颗粒活性炭加速厌氧反应器污泥颗粒化的研究

为克服厌氧反应器启动慢和启动难的问题,以UASB反应器为代表,向反应器内投加颗粒活性炭以加快厌氧污泥颗粒化进程,并采用扫描电子显微镜观察颗粒污泥的生长情况.结果表明,在试验的第64天即完成了厌氧污泥颗粒化的全部过程,培养出的颗粒污泥具有厌氧颗粒污泥的基本特征和典型的生化特性,并对啤酒废水有很好的处理效果.可见,投加颗粒活性炭可加速厌氧污泥颗粒化进程,并能有效维持厌氧反应器的稳定运行.     

聚季胺物对厌氧污泥特性的影响研究

通过对聚季胺物的生物化学甲烷势(BMP)和厌氧微生物在不同聚季胺物浓度下的毒性测定(ATA)，评价了聚季胺物的厌氧生物可降解程度，对比了不同聚季胺物浓度对厌氧微生物的比产甲烷活性(SMA)和沉降性能(SVI)的影响。试验结果表明：聚季胺物适宜作为厌氧微生物自身固定化的促进剂，建议采用间隔9～10d的多次投加方式，厌氧反应器中聚季胺物浓度为10～20mg／L，聚季胺物与厌氧接种污泥的质量比≤3．2。     

ASBR反应器中污泥颗粒化的工艺条件

在小试规模的厌氧序批式反应器(ASBR)中,采用城市污水厂厌氧消化污泥接种,以蔗糖为基质,在中温[(35±1)℃]条件下经过121d实现了污泥颗粒化。对颗粒化过程和颗粒污泥扫描电镜的观察结果表明,在适宜的操作条件下ASBR反应器能够成功培养出以甲烷八叠球菌为主的颗粒污泥。污泥负荷、搅拌和微量元素对颗粒化过程具有显著影响。     

采用ASBR快速培养颗粒污泥及其菌群分析

厌氧序批式反应器(ASBR)因投资小、操作简单和运行灵活而倍受关注,但在ASBR中较难形成颗粒污泥,影响了该技术的推广应用。以葡萄糖为基质,探究在ASBR内快速培养颗粒污泥的方法,并对颗粒污泥的菌群结构进行了分析。结果表明,延长进水时间能够减少进水初期挥发酸(VFA)的积累,降低乙酸浓度,一个周期中乙酸的峰值浓度从93 mg/L下降到54 mg/L,促进了甲烷丝菌的增殖,有利于形成颗粒污泥;在进水中添加适量的Ca~(2+),大大促进了EPS的产生,其中蛋白质和多糖的含量均提高了3倍之多,这对加快污泥的颗粒化进程起到了重要作用。反应器运行80 d后以丝状菌为主的颗粒污泥形成,而后采用按梯度逐步提高进水COD负荷的方式继续培养,反应器运行150 d后以球状菌为主的颗粒污泥培养成熟,污泥粒径为0. 5～4. 0 mm,沉速为15. 0～38. 5 m/h。反应器中MLSS为7. 8 g/L,对COD的去除率达到97%～99%。     

A2N反硝化脱氮除磷工艺厌氧释磷的影响因素

利用富含反硝化聚磷菌的厌氧污泥进行静态释磷试验,探讨了A2N双污泥工艺中反硝化聚磷菌厌氧释磷的影响因素.试验结果表明:适当提高温度有助于厌氧释磷;增加污泥浓度(MLSS)和碳源浓度,可以有效强化厌氧释磷效果;碳源类型与厌氧释磷密切相关,投加醋酸钠的效果最佳.     

投加颗粒活性炭加快UASB反应器内颗粒化进程的研究

投加颗粒活性炭加快ＵＡＳＢ反应器内颗粒化进程的研究周律（清华大学）王宝泉于泮池（西安建筑科技大学）１引言厌氧生物处理工艺在处理有机废水中广泛采用。其中升流式污泥床（ＵＡＳＢ）反应器主要优点是系统内不必设有支承物，可以截留大量活性污泥，这就要求被截留的...     

培养过程中接种部分厌氧颗粒污泥促进好氧颗粒化

接种活性污泥启动SBR后,研究选择压法培养好氧颗粒污泥(AGS)的过程中接种部分厌氧颗粒污泥对好氧颗粒化进程的影响。随着沉降时间的缩短,在第6天时肉眼即可观察到一些明显的生物胶团,第11天接种质量分数为20%的厌氧颗粒污泥时已出现少量AGS。投加厌氧颗粒污泥后反应器内菌胶团及淡黄色的AGS的比例不断增加,22 d时AGS已处于主导地位,26d时颗粒化率首次超过90%并占据绝对优势,表明反应器成功实现好氧颗粒化。观察发现接种的厌氧颗粒污泥经历了先解体再重新颗粒化过程,并可作为新生颗粒的晶核而缩短自凝聚所需时间。培养过程中反应器表现出较好的污染物去除效果,对COD、TIN及TP的去除率基本在90%、90%及87%以上,表明在同一反应器内成功实现了去除有机物及同步脱氮除磷效果。     

絮凝剂与粉煤灰组合对厌氧污泥颗粒化影响

试验以阳离子聚丙烯酰胺(CPAM)为筛选物,结合粉煤灰的吸附特性,评价了絮凝剂与粉煤灰组合后对厌氧污泥颗粒化的影响,为进一步完善污泥处理工艺提供了科学指导.     

SBR不同沉降时间的污泥特性研究

对比了投加海藻酸钠与未投加海藻酸钠两种好氧颗粒污泥的培养方式,分析了絮状污泥通过改变沉降时间逐步实现颗粒化过程中污泥特性的变化。结果表明,未投加海藻酸钠(R1)和投加海藻酸钠(R2)的两组反应器分别经过40和20 d可使絮状污泥完全颗粒化,形成的好氧颗粒污泥沉降性能好、污染物去除效能高,且投加海藻酸钠培养的颗粒污泥具有更高的微生物量。在不断缩短污泥沉降时间过程中,胞外聚合物浓度逐渐升高,且以蛋白质类增加为主。随着颗粒形态趋于成熟,胞外聚合物含量维持稳定。另外,海藻酸钠的投加有利于胞外聚合物的增加,同时促进第二信使分泌,加速絮状污泥颗粒化过程。荧光光谱分析发现,两种颗粒污泥图谱峰的位置总体相同,但投加海藻酸钠污泥的EPS荧光强度略高。     

磁性颗粒对厌氧氨氧化启动过程的影响

为探究磁性颗粒对厌氧氨氧化启动过程的影响,采用2个ASBR反应器进行实验,其中一个反应器不添加磁性颗粒,另一个反应器添加磁性颗粒,初步探明了磁场对ASBR反应器内氮转移过程的影响机理。通过小试方式对比研究了不同磁性颗粒投加量对于反应周期内氨氮和亚硝态氮去除效能以及脱氢酶活性的影响。结果表明,磁场的存在能够促进厌氧氨氧化启动过程中的优势菌落演替以及厌氧氨氧化菌的富集,有效缩短厌氧氨氧化的启动周期;投加30 g/L磁性颗粒可以有效提升微生物的活性,提高反应速率。     

厌氧序批式反应器(ASBR)的六大优点

分析了厌氧序批式反应器（ASBR）的六大优点,与连续流厌氧反应器相比,ASBR构造简单、投资省,生物絮凝和固液分离效果好,水头损失小、动力费用低,生化反应推动力大,可形成以甲烷八叠球菌为优势茵的颗粒污泥,处理高浓度有机废水时对碱度的需求量少,运行费用低。     

Sludge characteristics in anaerobic SBR system producing hydrogen gas

In this study, sludge characteristics of anaerobic sequencing batch reactor (ASBR) were investigated to improve and optimize the efficiency of the system converting starch into biohydrogen. The effect of stratification in settling phase on H2-producing ASBR, which results in settleable and non-settleable sludge, was observed using a batch experiment. It was concluded that specific H2 activity of decanting non-settleable sludge was higher than that of settleable sludge, which may be the reason of low yield in H2-producing ASBR. In addition, effect of settling time on settleable sludge, which is another key operational parameter, was also analysed using another set of batch experiment. Settling time of the sludge was found to be an important parameter in H2-producing ASBR. Specific H2 activity varied inversely with the duration for which settleable microorganisms were contained in settling phase. Microbial species, responsible for H2 activity in each condition, were identified using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis.     

Methanogenic population dynamics during startup of a full-scale anaerobic sequencing batch reactor treating swine waste

Changes in methanogenic population levels were followed during startup of a full-scale, farm-based anaerobic sequencing batch reactor (ASBR) and these changes were linked to operational and performance data. The ASBR was inoculated with anaerobic digester sludge from a municipal wastewater treatment facility. During an acclimation period of approximately 3 months, the ASBR content was diluted to maintain a total ammonia-N level of approximately 2000mg l(-1). After this acclimation period, the volatile solids loading rate was increased to its design value of 1.7g l(-1) day(-1) with a 15-day hydraulic retention time, which increased the total ammonia-N level in the ASBR to approximately 3,600 mg l(-1). The 16S ribosomal RNA (rRNA) levels of the acetate-utilizing methanogens of the genus Methanosarcina decreased from 3.8% to 1.2% (expressed as a percentage of the total 16S rRNA levels) during this period, while the 16S rRNA levels of Methanosaeta concilii remained low (below 2.2%). Methane production and reactor performance were not affected as the 16S rRNA levels of the hydrogen-utilizing methanogens of the order Methanomicrobiales increased from 2.3% to 7.0%. Hence, it is likely that during operation with high ammonia levels, the major route of methane production is through a syntrophic relationship between acetate-oxidizing bacteria and hydrogen-utilizing methanogens. Anaerobic digestion at total ammonia-N levels exceeding 3500mg l(-1) was sustainable apparently due to the acclimation of hydrogen-utilizing methanogens to high ammonia levels.     

Development of anaerobic migrating blanket reactor (AMBR), a novel anaerobic treatment system

A novel anaerobic treatment system, the anaerobic migrating blanket reactor (AMBR), was developed after completing a parallel study with upflow anaerobic sludge blanket (UASB) and anaerobic sequencing batch reactor (ASBR) processes. Using sucrose as the main component of a synthetic wastewater, the AMBR achieved a maximum chemical oxygen demand (COD) loading rate of 30 g.l-1.day-1 at a 12-h hydraulic retention time (HRT). This resulted in a standard methane production rate (SMPR) of 6.51.l-1.day-1 and an average methane-based COD (MCOD) removal efficiency of 62.2%. A key element in granular biomass formation was migration of the biomass blanket through the reactor. Although a carbohydrate-rich wastewater was used, no separate pre-acidification was required for the AMBR, because of high mixing intensities and wash out of acidogenic bacteria. In contrast, the absence of pre-acidification created "bulking" problems (caused by abundant acidogenic bacteria at the surface of granules) in a UASB reactor, operated under conditions similar to that of the AMBR. As a result, a maximum COD loading rate and SMPR of 21 g.l-1.day-1 and 4.91.l-1.day-1 were achieved, respectively, for the UASB reactor at a 12-h HRT. These values were 18 g.l-1.day-1 and 3.71.l-1.day-1, respectively, for an ASBR at a 12-h HRT. Hence, the performance of the AMBR in treating a carbohydrate-rich wastewater was found to be superior in terms of maximum loading rate and SMPR.     

Improving anaerobic sequencing batch reactor performance by modifying operational parameters.

A lab-scale anaerobic sequencing batch reactor (ASBR) that had operated with glucose at an organic loading rate of 2.1 kg COD m(-3) d(-1) was stressed with an organic loading rate of 3.2 kg COD m(-3) (-1). Five different combinations of influent concentration, total cycle time, and fill time to cycle time ratio were examined. No external pH control was used. In all cases, acetate and propionate were the main constituents of the effluent. Larger fill time to cycle time ratios and lower initial substrate concentrations resulted in improved performance suggesting that ASBR operation may be improved by changing operational parameters.     

Anaerobic biodegradability and treatment of grey water in upflow anaerobic sludge blanket (UASB) reactor

Feasibility of grey water treatment in an upflow anaerobic sludge blanket (UASB) reactor operated at different hydraulic retention time (HRT) of 16, 10 and 6h and controlled temperature of 30 degrees C was investigated. Moreover, the maximum anaerobic biodegradability without inoculum addition and maximum removal of chemical oxygen demand (COD) fractions in grey water were determined in batch experiments. High values of maximum anaerobic biodegradability (76%) and maximum COD removal in the UASB reactor (84%) were achieved. The results showed that the colloidal COD had the highest maximum anaerobic biodegradability (86%) and the suspended and dissolved COD had similar maximum anaerobic biodegradability of 70%. Furthermore, the results of the UASB reactor demonstrated that a total COD removal of 52-64% was obtained at HRT between 6 and 16 h. The UASB reactor removed 22-30% and 15-21% of total nitrogen and total phosphorous in the grey water, respectively, mainly due to the removal of particulate nutrients. The characteristics of the sludge in the UASB reactor confirmed that the reactor had a stable performance. The minimum sludge residence time and the maximum specific methanogenic activity of the sludge ranged between 27 and 93 days and 0.18 and 0.28 kg COD/(kg VS d).     

Effect of the presence of the antimicrobial tylosin in swine waste on anaerobic treatment

An anaerobic sequencing batch reactor (ASBR), seeded with a biomass inoculum that previously had not been exposed to the macrolide antimicrobial tylosin (mixture of Tylosin A, B, C, and D), was operated for 3 months with swine waste without Tylosin A and for 9 months with swine waste containing Tylosin A at an average concentration of 1.6 mg/L. When swine waste with tylosin was fed to the ASBR, methane production and volatile solids removal did not appear to be inhibited and a methane yield of 0.47 L methane per gram volatile solids fed to the ASBR was observed. Throughout the operating period, Tylosin A levels in ASBR biomass and effluent were below the detection limit of 0.01 mg/L. However, during the first 3 months of operation, the levels of macrolide-lincosamide-streptogramin B (MLSB)-resistant bacteria in the ASBR biomass increased substantially as determined by hybridizations with oligonucleotide probes designed to target MLSB-resistant bacteria. Since no Tylosin A was present in the swine waste during the initial 3 months, the presence of MLSB-resistant bacteria in the swine waste was likely the reason for the increase in resistance. Subsequently, the levels of MLSB-resistant bacteria in ASBR biomass stabilized with an average of 44.9% for the 9 months of operation with swine waste containing Tylosin A. The level of MLSB-resistant bacteria in the swine waste fed to the ASBR during this period averaged 18.0%. The results indicate that anaerobic treatment of a waste stream containing tylosin was effective (based on reactor performance) and that the level of resistant bacteria in the ASBR was substantially higher than in the waste stream fed to this system.     

Carbohydrate storage in anaerobic sequencing batch reactors

This study demonstrates the accumulation and degradation of trehalose as a storage compound in a glucose-fed anaerobic sequencing batch reactor (ASBR). One hour after substrate addition, only 40% of the added organic matter (as chemical oxygen demand, COD) was accounted for by the cumulative methane production and soluble COD remaining in the reactor. All influent COD was accounted for by methane and biomass production by the end of the 24-h ASBR cycle. These dynamics can be explained by the production of an intracellular storage product. Total carbohydrate analysis showed that 26% of the glucose added to the reactor transiently accumulated within the biomass. Based on ¹³C-nuclear magnetic resonance (NMR) analysis, trehalose (-d-glucopyranosyl-(d-glucopyranoside)) was identified as the main carbohydrate produced. Mathematical modeling was performed and the IWA Anaerobic Digestion Model No. 1 (ADM1) was modified to include microbial storage. The modified model adequately described the ASBR dynamics during a 24-h cycle.     

A full scale worm reactor for efficient sludge reduction by predation in a wastewater treatment plant

Sludge predation can be an effective solution to reduce sludge production at a wastewater treatment plant. Oligochaete worms are the natural consumers of biomass in benthic layers in ecosystems. In this study the results of secondary sludge degradation by the aquatic Oligochaete worm Aulophorus furcatus in a 125 m³ reactor and further sludge conversion in an anaerobic tank are presented. The system was operated over a period of 4 years at WWTP Wolvega, the Netherlands and was fed with secondary sludge from a low loaded activated sludge process. It was possible to maintain a stable and active population of the aquatic worm species A. furcatus during the full period. Under optimal conditions a sludge conversion of 150-200 kg TSS/d or 1.2-1.6 kg TSS/m³/d was established in the worm reactor. The worms grew as a biofilm on carrier material in the reactor. The surface specific conversion rate reached 140-180 g TSS/m²d and the worm biomass specific conversion rate was 0.5-1 g TSS sludge/g dry weight worms per day. The sludge reduction under optimal conditions in the worm reactor was 30-40%. The degradation by worms was an order of magnitude larger than the endogenous conversion rate of the secondary sludge. Effluent sludge from the worm reactor was stored in an anaerobic tank where methanogenic processes became apparent. It appeared that besides reducing the sludge amount, the worms’ activity increased anaerobic digestibility, allowing for future optimisation of the total system by maximising sludge reduction and methane formation. In the whole system it was possible to reduce the amount of sludge by at least 65% on TSS basis. This is a much better total conversion than reported for anaerobic biodegradability of secondary sludge of 20-30% efficiency in terms of TSS reduction.     

Evaluation of continuous mesophilic, thermophilic and temperature phased anaerobic digestion of microwaved activated sludge

The effects of microwave (MW) pretreatment, staging and digestion temperature on anaerobic digestion were investigated in a setup of ten reactors. A mesophilic reactor was used as a control. Its performance was compared to single-stage mesophilic and thermophilic reactors treating pretreated and non-pretreated sludge, temperature-phased (TPAD) thermophilic-mesophilic reactors treating pretreated and non-pretreated sludge and thermophilic-thermophilic reactors also treating pretreated and non-pretreated sludge. Four different sludge retention times (SRTs) (20, 15, 10 and 5 d) were tested for all reactors. Two-stage thermo-thermo reactors treating pretreated sludge produced more biogas than all other reactors and removed more volatile solids. Maximum volatile solids (VS) removal was 53.1% at an SRT of 15 d and maximum biogas increase relative to control was 106% at the shortest SRT tested. Both the maximum VS removal and biogas relative increase were measured for a system with thermophilic acidogenic reactor and thermophilic methanogenic reactor. All the two-stage systems treating microwaved sludge produced sludge free of pathogen indicator bacteria, at all tested conditions even at a total system SRT of only 5 d. MW pretreatment and staging reactors allowed the application of very short SRT (5 d) with no significant decrease in performance in terms of VS removal in comparison with the control reactor. MW pretreatment caused the solubilization of organic material in sludge but also allowed more extensive hydrolysis of organic material in downstream reactors. The association of MW pretreatment and thermophilic operation improves dewaterability of digested sludge.