多元微电解技术对高浓度化学清洗废水预处理的影响

以高浓度化学清洗废水为研究对象,分别考察了常规混凝沉淀、多元微电解2种工艺对有机物污染物的去除效率和改善废水可生化性的效果。结果表明:多元微电解工艺的最佳pH 3.0,填充比1∶3,微电解1 h,气水比1∶1的条件下,其对COD平均去除率可达到60%,而直接混凝沉淀仅为10.5%,多元微电解工艺能使BOD5/COD值由原来的0.12升高到0.32,提高了废水的可生化性,减轻了后续生化处理负荷,是对高浓度化学清洗废水的有效预方法。     

Fenton法处理电镀有机废水

采用Fenton法处理某电镀厂强碱性有机废水。考察了pH和Fenton氧化对废水特性的影响,优化了处理参数,研究了Fenton氧化对废水可生化性的影响。结果表明:Fenton氧化前,调节pH可提高有机物去除效果,一定程度上去除重金属;Fenton法能够有效处理电镀有机废水,并充分提高废水可生化性,最高COD去除率可达75%;在反应时间为30min、H_2O_2投加量为68mg·L~(-1)、Fe~(2+)投加量为111mg·L~(-1)条件下,废水COD去除率为22%,B/C为0.28,适宜后续接入生化工艺以进一步提高废水处理效果,可降低成本并提高处理效率,为电镀企业处理强碱性有机废水提供参考。     

微电解法预处理大蒜废水试验研究

分析了大蒜废水的特点,探讨了微电解法预处理大蒜废水的可行性,并采用微电解一接触氧化工艺分别对大蒜废水和大蒜蔬菜混合废水进行了试验研究.结果表明,微电解法预处理大蒜废水是可行的,提高了废水的可生化性,微电解较佳停留时间为20 min,微电解-接触氧化工艺处理出水水质为COD≤100 mg/L.     

微电解-Fenton联合工艺预处理煤层气井压裂废水

利用Fenton强化微电解工艺对煤层气井压裂废水展开预处理研究,以COD去除率和可生化性(B/C)为考察指标,单独工艺正交实验结果表明pH为3、反应时间为90 min、铁碳体积比为1.5∶1和pH为4、反应时间为80 min、H2O2投加量为4 mL/L分别是微电解与Fenton反应的最优条件,各可获得48.1%和44.9%的COD去除率。在最优条件下进行微电解-Fenton联合运行实验,连续61 h内COD去除率均稳定在65%以上,B/C由0.158上升到0.3以上,有利于后续生化处理的运行。     

微电解预处理靛蓝牛仔布印染废水

靛蓝牛仔布印染废水组分复杂,浓度高、水量大,属于难处理的工业废水,为了有效降低后续生物处理单元的负荷,采用铁炭微电解工艺对该废水进行预处理;通过正交实验考察pH、反应时间及铁炭比处理效果的影响规律及COD去除反应动力学,并对各因素作了单因素影响实验,确定了最佳工艺条件.结果表明,铁炭微电解法是预处理靛蓝牛仔布印染废水的一种有效方法,在Fe/C为2:1、pH为3的条件下反应90 min,铁炭微电解出水COD的去除率在49.2％,色度去除率达到80％,该印染废水经微电解处理后,BOD5/COD比值可从原来的0.248上升至0.436,可生化性明显提高.此外,微电解预处理靛蓝牛仔布印染废水中COD的去除反应符合二级反应动力学规律.     

新型微电解填料-Fenton联用处理硝基苯废水

研究通过单因素分析和正交实验法确定新型微电解填料-Fenton联用预处理硝基苯废水的最佳操作条件。结果表明,新型微电解填料降解硝基苯的影响因素从大到小依次为固液比>进水p H值>气水比>HRT,在微电解最佳条件:HRT为60 min,固液比为0.6,进水p H值为2,气水比为15∶1;Fenton试剂最佳条件:反应时间为20 min、p H值为4.5、m(H2O2):m(COD)为2.5、n(H2O2)∶n(Fe2+)为6,硝基苯和COD总去除率可分别达到97.6%和68.3%。处理后的废水可生化性提高,为后续的生物处理创造了良好的条件。     

两级预处理/MBR工艺处理制药废水

湖北西北部某工业园已建成污水处理厂(反应沉淀/水解酸化/MBR工艺)以处理合成制药废水为主,由于其预处理段处理效果难以满足后续MBR工艺要求,导致出水水质不能达到国家相关标准,急需升级改造。针对该合成制药废水污染物成分复杂、污染当量大、冲击负荷高、可生物降解性差以及水量水质变化大等特点,采用铁碳微电解/水解酸化两级预处理工艺对该制药废水进行强化预处理,并建立两级预处理/MBR工艺进行小试实验,实验结果表明,铁碳投加量为400g·L~(-1),铁碳质量比为4∶5,HRT=3 h,pH=4,曝气量为3 L·min-1时,一级预处理效果较好,铁碳微电解对COD去除率达47.50%,废水可生化性由0.23提升到0.38;二级预处理水解酸化将废水可生化性由0.38提升至0.46,促使MBR工艺运行效果大幅提升,最终出水达到《化学合成类制药工业水污染排放标准》(GB 21904-2008)。     

铁碳微电解联合两相UASB处理丙烯酸废水

通过采用铁碳微电解预处理丙烯酸废水的实验研究,分析了物理吸附、进水p H、反应时间和固液比(填料废水比)这4个因素对COD和甲醛去除率的影响规律,同时研究了铁碳微电解结合两相UASB处理丙烯酸废水的技术优势。单因素实验的结果表明,当p H=3.0、反应时间=4 h、固液比=300 g∶200 m L时,铁碳微电解预处理可取得37%的COD去除率和30%的甲醛去除率,而且废水可生化性得到明显的改善,与单独两相UASB相比,预处理可显著提高两相UASB运行的稳定性和高效性,综合处理后出水COD达到《污水综合排放标准(GB 8978-1996)》二级排放标准;出水甲醛浓度降低至13~20 mg/L。     

生化-Fenton氧化联合工艺处理石化净化水的回用

净化水是经过一定预处理的石化废水,具有很高的回用价值,为此采用生化-Fenton联合工艺对净化水进行了处理,研究了初始pH、反应温度、H2O2与Fe2+的摩尔投加比、投加量和反应时间等因素对废水COD去除率的影响。结果表明,Fenton氧化反应可有效去除生化处理出水中的COD,在H2O2(30%)投加量为6.34 m L/L,H2O2与Fe2+的摩尔投加比为5∶1,pH值为4,温度30℃,反应时间2h条件下,废水COD的去除率可达79.7%。GC-MS分析结果表明,Fenton氧化反应对难降解有机污染物具有较好的去除效果,同时可有效提高废水的可生化性,B/C比最大可提升至0.58,氧化出水经生化处理后的剩余COD可降至77.9 mg/L,达到工业回用水标准。     

铁炭微电解预处理高浓度高盐制药废水

采用铁炭微电解法预处理高浓度高盐制药废水,并对反应条件、处理效果、反应动力学和机理进行研究。通过单因素实验初步研究进水pH、铁用量、反应时间和铁炭比对处理效果的影响;通过正交实验表明进水pH对处理效果影响最大,并得到最佳反应条件为:进水pH为4.5,铁投加量40 g/L,铁炭质量比1∶1,反应时间4 h,COD去除率可达40%以上,并可以提高废水的可生化性,后续通过厌氧生物处理出水可达二级污水综合排放标准。通过对各级反应动力学方程进行回归分析,表明微电解处理制药废水基本遵循一级反应动力学。铁炭微电解处理制药废水效果好,并可以提高可生化性,同时具有操作简单和成本低的优点,为制药废水的预处理提供新的途径。     

Chloroaromatic pollutants in mussels incubated in two finnish watercourses polluted by industry

Concentrations of different chlorinated compounds were measured in mussels incubated in two polluted watercourses, a river (the River Kymijoki) and a lake (Lake Vanaja) for four weeks in summer 1995. The sum concentrations of polychlorinated phenols (PCP) and biphenyls (PCB) were both about 1 μg/g lipid weight (lw) in Lake Vanaja mussels, while in the River Kymijoki mussels PCPs were non-detectable and PCBs were measured 120 ng/g lIw. The concentrations of toxic polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners ranged between <17 and 370 pg/g Iw in Lake Vanaja mussels and between <38 and 11,000 pg/g lw in the River Kymijoki mussels. Polychlorinated diphenyl ethers (PCDE) were detected in the mussels incubated in the River Kymijoki (0.4–1.1 ng/g Iw), but not in those incubated in Lake Vanaja. Polychlorinated phenoxyanisoles (PCPA) were measured 33 ng/g lw and polychlorinated phenoxyphenols (PCPP) 300 ng/g lw in the mussels incubated in the River Kymijoki. PCPAs were also detected in reference samples, which were sediment and pike from the River Kymijoki and Baltic salmon, seal and white-tailed sea eagle.     

Book review

The Pesticide Manual ‐ A World Compendium, 8th Edition, C.R. Worthing, Editor and S.B. Walker, Assistant Editor, British Crop Protection Council, BCPC Publications Sales, Bear Farm, Binfield, Bracknell, Berkshire RG12 5QE, England. 1987, 1100 pp., UK £50; Overseas £56. ISBN 0–948404–01–9.     

Organochlorine compounds in a three-step terrestrial food chain

The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.     

The chemical stability of formulations of some hydrolyzable insecticides in aqueous mixtures with hydrolysis catalysts

Abstract

The active ingredients in commercial formulations of malathion, oxamyl, carbaryl, diazinon, and chlorpyrifos diluted to “spray tank”; concentrations with buffered distilled or natural water of pH 4–9 were stable for at least 24 hr. Formulations of trichlorfon were not stable at pH 7 or above but disappearance rates were slower than for the pure chemical in homogeneous solution. Cupric ion was observed to be an effective catalyst for the hydrolysis of a variety of pure organophosphorus insecticides but did not catalyze hydrolysis of the active ingredients of the formulations examined. Increasing the dilution of the formulation increased the susceptibility of malathion, oxamyl, and carbaryl to hydrolysis.     

Radionuclides in pinon pine (Pinus edulis) nuts from los alamos national laboratory lands and the dose from consumption

Abstract

One of the dominant tree species growing within and around the eastern portion of Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis). Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food—the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of ³H, ¹³⁷Cs, ⁹⁰Sr, ^totU, ²³⁸Pu, ^{239, 240}Pu, and²⁴¹ Am in soils (0‐ to 12‐in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (3) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of ³H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 μSv); this is far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem (1000 μSv). Soil‐to‐nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.     

Degradation and sorption of imidacloprid in dissimilar surface and subsurface soils

Degradation and sorption/desorption are important processes affecting the leaching of pesticides through soil. This research characterized the degradation and sorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine) in Drummer (silty clay loam) and Exeter (sandy loam) surface soils and their corresponding subsurface soils using sequential extraction methods over 400 days. By the end of the incubation, approximately 55% of imidacloprid applied at a rate of 1.0 mg kg^?1 degraded in the Exeter sandy loam surface and subsurface soils, compared to 40% of applied imidacloprid within 300 days in Drummer surface and subsurface soils. At the 0.1 mg kg^?1 application rate, dissipation was slower for all four soils. Water-extractable imidacloprid in Exeter surface soil decreased from 98% of applied at day 1 to > 70% of the imidacloprid remaining after 400 d, as compared to 55% in the Drummer surface soil at day 1 and 12% at day 400. These data suggest that imidacloprid was bioavailable to degrading soil microorganisms and sorption/desorption was not the limiting factor for biodegradation. In subsurface soils > 40% of ¹⁴C-benzoic acid was mineralized over 21 days, demonstrating an active microbial community. In contrast, cumulative ¹⁴CO₂ was less than 1.5% of applied ¹⁴C-imidacloprid in all soils over 400 d. Qualitative differences in the microbial communities appear to limit the degradation of imidacloprid in the subsurface soils.     

Biochemical interaction of six op delayed neurotoxicants with several neurotargets

Abstract

Five organophosphorous insecticides: Leptophos, EPN, Cyano‐fenphos, trichloronate and salithion proved to cause irreversible ataxia not only to chicken but also to mice and sheep. TOCP was included as a reference. Cyanofenphos blocked the catecholamine B‐receptor binding activity with ³H‐norepinephrine at a level similar to that of the specific inhibitor propranolol in the mouse heart preparation. In the lamb heart preparation, the B‐receptor was more sensitive to Leptophos, salithion and TOCP than to propranolol. The six compounds and their oxons were screened for their in‐vitro inhibition to monamine oxidase (MAO), acetyl cholinesterase (AChE) and neurotoxic esterase (NTE) in the brain of either mouse, lamb or chicken. It is believed that their AChE inhibition stands for their acute toxicity, while NTE inhibition is responsible for their paralytic ataxia.     

土壤中砷的化学平衡

本文比较详细地综述了砷的化学特性,环境背景值及来源和循环,土壤中砷的三大化学平衡即沉淀溶解平衡,氧化还原平衡,吸附解吸平衡,以及微生物对砷的转化。     

Elemental uptake by edible herbs and lettuce (Latuca sativa)

The total concentration of toxic elements (aluminum, cadmium, chromium and lead) and selected macro and micro elements (iron, manganese, copper and zinc) are reported in six leafy edible vegetation species, namely lettuce, spinach, cabbage, chards and green and red types of Amaranth herbs. Although spinach and chards had greater than 125 mv of iron, both the amaranthus herbs recorded > than 320 μ g g^{? 1} dry weight. In both the spinach and chard species, the Mn and Zn levels were appreciable recording > 225 μ g g^{? 1} and 150 μ g g^{? 1} dry weight, respectively. Aluminum concentrations were (in μ g g^{? 1} dry weight) lettuce (10), cabbage (11), spinach (167), chards (65), amaranthus green (293) and amaranthus red (233). All the micro and macro elements and the toxic elements (Ni, Cr, Cd and Pb) elements analyzed, were below the recommended maximum permitted levels (RMI) in vegetables. Further the elemental uptake and distribution of the nine elements, at three growth stages of the lettuce plant grown on soil bed under controlled conditions are detailed. In the soil, except for iron (16%), greater than 33% of the other cations were in exchangeable form. Generally in the lettuce plant, roots retained much of the iron (> 224 μ g g^{? 1}) and aluminum (> 360 μ g g^{? 1}), while leaves had less than 200 μ g g^{? 1} of iron and 165 μ g g^{? 1} of Al. Although the concentrations of elements marginally decreased with growth, the lettuce leaves had significant amounts of Mn (30 μ g g^{? 1}), Zn (50 μ g g^{? 1}) and Cu (3.6 μ g g^{? 1}). Some presence of lead in leaves (2.0 μ g g^{? 1}) was noticed, but all the toxic and other elements analyzed were well below the RMI values for the vegetables.     

The dissipation of nonlyphenol in stream and pond water under simulated field conditions

Abstract

The dissipation of 1.0 ppm nonylphenol in stream and pond water, incubated in flasks at 16°C under simulated field conditions up to 44 days indicated that the half‐life was 2.5 days if the flasks were open, and 16 days if they were closed. A transformed product was detected in the closed flasks.

Translocation of nonylphenol in water occurred when treated water samples were incubated in the presence of sediment. After 10 days, nonylphenol was detected only in the sediment, but not in water (detection limit = 10 ppb). About 80% of the nonylphenol was degraded in 71 days, but no degradation occurred if the water and the sediment were autoclaved prior to incubation.