A-A~2/O工艺脱氮实践运行效果及优化

A-A2/O工艺是预缺氧/厌氧/缺氧/好氧组成的生物脱氮除磷工艺,广州市某污水处理厂采用该工艺处理城市污水,具有同时去除有机物、脱氮除磷能力,但是TN去除率较低。分析了其TN去除率低的原因,并提出相应措施。该水厂针对本厂水质特征以及影响工艺脱氮性能的主要因素,优化了工艺控制参数,提高了TN去除率和TN达标保证率。     

高95井硫化氢处理及防治措施研究

文章分析总结了硫化氢对钻井的影响及在钻井中应注意的事项,并结合胜利油田高95井现场取芯钻井过程中硫化氢六次高显示的处理工艺,提出了主要防治措施,对该区块的高含硫化氢井有参考借鉴价值。     

Enhancement of chlorophenol sorption on soil by geophagous earthworms (Metaphire guillelmi)

Earthworms are the dominant soil biomass of many terrestrial ecosystems and markedly influence the physico-chemical and biological properties of soil; however, little is known about the effects of earthworm activities on the environmental behavior of micropollutants in soil. We studied the sorption and desorption of 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol on geophagous earthworm (anecic Metaphire guillelmi) casts of various aging times and on the parent soil. The casts were characteristic of lower pH and higher content of fine particles (silt and clay) than the parent soil. The sorption of the chlorophenols on the soil and casts were well fitted to linear isotherms, with sorption capacity in the order of pentachlorophenol > 2,4-dichlorophenol > 2,4,6-trichlorophenol. The sorption on the cast with different aging time was quite similar and was higher than on the parent soil. The sorption on the soil did not change between pH 7.07 of the soil and pH 6.76 of the casts. The desorption hysteresis of the chlorophenols on the soil and casts was compound specific and 2,4,6-trichlorophenol showed the highest hysteresis. The higher sorption capacity of the casts was not owing to the lowered pH of the casts, but mainly to the higher fine particles in the casts and the possible changes of nature of the soil organic matter through the earthworm gut passage. Our results indicate that geophagous earthworms may change sorption behavior and thus the bioavailability and transport of chlorophenols in soil. Earthworm effects should be considered when evaluating the environmental behavior and risk of organic pollutants in the ecosystems where earthworms are abundant.     

Increased urinary 8-hydroxy-2��-deoxyguanosine levels in workers exposed to di-(2-ethylhexyl) phthalate in a waste plastic recycling site in China

Background

Di-(2-ethylhexyl) phthalate (DEHP) is a common plasticizer used in industrial and diverse consumer products. Animal studies indicate DEHP caused developmental, reproductive, and hepatic toxicities. However, human studies of the potential effects of DEHP are limited.

Methods

The exposed site with a history of over 20 years of waste plastic recycling was located in Hunan Province, China. The reference site without known DEHP pollution source was about 50 km far away from the exposed site. In this study, 181 workers working in plastic waste recycling and 160 gender?Cage matched farmers were recruited. DEHP concentrations in water and cultivated soil samples, serum thyroid-stimulating hormone, malondialdehyde (MDA), superoxide dismutase (SOD), urinary 8-hydroxy-2??-deoxyguanosine (8-OHdG), and micronuclei frequency in human capillary blood lymphocytes were analyzed.

Results

Mean levels of DEHP were greater in environment at the recycling site than at reference site (industry wastewater for the exposed: 42.43 ??g/l; well water: 14.20 vs. 0.79 ??g/l, pond water: 135.68 vs. 0.37 ??g/l, cultivated soil: 13.07 vs. 0.81 mg/kg, p?p?p?Conclusions The occupational DEHP exposure might contribute to oxidative deoxyribonucleic acid damage in the male workers.     

三维与二维电解工艺处理丙烯腈废水的效果比较

采用三维电解工艺和二维电解工艺处理高浓度丙烯腈废水。实验结果表明:三维电解工艺对COD、TOC、TN和总凯氏氮(TKN)的去除率分别为45.32%、59.55%、61.42%和59.24%,二维电解工艺对COD、TOC、TN和TKN的去除率分别为32.65%、43.53%、46.04%和46.08%;三维电解工艺去除单位COD的能耗为2.72 kW·h/kg,二维电解工艺为1.52 kW·h/kg;三维电解工艺和二维电解工艺的出水BOD_5/COD分别由原水的0.14提高至0.38和0.29。三维电解工艺具有较高的去除率,但能耗也较高。在实际应用中可根据具体情况选择所采用的工艺。     

催化湿式氧化法处理高浓度唑螨酯生产废水的研究

对唑螨酯生产过程中产生的高浓度实际废水采用催化湿式氧化技术在鼓泡式固定床反应器连续反应装置上进行处理。实验表明,制备的复合负载型催化剂CuO-MnO₂-Cr₂O₃/ZrO₂-CeO₂在处理该废水时具有较好的催化活性。通过对反应温度、反应压力、反应空速、气液比和进水pH等工艺条件的考察,得出最佳的工艺条件为：反应温度=220℃,反应压力=5.8 MPa,空速＝1.8 h^-1,V（气）∶V（水）＝260∶1,进水pH＝9,在此条件下COD去除率达到95.2％。     

电梯门机智能维护系统的研究进展

探讨了研发电梯门机智能维护系统的必要性和实际意义,介绍国外在门机智能维护领域的研究进展,从理论和技术方面论述该系统的整体流程和涉及到的重要模块和硬件平台,最后指出电梯门机智能维护系统主要的研究方向并建议国内学者对该系统进行更深入的研究。     

LFX-20型逆燃式医疗废物焚烧炉二恶英实测分析

概述我国目前医疗废物焚烧处置中的主要炉型,着重介绍LFX-20型逆燃式焚烧炉焚烧处置医疗废物的实际运行工况。在1燃室、2燃室平均温度分别为869.5℃和898.7℃条件下,对医疗废物焚烧烟气进行检测。各项常规指标均低于国标限值,二恶英检测中其质量浓度实测值为15ng/m3,相应毒性当量为0.46ngTEQ/m3,同时对医疗废物焚烧后产生烟气中二恶英和灰渣的检测结果进行了分析,焚烧后底渣体积约为焚烧前医疗废物体积的1/10,重量为原来的12%～18%,飞灰热灼减率为34.6%,并给出分析结果。     

水环境中氨氮的分析方法进展

氮是天然水体的重要生源要素,是水体质量评价的重要指标之一。本文重点归纳总结了近年来我国在水环境中氨氮分析方法的研究进展,内容主要包括：氮的存在形态、样品预处理和氨氮的各种分析方法,指出了未来的主攻方向、重点研究领域和发展趋势。     

Role of dissolved humic acids in the biodegradation of a single isomer of nonylphenol by Sphingomonas sp

This study shows the important role of humic acids in the degradation of ¹⁴C and ¹³C labeled isomer of NP by Sphingomonas sp. strain TTNP3 and the detoxification of the resulting metabolites. Due to the association of NP with humic acids, its solubility in the medium was enhanced and the extent of mineralization of nonylphenol increased from 20% to above 35%. This was accompanied by the formation of significant amounts of NP residues bound to the humic acids, which also occurred via abiotic reactions of the major NP metabolite hydroquinone with the humic acids. Gel permeation chromatography showed a non-homogenous distribution of NP residues with humic acids molecules, with preference towards molecules with high-molecular-weight. Solid state ¹³C nuclear magnetic resonance spectroscopy indicated that the nonextractable residues resulted exclusively from the metabolites. The chemical shifts of the labeled carbon indicated the possible covalent binding of hydroquinone to the humic acids via ester and possibly ether bonds, and the incorporation of degradation products of hydroquinone into the humic acids. This study provided evidences for the mediatory role of humic acids in the fate of NP as a sink for bacterial degradation intermediates of this compound.