剩余活性污泥和厨余垃圾续批式混合中温消化试验研究

将加碱水解和未水解剩余活性污泥与厨余垃圾混合后进行序批式中温厌氧消化,对生化产甲烷势(BMP)进行了测定.剩余活性污泥的水解通过添加NaOH进行,合理的NaOH投量为40 mmol/L,在25 ℃和35 ℃下经过6 h的水解后SCOD水解率分别提高27.4%和31.1%.厨余垃圾、25℃和35℃下水解污泥的最终甲烷产量分别为607、284、312 mL/g(VS),两种水解污泥比未水解污泥分别高出43%、57.6%,水解污泥和厨余垃圾混合消化的可降解能力要优于未水解污泥和厨余垃圾的混合进料.     

剩余污泥发酵沼渣成分分析及脱水性能研究

通过对剩余污泥发酵沼渣进行成分分析,判断其是否适合于有机肥料的原料,并研究了其脱水性能。结果表明,剩余污泥发酵沼渣总养分和有机质质量分数分别为4.22%~4.48%、9.17%~9.26%,未达到《有机肥料》(NY 525—2012)的标准值。重金属Cr、Cd、As、Pb、Hg的质量浓度分别为116.57~137.06、1.16~1.57、9.76~10.75、41.23~48.29、1.67~1.94mg/kg,均达到NY525—2012的标准值。二次厌氧发酵沼渣实验证明,其含水率和有机质已基本稳定。因此,剩余污泥发酵沼渣不能直接用作有机肥料,但可以作为有机肥料的原料。当聚丙烯酰胺(PAM)、聚合氯化铝(PAC)投加量分别为2、5g/L时,剩余污泥发酵沼渣离心后含固率可分别提高到30.24%、30.34%,可显著改善其脱水性能。     

pH值对污泥发酵产酸的影响

利用剩余污泥厌氧发酵产生挥发性脂肪酸,可作为污水脱氮除磷的有机碳源,而pH值是发酵产酸过程中重要的控制参数.研究了不同pH值条件下剩余污泥厌氧发酵产酸过程中各参数变化规律,探索pH值对其过程的影响及其分析.结果表明,碱性条件有利于污泥发酵产酸过程,实验最佳条件是控制反应初始pH值为10.0,仅8d发酵挥发性脂肪酸浓度就达到8.90 mmol/L.此外,污泥在发酵过程中,酸性条件下NH4+-N和PO43--P的释放量均大于碱性条件.     

蓝藻与污泥混合厌氧发酵产沼气的初步研究

为了实现太湖蓝藻打捞后的快速处置,对厌氧颗粒污泥、消化污泥、剩余污泥与蓝藻混合厌氧发酵产沼气进行了研究。结果表明,蓝藻与污泥混合可以有效促进沼气发酵。在蓝藻与厌氧颗粒污泥物料比为6∶1时,产气效果最佳,沼气产率为73 mL/g VS,平均甲烷含量为69%,最大产气速率为138 mL/d,累计产甲烷量为50 mL CH₄/g干物质,分别是蓝藻与消化污泥、剩余污泥混合发酵时的1.5倍和2.3倍。厌氧颗粒污泥、消化污泥、剩余污泥与蓝藻混合,其VS降解率为11.40%～13.73 %,COD减少了27.97%～46.38%。厌氧发酵对蓝藻藻毒素的含量有较大影响,分别从356、366和244 μg/L降低到检测限5 μg/L 以下。     

剩余污泥发酵产酸特征及基质释放规律研究

剩余污泥发酵既能实现污泥减量,又能获得污水生物脱氮除磷所需的挥发性脂肪酸VFAs等。采用序批式污泥发酵实验,在(30±1)℃的条件下,研究剩余污泥投配比对序批式污泥发酵系统污泥减量、产酸以及基质释放过程的影响,探索VFAs生成最大化的条件。实验结果表明:投加接种污泥不能明显提高序批式污泥发酵系统剩余污泥的减量效果,但可以改善污泥的产酸特性;当污泥投配比大于50%时,发酵过程中将出现2个VFAs浓度峰,且第二次峰浓度更大;较为理想的序批式污泥发酵投配比是60%~80%、发酵时间为5 d或25 d,前者VFAs表观转化率最大(约24%),后者发酵液中VFAs浓度最高(约600 mg/L);发酵过程中,NH4+-N总体呈上升趋势,磷浓度发酵5 d时达到最大值。     

剩余污泥减量化工艺条件优化研究

运用超声处理连续流活性污泥系统中不同种类的污泥,并将其回流至原系统中,研究其剩余污泥减量化效果。按正交实验设计并进行试验,确定最优工艺条件。结果表明:当声能密度为0.6 W/mL,作用时间为5 min,超声污泥为混合污泥,回流比为7∶120时,减量效果最佳。且在该条件下经一周期的运行,污泥减量效果达到96.24%,COD由进水的830 mg/L降至44 mg/L,NH4+-N和TN分别由进水的62.43 mg/L和103.19 mg/L,降解到2.31 mg/L和6.52 mg/L,达到《城镇污水处理厂污染物排放标准》(GB18918-2002)一级排放标准。     

水解酸化应用于剩余污泥减量的试验研究

碱减量印染废水生物处理剩余污泥接种培养成熟的水解酸化菌,通过它们的新陈代谢作用,可以实现系统内生命物质的更新和减量,同时降解了污泥吸附的有机物等,达到对剩余污泥减量的目的.在系统污泥减量初期,水解酸化作用对微生物的"液化"、内容物释放和对有机物的生物降解作用是污泥减量的主要原因;随着中间代谢产物的积累,微生物活性受到抑制,试验后期剩余污泥减量主要是微生物内源呼吸的结果.试验条件下,接种了成熟水解酸化细菌的 2 组剩余污泥 MLSS 浓度分别为 7.765 和 11.250 g/L,MLVSS 浓度分别为 4.466和 6.360 g/L,经过 513 h后 MLSS、MLVSS 浓度较开始时分别下降了 40.31%、45.73%和 54.85%、63.18%.一定污泥浓度范围,污泥减量效果与污泥浓度正相关.     

活性污泥法合成可生物降解塑料的工程化可行性探讨

细菌发酵法仍是目前合成可生物降解塑料(PHA)的主要方法,但实现其工业化生产的最大瓶颈是生产费用较为昂贵,而活性污泥法因独具的优点,有望成为较为经济、具有良好前景的PHA生物合成方法。对利用活性污泥法合成PHA的工程化可行性进行了探讨,主要分析了活性污泥法的PHA合成代谢机制、工艺优化和PHA积累水平,以及方法的技术经济可行性。最后指出,活性污泥法合成PHA不仅在技术、投资和生产费用方面较细菌发酵法更具竞争力,而且能在有效去除污染物的同时积累PHA,具有很好的推广价值和应用前景。     

高效代谢解偶联剂的筛选及对SBR系统综合运行效能的影响

活性污泥法是最常用的污水处理技术,但它同时会产生大量的剩余污泥,需要进行额外的处理和处置.活性污泥的解偶联代谢能有效地减少剩余污泥的产量.比较了5种代谢解偶联剂,即2,4-二硝基苯酚(DNP)、邻氨基苯酚(AP)、2,4,6-三氯苯酚(TCP)、3,3',4,5-四氯水杨酰苯胺(TCS)、丙二酸的污泥减量效果和对COD去除能力的影响.结果表明,当它们在各自的最佳质量浓度20、1 5、4、1.2、15 mg/L时,污泥的表观增长系数分别降低了62.39%、63.75%、59.40%、34.58%和53.75%,而COD去除率仅有轻微下降.重点研究了15 mg/L的丙二酸和4 mg/L的TCP对SBR系统运行效能和污泥沉降性能的影响.发现在长期运行过程中,两者都能有效降低系统的污泥产量,而对COD去除率的影响较低,但使用丙二酸6 d后极大地影响了污泥的沉降性能,而TCP对污泥的沉降性能影响很小.     

剩余污泥的乳酸化及减量化研究

近年来,污水处理产生的剩余污泥,导致的环境问题日趋突出.利用乳酸菌通过糖代谢可生成乳酸这一原理,探讨了污泥的减量化,并且使之一部分乳酸化实现全新的处理方法.对浓缩剩余污泥的稀释倍数、前处理温度等条件进行了分析,结果表明,在前处理120℃,污泥和水的混合比10.5,添加糖浓度50 mmol/L,发酵温度40℃,发酵时间5 d的条件下,达到SS减少35%,乳酸生成量17.5 g/L的效果.     

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.