活性污泥EPS生成的影响因素研究

研究活性污泥EPS生成量的影响因素,讨论了DO、pH值、污泥负荷、温度、C/N对EPS产生量的影响。实验结果表明:随DO升高,产生较多的EPS,多糖、蛋白质含量也随之缓慢增加;pH值对EPS影响显著;在低负荷条件下微生物有较慢的生长速率和较高的内源代谢水平,EPS较多;介于10~25℃适宜温度下或者在C/N为100/10~100/5环境中,微生物生长效率最高。     

氧化沟工艺污泥膨胀及出水水质影响因素的研究

针对丝状菌污泥膨胀造成改良式氧化沟工艺处理城市生活污水超标的问题,通过分析进水水质、溶解氧、温度、污泥膨胀指数、出水水质变化的关系,探讨了导致丝状菌膨胀的主要限制因子以及出水水质的变化.研究结果表明,此工艺中进水BOD5、CODcr、TP浓度和pH值变化不是导致污泥膨胀的原因,进水TN和环境温度对污泥膨胀略有影响,DO、NH3-N变化与SVI有较强的相关性,DO和NH3-N越高,SVI越低.     

AOMBR处理高氨氮废水的效能稳定性及影响因素研究

对AOMBR(缺氧-好氧膜生物反应器)处理高氨氮废水的脱氮效能进行了研究,着重考察了硝化效能的稳定性及影响系统稳定运行的因素.研究结果表明:在适宜的pH、DO和温度下,容积负荷＜1.5 kgNH3-N/(m3·d)时,硝化率可保持在99%以上;好氧池中DO＞1.5 mg/L能满足硝化需要;好氧池pH维持在6.8～7.2时可稳定高效地去除氨氮;碱度、污泥龄等也会对硝化效率产生影响.在好氧池中硝化率较高的情况下,影响反硝化效果主要是回流比和碳源.     

EPS对污水处理效果及污泥性能影响

通过分析EPS产生量对污水处理中多糖、蛋白质对污泥的沉降、絮凝性能及生物处理效果的影响,得出曝气0.5h COD去除率达85%,MLSS增大。EPS含量对污泥絮凝和沉降性能影响显著,随着EPS含量的增加,污泥的絮凝沉降性能变差;多糖、蛋白质含量的增加使反应器中SVI及出水浊度增加,以多糖影响为主。     

水库沉积物中铁、锰季节性释放的实验研究

分析青岛市王圈水库水质和沉积物长期监测资料,研究环境因子(DO、pH值、温度等)对水库沉积物铁、锰释放的影响。结果表明:厌氧、中酸性条件有利于铁、锰的释放,而好氧(ρ(DO)>6.5 mg/L)和碱性条件(pH=9.2)会抑制铁、锰的释放;温度对铁、锰的释放有很明显的影响,升高温度有利于铁、锰的释放。     

pH值对污泥好氧消化的影响

本文作者研究了调节pH值对污泥好氧消化的影响。试验结果表明,污泥好氧消化效率与污泥性质和使用的药剂种类密切有关。延时曝气污泥采用Ca(OH)_2调节pH至7～8后,TVSS去除率可从20%提高到36%;而传统高负荷法污泥,不论采用 Ca(OH)_2还是采用 NaHCO_3,对其影响都不明显。从药剂种类来看,以采用 Ca(OH)_2为宜。     

水生植物对水塘水质影响的实例研究

水生植物在调节水塘水质方面发挥着重要作用。为揭示水生植物对水塘水质的影响,选取扬州大学江阳路南校区水塘为研究区,对该水塘水生植物区和无水生植物区水质参数水温(WT)、pH、溶解氧(DO)、电导率(EC)进行观测,采用变异系数法、单因子水质标识指数法及多元线性回归模型对各水质参数的变化特性进行分析,评价水生植物对水质的影响。结果表明:(1)观测期间内水生植物区WT、DO均低于同期无水生植物区;(2)水体呈碱性,无水生植物区的pH普遍高于水生植物区;(3)无水生植物区各水质参数的波动程度多高于同期水生植物区,两区域各水质参数变异性权重由高到低依次为DOWTECpH;(4)无水生植物区水质优于水生植物区,无水生植物区DO达III类水质要求时段占总时段的67.7%;(5)研究期间内,无水生植物区和水生植物区WT对DO的影响不一致,Phyco及pH的变化对DO浓度的影响相对于WT大。     

郝现废水处理站水质稳定处理工艺方案选择

针对郝现废水处理站废水沿程水质不稳定的问题,分析了油田偏酸性含油废水对沿程水质稳定的影响因素。在前期试验的基础上,对电化学预氧化工艺和水质改性工艺进行方案比选,最终确定采用电化学预氧化工艺。该工艺可有效控制废水腐蚀,提高水质稳定性,且投药量少、pH控制值低、产出污泥量大量减少,降低了处理成本,防止了二次污染。     

UNITANK工艺深度处理漂染废水

介绍UNITANK工艺深度处理漂染废水的效果,并探讨UNITANK工艺运行规律、HRT及水质变化等对处理效果的影响.结果表明,在中等有机负荷下,HRT 6 h,中间池DO为1.5～2 mg/L、边池DO为2 mg/L的条件下,处理效果较佳且稳定.经济方面也具有一定优势.     

钙沉淀法处理核燃料元件高氟废水的工艺优化

为探究钙沉淀法在处理F-浓度为10 000mg/L核元件废水时的操作参数,采用烧杯试验,分别考察了石灰投加量、氯化钙投加量、混凝剂投加量、温度、pH等因素对除氟效果的影响。研究表明,联合Ca(OH)2和CaCl2沉淀除F-时,在控制Ca(OH)2投加量为理论值的110%、CaCl2投加量为95%、Al2(SO4)3投加量为600mg/L、混合液温度为50℃、pH为8的情况下,能够实现高氟废水的达标排放。     

Comparison of extracellular polymeric substances (EPS) extraction from two different activated sludges

The characteristics of extracellular polymeric substances (EPS) extracted with five different extraction protocols from two different activated sludges were studied. The results showed that the major EPS constituent extracted by centrifugation was protein for the sludge in sequencing batch reactor treating chemical wastewater, and nucleic acid for the sludge in moving bed biofilm reactor treating synthetic urban wastewater. The order of EPS extraction amounting from the two sludges was formaldehyde + NaOH > formaldehyde + heating > EDTA > heating > centrifugation. The different extraction methods, the wastewater type, and activated sludge source greatly affected the amount and composition of EPS. The chemical extracted methods were more effective than the physical methods in extracting EPS for the two sludges. Moreover, formaldehyde combined NaOH was most effective in extracting EPS for the two sludges. However, chemical extraction could contaminate the EPS solution, which was pointed out by infra-red analysis and was also proved by cell lyses during EPS extraction and carrying over of the chemical extractant. Therefore, this study highlights that the choice of EPS extraction method should consider both the extraction yield and content and the contamination of extracting reagents to the EPS solution. The extraction procedures should be optimized and most effective.     

Identification of the effect of extracellular polymeric substances on bacterial adhesion to the membrane surface in a membrane bioreactor using Pseudomonas fluorescens.

In a membrane bioreactor (MBR) process containing a variety of bacteria, the bacterial adhesion to the membrane surface, prior to cake formation, causes an increased filtration resistance. In this study, Pseudomonas fluorescens, commonly found in the municipal wastewater treatment process with activated sludge, was used to show the effects of extracellular polymeric substances (EPS) on bacterial adhesion to the membrane surface in the MBR. Of the various roles of EPS in promoting membrane fouling, the adhesion of bacteria to the membrane surface was calculated using the specific cake resistance (alpha, m/kg). Although the amount of EPS binding with bacteria was increased by the addition of Ca2+, there was no significant effect on the bacterial growth. The results of the particle size distribution showed that the addition of Ca2+ increased flocculation, allowing the formation of a complex with the bacteria and EPS. In order to identify the effects of the addition of Ca2+ on the hydrophobicity, the contact angle was also measured. The result showed that the addition of Ca2+ showed no significant differences in the hydrophobicity, even though there was an increase in flocculation. With the bacteria containing a higher EPS concentration, a higher specific cake resistance was observed. From the results of the adhesion experiment, which was conducted with various EPS levels, displayed as the COD and TOC concentration, an increased EPS concentration was shown to promote bacterial adhesion to the membrane surface.     

The effect of drastic temperature changes on the performance of MBR treating municipal wastewater

A study has been carried out to define the effect of drastic temperature changes on the performance of lab-scale hollow-fibre MBR in treating municipal wastewater at a flux of 10 L m(-2) h(-1) (LMH). The objectives of the study were to estimate the activated sludge properties, the removal efficiencies of COD and NH(3)-N and the membrane fouling tendency under critical conditions of drastic temperature changes (23, 33, 42 & 33 °C) and MLSS concentration ranged between 6,382 and 8,680 mg/L. The study exhibited that the biomass reduction, the low sludge settleability and the supernatant turbidity were results of temperature increase. The temperature increase led to increase in SMP carbohydrate and protein, and to decrease in EPS carbohydrate and protein. The BRE of COD dropped from 80% at 23 °C to 47% at 42 °C, while the FRE was relatively constant at about 90%. Both removal efficiencies of NH(3)-N trended from about 100% at 33 °C to less than 50% at 42 °C. TMP and BWP ascended critically with temperature increase up to 336 and 304 mbar respectively by the end of the experiment. The values of suspended solids (SS) and the turbidity in the final effluent were negligible. The DO in the mixed liquor was varying with temperature change, while the pH was within the range of 6.7-8.3.     

Reuse of treated wastewater and sewage sludge for fertilization and irrigation

The objective of the present work was to assess the short-term potential of treated wastewater and sewage sludge for ornamental lawn fertilization and irrigation. A field experiment was performed and the following treatments were considered: sewage sludge application + irrigation with public water; sewage sludge application + irrigation with treated wastewater; irrigation with public water; irrigation with treated wastewater (TW). Irrigation with treated wastewater showed a positive effect on lawn installation through higher growth of grass (1,667 cm) and higher dry matter yield (18,147 g m(-2)). These results represent a significant increase in the grass yield compared with public water irrigation. The grass height (2,606 cm) and dry matter yield (23,177 g m(-2)) increased even more, when sewage sludge produced in the wastewater treatment plant (WWTP) was applied to soil, which proves once more its benefits as an organic fertilizer. At the end of the experiment, an increase of some soil parameters (pH, electrical conductivity, organic matter, Ca2+, Na+, K+, Mg2+ and NH4+) was observed, indicating that treated wastewater irrigation can cause a soil sodization. This short-term study indicated that use of treated wastewater and sewage sludge for ornamental lawn fertilization and irrigation is an environmentally sustainable option for re-use of the WWTP by-products.     

生物颗粒活性炭处理苯酚废水

研究了生物颗粒活性炭(BGAC)处理合成苯酚废水的效果和机理。结果表明,BGAC能够高效处理苯酚废水,处理效果优于活性污泥法和颗粒活性炭(GAC)吸附。BGAC、活性污泥和GAC分别对75 mg/L的苯酚废水连续处理,平均去除率分别为98%、60%和90%。通过苯酚出水pH值和反应器中溶解氧的变化情况分析,BGAC对苯酚废水的处理主要借助于活性炭的吸附和微生物降解的交替作用。     

溶解氧对低负荷CAST 工艺除磷效果的影响

结合北京市某污水处理厂CAST工艺的运行情况,考察了DO对除磷及污泥性质的影响.研究表明选择区的厌氧状态很重要.处理低浓度污水时,主区DO对污泥的活性和污泥含磷量有影响,较低的DO有利于提高污泥的活性和含磷量,从而提高除磷率.     

Dynamics of dewaterability and bacterial populations in activated sludge

Relationships of bacterial populations and extracellular polymer substances (EPS) to dewaterability of activated sludge were studied on three laboratory-scale activated sludge reactors fed with synthetic wastewater. Dewaterability of activated sludge was evaluated by a novel method developed by the authors, in which small amount of sludge was centrifugally dewatered, and its water content was measured. Bacterial populations during the reactor operation were analyzed by the polymerase chain reaction/terminal-restriction fragment length polymorphism (PCR/T-RFLP) targeted at a partial 16S rRNA gene. Extracellular polymeric substances (EPS) were extracted using cation exchange resin (CER), and polysaccharides and total protein in EPS were determined. Some of the dominant terminal-restriction fragments (T-RFs) were observed to have significant relationships with dewaterability of sludge, and it was suggested that bacterial species corresponding to those peaks significantly affected dewaterability. On the other hand, significant relationships were not found between EPS concentration and dewaterability of sludge.     

Alkaline and acid hydrolytic processes in aerobic and anaerobic sludges: effect on total EPS and fractions.

Sludge samples from an upflow anaerobic sludge blanket (UASB) reactor and four submerged aerated biofilters (BFs) of a wastewater treatment plant (1,000 inhab.) were processed at bench scale by alkaline and acid hydrolysis with the objective to evaluate the organic matter solubilization, volatile solids (VS) destruction and the effect of hydrolytic processes on the extracellular polymeric substances (EPS) fraction of the sludge samples. The results showed that alkaline hydrolysis of sludge samples treatment with 1.0% total solids (TS) using NaOH 20 meq L(-1) was more efficient on organic matter solubilization and VS destruction than acid hydrolysis. The EPS sludge content was also affected by the alkaline treatment of anaerobic sludge samples. The EPS concentrations (mg EPS/gVSS) on the anaerobic sludge after the alkaline treatment were significantly lowered according to sample height in the UASB reactor. Data indicated that the EPS sludge fraction is the main component affected by the alkaline hydrolytic process of anaerobic sludge samples.     

污泥膨胀的原因分析及预警监测研究

通过分析活性污泥法污水处理系统的实际运行工况,筛选出丝状细菌数量级、污泥沉降比、负荷比、溶解氧、泥龄、温度和营养物类型作为污泥膨胀指标,并根据研究得出污泥膨胀监控指示范围.