不同生物营养物处理工艺剩余污泥中温水解特性简

为了解不同生物营养物处理（BNR）工艺剩余污泥性质差异及其中温水解特性,采用序批式实验研究了来源于Orbal氧化沟（OD）和倒置A²/O工艺剩余污泥在中温水解过程中污泥浓度、营养物释放、污泥粒径、污泥絮凝性、污泥比阻及污泥胞外聚合物（EPS）的历时变化。结果表明,相同泥龄（约18 d）条件下,Orbal OD剩余污泥氮含量较高,倒置A²/O剩余污泥磷含量较高,两者VSS/SS均低于0.6,导致中温水解过程污泥减量空间有限、氮磷释放速率不同。此外,尽管倒置A²/O工艺剩余污泥絮体尺寸及絮凝能力明显大于Orbal OD工艺剩余污泥的对应值,但两污泥比阻相近。中温水解过程中,两污泥絮体的尺寸均变小、絮凝能力均降低、比阻均增高;两者的胞外聚合物均呈现增高再降低趋势,且蛋白质均占EPS质量的75%以上,为主要的胞外物质。     

不同生物营养物处理工艺剩余污泥中温水解特性

为了解不同生物营养物处理（BNR）工艺剩余污泥性质差异及其中温水解特性,采用序批式实验研究了来源于Orbal氧化沟（OD）和倒置A2／O工艺剩余污泥在中温水解过程中污泥浓度、营养物释放、污泥粒径、污泥絮凝性、污泥比阻及污泥胞外聚合物（EPS）的历时变化。结果表明,相同泥龄（约18d）条件下,OrbalOD剩余污泥氮含量较高,倒置A2／O剩余污泥磷含量较高,两者VSS／SS均低于0．6,导致中温水解过程污泥减量空间有限、氮磷释放速率不同。此外,尽管倒置A2／O工艺剩余污泥絮体尺寸及絮凝能力明显大于OrbalOD工艺剩余污泥的对应值,但两污泥比阻相近。中温水解过程中,两污泥絮体的尺寸均变小、絮凝能力均降低、比阻均增高;两者的胞外聚合物均呈现增高再降低趋势,且蛋白质均占EPS质量的75％以上,为主要的胞外物质。     

Odours from pulp mill effluent treatment ponds: the origin of significant levels of geosmin and 2-methylisoborneol (MIB)

Pulp and paper mills are well known for their sharp, sulphurous stack emissions, but the secondary treatment units also can be significant contributors to local odour. This study investigated the source(s) of earthy/musty emissions from a mixed hardwood pulp mill in response to a high local odour. Samples from five sites in the mill over five months were analyzed for earthy/musty volatile organic compounds (VOCs), examined microscopically, and plated for bacteria and moulds. In all cases, activated sludge showed substantial geosmin levels and to a lesser extent 2-methylisoborneol (MIB) at 2000-9000 times their odour threshold concentrations (OTCs). These VOCs were lower or absent upstream and downstream, suggesting that they were produced within the bioreactor. Geosmin and MIB were highest in late summer and declined over winter, and correlated with different operating parameters. Geosmin was most closely coupled with temperature and MIB with nitrogen uptake. Cyanobacteria were present in all sludge samples, but actinomycetes were not found. Gram-negative bacteria and one fungal species isolated from the bioreactor and secondary outfall tested negative for geosmin or MIB. We conclude: (i) geosmin and MIB contribute significantly to airborne odours from this mill, but are diluted below OTC levels at the river; (ii) these VOCs are generated by biota in the activated sludge; and (iii) cyanobacteria are likely primary source(s). The growth of cyanobacteria in activated sludge represents a loss of energy to the heterotrophic population; thus earthy/musty odours may represent a diagnostic for less than optimal conditions.     

限氮和限磷对活性污泥合成聚羟基烷酸的影响

聚羟基烷酸(PHA)是微生物在不平衡营养条件下贮存的一种胞内聚合物,限磷和限氮两种方式均有助于活性污泥中的混合菌群合成PHA,研究考察了两种不同方式下活性污泥合成PHA的情况。实验结果表明,当C∶N为125时,活性污泥中PHA的合成量达到细胞干重的59%;当C∶P为750时,活性污泥积累的最大PHA含量占细胞干重的37%,说明限氮和限磷两种方式对活性污泥合成PHA均有很大影响,且限氮方式更有效。     

艰氮和限磷对活性污泥合成聚羟基烷酸的影响

聚羟基烷酸（PHA）是微生物在不平衡营养条件下贮存的一种胞内聚合物,限磷和限氮两种方式均有助于活性污泥中的混合菌群合成PHA,研究考察了两种不同方式下活性污泥合成PHA的情况。实验结果表明,当C：N为125时,活性污泥中PHA的合成量达到细胞干重的59％;当c：P为750时,活性污泥积累的最大PHA含量占细胞干重的37％,说明限氮和限磷两种方式对活性污泥合成PHA均有很大影响,且限氮方式更有效。     

磺胺和四环素类抗生素对活性污泥性能的影响简

废水处理工艺中抗生素类污染物的存在可能会对生物处理过程产生长期而深远的影响,为探明此类污染物对废水生物处理主体活性污泥性能等方面的影响,采用间歇培养法研究了活性污泥法处理污水时,抗生素类污染物的存在对活性污泥性能如胞外聚合物（EPS）、污染物处理能力、脱氢酶活性和群落结构的影响。结果表明,抗生素的存在会导致活性污泥的胞外聚合物总量及其主要组分蛋白质和多糖增加,以产生保护屏障;且由于污泥絮体解体,细胞破裂导致EPS中DNA和色氨酸含量增加。同时,由于蛋白质大量增加引起的表面负电荷的增加,使污泥疏水性增强,絮凝性能恶化;污泥絮体解体导致污泥颗粒变小,SVI也随之下降;在活性污泥脱氢酶活性急剧下降的同时,出水TOC迅速升高。此外,抗生素类污染物在抑制活性污泥中大部分细菌的同时,对部分菌群也有刺激生长作用,最终导致活性污泥生物群落结构的改变。四环素类抗生素对活性污泥的EPS和絮凝沉降性能的影响大于磺胺类,而对污水处理能力和群落结构的影响则不如磺胺类。抗生素类污染物的长期存在会对活性污泥沉降性能、絮凝性能、脱氢酶活性以及活性污泥群落结构等产生一系列负面影响,进而影响污染物去除效果,导致出水水质恶化。     

Changes in biomass activity and characteristics of activated sludge exposed to low ozone dose

In this paper, the response mechanism of activated sludge exposed to low-dose ozone at less than 20 mg O₃ g⁻¹ total suspended solids (TSS) was studied by analyzing the changes in sludge activity and the evolution of C, N, P and metals from sludge following ozonation. The intracellular ATP concentration was not affected at less than 5 mg O₃ g⁻¹ TSS and thereafter decreased rapidly to around 60% when the ozone dose increased to 20 mg O₃ g⁻¹ TSS. Similarly, the efficiency of sludge solubilization initially changed a little and then increased rapidly to around 30% at an ozone dose of 20 mg O₃ g⁻¹ TSS. However, the activities of superoxide dismutase and protease decreased immediately upon exposure to ozone. These findings indicate that ozone firstly destroys the floc, leading to the disruption of the compact aggregates, which does not affect cells viability but induces a decrease in enzyme activities. Ozone then attacks the bacterial cells of the sludge, causing a decrease in cells viability. During ozonation, the content of carbon, nitrogen and phosphorus in the sludge matrix decreased, while the content of these elements in the micro-solids and supernatant gradually increased. Most of the released metals from the sludge matrix were found in the micro-solids.     

Effects of simultaneous ozone exposure and nitrogen loads on carbohydrate concentrations, biomass, growth, and nutrient concentrations of young beech trees (Fagus sylvatica)

Beech seedlings were grown under different nitrogen fertilisation regimes (0, 20, 40, and 80 kg Nha(-1)yr(-1)) for three years and were fumigated with either charcoal-filtered (F) or ambient air (O3). Nitrogen fertilisation increased leaf necroses, aphid infestations, and nutrient ratios in the leaves (N:P and N:K), as a result of decreased phosphorus and potassium concentrations. For plant growth, biomass accumulation, and starch concentrations, a positive nitrogen effect was found, but only for fertilisations of up to 40 kg Nha(-1) yr(-1). The highest nitrogen load, however, reduced leaf area, leaf water content, growth, biomass accumulation, and starch concentrations, whereas soluble carbohydrate concentrations were enhanced. The ozone fumigation resulted in reduced leaf area, leaf water content, shoot growth, root biomass accumulation, and decreased starch, phosphorus, and potassium concentrations, increasing the N:P and N:K ratios. A combined effect of the two pollutants was detected for the leaf area and the shoot elongation, where ozone fumigation amplified the nitrogen effects.     

磺胺和四环素类抗生素对活性污泥性能的影响

废水处理工艺中抗生素类污染物的存在可能会对生物处理过程产生长期而深远的影响,为探明此类污染物对废水生物处理主体活性污泥性能等方面的影响,采用间歇培养法研究了活性污泥法处理污水时,抗生素类污染物的存在对活性污泥性能如胞外聚合物（EPS）、污染物处理能力、脱氢酶活性和群落结构的影响。结果表明,抗生素的存在会导致活性污泥的胞外聚合物总量及其主要组分蛋白质和多糖增加,以产生保护屏障;且由于污泥絮体解体,细胞破裂导致EPS中DNA和色氨酸含量增加。同时,由于蛋白质大量增加引起的表面负电荷的增加,使污泥疏水性增强,絮凝性能恶化;污泥絮体解体导致污泥颗粒变小,SVI也随之下降;在活性污泥脱氢酶活性急剧下降的同时,出水TOC迅速升高。此外,抗生素类污染物在抑制活性污泥中大部分细菌的同时,对部分菌群也有刺激生长作用,最终导致活性污泥生物群落结构的改变。四环素类抗生素对活性污泥的EPS和絮凝沉降性能的影响大于磺胺类,而对污水处理能力和群落结构的影响则不如磺胺类。抗生素类污染物的长期存在会对活性污泥沉降性能、絮凝性能、脱氢酶活性以及活性污泥群落结构等产生一系列负面影响,进而影响污染物去除效果,导致出水水质恶化。     

Biodegradability of biofilm extracellular polymeric substances

This study discovered that biofilm extracellular polymeric substances (EPS) are biodegradable by their own producers and by other microorganisms when they are starved. The study was performed in a comparative fashion to examine the biodegradability of biofilm EPS by the microorganisms from the original biofilm (its own producers) and from activated sludge (other microorganisms). Four distinctive phases were observed during EPS biodegradation. In the first phase, instantaneous concentration increases of carbohydrate and protein in the test solutions were observed when EPS was added; in the second phase, easily biodegradable EPS from the added EPS was quickly utilized; in the third phase, microorganisms began to produce soluble EPS, using the minimally biodegradable EPS left from the previously added EPS; in the fourth phase, cells consumed the newly produced EPS and microbial activity gradually stopped. This study suggests that EPS can be used as a substrate, and that the EPS carbohydrate can be utilized faster than the EPS protein. The EPS utilization rates (including carbohydrate and protein) in the activated sludge suspension were greater than those in the biofilm suspension. It may take microorganisms longer to get acclimated to a new nutrient environment if they are in a starved state.     

Effects of simultaneous ozone exposure and nitrogen loads on carbohydrate concentrations, biomass, and growth of young spruce trees (Picea abies)

Spruce saplings were grown under different nitrogen fertilization regimes in eight chamberless fumigation systems, which were fumigated with either charcoal-filtered (F) or ambient air (O3). After the third growing season trees were harvested for biomass and non-structural carbohydrate analysis. Nitrogen had an overall positive effect on the investigated plant parameters, resulting in increased shoot elongation, biomass production, fine root soluble carbohydrate concentrations, and also slightly increased starch concentrations of stems and roots. Only needle starch concentrations and fine root sugar alcohol concentrations were decreased. Ozone fumigation resulted in needle discolorations and affected most parameters negatively, including decreased shoot elongation and decreased starch concentrations in roots, stems, and needles. In fine roots, however, soluble carbohydrate concentrations remained unaffected or increased by ozone fumigation. The only significant interaction was an antagonistic effect on root starch concentrations, where higher nitrogen levels alleviated the negative impact of ozone.     

活性污泥胞外聚合物提取方法优化

试验对比了不同离子交换树脂(CER)含量和pH条件下胞外聚合物(EPS)的提取效果差异。结果表明,EPS各组分提取浓度均随离子交换树脂用量增加而增加,但各组分趋势不同。TOC的最佳树脂剂量为100 g CER/g VSS,而蛋白质、多糖和DNA的最佳树脂剂量约为70 g CER/g VSS。pH值对TOC、DNA和多糖的提取浓度影响较小,但对蛋白质影响比较大。各提取条件下,EPS各组分提取浓度随时间的变化过程可以分为平稳增长期、快速增长期及稳定期。     

响应面分析法优化造纸污泥吸附剂除磷工艺

以造纸厂废水污泥为原料,采用微波加热法制备造纸污泥吸附剂。利用制备的造纸污泥吸附剂对模拟含磷废水进行了吸附研究,探讨了吸附时间、投加量、pH值、转速和温度等因素对除磷效果的影响,并采用响应面设计法优化吸附工艺条件。结果表明,获得了最佳除磷工艺条件为吸附时间97 min,投加量6.9 g/L,pH=6,转速200 r/min,温度30℃,在此条件下磷的去除率可达99%以上。因此,造纸污泥吸附剂对磷的吸附效果良好,具有重要的实际应用价值。     

Diffusion of oxygen through activated sludge flocs: experimental measurement, modeling, and implications for simultaneous nitrification and denitrification.

Diffusion of dissolved oxygen through activated sludge flocs was studied, as it represents a potential mechanism for simultaneous nitrification and denitrification in activated sludge systems. Dissolved oxygen profiles through six floc particles collected at different times from a full-scale activated sludge plant demonstrated that that the dissolved oxygen concentration declines through all floc particles. For larger floc particles (2-mm diameter and greater), the dissolved oxygen concentration reached near-zero values at depths depending on process operating conditions. A mathematical model based on diffusion of dissolved oxygen, organic substrate (methanol), ammonia, nitrite, and nitrate through a spherical floc and consumption of dissolved oxygen by heterotrophs and autotrophs accurately predicted the dissolved oxygen profile and required adjustment of only one model parameter--the concentration of heterotrophs. A different dissolved oxygen decline pattern was exhibited for the smaller floc particles characterized, with the dissolved oxygen reaching a non-zero plateau toward the center of the floc. This pattern was not reproduced with the mathematical model developed and suggests that additional mechanisms are responsible for the transport of dissolved oxygen into the center of these flocs. Implications of these results regarding the occurrence of simultaneous nitrification and denitrification include consideration of the factors that affect floc size and distribution (simultaneous nitrification and denitrification is maximized with larger floc particles), coupling of the International Water Association (London) activated models to predict activated sludge composition with diffusion models to consider intrafloc effects, and the effects of substrate diffusion on the apparent half-saturation constant for various substrates in activated sludge systems.     

胞外多聚物对活性污泥絮凝性能影响的研究进展

活性污泥的絮凝性能直接影响出水SS浓度,而胞外多聚物(EPS)是影响活性污泥絮凝性能的重要因素。从EPS的组分及其化学性质入手,结合现有的活性污泥絮凝机制评价了EPS在活性污泥絮凝性能中的重要作用,系统分析了EPS组分对污泥絮凝性能的影响,以及EPS产量和组分的影响因素,并就近年来的研究热点———松散层EPS、致密层EPS与活性污泥絮凝性能的关系进行了归纳,还对利用EPS提高活性污泥絮凝性能的技术应用进行了总结。最后,对该领域的研究方向进行了展望。     

Comparison of mechanical pretreatment methods for the enhancement of anaerobic digestion of pulp and paper waste activated sludge

The conventional anaerobic digestion process, requiring long solids retention times (SRTs) to digest solids, is currently viewed as impractical for the pulp and paper industry because of high capital costs associated with the construction of new digesters. Recent developments in sludge solubilization technology could be promising in reducing digester size, which also allows for the potential use of decommissioned tanks, both of which can reduce the capital cost. Three pretreatment technologies for use with anaerobic digestion were tested on laboratory-scale to investigate their feasibility. The SRTs in all three digesters systematically decreased from 20 to 3 days. The reference digester was fed waste activated sludge (WAS) to serve as the control at the same SRTs. The other digesters were fed WAS that had been preconditioned using mechanical shearing, sonication, or high-pressure homogenization technology. Anaerobic digestion with high-pressure homogenization produced as much methane at 3-day mean SRT as that from the reference digester operated at 20-day SRT. Therefore, a new digester can theoretically be 85% smaller than a conventional digester. An added benefit of WAS to methane conversion is the recovery of nutrients nitrogen and phosphorus.     

Characterization of the humic material formed by composting of domestic and industrial biowastes Part 1. HPLC of the cupric oxide oxidation products from humic acids

The changes induced by humification of anaerobically digested sewage sludge, source separated biowaste, and pulp mill biosludge were determined by extracting the fractions of bitumen and humic and fulvic acids from the samples of fresh and humified composts. In all cases, a distinct decrease in the amount of bitumen could be detected during humification. The amount of humic acids increased in sewage sludge and biowaste samples, but decreased in pulp mill biosludge sample during humification. The humic acids were degraded by CuO oxidation and the phenolic degradation products were analysed by reversed-phase high-performance liquid chromatography. The yield of these aromatic degradation products was in the range 0.9–2.0 % for each sample. The main phenolic degradation products were 4-hydroxybenzoic acid, vanillic acid, 4-hydroxybenzaldehyde, vanillin, syringaldehyde, and acetovanillone. Two lignin dimers, dehydrodivanillin and dehydrodiacetovanillone, were also identified.     

蠕虫捕食对污泥性质的影响

利用一种新型静态序批式蠕虫生物反应器处理剩余污泥,另设一个未加蠕虫的反应器作为对照。通过对比分析2个反应器中污泥的比减量速率、沉降性能、脱水性能和比好氧速率来研究蠕虫捕食对污泥性质的影响。实验结果表明,蠕虫具有良好的污泥减量效果,蠕虫加入后可使污泥比减量速率增加（0．15±0．02）mg／（mg·d）。蠕虫作用后污泥沉降性能明显改善,污泥容积指数（SVI）降低28．9％,胞外聚合物（EPS）含量减少和污泥絮体结构变得更加密实规则是污泥沉降性能得到改善的重要原因。蠕虫捕食后污泥脱水性能变差,污泥标准化毛细吸水时间和比阻分别增大2．45倍和1．16倍,推测主要是由污泥絮体平均粒径减小造成的。另外,蠕虫的存在会降低污泥的微生物活性,异养细菌、氨氧化细菌和亚硝酸盐氧化细菌的比好氧速率分别降低7．09％、7．84％和8．29％。     

溶解氧对活性污泥合成可生物降解塑料—PHB的影响

聚-β-羟基丁酸酯（polyhydroxybutyrate,PHB）是一种可完全生物降解和具有良好生物相容性的高分子材料,许多情况下可作为传统塑料的替代品。以活性污泥微生物作为PHB合成菌,研究了动态底物投加方式下,溶解氧对污泥贮存PHB过程的影响。结果表明,PHB的贮存过程相当程度上取决于氧的提供。溶解氧浓度的提高明显加快了底物乙酸的吸收,进而导致更大比例的乙酸被活性污泥贮存为PHB。试验中,溶解氧浓度由饱和浓度的10%提高到70%,PHB的产率由0.36 C mmol/C mmol 提高到0.56 C mmol/C mmol,PHB的胞内含量也由26%提高到37%。试验证明溶解氧是控制活性污泥合成PHB工艺的重要因素。     

造纸白泥和粉煤灰的添加对污泥消化液中氮磷回收的影响

污泥厌氧消化液中含有丰富的氮磷,若直接排放到环境中,将会对附近水体造成严重污染。由于消化液中Mg^2＋和Ca^2＋的含量很低,严重影响了氮磷的回收效果。把造纸白泥和粉煤灰引入到污泥厌氧消化液氮磷的回收当中,可以明显地提升消化液pH和提高PO4^3-P和NH3-N回收率。实验结果表明：当造纸白泥添加量为4g／（L·h）时,曝气12h后,pH可达10．19,此时PO4^3-P和NH3-N回收率分别达到64％和45％;而当粉煤灰添加量为4g／（L·h）时,曝气12h后,pH达到9．63,PO4^3-P和NH3-N回收率分别为46％和41％。但仅用曝气方式处理,12h后,pH值仅为8．52,PO4^3-P和NH3-N回收率分别只有20％和18％。实验结果还表明,水力停留时间（HRT）越大,pH上升速度越快,幅度越大,氮磷的回收效果就越好。