中国城市污泥土地利用关注的典型有机污染物

污泥土地利用是国内外城市污泥主要的处置方式之一,而污泥中的有机污染物是污泥土地利用的限制性因素之一.本文分析了国内外城市污泥中有机污染物的浓度和研究现状,针对我国国情,认为多环芳烃(PAHs)是城市污泥中一种常见的有机污染物,总含量一般在1 ～ 10 mg·kg-1,有的因污水来源复杂而超过了100 mg·kg-1;壬基苯酚(NP/NPE)在我国污水处理厂污泥样品中均有检出,浓度在1～128 mg·kg-1.污泥园林绿化、林地利用、土壤改良等将是今后主要的利用方向,要实现污泥安全、环保的土地利用,多环芳烃(PAHs)和壬基苯酚(NP/NPE)将是主要考虑的典型有机污染物.     

我国城市污泥中含氮有机污染物的初步研究

应用GC/MS联机检测技术对11个城市污泥中6种含氮有机污染物进行分析.结果表明,城市污泥中6种含氮有机化合物的总含量在0.087～26.438 mg·kg-1,高低依次为兰州污泥＞北京污泥＞无锡污泥＞大埔(香港)污泥＞沙田(香港)污泥＞佛山污泥＞广州污泥＞元朗(香港)污泥＞珠海污泥＞西安污泥＞深圳污泥.不同化合物在各城市污泥中的含量和分布特征有明显差异.硝基苯类的含量较高,胺类的含量较低.兰州污泥中含氮有机化合物的含量普遍较高,其次是无锡污泥、北京污泥和大埔污泥.污泥中含氮有机化合物的种类和含量与污水来源、污水处理方式、污泥类型、化合物的结构和理化性质等因素有关.     

城市污泥和土壤中苯并（a）芘的初步研究

应用GC／MS技术对我国11个城市污泥和4种土壤中的苯并（a)芘进行研究,探讨苯并（a)芘在城市污泥和土壤中的含量和分布特征,结果表明,城市污泥中苯并（a)芘的含量在0．007－0．578mg.kg^-1之间,平均为1．272mg/kg^-1,绝大部分低于1．0mg/kg^-1,但在珠海和北京污泥中超过我国农用污泥的控制标准,褐土,水稻土和石灰性土中苯并（a)芘的含量分别为2．138,0．782和0．664mg.kg^-1,在赤红壤中未检出,城市污泥中苏并（a)芘含量与污水来源,污水处理方式和污泥类型等因素有关,土壤中苯并（a)芘含量与母质,大气污染,污水灌溉,污泥农用等因素有关。     

城市污泥资源化利用研究

城市污水污泥产量巨大且成分复杂 ,如何对它进行合理利用已越来越受人们关注。文章系统地综述了我国城市污泥处置与利用的现状和趋势 ,并重点讨论了污泥土地利用的可行性以及我国近年来的研究进展。认为将污泥进行稳定化、无害化、资源化处理并作为有机肥料或土壤改良剂等进行资源化利用是符合我国国情的 ,并将成为我国污泥处置与利用的一种有效途径     

城市污泥生物好氧发酵对有机污染物的降解及其影响因素

分析了国内部分城市脱水污泥中几种主要有机污染物浓度,PAHs含量为1.156—34.940mg/kg,PCBs含量为0—115.730mg/kg;PCDD/Fs含量为9.530—22.900 ngTEQ/g干泥,NP含量为177.000mg/kg。提出要实现污泥安全、环保的土地利用,可采用生物好氧发酵技术降解污泥中的有机污染物,降低污泥在土地利用时有机污染物带来的环境风险。同时通过优化污泥生物好氧发酵控制条件:C/N值范围为25∶1—40∶1,温度在30—55℃,氧气浓度5%—15%,强制通风量控制在1.5—2.0m3.min-1.t-1(干泥)左右,pH6—9,混料含水率为50%—65%,经生物好氧发酵后的污泥施用土地,可以大大降低污泥在土地利用时的环境风险,避免污泥资源化利用带来的二次污染问题。     

中国城市污泥有机质及养分含量与土地利用

土地利用是城市污泥的重要处理处置方法,其有机质和养分含量是土地利用中很受关注的问题。关于中国的城市污泥虽然已有不少研究报道,但不同研究结果之间结论并不一致,且缺乏系统的总结。通过系统搜集了20世纪80年代以来全国城市污泥相关的文献资料,重点评述中国城市污泥的有机质含量及其土地利用问题。通过29个城市污泥组成的统计分析发现,中国城市污泥(不包括工业污泥)的有机质平均含量达到384g／kg,全氮、全磷和全钾分别为27、14．3和7g／kg;有机质、全氮、全磷比纯猪粪分别高出1／3～2／3,但全钾比纯猪粪低1／3。中国城市污泥的有机质含量呈逐年增加的趋势,但氮、磷含量变化规律不明显。研究证明,城市污泥在粮食作物、蔬菜、经济作物及园林绿地上使用,具有明显的肥效和改良土壤的效果。近年来,城市污泥中重金属含量越来越低,这有利用促进城市污泥的土地利用,但中国在有机污染物和病原体的危害方面研究相对较少,对城市污泥土地利用的潜在风险仍缺乏长期的定位试验研究。     

基于CiteSpace可视化图谱的污泥土地利用现状研究分析

以2010-2020年间Web of Science(WoS)核心合集和中国知网(CNKI)数据库为数据源, 运用CiteSpace软件对污泥土地利用研究发文量、研究力量和研究热点进行计量可视化分析, 旨在探析当前国内外研究现状, 探索前沿动态和未来发展趋势。结果表明, 污泥土地利用研究总发文数量变化幅度较小, 该领域研究热度处于平稳状态; 在两大数据库中, 美国和中国是该领域中合作研究多且影响力大的国家, 最活跃的研究机构是中国科学院, 作者及研究团队间的合作相对较少; 国际上污泥土地利用研究趋于多元化发展, 而我国在该领域的研究方向则比较单一, 偏重于重金属研究。基于文献共现聚类和研究热点分析, 提出污泥土地利用研究的未来展望: 在多个层面开展合作研究, 积极研发无害化污泥土地利用技术, 全方面跟踪监测和评估污泥土地利用对陆地生态系统的影响, 多部门联合制定污泥土地利用相关政策和技术规范。     

城市污泥复合肥的肥效及其对小麦重金属吸收的影响

通过盆栽和大田试验,初步探讨了污泥复合肥种植小麦的肥效及其对小麦重金属吸收的影响。试验结果表明,污泥复合肥对小麦的增产效果和土壤的增肥效果明显优于化肥,等同于市售复合肥,它能促进植株生长发育,提高小麦产量,对土壤速效养分的积累有明显的促进作用;污泥复合肥处理的小麦籽粒中重金属Cu、Zn、Pb、Cd的含量均在国家食品卫生标准范围内。     

城市污泥和化肥对水稻土种植的通菜中多环芳烃(PAHs)的影响

在水稻土上施用城市污泥和化肥盆栽通菜,应用GC／MS联机检测技术对通菜中17种多环芳烃化合物进行了分析。结果表明,各处理通菜中的∑PAHs含量在0．414-5.404mg/kg之间,依次是佛山污泥＋化肥＞广州污泥＋化肥＞化肥＞广州污泥＞佛山污泥＞空白,致癌性PAHs化合物的总含量（∑PAHscarc)在0.068-0.944mg/kg之间,绝大部分化合物在通菜中的含量大于在根系中的含量,与空白对照相比,施用城市污泥和化肥均使通菜中的∑PAHs含量明显提高,各处理通菜中的PAHs都只是以一种或几种化合物为主,主要是3,4个苯环的化合物,显示不同的分布特征,。     

城市污泥处理处置技术及资源化利用研究

城市污泥的产量巨大并且成分复杂,如何对城市污泥处置与利用已成为人们所关注的问题.污泥是有用的生物资源,如能合理利用则不仅能变废为宝,还能增加经济效益,所以,探讨适合我国国情的有效处理处置和利用污泥的技术具有重要的现实意义.本文对城市污泥的特性、国内外处理、处置技术和污泥资源化技术的现状进行了分析,认为对污泥进行资源化利用是符合我国国情的一种经济、有效的途径,污泥的资源化利用尤其是农业利用不但可以节省大量的污泥终端处置费用,更可以为肥力低下的农田增添有机质、提高肥力,促进农业生产发展、实现农业生态环境的良性循环.     

Phytoextraction of heavy metals from municipal sewage sludge by Rosa multiflora and Sida hermaphrodita

The aim of the study was to evaluate the efficacy of the multiflora rose var. “Jatar” (Rosa multiflora Thunb. ex Murray) and the Virginia fanpetals (Sida hermaphrodita Rusby) to phytoextract heavy metals from municipal sewage sludge. The 6-year field experiment involved four levels of fertilization with sewage sludge at doses of 0, 10, 20, 40, and 60 Mg DM (Dry Mass) sludge ha^?1. The increasing doses of sewage sludge were found to significantly increase the yield of multiflora rose and Virginia fanpetals biomass. They also significantly increased the content of heavy metals in these plants. The highest uptake of heavy metals by the multiflora rose and Virginia fanpetals crops was recorded at the fertilization dose of 60 Mg DM ? ha^?1. Our investigations show that the Virginia fanpetals was more efficient in the phytoextraction of Cr, Ni, Cu, Zn, and Cd from the sewage sludge than the multiflora rose, due to the greater yields and higher heavy metal uptake by the former plant. In turn, the multiflora rose phytoextracted greater amounts of Pb from the sewage sludge. The analyses indicate that the Virginia fanpetals can be used for phytoremediation (phytoextraction) of heavy metals contained in sewage sludge.     

施用污泥对小白菜生长及其迁转重金属的影响

采用盆栽方式,以厦门市筼筜污水处理厂的污泥作为有机肥种植小白菜,探讨污泥施用对小白菜生长和产量的影响及重金属在小白菜-土壤间的迁移转化和积累情况.结果表明:污泥中氮、磷、钾和有机质含量丰富,重金属含量均低于国家农用污泥中污染物控制标准;适宜的污泥施用量可促进小白菜的生长,污泥用量为5%时,小白菜长势最好,生物量最大;污...     

温度对赤子爱胜蚓堆肥处理有机垃圾混合剩余污泥效率的影响

为了探讨环境温度对蚯蚓的生物量及其堆肥效率的影响,进行了不同培养温度条件下赤子爱胜蚓堆肥处理有机垃圾混合剩余污泥的研究。试验结果表明,在其他生态因子保持不变的情况下,赤子爱胜蚓的生长和繁殖具有一个适宜的温度范围,可能在20℃左右,温度太高或太低都对蚯蚓的生长和繁殖不利。赤子爱胜蚓对有机垃圾混合剩余污泥的堆肥效率在20℃达到最高,而在其他温度时较低,特别是低温(5℃、10℃)情况下堆肥效率显著降低,但温度较高(30℃、35℃)时其堆肥效率下降不显著。从产业应用的角度,如果同时考虑蚯蚓维持种群繁衍的再生产能力以及蚯蚓堆肥效率这两个因素,环境温度维持在20℃附近可能最适宜赤子爱胜蚓处理有机垃圾混合剩余污泥。     

Phytotoxicity and distribution of copper in tropical soil amended with sewage sludge and copper sulfate

Abstract

A greenhouse experiment was conducted to evaluate phytotoxicity and distribution of Cu in a tropical soil amended with sewage sludge (Sw) and copper sulfate (CuSO₄.5H₂O). Samples of a clay soil from the State of Paraná, Brazil were collected at depth of 0–20; 20–40 and 40–60 cm, and brought to the laboratory to be properly accommodated in experimental units (PVC tubes). The Cu treatments were performed by the application of Sw (10 t ha-¹) amended with Cu (SB-T), and by CuSO₄. H₂O (WB-T). Lettuce plants were cultivated in the amended soil in order to predict the toxicity of the Cu. The experiment was conducted for 70 days, and then the lettuce plants and soil samples were collected for analysis. A sequential method was used to separate soil Cu into following fractions: exchangeable, amorphous iron oxide bound, crystalline iron oxide bound, organic matter bound and residual bound. The experimental results showed that Fe, Zn, K, P, Cu and organic matter amounts of the soil increased with the treatment SB-T. The toxic phyto-available Cu content in the soil for the lettuce plants was 80.00 mg kg^-1. A percolation study showed that the Cu contents were larger for the first 20 cm of depth, indicating that the metal was not transported down the soil profile. The Cu content of different fractions declined in an order residual > amorphous iron oxide > crystalline iron oxide > organic matter > exchangeable, regardless of treatment performed. Additionally, the Cu contents added from treatments were determined mainly in amorphous iron oxide fraction.     

Using event trees to quantify pathogen levels on root crops from land application of treated sewage sludge

AIMS: To quantify the incremental exposure of root crops, at point of harvest, to enteric pathogens from sewage sludge applied to agricultural land according to current regulations and guidance (Safe Sludge Matrix). METHODS AND RESULTS: A quantitative risk assessment based on the Source-Pathway-Receptor approach is developed for Cryptosporidium and salmonellas. Event trees are constructed to model the partitioning of pathogens present in raw sewage into sludge at the sewage treatment works and to model to the pathways by which root crops may be exposed to those pathogens after treatment and land application of the sludge. The main barriers are sewage sludge treatment, and decay and dilution of the pathogens in the soil. The exposures are expressed in terms of the arithmetic mean. This represents the total loading and accommodates fluctuations not only in the levels of pathogens present in sewage but also in the removal efficiencies by the various barriers. One source of uncertainty is the degree of by-pass of sludge treatment at operational scale. CONCLUSIONS: The models predict that land application of sewage sludge treated by conventional processes (achieving 2-log removal) increases the exposures of root crops to salmonellas and Cryptosporidium oocysts by counts of 0.070 and 0.033 kg(-1), respectively. These predictions are based on decay periods in the soil of 5 and 12 weeks, respectively, and are therefore worst case in not allowing for the full extent of no harvesting periods. A Monte Carlo simulation predicts that 0.01% of 1-kg batches contained > 50 salmonellas and demonstrates that, for risk assessment, it is acceptable to use the arithmetic mean exposure directly in the dose-response curve. SIGNIFICANCE AND IMPACT OF THE STUDY: The predicted numbers of pathogens on root crops at point of harvest provide a basis for modelling the excess risks to humans consuming such crops. The approach underpins scientifically the Safe Sludge Matrix.     

Terrestrial Chironomidae on agricultural soil treated with sewage sludge

Adult Chironomidae were caught in emergence traps for three subsequent years (1988–1990) on agricultural soil. Larvae were extracted from soil samples taken since June 1989. The field was subdivided into 5 plots treated with different amounts of sewage sludge. On some plots the sludge was artificially enriched with heavy metalts. The phenology of Chrinonomidae in the three years and their distribution over the different plots are discussed. The results suggest that the abundance of Chironomidae is increased by sewage sludge and appears to be also increased by heavy metals.     

Isolation of bacteria producing polyhydroxyalkanoates (PHA) from municipal sewage sludge

Bacterial isolates from sludge samples collected at a local municipal sewage treatment plant were screened for bacteria producing polyhydroxyalkanoates (PHA). Initially Sudan black B staining was performed to detect lipid cellular inclusions. Lipid-positive isolates were then grown in a nitrogen limitation E2 medium containing 2% (w/v) glucose to promote accumulation of PHA before the subsequent staining with Nile blue A. The positive isolates were quantified initially with a u.v. spectrophotometer, for a very large number of isolates (105) and among them high PHA-producing isolates (15) were selected and were confirmed by gas chromatographic analysis. The GC analysis showed the polymers produced by 13 of the selected isolates to be polyhydroxybutyrate (PHB), and the remaining two isolates produced polyhydroxybutyrate-co-hydroxyvalerate (PHB-co-HV) copolymer. The proportion of the PHA-positive bacterial isolates showed variability in the number of PHA accumulators during various months. The correlation of PHB production with the cell dry weight (CDW) was found to be statistically significant. The metabolism of PHB in these selected 15 isolates was studied using the Nile blue A staining, which showed an initial increase in the fluorescence followed by a decline, on further incubation. All the selected 15 isolates were classified to genus level by studying their morphological and biochemical characteristics. There were seven Bacillus species, three Pseudomonas species, two Alcaligenes species, two Aeromonas species, and one Chromobacterium species.     

Land application of treated sewage sludge: quantifying pathogen risks from consumption of crops

AIMS: To predict the number of humans in the UK infected through consumption of root crops grown on agricultural land to which treated sewage sludge has been applied in accordance with the current regulations and guidance (Safe Sludge Matrix). METHODS AND RESULTS: Quantitative risk assessments based on the source, pathway, receptor approach are developed for seven pathogens, namely salmonellas, Listeria monocytogenes, campylobacters, Escherichia coli O157, Cryptosporidium parvum, Giardia, and enteroviruses. Using laboratory data for pathogen destruction by mesophilic anaerobic digestion, and not extrapolating experimental data for pathogen decay in soil to the full 30-month harvest interval specified by the Matrix, predicts 50 Giardia infections per year, but less than one infection per year for the other six pathogens. Assuming linear decay in the soil, a 12-month harvest interval eliminates the risks from all seven pathogens; the highest predicted being one infection of C. parvum in the UK every 45 years. Computer simulations show that a protective effect from binding of pathogens to particulate matter could potentially exaggerate the observed rate of decay in experimental systems. CONCLUSIONS: The results confirm, assuming pathogens behave according to our current understanding, that the risks to humans from consumption of vegetable crops are remote. Furthermore the harvest intervals stipulated by the Safe Sludge Matrix compensate for potential lapses in the operational efficiency of sludge treatment. SIGNIFICANCE AND IMPACT OF THE STUDY: The models demonstrate the huge potential impact of decay in the soil over the 12/30-month intervals specified by the Matrix, although lack of knowledge on the exact nature of soil decay processes is a source of uncertainty. The models enable the sensitivity of the predicted risks to changes in the operational efficiency of sewage sludge treatment to be assessed.     

Solubilization profiles of metal ions from bioleaching of sewage sludge as a function of pH

Two patterns of solubilization of metal ions resulting from bioleaching of sewage sludge by sulphur-oxidizing Thiobacillus spp. were established as a function of pH. Chromium and copper ions required a pH of 2–3 to initiate their solubilization, whereas nickel and zinc ions had their solubilization initiated at pH 6–6.5. The patterns obtained were independent of the sludge solids concentrations investigated (10, 17, 25, 32.5 and 40 g l^–1).