问题产生的经济，制度根源，并运用经济计量工具建立模型预测环境－经济系统下我国工业“三废－排放情况，提出控制，提出控制我国工业”三废“排放的政策建议。     

武汉市耕地资源非农化过程的时空变化特征分析

耕地非农化现象是实现工业化和城市化所必须付出的一种代价，已经成为经济发展和城市化，工业化进程中的一个普遍现象。根据武汉市1988-2002年来耕地资源变化的详查数据资料，分析其耕地资源非农化过程的时空变化特征。结果表明：①1988-2002年武市非农建设用地扩张占用耕地面积16394.57hm^2，占耕地资源减少面积的48.75%,耕地非农化成为耕地资源减少的一个重要的原因。②近年来城市非农建设基本上是占用质量较好的耕地，以灌溉水田和菜地为主。③随着城市化进程的加快，耕地非农化的速度在加快。④耕地非农化的区域差异明显，主要集中颁在城市主城区的新区及城郊区。⑤耕地非农人的区域指向性变化明显，主城区扩展的建设用地主要以城市、建制镇、村庄等居民点用地为主，城郊区以交通用地及工矿用地为主。     

以科技创新确保安全生产--神华集团神东煤炭公司安全生产纪实

公司概况神华集团是1995年组建的国有独资公司,中央直接管理的44户国有重要骨干企业之一,一个以能源、交通为主,实行矿、电、路、港一体化建设和产运销一条龙经营的企业集团。神东煤炭公司是神华集团的全资子公司。神东煤炭公司于1998年     

Role of nitric oxide in the genotoxic response to chronic microcystin-LR exposure in human–hamster hybrid cells

Microcystin-LR (MC-LR) is the most abundant and toxic microcystin congener and has been classified as a potential human carcinogen (Group 2B) by the International Agency for Research on Cancer. However, the mechanisms underlying the genotoxic effects of MC-LR during chronic exposure are still poorly understood. In the present study, human–hamster hybrid (A_L) cells were exposed to MC-LR for varying lengths of time to investigate the role of nitrogen radicals in MC-LR-induced genotoxicity. The mutagenic potential at the CD59 locus was more than 2-fold higher (p < 0.01) in A_L cells exposed to a cytotoxic concentration (1 μmol/L) of MC-LR for 30 days than in untreated control cells, which was consistent with the formation of micronucleus. MC-LR caused a dose-dependent increase in nitric oxide (NO) production in treated cells. Moreover, this was blocked by concurrent treatment with the NO synthase inhibitor N^G-methyl-l-arginine (l-NMMA), which suppressed MC-LR-induced mutations as well. The survival of mitochondrial DNA-depleted (ρ⁰) A_L cells was markedly decreased by MC-LR treatment compared to that in A_L cells, while the CD59 mutant fraction was unaltered. These results provided clear evidence that the genotoxicity associated with chronic MC-LR exposure in mammalian cells was mediated by NO and might be considered as a basis for the development of therapeutics that prevent carcinogenesis.     

流域综合管理系统的技术探讨——以拉萨河为例

河流受人类活动破坏日益严重,水质污染、生态退化、水资源不足、管理分散等问题尤为突出,多部门协同,实现综合管理是河流水资源、水质、水生态恢复和改善的必然趋势。文章探讨水资源、防汛、水质、水生态多方面综合管理,实现"多管合一"的技术基础。以拉萨河为例,将地理信息系统、物联网技术与地表水环境管理相结合,建设水环境综合管理决策平台,以信息技术为支撑,实现有效的水环境监控和管理。