UASB-SBR组合工艺处理畜禽养殖废水的研究

近年来,随着中国畜禽养殖业的快速发展,落后的养殖模式和污染防治设施,使畜禽养殖污染日趋严重,畜禽养殖污染已居农业污染源之首,已成为中国环境污染的重要因素,对环境质量乃至人体健康都会产生不良影响。文中采用UASB—SBR组合工艺处理畜禽养殖废水,通过试验探讨SBR反应器启动方法及最佳运行模式,同时研究UASB反应器的启动方法。结果表明,SBR运行的最佳模式为进水0.5 h、反应8 h、沉淀1 h、出水0.5 h、闲置14 h。经过一段时间的启动,UASB和SBR反应器均成功启动,UASB—SBR组合工艺在处理畜禽养殖废水时可获得稳定的处理效果,COD、氨氮、总磷等出水水质均达到《畜禽养殖业污染物排放标准》(GB18596-2001)要求,为畜禽养殖废水处理的工程化应用提供了参考依据。     

永定河上游张家口地区主要河流污染物来源解析

运用内梅罗污染指数评价法对永定河上游张家口地区主要河流水质进行定量评价,在多元统计分析方法的基础上,结合产业结构与布局对其污染物来源进行解析。结果表明:(1)2013—2016年,永定河上游主要河流水质逐渐改善,但仍存在水污染问题,主要超标的水质指标为TP和氟化物,超标率分别为28.24%和22.59%。(2)空间聚类分析发现,洋河中下游断面鸡鸣驿、响水铺和八号桥,水污染相对较严重;清水河上游断面北泵房和洋河上游断面左卫,水污染较轻;桑干河断面石匣里、温泉屯、小渡口和清水河下游断面老鸦庄,水质清洁。(3)洋河中下游污染物来源于工业污染和城市生活污水,清水河下游和桑干河污染物来源于农业面源污染、畜禽养殖污染和有机物污染,洋河上游和清水河上游污染物来源于农业面源污染和生活污水。     

垃圾焚烧发电厂废水零排放工艺及其环境经济效益分析

介绍了1种垃圾焚烧发电厂废水零排放工艺,即升流式厌氧污泥床(UASB)+膜生物反应器(MBR)+纳滤(NF)组合工艺,能很好地处理垃圾焚烧发电厂的废水。以广东某垃圾焚烧发电厂为例,对UASB+MBR+NF组合工艺进行了环境经济效益分析,为中国垃圾焚烧发电厂的废水处理提供借鉴。     

基于InfoWorks ICM模型的白龙江流域甘肃段水质模拟及分析

针对白龙江沿岸农业种植、畜禽养殖等产业发展影响河流水质的问题,以甘肃省南部白龙江流域为研究对象,采用改进输出系数模型计算丰、平、枯水年等典型水文情景下流域内工业、农村生活垃圾、农村生活污水、畜禽养殖、城镇生活污水、城镇径流和农田径流等污染源污染负荷,基于InfoWorks ICM构建了白龙江水动力水质模型,模拟分析COD、TN、NH₄⁺-N和TP等污染负荷分布特征,评估了最不利水文条件下白龙江水质污染风险,验证了该模型在流域水质污染模拟评估的适用性。研究结果表明,不同水文情景下污染物入河负荷主要来源存在显著差异,如丰水年和平水年农田径流是COD污染的主要来源,污染负荷分别达到1 382.56、1 058.98 t,而枯水年污染源主要是城镇径流。污染物负荷存在明显空间差异,研究区内子流域污染负荷空间分布不均匀,高污染负荷主要出现在中下游子流域。白龙江水质在汛期和非汛期差异较大,非汛期水质更差。通过模拟最不利水文情景(枯水年非汛期)发现,研究区内白龙江NH₄⁺-N浓度最大位置出现在中下游,最高可达1.4...     

通化市创建国家环境保护模范城市期间主要水污染物削减对策的研究

分析了通化市主要污染物排放现状及其创建国家环境保护模范城市(简称创模)的基础条件。预测了2013-2015年通化市农业源、城镇生活源、工业源新增的COD及氨氮排放量,在削减空间有限的条件下,结合环境统计数据分析,合理测算新增项目削减潜力。提出了通化市在创模的3年里,应以重点工业企业深度治理、生活污水设施扩建以及畜禽养殖干清粪工艺改造等为抓手,扎实推进污染物减排工作,以期达到创模考核的目标要求。     

低污泥产量印染废水处理工艺与运行条件

采用UASB反应器+三段好氧+混凝沉淀组合工艺处理印染工业园废水,对污泥减量化进行探索。结果表明,工程运行中,通过控制运行参数、以及运用UASB水解酸化反应器及生物捕食技术,在出水稳定在《城镇污水处理厂污染物排放标准》(GB18918-2002)一级A标准时,该系统处理每吨污水污泥产量为1 046 g。     

模拟光伏间歇曝气两级SBR的脱氮除磷效果

基于农村生活污水间歇排放和太阳能能量密度昼夜变化特征,模拟光伏间歇曝气两级SBR处理农村污水,将聚磷菌(PAOs)和硝化菌分开控制在2个反应器中生长,分别命名为厌氧(缺氧)/好氧SBR(A/OSBR)和硝化SBR(NSBR)。考察进水时间和回流对系统脱氮除磷效果的影响以及单个运行周期内污染物、溶解氧(DO)、氧化还原电位(ORP)和p H变化规律。结果表明,当进水时间为60 min和5 min,系统对TP的去除率分别为20.6%和56.5%;N-SBR出水与生活污水按1∶2比例进入A/OSBR中,系统对TN、TP的去除率分别为57%和30.6%;N-SBR具有稳定的硝化效果,NH+4-N的去除率均能达到90%以上。DO和p H曲线的突跃点与反应终点保持一致,可将其作为实时控制参数。     

UASB-SBR工艺处理规模化畜禽养殖废水

针对规模化畜禽养殖废水常规厌氧-好氧组合处理工艺及SBR处理工艺脱氮效率低、运行费用高等问题,采用UASB-SBR工艺,研究3种不同的SBR模式对处理效果的影响。结果表明,UASB容积负荷(以COD计)8 kg·(m~3·d)-1、pH 7.0、温度35℃、HRT 25 h时,COD去除率为80%~85%;SBR在进水15 min、反应480 min、沉淀60 min、出水15 min、闲置810 min条件下,对废水COD、NH_4~+-N、和TN去除率分别为91.8%、98.7%和71.6%,出水COD≤180 mg·L~(-1)、NH_4~+-N15 mg·L~(-1)、TN50 mg·L~(-1),达到《畜禽养殖业污染物排放标准》(GB 18596-2001)。该运行条件下NO_2~--N积累率超过50%,出现了NO_2~--N积累,短程硝化反硝化是主要脱氮方式。     

河南省农业面源污染负荷估算及控制分区

农业面源污染问题是造成水环境污染的重要原因之一,识别农业面源污染空间分布并进行分区控制是农业面源污染防治的前提。运用清单分析法、等标污染负荷法和聚类分析法对河南省2020年农业面源的污染源、污染物及其空间分布特征进行分析。结果如下：1)河南省农业面源主要污染源为化肥施用和畜禽养殖,污染物COD排放量最大,南阳市排放总量最高;河南省农业面源污染呈较强的区域分异特征,化肥施用污染主要集中在周口市,畜禽养殖以南阳市为最严重;总等标污染指数最高为濮阳市。2)通过聚类分析将河南省划分3个一级面源污染控制分区：高度、中度和轻度风险区,并在此基础上细分为7个二级面源污染控制分区,并针对性地给出了河南省农业面源的防治对策,为河南省农业面源污染的分类管控提供参考依据。     

混凝沉淀—UASB—MBR耦合工艺处理屠宰废水

为解决分散式小型屠宰厂在生产过程中产生的高浓度有机废水处理的问题,开展了物化单元(混凝沉淀)、生化单元(上流式厌氧污泥床反应器(UASB)工艺和膜生物反应器(MBR)工艺)对屠宰废水处理效果及影响因素的研究。结果表明:在混凝沉淀实验中,聚合氯化铝(PAC)最佳投加量为60mg/L、最佳pH范围为6.5~8.5;UASB工艺中,最佳进水上升流速为0.12m/h;MBR工艺中,最佳C/N(质量比)为5∶1~7∶1,DO在0.92~1.24mg/L时,对TN有较好处理效果,DO在1.24~1.68mg/L时,对COD及氨氮有较好处理效果。混凝沉淀—UASB—MBR耦合工艺连续运行的28d中,生化单元COD、TN和TP平均去除率分别为95.78%、89.17%、92.46%,出水水质良好。     

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.     

Evaluation of trichloroethene recovery processes in heterogeneous aquifer cells flushed with biodegradable surfactants

The ability of two biodegradable surfactants, polyoxyethylene (20) sorbitan monooleate (Tween 80) and sodium dihexyl sulfosuccinate (Aerosol MA), to recover a representative dense non-aqueous-phase liquid (DNAPL), trichloroethene (TCE), from heterogeneous porous media was evaluated through a combination of batch and aquifer cell experiments. An aqueous solution containing 3.3% Aerosol MA, 8% 2-propanol and 6 g/l CaCl(2) yielded a weight solubilization ratio (WSR) of 1.21 g TCE/g surfactant, with a corresponding liquid-liquid interfacial tension (IFT) of 0.19 dyn/cm. Flushing of aquifer cells containing a TCE-DNAPL source zone with approximately two pore volumes of the AMA formulation resulted in substantial (>30%) mobilization of TCE-DNAPL. However, a TCE mass recovery of 81% was achieved when the aqueous-phase flow rate was sufficient to displace the mobile TCE-DNAPL toward the effluent well. Aqueous solutions of Tween 80 exhibited a greater capacity to solubilize TCE (WSR=1.74 g TCE/g surfactant) and exerted markedly less reduction in IFT (10.4 dyn/cm). These data contradict an accepted empirical correlation used to estimate IFT values from solubilization capacity, and indicate a unique capacity of T80 to form concentrated TCE emulsions. Flushing of aquifer cells with less than 2.5 pore volumes of a 4% T80 solution achieved TCE mass recoveries ranging from 66 to 85%, with only slight TCE-DNAPL mobilization (<5%) occurring when the total trapping number exceeded 2 x 10(-5). These findings demonstrate the ability of Tween 80 and Aerosol MA solutions to efficiently recover TCE from a heterogeneous DNAPL source zone, and the utility of the total trapping number as a design parameter for a priori prediction of DNAPL mobilization and bank angle formation when flushing with low-IFT solutions. Given their potential to stimulate microbial reductive dechlorination at low concentrations, these surfactants are well-suited for remedial action plans that couple aggressive mass removal followed by enhanced bioremediation to treat chlorinated solvent source zones.     

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.     

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 variation of street air levels of PAH and other mutagenic PAC in relation to regulations of traffic emissions and the impact of atmospheric processes

The occurrence of particle associated PAH and other mutagenic PAC was determined in 1996 in the street air of Copenhagen. In addition, particle extracts were tested for mutagenicity. The measurements were compared with previous measurements in 1992/1993. The levels had decreased in this period. The decrease was caused by an implementation of light diesel fuels for buses and the exchange of older petrol-driven passenger cars with catalystequipped new ones. About 65% of the reduction was caused by the application of the light diesel fuels. Under special conditions, chemical processes in the atmosphere produced many more mutagens than the direct emissions. The concentrations of S-PAC and N-PAC were 10 times lower than those of PAH, while the levels of oxy-PAH were in the same order of magnitude as those of PAH. Benzanthrone, an oxy-PAH, is proposed to be formed in the atmosphere in addition to direct emissions. Benzo(a)pyrene, often applied as an air quality criteria indicator, was photochemically degraded in the atmosphere. A strong increase in the mutagenic activities was observed to coincide with a depletion of benzo(a)pyrene.     

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.     

Teratological effects of pesticides in vertebrates: a review

Abstract

In the last decades, the use and misuse of pesticides in the agriculture have increased, having a severe impact on ecosystems and their fauna. Although the various effects of pesticides on biodiversity have been already documented in several studies, to our knowledge no consistent overview of the impact of pesticides in vertebrates, both terrestrial and aquatic, is available. In this review, we try to present a concise compilation of the teratogenic effects of pesticides on the different classes of vertebrates – mammals, birds, reptiles, amphibians and fish.     

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.