剩余污泥生态稳定化研究

利用中试规模的人工湿地对污泥进行了为期4 a的生态稳定化处理。系统占地80 m 2,填料层厚度为0.6 m,超高0.5 m,湿地植物选用芦苇。系统前2 a为污泥负荷期,后2 a自然稳定期。进泥TS、VS、含水率分别为平均22.34 g/L、7.76 g/L和97%,污泥负荷平均0.691 kg(TS）/m 2·d。在第1 a的系统调整期内,渗滤液COD去除率在60%～80%;而第2 aCOD去除率低于第1 a,为40％～50%;出水COD在100～200 mg/L之间。在负荷期内,随着运行时间的延长,也即随着污泥积存厚度的增加,渗滤液透过积泥层的时间变化不定,即渗滤液并非均匀下渗,而是部分渗滤液优先沿阻力最小的植物茎壁、根系以及积存污泥中大的孔隙向下流动。在第3 a和第4 a的自然稳定期内,污泥脱水较为充分,含水率分别降至平均34.3%和30.5%;污泥有机质含量分别降至平均16.8%和10.24%;稳定化污泥的全氮和全磷含量分别为平均0.98%和0.27%。对比发现,系统内植物量和植物营养成分都比野生植物高。     

Organic matter in degraded agricultural soils amended with composted and thermally-dried sewage sludges

The cumulative and residual effects of composted and thermally-dried sewage sludge (CSS and TSS, respectively) on soil organic matter and its humified fraction were evaluated in a field experiment under Mediterranean conditions. The experimental design included soil plots either unamended (control) or amended with mineral fertilizer, CSS and TSS at rates of 20 and 80 t ha(-)(1). After the first year of sewage sludge application, each plot was divided into two subplots. In one subplot group, no additional application of SS was made in the following 3 years, and the residual effect of the first applications was evaluated. In the second subplot group, the cumulative effect of sludge amendments was evaluated by applying CSS and TSS also in the following three consecutive years. Nine months after the yearly sludge and mineral fertilizer applications, surface soil samples from control and amended soils were collected and analyzed for total organic C (TOC), total extractable C (TEC), and humified C fractions, both humic acid C (HAC) and fulvic acid C (FAC) fractions. Compared with the control and mineral treatments, which showed similar results, the repeated application to soil of TSS, and specially CSS, induced an increase on the content of the organic fractions examined, as well as HA percentage (%HA=HAC/TOC) and degree of polymerisation (DP=HAC/FAC). In the residual experiment, the TOC, TEC, HAC and FAC content of soils amended once with CSS and TSS decreased slightly when increasing the time from the amendment, whereas the %HA and DP tended to increase. Further, three years after the sludge applications, with respect to the control soil, the soils amended once with CSS exhibited similar TOC, TEC, and FAC content, and slightly larger HAC content, %HA and DP; whereas those amended once with TSS, featured still larger TOC, TEC, HAC content, similar FAC content, and slightly larger %HA and DP values. As a whole, the results obtained suggested that both kind of sludges contribute to improved soil organic matter levels and humified fractions, although the CSS contribution can be considered as a more efficient organic amendment than the TSS, which may present problems of maturity and degradability.     

对《农用污泥中污染物控制标准》中几个问题的商榷

系统的、科学的污泥农用标准是监控污泥土地利用和防止污泥污染的重要前提.根据城市污泥农用过程中重金属、病原菌、有机污染物、杂草种子、蚊蝇滋生及盐分、N、P的流失等方面存在的环境风险问题,重点分析了<农用污泥中污染物控制标准>(GB 4284-84)在标准名称、施用范围、污染物限定值以及标准的可操作性等方面存在的问题,并提出了相应的修改意见和建议.     

Behavior of inorganic elements during sludge ozonation and their effects on sludge solubilization

The behavior of inorganic elements (including phosphorus, nitrogen, and metals) during sludge ozonation was investigated using batch tests and the effects of metals on sludge solubilization were elucidated. A decrease of ∼50% in the ratio of sludge solubilization was found to relate to a high iron content 80-120 mgFe/gSS than that of 4.7-7.4 mgFe/gSS. During sludge ozonation, the pH decreased from 7 to 5, which resulted in the dissolution of chemically precipitated metals and phosphorus. Based on experimental results and thermodynamic calculation, phosphate precipitated by iron and aluminum was more difficult to release while that by calcium released with decrease in pH. The release of barium, manganese, and chrome did not exceed 10% and was much lower than COD solubilization; however, that of nickel, copper, and zinc was similar to COD solubilization. The ratio of nitrogen solubilization was 1.2 times higher than that of COD solubilization (R² = 0.85). Of the total nitrogen solubilized, 80% was organic nitrogen. Because of their high accumulation potential and negative effect on sludge solubilization, high levels of iron and aluminum in both sewage and sludge should be considered carefully for the application of the advanced sewage treatment process with sludge ozonation and phosphorus crystallization.     

A/A/MBBR工艺处理混合污水的脱氮除磷中试研究

采用A/A/MBBR工艺处理由粪便液和生活污水组成的混合污水,试验条件:填料投配比为20%,好氧池1和好氧池2中的填料体积比为1:3,好氧池的水力停留时间为5 h,混合液回流比为120%,污泥回流比为60%,泥龄为6 d,好氧池的溶解氧为3.0 mg/L,温度为16～20℃.系统稳定运行一个月的结果表明:脱氮除磷效果及对有机物的去除效果均稳定而良好,出水氨氮、总氮、总磷和COD平均浓度分别为0.3、12.9、0.35和36.22 mg/L,均达到了国家一级A排放标准.     

The value of sewage sludge to agriculture and effects of the agricultural use of sludges contaminated with toxic elements: A review

The effects of organic matter, nitrogen, phosphorus and toxic elements in sewage sludges applied to agricultural land are reviewed. Organic matter may improve the structure and water holding capacity of poor soils and the nitrogen and phosphorus in sludge have fertiliser value. However, an important consideration in applying sludge to land is the limitation of addition of toxic elements and any beneficial effects are secondary to this. Crops can accumulate toxic elements from sludge-amended soils and where heavily contaminated sludges and excessive rates of application are used plants may accumulate concentrations which are phytotoxic. The extent of accumulation varies considerably with plant species and cultivar; cereals and legumes accumulating lower concentrations than leafy plants such as lettuce and spinach. Although guidelines limit the addition of toxic elements in sludges and soils, thus reducing the quantities of these elements accumulated by plants, total concentrations of toxic elements in soil provide no indication of their availability to plants. The procedures applied to the determination of the forms of elements in sludges and soils and attempts to relate forms extractable in a variety of reagents to their availability to plants have been discussed. The factors which influence the forms of nutrient and toxic elements, their long term availability and hence their accumulation by crops are also reviewed.     

Mass balance and distribution of sludge-borne trace elements in a silt loam soil following long-term applications of sewage sludge

Soil samples were collected at 15-cm increments to a depth of 75 cm from plots on a silt loam soil where until several years earlier and for 14 years, anaerobically digested sewage sludge had been annually applied by furrow irrigation. The study protocol consisted of four replications of 6.1 x 12.2-m plots with 0 (T0), 1/4-maximum (T1), 1/2-maximum (T2) and maximum (T3) sludge application rates randomized within blocks. When sludge applications were terminated, maximum sludge-treated plots had received 765 Mg ha-1 (dry weight equivalent) of sludge solids. Total soil concentrations of Cd, Cr, Cu, Ni, Pb and Zn had been significantly enhanced by all sludge application rates to a soil depth of 30 cm. Below the 30-cm depth, total soil Cd was increased to 75 cm, total Zn to 45 cm (T2 and T3 only), total Cr to 60 cm (T2 and T3 only), but total Cu, Pb, and Ni were not increased at depth. Despite the lack of significant increases in subsoil concentrations for some metals, mass balance calculations showed a relatively high proportion of all the above sludge-borne heavy metals to be unaccounted for in the soil profile for each application rate. Mass balance calculations of losses ranged from a high of 60% for Ni to a low of 36% for Cu and Pb. Similar losses were calculated from metal concentrations measured in soil samples taken at the time the sludge was applied. In soil surface samples (0-15 cm) from maximum sludge-treated plots, percentages of total metal concentration extracted with 4.0 M HNO3 ranged from a low of 31 for Zn to a high of 75 for Cu. Efficiency of metal extraction by HNO3 was inconsistent, depending on the soil horizon and sludge treatment, so that evaluation of HNO3-extractable metals is not a reliable method of estimating total metal retention in the profiles. In soil surface samples from maximum sludge-treated plots, the percentage of total metal contents extracted with DTPA ranged from a low of 0.03 for Cr to a high of 59 for Cd. The DTPA extractable levels of Cu, Ni, and Pb were higher in the subsoils of the sludge-treated soils, indicating that these metals had been redistributed from the surface layer to deeper zones in the profile of sludge-amended soil, despite the absence of elevated total concentrations of these three metals in the deeper subsoil.     

污泥消毒技术的应用及进展

污泥是污水处理过程中产生的固体物质,不仅含有大量的有机质和N、P、K等营养元素,同时还含有大量细菌、病毒及寄生虫,需进行消毒处理后才能处置,但其消毒副产物会引起生态环境的负面效应。安全、可靠的消毒技术成为近年来污泥处理研究的热点。介绍了目前污泥消毒技术的应用及进展,并指出了今后的发展方向。     

污泥回流比对A_2N反硝化除磷工艺脱氮除磷的影响

以城市生活污水为研究对象,探讨了不同的超越污泥和回流污泥回流比对A2N工艺脱氮除磷的影响.在超越污泥回流比与回流污泥回流比相同且分别为0.3、0.4和0.6的条件下,A2N工艺对COD的平均去除率分别为92.5%、90.3%、91.6%,相应的出水COD为20.3、28.4、25.3 mg/L;对总氮的平均去除率分别为87.1%、90%、84.9%,出水总氮分别为6.75、5.43、6.95mg/L;对磷的平均去除率分别为99.5%、99.6%和99.0%,出水磷浓度分别为0.02、0.02、0.05mg/L.当回流比为0.4时,A2N系统的除污效果最好.研究还发现,超越污泥流量直接决定了未经硝化而直接进入缺氧池的氨氮量,进而影响出水氨氮浓度.因此,在保证缺氧池有足够污泥的前提下,应尽可能减小超越污泥流量,以降低出水氨氮浓度.     

Monitoring of the evolution of an industrial compost and prediction of some compost properties by NIR spectroscopy

Sewage treatment plants produce wastes resulting from the organic matter concentration in the form of sludge. A way of jointly treating and exploiting these increasing wastes jointly is the composting. Composting makes it possible to reduce volumes and the masses of wastes all while developing them in a product usable like organic soil enrichment. In this work, the composting process of an industrial sewage sludge composting plant was monitored to study the evolution of different physico-chemical parameters (temperature, moisture, pH, organic carbon, organic and inorganic nitrogen, organic carbon/organic nitrogen ratio, humic substances) and biochemical parameters (soluble fraction, hemicellulose, cellulose, lignin). Because these analyses are expensive and time consuming, we wanted to develop an alternative method to determine the maturity of compost related to compost properties with raw samples. Acceptable predictions were found for moisture, temperature, pH, organic carbon, organic carbon/organic nitrogen ratio, total-, organic- and ammoniacal nitrogen, fulvic- and humic acids and fulvic acids/humic acids ratio, but the error values were too high for the compost age to consider a quantification model. With regard to the biochemical parameters, this study is rather a preliminary test which shows the interest of the approach, but requires to be continued. Finally, the age of compost can be evaluated with Principal Component Analysis applied to NIR spectra.     

Behavior of nitrogen and phosphorus during batch aerobic digestion of waste activated sludge—continuous aeration and intermittent aeration by control of DO

The purpose of this study is to find the behavior of nitrogen and phosphorus during aerobic digestion. Waste activated sludge samples from a municipal wastewater treatment plant were digested under 30 days batch operation, aerating continuously and intermittently. If the cycle time of intermittent aeration was decided so that the DO in a digestion tank did not become zero, the reduction rate of sludge solids and the behavior of nitrogen and phosphorus in the intermittent aeration were similar to those in the continuous aeration. The percentage of biomass nitrogen (phosphorus) in the initial total nitrogen (phosphorus) decreased and finally became 20% (30%). Forty per cent of the initial MLSS remained finally. On the other hand, the percentage of liquid phase nitrogen (phosphorus) increased during digestion and reached 60% (70%). It is considered that considerable portion of the initial total nitrogen (phosphorus) remains in liquid phase after aerobic digestion under sufficient supply of oxygen. Contents of nitrogen and phosphorus in residual biomass increased a little and decreased thereafter. Also, contents of them in reduced biomass increased monotonously.     

Phosphorus recovery from sewage sludge with a hybrid process of low pressure wet oxidation and nanofiltration

Phosphorus recovery from sewage sludge will become increasingly important within the next decades due to depletion of mineral phosphorus resources. In this work a new process concept was investigated, which aims at realising phosphorus recovery in a synergistic way with the overall sewage sludge treatment scheme. This process combines a low pressure wet oxidation for sewage sludge decomposition as well as phosphorus dissolution and a nanofiltration process to separate phosphorus from heavy metals and obtain a clean diluted phosphoric acid, from which phosphorus can be recovered as clean fertiliser.It was shown that this process concept is feasible for sewage sludge for wastewater treatment plants that apply enhanced biological removal or precipitation with alumina salts for phosphorus removal. The critical parameter for phosphorus dissolution in the low pressure wet oxidation process is the iron concentration, while in the nanofiltration multi-valent cations play a predominant role.In total, a phosphorus recovery of 54% was obtained for an exemplary wastewater treatment plant. Costs of the entire process are in the same range as conventional sewage sludge disposal, with the benefit being phosphorus recovery and reduced emission of greenhouse gases due to avoidance of sludge incineration.     

微波加热对污泥肥效和卫生指标的影响

污泥经微波辐照处理后，氮、磷、有机质的含量有所降低，但仍是很好的有机肥原料；污泥的卫生学指标能达到控制标准的要求；污泥机械脱水时加入絮凝剂（PAM）的分子质量也明显降低，有利于污泥的农用化。设计制作了一台大型试验装置，在污水处理厂的现场试验结果与实验室的试验结果是一致的。     

Total phosphorus content of river sediments in relationship to calcium,iron and organic matter concentrations

Data on the total concentrations of phosphorus, calcium, iron and organic matter in surface bed-sediments taken from rivers in the Thames catchment (Wey, Blackwater, Thame and Kennet), the River Swale in Yorkshire (data excludes the organic matter content) as well as the headwaters of the Great Ouse, are collated and compared. Total concentrations of phosphorus, iron and calcium range from 1.7–649, 12–8333 and 9–4605 μmol g⁻¹ (dry weight), respectively, with organic matter in the range of 0.6–19% by dry weight. For the Wey, Blackwater and Great Ouse, sewage inflows had no detectable effect on the sediment concentrations of total calcium, iron and organic matter whereas for the Blackwater and Great Ouse, the total phosphorus contents of the sediment were higher downstream of the effluent input in comparison with a less impacted upstream location. Relationships between the total phosphorus content of the sediments and contents of iron, calcium and organic matter indicated marked differences between the rivers. Although the organic matter content of the sediments was found to be a significant predictor for the total phosphorus concentration for the Blackwater and Great Ouse, the total iron content was also useful for the Blackwater and total calcium for the Great Ouse. It is postulated that this difference is a result of the sediment processes that are known to occur in these two systems, i.e. co-precipitation of phosphate with calcite in the Great Ouse and the formation of vivianite in anoxic sediments of the Blackwater.     

厌氧—生物接触氧化—滤布滤池深度处理校园污水

西北干旱地区某校园污水先采用水解酸化阶段-产甲烷阶段分离的厌氧生物处理及两级生物接触氧化处理,出水再进行滤布滤池深度处理。结果表明,该工艺能有效地将高有机物浓度、高氨氮的校园生活污水处理后达到城市污水再生利用杂用水的水质标准。该工程利用厌氧污泥回流到产甲烷阶段前,腐殖污泥回流到水解酸化池并加大污泥回流率的方法,基本无剩余污泥排放。     

Application of microwaves for sewage sludge conditioning

The article focuses on the effect of microwave treatment on the de-waterability of sewage sludge. The specific resistance to filtration, capillary suction time, and dry matter content in centrifuged sludge cake were measured. The quality of sludge liquor obtained after microwave processing was also analysed. It was found out that microwaves improve sludge de-waterability. The quantitative improvement depends on sludge type-better effect of microwave processing were observed in the primary sludge compared to mixed or digested sludges. If microwave treatment is followed by polyelectrolyte conditioning, the effects are considerably better than while these conditioning methods are used separately. Microwave conditioning increased burden of organic matter (BOD(5), COD) in the sludge liquor.     

复合人工湿地系统处理城市污水的降解过程

在HRT为4 d并进行微曝气及添加除磷材料的条件下,对复合人工湿地系统的降解过程进行了研究。结果表明,添加除磷材料后,系统最终出水比未添加除磷材料时对TP的去除率平均提高了约8.36%;TN浓度沿流程呈下降趋势, NH +4-N浓度除在水解池出水处升高外,其余均保持与TN浓度相同的沿程下降趋势; CODCr也沿程逐渐下降,湿地第一段和第二段对CODCr的去除起着主要作用,累计去除率约占系统总去除量的72.78%。     

The influence of macrophytes on sedimentation and nutrient retention in the lower River Spree (Germany)

Nutrient retention due to sedimentation in running waters has been little studied. The knowledge about the processes of self-purification is important for the management of rivers. The principal aim of our investigations was to quantify nutrient retention by sedimentation within and adjacent to stands of submerged macrophytes. In addition, we examined the relationship between deposition and sedimentation patterns and the flow regime. In the summer of 2001, investigations were performed in the lower River Spree with sediment traps and sediment cores and measurement of flow velocities. The spatial distribution of macrophytes was described and related to sedimentation and flow patterns. Water and sediment samples were analysed for total phosphorus and total organic nitrogen concentrations. Macrophytes significantly enhanced water residence time by factors between 2 and 18. Trapping rates were high within and downstream of macrophyte stands due to the prevailing quiescent conditions. Trapping rates were low in regions not covered by macrophytes, where flow velocities were high. Calculated deposition of organic matter due to trapping rates accounted for 15-49% of observed deposition between May and September, the vegetation period. The difference between calculated and observed deposition can partly be attributed to an incomplete erosion of the organic sediments between October and April. Between May and September, nitrogen and phosphorus were retained by deposition by as much as 2.5% and 12.2%, respectively (% of total load). Therefore, macrophytes considerably contributed to total monthly phosphorus retention (up to 25%) by increasing deposition of particulate organic matter.     

乌鲁木齐河东污水厂的脱氮除磷运行效果分析

对乌鲁木齐河东污水处理厂AB工艺的实际脱氮除磷效果进行了监测分析。结果表明：AB工艺处理鸟鲁木齐城市污水的除磷效果优于脱氮效果，对TP的去除率平均为80％；A段对TN的去除率平均为44．7％，经过B段后NH4^＋—N含量升高，使AB工艺对TN的总去除率降至35．7％左右。A段厌氧污泥进入B段可以取得稳定的除磷效果，去除率平均为96．2％；B段污泥进入A段对AB工艺的脱氮除磷效果没有产生明显影响。B段出现NH4^＋-N升高的主要原因是该段的水力停留时间未达到硝化所需时间的要求。     

Geotechnical and hydrochemical properties of sewage sludge

The geotechnical and geochemical properties of sewage sludge from Kaunas city, Lithuania, were investigated to assess whether it could form a low permeability landfill cover. New sludge, sludge stored or kept in the atmosphere and old sludge were studied. It was found that over time the strength of the sewage sludge increased due to self-consolidation and destruction of organic material. The concentration of metals in the sewage extract was considerably lower than in the landfill leachate. It was concluded that if kept in an open polygon for 1–2 years, the sewage sludge can be used as a low permeability landfill cover.