污泥厌氧发酵产沼气抑制物影响的研究进展

厌氧发酵产沼气作为污泥处置的重要技术,不仅能够解决生成量见长的污泥所造成的环境问题,而且能够缓解当前日益紧张的能源供需矛盾。氨、硫化物、金属离子、氢、短链及长链脂肪酸等物质可抑制厌氧发酵菌群的活性,从而显著降低污泥厌氧发酵产沼气效率。本文围绕影响污泥厌氧发酵产沼气过程的氨、硫化物、金属离子、氢、短链及长链脂肪酸等抑制物的研究进展进行了阐述及分析,以期为高效污泥厌氧发酵产沼气技术的研发提供参考。     

污泥厌氧发酵产酸机理及应用研究进展

为了实现污水中污泥减量化和资源化，对其进行厌氧消化是目前国际上应用最广泛的处理方法。酸化阶段的重要产物——挥发性脂肪酸（VFAs）不仅可以作为污水脱氮除磷的碳源，还是合成生物质塑料聚羟基脂肪酸酯（PHAs）的理想底物。简单介绍了污泥厌氧发酵产酸的代谢机理和微生物机理，对近年来污泥厌氧发酵产酸的研究成果进行了梳理，重点论述了底物种类、预处理技术、pH值、发酵温度等因素对污泥厌氧发酵产酸的影响及研究进展，总结并对比了不同底物类型、发酵温度、酸性和碱性条件下都可影响发酵产酸的产量及酸种类分布，而污泥预处理技术则倾向于提高酸的产量，对酸种类分布影响不大。介绍了污泥厌氧发酵产酸在合成PHAs、生物能源和污水的脱氮除磷等方面的应用情况。最后，针对污泥厌氧发酵产酸会因底物有机成分不同，导致酸化效率有所差异，同时控制底物种类、pH值和温度等因素不仅影响产酸量，还会影响产酸类型和产物种类。提出了今后的研究方向主要是深入分析不同底物的酸化效率差异原因、污泥定向发酵产酸，实现总VFAs中各种酸比例调控。     

污水厂污泥厌氧消化产短链脂肪酸研究进展

污泥厌氧消化产短链脂肪酸是实现污泥资源化的重要途径,短链脂肪酸不仅是产甲烷的底物、污水脱氮除磷的碳源,而且可以作为原料产生一系列高附加值的产品。本文介绍了污泥厌氧消化产有机酸的机理,重点阐述了污泥性质、温度、pH值、碳氮比（C/N）、水力停留时间（HRT）和固体停留时间（SRT）等影响污泥厌氧消化产酸的主要因素及研究进展,指出这些因素通过改变底物性质、微生物活性及二者接触反应时间等对产酸过程产生影响,其中温度和pH值是研究热点,目前大多数研究者认为高温和碱性条件更有利于污泥产酸。此外,还论证了这些影响因素对于实现污泥产酸最大化的重要意义,提出各因素之间的相互关系以及通过调控温度、pH值、碳氮比等发酵影响因素来控制产酸类型是今后值得研究的方向。     

HTAB对污泥发酵效能及微生物种群结构的影响

探究了典型杀菌剂十六烷基三甲基溴化铵(HTAB)对污泥厌氧发酵产短链脂肪酸的影响,采用16S rRNA和16S rRNA(genes)等测序手段分析比较了发酵系统中微生物的种群结构。结果表明,HTAB暴露有效促进了污泥产酸的效能,第6天达到(2 012±101) mg COD/L,相比空白组提高将近4倍,特别是乙酸。进一步发现,HTAB能加速污泥中蛋白质等有机底物的溶解和水解,促进发酵功能微生物的富集,有利于短链脂肪酸的积累。与传统的16S rRNA相比,16S rRNA(genes)测序分析能更加真实、有效地反映发酵系统中功能微生物的重要作用。     

过硫酸钾对剩余污泥厌氧发酵过程的影响

为了提高污泥产酸量,研究了氧化剂过硫酸钾(K_2S_2O_8)对剩余污泥厌氧发酵过程的影响,考察了K_2S_2O_8对厌氧发酵过程中SCOD、短链脂肪酸(SCFAs)、溶解性蛋白质和多糖及污泥比阻和挥发性固体的影响。结果表明:适宜的K_2S_2O_8浓度有利于污泥的水解、产酸类型的优化以及SCFAs产量的提高。当K_2S_2O_8投加量为0.12g/g时,可以获得较高的产酸量,污泥产酸量达209.21 mgSCFAs/gVSS。同时,投加适量的K_2S_2O_8能提高有机质减少率,改善污泥脱水性能。当K_2S_2O_8投加量为0.12 g/g时,有机质减少率可达34.75%,污泥比阻与对照组相比可下降38.5%。     

污泥发酵产酸技术研究及应用进展

活性污泥中含有大量的糖类、脂肪和蛋白质等有机物质,这些物质能够在厌氧条件下发生水解,生成易生物利用的挥发性短链脂肪酸。综合论述了提高污泥发酵产酸的方法,并对污泥发酵产酸技术的发展前景进行了分析与展望,希望该技术能够在污泥处理领域得到进一步发展,使污泥达到减量化、稳定化、资源化,带来更大的环境效益。     

皂苷强化生物膜污泥厌氧发酵产酸的研究

采用向生物膜污泥中投加生物表面活性剂皂苷的方法,探究了皂苷对膜污泥厌氧发酵产酸的影响。实验结果表明,皂苷能够强化MBR污泥产酸,且皂苷的最佳投加量为0.1 g/(g TSS),相应地,SCFA的产量为2 153 mg/L。机理研究表明,皂苷能够促进MBR污泥水解,抑制产甲烷,进而促进了短链挥发性脂肪酸(SCFA)的积累。同时皂苷也能够强化与SCFA生产有关酶的活性。     

碱性蛋白酶与烷基糖苷协同促进剩余污泥厌氧发酵产酸

针对剩余污泥厌氧发酵产短链脂肪酸(SCFAs)面临的污泥水解效率低的问题,将碱性蛋白酶(AP)与烷基糖苷(APG)联合用于污泥厌氧发酵产酸中。结果表明,AP与APG在强化污泥厌氧发酵产SCFAs过程中具有协同作用,在9%g AP/g SS和0.20 g APG/g SS的作用下,在厌氧发酵第3 d取得的最大SCFAs产率为214.80 mg COD/gVSS,显著高于两者单独作用时,且以乙酸为主。AP与APG的协同作用提高了污泥增溶与水解效率,改善了污泥发酵液的生物可降解性能,为酸化阶段提供了良好的发酵底物。同时,蛋白酶、α-葡萄糖苷酶、乙酸激酶的活性得到提高。微生物群落结构分析表明,AP与APG的协同作用提高了Firmicutes、Bacteroidetes和Actinobacteriota等水解酸化类微生物的相对丰度,而Proteobacteria和Cloroflexi等消耗SCFAs的微生物的相对丰度显著降低。     

资源化利用污水厂剩余污泥产生的短链脂肪酸的研究进展

活性污泥法在污水处理过程中会产生大量剩余污泥.剩余污泥既是污水处理厂的废物和环境污染物,又是很好的有机资源,其中有机物(主要是多糖、蛋白质等)质量分数在60%左右.剩余污泥在碱性条件下发酵产生的短链脂肪酸约为酸性、中性,或不控制pH时的3～4倍.介绍了资源化利用污泥发酵产生的短链脂肪酸的研究进展,包括:提高污水增强生物除磷效果;提高污水同时除磷脱氮效果;高效合成生物可降解塑料聚羟基脂肪酸酯(PHA).     

高温消化条件下污泥内碳源释放进程及特性

为适应低C/N废水生物脱氮除磷的需求，利用剩余污泥开发内碳源备受重视。本文研究了不同温度条件下污泥消化过程内碳源释放进程的变化特征，探讨了污泥消化过程对上清液中有机物分子量分布的影响。研究表明：消化温度由40℃升至60℃时，污泥挥发性固体物（VS）减量化效果及消化液中化学需氧量（SCOD）浓度明显增加，高温条件有利于污泥内碳源的释放。60℃消化处理120h时，污泥消化体系短链脂肪酸（SCFAs）总量为8797mg/L，C/N（以SCOD/TN表示）、C/P（以SCOD/TP表示）分别达到11.7与38.2；消化温度对污泥上清液中有机物分子量分布影响显著，并使微生物副产物、有机质大分子物质更容易转化为其他代谢中间组分和小分子中间产物。若消化时间超过120h，污泥上清液中M _w＞100000的大分子物质呈下降趋势，M _w＜10000的小分子物质所占比例逐步增加，但SCFAs总量也呈降低趋势，不利于污泥内碳源的累积。     

Evaluation of industrial organic waste as an alternative external carbon source for denitrification in the biological nutrient removal process

The mixed liquor of organic wastes (MLOW) produced from a 1,4-butanediol production process was tested as an external carbon source for denitrification in the biological nutrient removal (BNR) process. The fraction of non-biodegradable chemical oxygen demand (NBDCOD) in the MLOW was estimated to be approximately 0.2% by measuring the oxygen uptake rate (OUR). The specific denitrification rate (SDNR) of MLOW and methanol from a nitrate utilization rate (NUR) test was confirmed to be approximately 13.02 and 12.68 mgN/gVSS/hr, respectively. The results indicated that the denitrification capability of microorganisms applying the MLOW was similar to that of using methanol as an external carbon source for the BNR process. The feasibility of MLOW for a stainless steel wastewater treatment plant (WWTP) was investigated. The low concentration of effluent nitrogen indicated a denitrification capability for MLOW similar to that for methanol. These results support the potential of MLOW as a substitute for methanol in the BNR process.     

Biological nutrient removal in a sequencing batch reactor using ethanol as carbon source

BACKGROUND: When organic matter is limiting for biological nutrient removal (BNR) from wastewater, external organic carbon can be added to a wastewater treatment plant (WWTP). This increases the overall treatment cost, so the choice of substrate is critical. The effect of using ethanol as the carbon source for BNR is investigated. RESULTS: The results clearly showed that using ethanol as a carbon source is a promising strategy for removing nutrients from wastewater. Effluent concentrations of 3.0 mg total nitrogen (TN) L^?1 (96% N removal efficiency) and 0.05 mg phosphate (P‐PO₄) L^?1 (99.9% P removal efficiency) were obtained. Furthermore, tests performed in order to identify the carbon source used by polyphosphate‐accumulating organisms (PAOs) showed that the phosphorus release/carbon uptake ratio using ethanol (0.41 mmol P mmol^?1 C) was slightly lower than that with acetate (0.50 mmol P mmol^?1 C) but close to that with propionate (0.42 mmol P mmol^?1 C). CONCLUSION: Therefore, taking into account the results presented for ethanol‐acclimatised biomass and the fact that the cost of ethanol is lower than that of acetate or propionate, ethanol can be considered as an alternative carbon source if one is needed in a WWTP. Copyright © 2007 Society of Chemical Industry     

Enhanced biological nutrient removal in modified carbon source division anaerobic anoxic oxic process with return activated sludge pre-concentration☆

A pilot-scale modified carbon source division anaerobic anoxic oxic (AAO) process with pre-concentration of returned activated sludge (RAS) was proposed in this study for the enhanced biological nutrient removal (BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60%and 50%, respectively, with an inner recycling ratio of 100%under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L?1 with a removal efficiency of 63%and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.     

Biological Nutrient Removal in a Full Scale Anoxic/Anaerobic/Aerobic/ Pre-anoxic-MBR Plant for Low C/N Ratio Municipal Wastewater Treatment

A novel full scale modified A2O （anoxic/anaerobic/aerobic/pre-anoxic）-membrane bioreactor （MBR） plant combined with the step feed strategy was operated to improve the biological nutrient removal （BNR） from low C/N ratio municipal wastewater in Southern China. Transformation of organic carbon, nitrogen and phosphorus, and membrane fouling were investigated. Experimental results for over four months demonstrated good efficiencies for chemical oxygen demand （COD） and NH4^＋-N removal, with average values higher than 84.5%and 98.1%, re-spectively. A relatively higher total nitrogen （TN） removal efficiency （52.1%） was also obtained at low C/N ratio of 3.82, contributed by the configuration modification （anoxic zone before anaerobic zone） and the step feed with a distribution ratio of 1：1. Addition of sodium acetate into the anoxic zone as the external carbon source, with a theoretical amount of 31.3 mg COD per liter in influent, enhanced denitrification and the TN removal efficiency in-creased to 74.9%. Moreover, the total phosphate （TP） removal efficiency increased by 18.0%. It is suggested that the external carbon source is needed to improve the BNR performance in treating low C/N ratio municipal waste-water in the modified A^2O-MBR process.     

废水生物脱氮除磷工艺的进展与评述

针对传统生物脱氮除磷工艺存在的一些不足,即微生物的混合培养,泥龄,碳源和回流污泥中的硝酸盐问题,概要介绍了双循环两相生物处理(BICT)工艺,厌氧/缺氧和硝化(A2N)工艺,BCFS工艺,分段进水BNR工艺,厌氧-往复好氧组合式工艺等几种近年来针对这些问题提出的改进工艺,并从处理工艺的原理、流程和应用于实际工程尚需进一步研究的问题等方面对这些工艺进行了比较和评述。     

Removal of nitrogen and phosphorus using a new biofilm process-INRS (Innovative Nutrient Removal System)

Adopting various process configurations may perform biological nutrient removal (BNR) from sewage. To get a compact BNR process, biofilm reactors were chosen for nitrification and denitrification. Enhanced biological nitrogen and phosphorus removal in a new fixed biofilm reactor was investigated in operation strategies with two reaction phases: anaerobic/anoxic/aerobic process with post-anoxic/aerobic biofilm process (Run 2A) and Run 2A with exogenous carbon sources for denitrifying and removing phosphorus (Run 2B). The influent used was “J” WWTP influent that consisted of wastewater from nearby a factory district area, leachate, and sewage. Therefore, the influent contained a great deal of refractory organic compound. The mean concentrations of COD, NH ₄ ⁺ -N and T-P in the influent were about 297.0 mg/L, 64.92 mg/L and 2.63 mg/L, respectively. The C: N: P ratio of influent was 113: 25: 1 and it was not suitable for growth of microorganism compared with 100: 5: 1 of proper growth C:N:P ratio. But, at a total HRT of the system of 16 hours in Run 2, the system worked successfully obtaining removal of COD, T-N and T-P of the case of Run 2A, 80.1 %, 74.9 %, and 50.8 %, respectively, and Run 2B(c) with exogenous carbon source (Na-acetate) obtained 86.2 % T-N removal efficiency. The results of this research showed that an innovative nutrient removal system (INRS) process packed with SAC media could be applicable for treatment of nutrients from municipal wastewater.     

溴化天然橡胶的热降解研究

用傅立叶变换红外光谱法和热失重分析法研究了溴质量分数分别为31%、51%和69%的溴化天然橡胶（BNR）的热降解和热氧降解过程。结果表明,BNR热降解为两步反应,第1步BNR发生脱溴化氢反应,失重率近似等于其溴含量;第2步BNR31、BNR51和BNR69在475℃降解时仍有9.7%、15.6%和12.7%的残留物存在,且较稳定。BNR热氧降解分3步进行,第1步反应的温度及降解率与热降解相近,产物主要是溴化氢,此外还有少量二氧化碳;第2步和第3步产物为二氧化碳,且分解彻底。     

Identification and modelling of aerobic hydrolysis – application of optimal experimental design

Hydrolysis mechanism plays a dominant role in the delicate balance of electron donor/electron acceptor ratios in BNR and EBPR systems as an important carbon source. In this study, the surface‐saturation‐type hydrolysis kinetics was investigated based on respirometric measurements, within the context of the theoretical and the practical identifiability of mathematical models. The identifiable parameters of a selected model were derived from respirograms. In addition, the information from the experiments was evaluated on the basis of Optimal Experimental Design (OED) methodology for different initial conditions of the batch respirometric experiment. © 2003 Society of Chemical Industry     

低溴化天然橡胶的研究

对自制的低溴化天然橡胶(BNR)的溴含量、红外谱图、在甲苯中溶解性能、不饱和度及综合力学性能进行研究分析。结果表明:随着反应过程中溴化液用量的增加,制得的低溴BNR的溴含量也增大,且溴含量不与溴化液用量成线性正比关系;溴化天然胶乳的红外光谱分析表明,溴已经接到天然橡胶分子链上,其C-Br键对应的红外光谱位置分别为956 cm-19、08 cm-1;在常温下,低溴BNR在甲苯中溶解性较差,在水浴加热70℃情况下,对低溴BNR在甲苯中的溶解性略有改善,同时随溴含量的增加,溶解性也越差。经塑炼后的低溴BNR在水浴加热70℃的情况下,对低溴BNR能完全溶于甲苯溶剂中;制得的低溴BNR的不饱和度略有降低,不饱和度随溴化液用量的增加变化不大;低溴BNR的加工性能总体较好,经溴化后的天然橡胶较纯胶的综合力学性能都有所下降,其中当硫磺用量为2.7份时,综合力学性能相对较好。     

反硝化脱氮工艺补充碳源选择与优化研究进展

碳源是制约生物脱氮效率的重要因素。我国城市污水碳源不足,需要考虑碳源补充提供反硝化电子供体,开发各种新型碳源作为生物反硝化脱氮工艺可选择的碳源,如工业废水、初沉污泥水解产物、植物秸秆等,或改变工艺优化系统碳源。结合国内外对于反硝化碳源补充的研究成果,对反硝化脱氮速率以及动力学的研究现状进行了综述,并对不同碳源的选择和优化进行了分析和总结。