对湖河池底沼气开采的综合试验研究

湖河池底的污泥不断进行着沼气发酵,产生大量的沼气吸附在污泥上。沼气开采做为能源有较高的经济价值。沼气开采又能减少恶臭而有害的H₂S气体和温室效应很高的CH₄气体,减少其逃逸到空气中,改善空气质量;沼气开采也能促进水体自净功能的提高,改善水体质量。     

城市污泥的污染现状及其土地利用评价

随着城市污泥产生量的迅速增加,污泥的科学处置及土地利用是当前城市固体废弃物资源化的主要研究内容。本文较系统地阐述了污泥的基本性质、污泥污染和处置现状及土地利用的风险评价等相关研究,并指出了目前城市污泥研究中存在的问题。     

日本下水道污泥的农业利用概况

下水道污泥含有许多有机物质、植物营养元素、多种污染物及大量的水分。日本年产污泥约为240万立方米,其中80％用填埋和投海等方法处置,农业利用的仅占百分之十几。投海和焚烧都存在一定问题,而填埋、污泥施入农田既利用了土壤的自净能     

城市污泥与湖泊底泥土地利用对土壤-植物系统中养分及重金属Cd、Pb的影响

采用田间小区试验，探讨了城市污泥与湖泊底泥土地利用对土壤-植物系统中养分及重金属Cd、Pb的影响。结果表明，城市污泥与湖泊底泥能有效增加土壤养分含量；重金属Cd、Pb仅累积在土壤耕层，难以向下迁移；随施用量的增加，小麦籽粒产量及其对养分的吸收量均随之增加，但仍有大量养分存留在土壤中；植株对重金属的富集顺序表现为根系〉茎叶〉籽粒，Cd〉Pb，其中，籽粒中重金属Cd、Pb含量均未超出我国食品中重金属限量的卫生标准；如果该污泥、底泥分别以100，200t／hm^2的施用量施入土壤，可以连续施月5a和6a     

污泥保水功能的研究及应用初报

污泥的透水性差,难以干燥是污泥资源化利用的技术障碍。可以利用污泥的这一特性,开发污泥保水的新功能。以土培及玉米盆栽研究污泥不同含量与在土壤中不同放置方式的保水效果,对土培的含水量、失水量及失水率,盆栽土壤水分含量及植株生物量进行了系统分析。污泥含量高的处理有一定保水效果但不及保水剂处理,而其盆栽结果却优于保水剂处理。污泥在土层的不同放置试验表明,在土壤中层状放置的土培及盆栽试验结果均优于全层混合,且双层的效果最优。污泥具有较强的保水性,是有待开发的新功能。与在土壤合适的放置方式结合,可更好地发挥其保水潜力。     

亚临界水解法处理城市污泥及其栽培试验

城市生活污泥富含有机质,是一类重要资源。长期以来,由于缺乏高效处理加工技术手段,大量城市污泥被焚烧、填埋,既浪费了资源,又污染环境。本文采集了北京市和天津市污水处理厂的代表性污泥样品,并采用亚临界水解技术进行了处理。研究结果表明,亚临界水解法较好地解决了城市污泥胶粘难以干燥和恶臭问题,保存了污泥中的有机质,同时消除了污泥中的病原,降低了重金属汞含量,是一项处理城市污泥的理想方法;城市污泥水解产物有机物含量高达80%,重金属含量远低于国家限制性标准,未检出有机污染物,蛔虫卵死亡率100%,未检出粪大肠菌群,是生产有机肥料、生物有机肥和农用微生物菌剂的理想原料;栽培试验表明,城市污泥热解产物配施半量化肥比单施全量化肥,可以节省化肥,提高小白菜品质,提高土壤肥力。     

污泥的林业利用

随着城市和工业生产的发展,污水和污泥的数量不断增加。就污泥而言,不仅某些行业,例如皮革,造纸、酿造行业,在生产过程中产生大量污泥,更主要的是在废水处理过程中也要产生大量污泥,其数量大约是废     

复合污泥堆肥施用于高速公路绿化带效果的研究：Ⅰ.中央分隔 …

高速公路绿化带土壤１多为生土，植物难以生长良好。污泥含植物养分及大量有机质，具有肥及改土作用。将其与秸秆进行堆肥化处理后，加入化肥制成事污泥堆肥，施用于高速避开了食物链，对环境也无影响。在西宝、西三及西临高速公路，既避开了食物链，对环境也无影响。在西宝、西三及西临高速公路的中央分隔带、护坡及转盘对几种树和草类进行的试验，证明植物响应良好；护坡及转盘内草坪草生物量增加，颜色加深，绿色期延长；护 草生     

贵州省典型城市污水处理厂污泥养分与重金属含量调查

分别采集贵州省8个典型地级城市污水处理厂冬季和夏季的脱水污泥样品,进行室内分析测试,研究其养分和重金属特性。结果表明,贵州省主要地级城市脱水污泥pH为6.5-7.4,盐分含量为0.4-0.9。城市污泥中有机质、全量N、P高于一般农家肥,但全K量较低。污泥中全量重金属Cu、Pb、Ni、Cr、Hg和As均远低于国家农用标准,但一个处理厂污泥Cd、Zn超标,另有一处理厂污泥Cd超标,有3个处理厂污泥存在Zn超标现象。形态分析表明,Cd在多数污泥中化学形态主要是以生物有效态的形式存在,而Zn主要以稳定的化学形态存在,说明Cd存在环境风险,而Zn相对安全,表明贵州地区脱水污泥多数可安全农用,冬季和夏季脱水污泥的养分和重金属浓度没有显著差异。     

长期施用污泥对土壤-萝卜系统重金属积累及土壤养分含量的影响

为了探究不同用量污泥长期施用后对土壤-萝卜系统中重金属及土壤养分含量的影响,采用长期定位试验,研究连续10年单施化肥(CK)以及施用不同用量(4.5、9、13.5、18 t·hm~(-2))污泥对土壤、萝卜叶(地上部)和萝卜(地下部)中重金属(Pb、Cd、Cr、Ni、Cu、Zn)累积情况及土壤pH、有机质及氮磷钾含量的影响。结果表明:连续施用10年后,单施化肥和不同用量污泥处理对萝卜产量影响不大,土壤、萝卜叶和萝卜中的Pb、Cd、Cr、Ni、Cu和Zn含量均随污泥施用量的增加而增加,且中高量和高量污泥处理中重金属的累积量较大,显著或极显著高于对照、低量和中量处理。中量以上污泥处理土壤的Pb、Cr、Ni和Cu超出了土壤环境质量国家标准;除高量污泥处理Pb超标外,其他处理萝卜的各重金属含量均未超过食品安全国家标准。与CK处理相比,长期施用不同用量污泥能提高土壤pH 0.58～0.71个单位,并显著或极显著地提高有机质、全量氮磷以及速效氮磷含量。研究表明,连续10年施用不同用量污泥,土壤和萝卜中Pb、Cd、Cr、Ni、Cu、Zn的含量随污泥用量的增加而增加,其中Pb、Ni、Cr和Cu出现超标现象,萝卜中的重金属含量除高量污泥处理中Pb超标外,其他处理均未超过食品安全国家标准。随着作物产地土壤中污泥施用年限增长或用量增加,食品安全应得到更多的重视。     

Concentrations of heavy metals in forty sewage sludges in England

Samples of forty sewage sludges taken in England during 1979 were analysed for ten heavy metals using a rapid flameless atomic absorption spectroscopic technique. For all metals the mean concentrations were influenced by a small number of sludges containing exceptionally high concentrations. Typically, the concentration ranges showed approximately a 100-fold spread. Calculations based on U.K. guidelines for limiting the addition of toxic metals in sludge to agricultural soils indicated that application rates would theoretically be limited for more than 75 % of the sludges by the concentrations of Zn, Cu and Ni, expressed additively as the Zn equivalent. Calculations of the theoretical maximum quantities of sludges which could be applied to land on an annual basis suggested that a significant proportion of the sludges would be unsuitable for application to agricultural land at rates of more than 2 t ha^?1 yr^?1     

长江三角洲地区污水污泥与健康安全风险研究Ⅰ.粪大肠菌群数及其潜在环境风险

粪大肠菌群(FecalColiform,FC)是判定污泥土地安全利用的重要指标之一。通过实地调查取样,收集了长江三角洲地区的南京、苏州、上海、杭州等15个城市的污水处理厂的48份污泥样品,测定了其粪大肠菌群数,旨在了解污泥中FC的数量与潜在污染风险;并在污泥自然风干过程的第7、14、21、28天分别取样测定了FC的数量和水分含量,以观察风干过程中FC和水分的动态变化及其与风干时间的关系。研究结果表明,污泥中FC的最大可能数(MPN)的范围在0～3.41×106(MPNg-1,DW),平均为3.79×105(MPNg-1,DW),检出率达89.6%。不同类型污泥中FC的数量差别较大,“河流”污水处理厂污泥和污泥制品的FC数量最低,以生活污水为主的污泥和混流污水污泥中FC数量较高。污泥风干过程中FC数量和水分含量均随风干时间的延长而减少,但FC数量有回升现象。总之,污泥样品的FC数量差异较大,部分污泥样品的数量超过了污泥农用的病原物标准,为了保护生态环境和人类健康,防止二次污染,污泥土地利用时需考虑FC数量,采取相应控制措施。     

The disposal of leather tannery wastes by land treatment—a review

Abstract. People in rural areas have disposed of their wastes on land for centuries, relying on the soil's ability to degrade and render harmless any toxic elements the wastes may contain. Leather tanneries produce a large amount of sludge and liquid wastes. The liquids contain much sodium and in most circumstances adversely affect both the soil and groundwater. However, in some countries they are used for irrigation. The sludges contain nitrogen, calcium, magnesium, phosphorus, trivalent chromium and some sodium. Given careful management these sludges can be used as soil amendments, either directly or after composting. Application rates of about 200 tonnes ha⁻¹ have proved toxic to crops in pot trials, though larger applications than this have not adversely affected crops in the field. Much smaller rates, of less than 20 tonnes ha⁻¹, have been used in the field to minimize nitrate contamination of groundwater. The effects of CrIII depend on complex interactions between the sludge, the soil to which it is added and the plant species grown. Safe limits for the disposal of the sludges and their long term effects are not known.     

Barley growth in response to potassium fertilization of soil with long term application of sewage sludge

Application of sludges to agricultural land depressed plant growth despite its beneficial effects on crop production. Hence it remained to be determined whether sludge application induced any adverse effect on crop nutrition or growth. Thus the growth response of barley on an Andosol to which two kinds of sewage sludge compost had been applied for 17 y was tested in pot experiments with and without application of chemical K fertilizer. The addition of K in the sewage sludge composts resulted in the improvement of plant growth, high dry matter production and increase of total K content both in plant and soil compared to the materials without K application. It was assumed that long term application of sewage sludge requires chemical fertilizer amendment for crop production.     

Fractionation of residual cadmium,copper, nickel,lead, and zinc in previously sludge‐amended soil

Abstract

The fractionation of heavy metals in previously sludge‐amended soil is important to evaluate their behavior in the environment in terms of mobility and availability to crop plants. A surface soil that received two types of sludges at two different rates, plus fertilizer only and no treatment (control), having been fallow for nine years, was used in this study. The contents of cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) fractions in previously sludge‐amended soils were governed by the total content of these metals in the sludges applied and by the rate of sludge application. The contents of these metals were higher for soils that received the Chicago sludge as compared to that receiving the Huntsville sludge. Furthermore, soils that received 20 Mg/ha/yr of sludge for five years generally had higher levels of these metals than those receiving a single dose at the 100 Mg/ha application rate. The percentage of the total content in the water soluble and exchangeable forms was very low (≤1%) regardless of sludge application. The application of sludges tended to reduce the residual fraction and to increase the organic and carbonate fractions. Overall, the predominant forms of the metals in the sludges were as the Cd‐, Ni‐, Pb‐, and Zn‐carbonate and Cu‐organic fractions.     

Aqueous release of heavy metals from two sewage sludges

Two anaerobically digested sewage sludges, one of relatively low and the other of relatively high heavy metal content, were extracted several times with water to determine the levels of Cu, Zn, and Cd that would be readily available for transport in the soil water if these sludges were applied to land. Generally, the quantity of metal released in the aqueous extracts was between 1 to 7% of the total content with Cu and Zn being released to a greater extent than Cd. The porportion of relatively mobile, non-cationic heavy metals in the aqueous extract differed in the two sludges and ranged from < 1% for Zn and Cd in one sludge to 56.2% for Cd in the other sludge.[/P ]     

Modification of soil porosity after application of sewage sludge

The effect of the application of sewage sludge on soil porosity over 28 months is discussed here. Anaerobic sludges of urban refuse waters were applied on a degraded limestone soil in a mining land by two ways. First, a previous mixture of sludge and soil was carried out; this was then applied to the target land. Second, a direct application of sludge to soil and tilling. Porosity and pore morphology were measured on thin sections prepared from undisturbed soil samples. Data were obtained from backscattered electron images and image-processing computer equipment. The application of sludge induced an increase of both soil fine microporosity (φ<50 μm) and coarse microporosity (φ>50 μm). However, this effect showed transient, since no significant differences were reported in relation to the control plot after one year from application. The incorporation of sludge and developed vegetation modified coarse micropore irregularity and orientation. On the other hand, fine micropore morphology remains unchanged.     

Rare earth elements and other trace elements in wastewater treatment sludges

In order to evaluate the possibility of contamination of soil with trace elements by the application of sludges to soil, the contents of rare earth elements (REEs; La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) and other trace elements (Be, As, Ag, Cd, Sb, Cs, Bi, and U) in wastewater treatment sludges were determined. In sludges of night soil treatment plants (night soil sludges) and sludges of wastewater treatment plants in the food industry (food industry sludges), the distribution patterns of REEs normalized versus average REEs in the continental crust were almost flat. It was considered that the REE patterns of uncontaminated sludges reflected the pattern of the continental crust. The crust-normalized REE patterns of sludges of wastewater treatment plants in the chemical industry (chemical industry sludges) and municipal sewage sludges did not always show flat plots. The sludges that did not show a flat REE pattern were considered to be contaminated with some of the REEs.

The coefficient of variation of each element determined among the 10 samples of night soil sludges and the 14 samples of sewage sludges ranged from 34 to 77% and from 26 to 84%, respectively. Among the 10 samples of food industry sludges and the 10 samples of chemical industry sludges, the coefficient ranged from 60 to 143% and from 67 to 172%, respectively. The variations of the content of each element among the food industry sludges or the chemical industry sludges were larger than those among the night soil sludges or the sewage sludges.

The contents of Be, As, Cs, REEs, and U in all the sludges were lower than or the same as those in a field soil. Some of the food and chemical industry sludges contained larger amounts of Ag, Cd, and Sb than the soil. All the night soil sludges and sewage sludges contained much larger amounts of Ag and Bi than the soil.     

The adhesion to leaf surfaces of heavy metals from sewage sludge applied to grassland

Abstract. When sewage sludge is surface-applied to grassland, herbage may become contaminated with heavy metals from adhering solids, posing a risk to the health of grazing livestock and possibly increasing the entry of heavy metals into food products. A field trial examined factors influencing sludge adhesion to leaf surfaces and changes in the concentration of heavy metals in herbage over time. Metals differed in their persistence on leaves. The time required for metal concentrations in herbage to reach background levels depended on herbage growth, the dry solid content of sludges, their rate of application and the height of the grass when the sludge was applied. The implications of the results for the length of a safe no-grazing period following sludge application are discussed in the context of UK and EC legislation governing sludge use on agricultural land.     

Cadmium and zinc additions to wisconsin soils by commercial fertilizers and wastewater sludge application

Cadmium and Zn concentrations were determined on 21 commercial fertilizer samples by atomic absorption. The Cd concentration ranged from 1.5 to 9.7 mg kg^?1, the median being 4.3 mg kg^?1. Zinc showed a much wider range. The Cd added to soil by commercial fertilizers may be as much as 2150 kg annually in Wisconsin, compared to a potential of 1700 kg if wastewater sludges from all municipal sewage treatment plants in the state were disposed of on land. However, because of the higher application rates, sludge Cd on a soil concentration basis is a much more concentrated source of Cd than that from phosphate fertilizers.