溅水充氧生物滤池处理农村污水的研究

开发了一种处理农村污水的低能耗地埋式一体化溅水充氧生物滤池装置,通过拔风和溅水复合充氧技术实现了大幅度节能条件下的好氧生物处理.考察了在不同水力负荷及COD、NH4 -N容积负荷条件下本装置的处理效果,结果表明,在水力负荷小于10 m3/(m2·d)、COD及NH4 -N容积负荷分别小于0.3 kg COD/(m3·d)和0.08 kg NH4 -N/(m3·d)的条件下,可以取得较高的去除效果和良好的出水水质,COD、NH4 -N和TN的平均出水浓度分别为58.94 mg/L、2.78 mg/L和8.23 mg/L,平均去除率分别为51.7%、86.4%和70.6%.     

宽叶香蒲表面流人工湿地脱氮除磷效果研究

以运行A/O工艺的生化反应器出水为处理对象,在中试规模上研究了宽叶香蒲表面流人工湿地的脱氮除磷效果及影响因素.结果表明,在工况Ⅰ条件下,COD去除率为43.2%,COD面积负荷去除率为4.79 g/(m2·d),COD面积负荷去除率常数为0.18 m/d,SS、NH4+-N和NO-3-N的去除率分别为41.2%、9.4%、3.4%,TN去除率为11.8%,TN面积负荷去除率为1.36g/(m2·d),TN面积负荷去除率常数为0.04 m/d,TP去除率为30.1%,TP面积负荷去除率为0.29 g/(m2·d),TP面积负荷去除率常数为0.13 m/d;在工况Ⅱ条件下,COD去除率为18.7%,COD面积负荷去除率为1.19 g/(m2·d),COD面积负荷去除率常数为0.06 m/d,SS、NH4+-N、NO2--N、NO3--N的去除率分别为31.6%、29.8%、65.0%,29.2%.TN去除率为31.4%,TN面积负荷去除率为2.33 g/(m2·d),TN面积负荷去除率常数为0.12 m/d,TP去除率为29.4%,TP面积负荷去除率为0.22 g/(m2·d),TP面积负荷去除率常数为0.11 m/d.在COD面积负荷去除率,TN面积负荷去除率、TP面积负荷去除率分别为4.90～9.80、2.76～8.83、0.57～1.39 g/(m2·d),水力停留时间(HRT)为0.4～1.1 d条件下,随HRT,水温、(NO2+-N+NO3--N)/TN的增加,表面流人工湿地的TN面积负荷去除率线性增加.     

好氧颗粒污泥的培养及处理味精废水

以厌氧颗粒污泥为接种污泥,在模拟废水条件下利用SBR 35 d成功培养出了具有同步硝化反硝化作用的好氧颗粒污泥,反应器对COD和NH4+-N去除率分别高于95%和99%。将该反应器用于处理味精废水,当COD、NH4+-N的容积负荷分别为2.4 kg/(m3.d)、0.24 kg/(m3.d)时,COD、NH4+-N和TN去除率分别高于90%、99%和85%。处理味精废水后的颗粒污泥粒径由之前的0.8～2.5 mm减小至0.6～1.8 mm,颗粒结构较之前更加密实。     

AFB-SBR工艺处理蓝皮制革工业废水

采用厌氧流化床(AFB)-序批式反应器(SBR)工艺处理蓝皮制革工业废水。分别考察了水力停留时间(HRT)、容积负荷对厌氧流化床以及曝气时间、污泥浓度、溶解氧浓度对SBR反应器处理效果的影响。试验结果表明,AFB将实验废水的BOD_5/COD(B/C)值由0.19～0.26提高至0.35～0.42,有效提高了其可生化性;在进水COD浓度为1 700～1 890 mg/L、HRT为1 d、容积负荷为1.792 kg COD/(m~3·d)时,COD去除率达65.2%～68.5%,且具有良好的抗冲击负荷能力。SBR在进水COD浓度为628～712 mg/L、污泥浓度为2.9 g/L、曝气时间为10 h、溶解氧浓度为2 mg/L工况下,COD去除率达87.6%,NH_3-N去除率达93.6%,处理后出水水质符合污水综合排放标准(GB 8978-1996)中的一级标准要求。     

二级活性炭生物流化床深度处理有机胺废水研究

采用二级活性炭生物流化床工艺深度处理有机胺废水,研究了有机容积负荷、NH3-N容积负荷以及曝气间歇对COD、NH3-N去除效果的影响.结果表明:当有机容积负荷为0.94～2.38 kg COD/(m3·d)时,二级流化床对COD的去除率为80.6%～95.5%,比一级流化床的抗有机负荷冲击的能力更强;当NH3-N容积负...     

复合生物滤池处理城市高污染水体

采用中试规模复合生物滤池处理城市高污染水体,考察了滤池的最佳运行参数以及对氮和有机物的去除效果。结果表明:滤池容积负荷宜控制为0.3～0.5 kg COD/(m3.d),水力负荷4.5～5 m3/(m2.d),适宜的通风比为9%,当C/N为5～8时,滤池COD、NH4+-N和TN平均去除率分别为80%、83%和63%,达到高效同步硝化反硝化状态。     

管式反应器处理生活污水的效能

研发了一种基于射流曝气的管式反应设备,考察了负荷和DO对反应器处理效能的影响。实验结果表明,在温度为15℃、DO 6.0 mg/L、有机负荷为1.0 kg COD/(m3.d)、氮负荷为0.30 kg TN/(m3.d)、HRT为8 h的条件下,管式反应器可使生活污水的COD、NH4+-N及TN分别从335 mg/L、105 mg/L及110 mg/L降至43 mg/L、14 mg/L及18 mg/L,去除率分别为87%、86%和83%。DO对反应器脱氮效能影响显著,DO为6 mg/L时,能构建出同步硝化反硝化系统,NH4+-N和TN的去除率分别为96.6%和86.7%。     

生物流化床及臭氧氧化处理中低浓度糖业废水

采用内循环好氧生物流化床对中低浓度糖业废水进行生物降解,当进水COD、NH3-N浓度分别为400～600mg/L和7～11 mg/L时,其相应去除率达到80%～90%和70%～80%,处理效果良好;COD容积负荷可达到5.1 kg COD/(m3·d),反应器具有较强的抗负荷冲击能力.采用臭氧氧化工艺对COD浓度为28...     

生物处理组合工艺用于制革废水处理

针对制革废水高COD、高总氮的问题,提出了基于上流式厌氧污泥床(UASB)、上流式反硝化污泥床(UDNSB)、生物接触氧化池的生物处理组合工艺,进行了为期321 d的现场中试研究。研究结果表明,对于COD、TN、NH_4~+-N平均浓度分别为2 740、278和193 mg·L~(-1)的制革废水,在硝化液回流比R为300%,UASB反应器、UDNSB反应器、生物接触氧化池的水力停留时间(HRT)分别为11、22和57 h,平均容积负荷分别为5.63 kg COD·(m~3·d)~(-1)、0.30 kg TN·(m~3·d)~(-1)和0.11 kg NH+4-N·(m~3·d)~(-1)的条件下,该组合工艺处理出水COD、TN和NH_4~+-N的平均浓度分别为190、69.8和4.6 mg·L~(-1),其平均去除率分别达到92%、73%和97%以上。     

ABR+复合人工湿地处理分散性生活污水的中试研究

研究了ABR+复合人工湿地组合工艺处理分散性生活污水的运行效能及ABR中颗粒污泥的特性。结果表明:在pH和温度的范围分别为6.5～8.5,17.0～28.8℃,ABR和复合人工湿地的HRT分别为3 h(容积负荷平均为1.3 kgCOD/(m3.d)及1.3 d(水力负荷平均为24.6 cm/d)的条件下,系统对COD、NH4+-N、TN、TP和浊度均有较好的去除效果,其平均去除率分别为76%、69%、56%、87%和86%,出水浓度平均分别为37 mg/L、2.73 mg/L、6.93 mg/L、0.18 mg/L和5.05 NTU,ABR中形成了性状良好的颗粒污泥。     

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.     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

Observations on the influence of water and soil pH on the persistence of insecticides

Abstract

The pH‐disappearance rate profiles were determined at ca. 25°C for 24 insecticides at 4 or 5 pH values over the range 4.5 to 8.0 in sterile phosphate buffers prepared in water‐ethanol (99: 1 v/v). Half‐lives measured at pH 8 were generally smaller than at lower pH values. Changes in half lives between pH 8.0 and 4.5 were largest (>1000x) for the aryl carbamates, carbofuran and carbaryl, the oxime carbamate, oxamyl, and the organophosphorus insecticide, trichlorfon. In contrast, half lives of phorate, terbufos, heptachlor, fensulfothion and aldicarb were affected only slightly by pH changes. Under the experimental conditions described half lives at pH8 varied from 1–2 days for trichlorfon and oxamyl to >1 year for fensulfothion and cyper‐methrin. Insecticide persistence on alumina (acid, neutral and basic), mineral soils amended with aluminum sulfate or calcium hydroxide to different pH values and four natural soils of different pH was examined. No correlation was observed between the measured pH of these solids and the rate of disappearance of selected insecticides applied to them. These observations demonstrate the difficulty of extrapolating the pH dependent disappearance behaviour observed in homogeneous solution to partially solid heterogeneous systems such as soil.     

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.     

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.     

Radionuclides and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

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.