组合填料生物滤池处理锦纶废水二级出水的性能研究

为解决纺织行业水回用问题,采用陶粒和活性炭组合填料生物滤池对锦纶废水二级生物处理出水进行了深度净化,并考察了气水比和水力负荷对曝气生物滤池处理效果的影响.研究结果表明,曝气生物滤池处理效果良好,平均出水COD、NH4 -N和TN分别为32 mg/L、1.5 mg/L和8.1 mg/L.随着气水比的增加,COD和NH4 -N平均去除率相应提高,TN平均去除率先增大后降低,当气水比为2∶1时,COD、NH4 -N和TN平均去除率分别为48.30%、84.24%和42.18%;随着水力负荷的增加,COD、NH4 -N和TN平均去除率均降低,当水力负荷为0.39 m3/m2·h时,COD、NH4 -N和TN平均去除率分别为48.33%、84.81%和42.54%.     

低温条件下生态槽深度处理农村生活污水的日变化特性

针对农村生活污水处理设施出水水质偏高污染环境的现状,构建了以水生植物为主体的生态槽深度处理农村生活污水,研究了低温条件下生态槽深度处理生活污水过程中DO、pH、COD、NH4+-N、TP等指标的日变化特性。结果表明,生活污水COD为37.67～60.23 mg/L、NH4+-N为13.66～16.76 mg/L、TP为1.32～1.78 mg/L、水温为9～11℃,HRT为5 d时,生态槽出水COD、NH4+-N和TP平均为21.07 mg/L、0.99 mg/L和0.19 mg/L,均可达《地表水环境质量标准》(GB3838-2002)之Ⅳ类水标准。各级生态槽内DO浓度夜间低于昼间。夜间植物对NH4+-N和TP具有较强的吸收作用,平均去除率分别达94.83%和89.87%;而TN去除效果稍差,平均去除率为59.9%。     

一种基于脱氮和除磷分开的强化污染物去除组合工艺中试研究

针对北京等严重缺水地区提高污水综合排放标准,用于地表水和地下水补充水的需求,以强化COD、N和P去除为目的,研发了N和P不同单元处理的缺氧立体循环氧化沟单元/好氧立体循环氧化沟单元/除磷过滤器单元组合工艺,通过中试实验研究了该工艺的去除效果,并优化了该工艺水力停留时间(HRT)和溶解氧(DO)参数。结果表明,当缺氧和好氧立体循环氧化沟单元的HRT和DO分别为12 h、DO 0.5 mg/L和6 h、2.0 mg/L,除磷过滤器滤速6~8 m/h时,该工艺的平均出水浓度COD 25 mg/L,TN 11 mg/L,NH_4~+-N 1.2 mg/L,TP 0.15 mg/L,平均去除率分别为88%、57%、94%和96%。其中缺氧立体循环氧化沟单元COD、NH_4~+-N和TN平均去除率为70%、80%和57%,好氧立体循环氧化沟单元进一步去除COD和NH_4~+-N(去除率为18%和14%);经缺氧、好氧氧化沟处理去除50%左右的TP,除磷单元吸附作用去除46%的TP。经过该组合工艺处理,COD、N和P都能达到北京市2013年出台的地方污水排放新标准一级B排放要求。     

改进型波形潜流人工湿地处理猪场废水

提出了一种改进型波形潜流人工湿地(improved wavy subsurface flow constructed wetland,IW-SFCW)并研究了该湿地系统在5个水力停留时间(hydraulic retention time,HRT)(2、3、4、6和8 d)下对猪场废水的处理效果。结果表明,该湿地系统对猪场废水中各污染物有较好的去除效果。在水力停留时间为4 d,进水COD、TN、NH4+-N和TP浓度分别为511、120、110和10 mg/L左右时,该湿地系统对COD、TN、NH4+-N和TP的去除率分别为86.0%、54.4%、70.1%和91.6%。此外,该湿地系统对废水中COD、TP的去除效率随水力停留时间的延长逐渐提高,在HRT=8 d时去除效果最好,去除率分别达到92.7%和96.8%;但对TN、NH4+-N的去除率却随水力停留时间的延长出现先上升后下降的趋势,在HRT=4 d时去除率最高,分别为54.4%和70.1%。     

蚯蚓生态滤池对农村生活污水的深度净化效果

本实验利用多级蚯蚓生态滤池对农村生活污水进行处理研究,分别考察了不同季节蚯蚓生态滤池对COD、TN、NH4+-N和TP的去除效果,同时利用PCR-DGGE技术对不同季节的微生物群落进行初步分析。结果表明,夏季COD、TN、NH4+-N和TP的平均去除率分别达到86.05%、89.02%、98.48%和99.1%;出水浓度17.86、4.96、0.605和0.047 mg/L。冬季COD、TN、NH4+-N和TP的平均去除率分别达到83.29%、93.26%、96.96%和92.7%;出水浓度22.68、2.63、1.02和0.37 mg/L。不同季节出水水质均达到了《城镇污水处理厂污染物排放标准》(GB18918-2002)一级A类标准。蚯蚓生态滤池内的微生物多样性冬季的要比夏季的丰富,且冬季滤池内微生物种类从上至下逐渐增加,符合污染物去除效率的变化。     

漂浮植物塘处理农村分散生活污水的强化措施研究

利用漂浮植物与园沟宅河构建漂浮植物塘,配合化粪池处理农村分散生活污水,对改善水乡地区农村水环境质量具有重要意义。针对自然条件下的漂浮植物塘对NH4+-N等污染物的去除速率较低的局限,考察了曝气和搅拌等人工强化措施对提高漂浮植物塘净化效果的作用。结果表明:(1)曝气和搅拌可显著提高模拟漂浮植物塘中NH4+-N的去除率,但是不能改善TN的去除效果。(2)只要保证一定的DO,曝气方式对NH4+-N的去除效果影响不大。(3)模拟化粪池出水以接近连续流方式进入模拟漂浮植物塘,在平均DO大于2mg/L、水温20℃左右的条件下,停留时间为7d,NH4+-N能达到良好的硝化效果,持续运行没有发生NH4+-N积累。进水NH4+-N平均负荷为1.6g/(m2.d)下,曝气模拟漂浮植物塘出水NH4+-N平均值均可达到《地表水环境质量标准》(GB3838—2002)中Ⅴ类标准(2.0mg/L)。     

新型人工湿地生态填料净化生活污水的试验研究

采用单一粒级的碎石作为粗骨料,水泥、粉煤灰和化学添加剂为胶结材料制备了2种新型人工湿地生态填料(以下简称人工生态填料),分别为普通人工生态填料(ES-C)和内置空隙人工生态填料(ES-V),对比研究了2种人工生态填料和普通碎石填料对模拟农村生活污水的净化处理效果,探讨了影响其去除效果的几个因素。结果表明,处理第5天,效果最好的ES-V对COD、NH4+-N和TP的去除率分别为83.13%、75.25%和75.17%,浓度达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级B标准;普通碎石填料的NH4+-N去除率比人工生态填料低30%左右,TP的去除率约为人工生态填料的一半。当COD/NH4+-N(质量比)为9～13,NH4+-N负荷为20～55mg/L时,人工生态填料对NH4+-N的去除效果较好;TP为3～10mg/L时,人工生态填料对TP有较高的去除率。最后从物理、化学和生化作用3个方面探讨了人工生态填料的去污机制。     

直接驯化嗜盐菌处理高盐废水的研究

从大连旅顺盐场底泥中筛选出适合高盐度的嗜盐菌,在序批式间歇反应器(SBR)中对其进行3.5%(质量分数)盐度的驯化,污泥混合液悬浮固体(MLSS)平均质量浓度达600mg/L。污泥比耗氧速率(SOUR)测量结果显示,内源呼吸阶段污泥SOUR为10.36mg/(g.h),外源呼吸阶段污泥SOUR达到29.09mg/(g.h),表明所筛选的嗜盐菌培养的污泥具有较高活性。利用培养的污泥进行高盐模拟废水处理试验,结果表明,对盐度为3.5%、COD为240～340mg/L的高盐废水,在每周期12h、曝气量0.6L/min、污泥MLSS为600mg/L、污泥龄为18d条件下,COD去除率达95%以上,NH4+-N去除率达61%,TP去除率达55%。改变进水有机负荷对出水COD去除影响不大,该系统耐有机负荷冲击能力较强;盐度负荷的改变对COD的去除影响不大,而NH4+-N去除率有明显变化,在3.5%和5.0%的盐度下,NH4+-N去除率分别为61%和31%。     

臭氧曝气沸石生物滤池处理硝基苯废水

利用臭氧曝气沸石生物滤池处理硝基苯废水,了解了该方法对废水中的硝基苯、氮和磷的去除效果,考察了水力停留时间的变化对污染物去除效果的影响。臭氧曝气沸石生物滤池与空气曝气沸石生物滤池相比,臭氧曝气生物滤池对硝基苯、COD、氨氮的去除效果优于空气曝气沸石生物滤池,对总磷的去除效果与空气曝气沸石生物滤池差别不大。当臭氧曝气沸石生物滤池的HRT=4 h、臭氧浓度为126 mg/L时,对初始浓度为100 mg/L的硝基苯污水去除率接近99%。在相同条件下,空气曝气沸石生物滤池对硝基苯的去除率仅为59%。在HRT=4 h、臭氧浓度为126 mg/L时,臭氧曝气沸石生物滤池与空气曝气沸石生物滤池对COD的去除率为94%和83%,对NH+4-N的去除率为64%和59%,对TP的去除率为42%和45%。     

生态-人工渗滤技术在高速公路收费站生活污水处理中的应用

研究了生态-人工渗滤组合技术在高速公路收费站生活污水中的处理效果。结果表明:在水力负荷为1.5m3/(m2.d),湿干比为1∶3的条件下,系统对COD、SS、NH4+-N、TP均有较好的去除效果,进水中COD、SS、NH4+-N以及TP浓度分别由126~218、123~186、19.89~32.69、2.75~4.53 mg/L降到出水的8~56、7~28、0.45~1.95和0.12~0.40 mg/L,COD、SS去除率分别在80%、85%以上,NH4+-N、TP的去除率均在90%以上。此研究显示,生态-人工渗滤技术在工程应用良好,基建和运行成本较低,在处理远离城市的生活废水时具有巨大的优势。     

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.     

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.     

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.     

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.     

Phytoextraction of lead-contaminated soil using vetivergrass (<Emphasis Type="Italic">Vetiveria zizanioides</Emphasis> L.), cogongrass (<Emphasis Type="Italic">Imperata cylindrica</Emphasis> L.) and carabaograss (<Emphasis Type="Italic">Paspalum conjugatum</Emphasis> L.)

Background, Aims and Scope The global problem concerning contamination of the environment as a consequence of human activities is increasing. Most of the environmental contaminants are chemical by-products and heavy metals such as lead (Pb). Lead released into the environment makes its way into the air, soil and water. Lead contributes to a variety of health effects such as decline in mental, cognitive and physical health of the individual. An alternative way of reducing Pb concentration from the soil is through phytoremediation. Phytoremediation is an alternative method that uses plants to clean up a contaminated area. The objectives of this study were: (1) to determine the survival rate and vegetative characteristics of three grass species such as vetivergrass, cogongrass and carabaograss grown in soils with different Pb levels; and (2) to determine and compare the ability of the three grass species as potential phytoremediators in terms of Pb accumulation by plants. Methods The three test plants: vetivergrass (Vetiveria zizanioides L.); cogongrass (Imperata cylindrica L.); and carabaograss (Paspalum conjugatum L.) were grown in individual plastic bags containing soils with 75 mg kg⁻¹ (37.5 kg ha⁻¹) and 150 mg kg⁻¹ (75 kg ha⁻¹) of Pb, respectively. The Pb contents of the test plants and the soil were analyzed before and after experimental treatments using an atomic absorption spectrophotometer. This study was laid out following a 3 × 2 factorial experiment in a completely randomized design. Results On the vegetative characteristics of the test plants, vetivergrass registered the highest whole plant dry matter weight (33.85–39.39 Mg ha⁻¹). Carabaograss had the lowest herbage mass production of 4.12 Mg ha⁻¹ and 5.72 Mg ha⁻¹ from soils added with 75 and 150 mg Pb kg⁻¹, respectively. Vetivergrass also had the highest percent plant survival which meant it best tolerated the Pb contamination in soils. Vetivergrass registered the highest rate of Pb absorption (10.16 ± 2.81 mg kg⁻¹). This was followed by cogongrass (2.34 ± 0.52 mg kg⁻¹) and carabaograss with a mean Pb level of 0.49 ± 0.56 mg kg⁻¹. Levels of Pb among the three grasses (shoots + roots) did not vary significantly with the amount of Pb added (75 and 150 mg kg⁻¹) to the soil. Discussion Vetivergrass yielded the highest biomass; it also has the greatest amount of Pb absorbed (roots + shoots). This can be attributed to the highly extensive root system of vetivergrass with the presence of an enormous amount of root hairs. Extensive root system denotes more contact to nutrients in soils, therefore more likelihood of nutrient absorption and Pb uptake. The efficiency of plants as phytoremediators could be correlated with the plants’ total biomass. This implies that the higher the biomass, the greater the Pb uptake. Plants characteristically exhibit remarkable capacity to absorb what they need and exclude what they do not need. Some plants utilize exclusion mechanisms, where there is a reduced uptake by the roots or a restricted transport of the metals from root to shoots. Combination of high metal accumulation and high biomass production results in the most metal removal from the soil. Conclusions The present study indicated that vetivergrass possessed many beneficial characteristics to uptake Pb from contaminated soil. It was the most tolerant and could grow in soil contaminated with high Pb concentration. Cogongrass and carabaograss are also potential phytoremediators since they can absorb small amount of Pb in soils, although cogongrass is more tolerant to Pb-contaminated soil compared with carabaograss. The important implication of our findings is that vetivergrass can be used for phytoextraction on sites contaminated with high levels of heavy metals; particularly Pb. Recommendations and Perspectives High levels of Pb in localized areas are still a concern especially in urban areas with high levels of traffic, near Pb smelters, battery plants, or industrial facilities that burn fuel ending up in water and soils. The grasses used in the study, and particularly vetivergrass, can be used to phytoremediate urban soil with various contaminations by planting these grasses in lawns and public parks. ESS-Submission Editor: Dr. Willie Peijnenburg (wjgm.peijnenburg@rivm.nl)