高硫酸盐难降解废水高温厌氧处理中限量曝气的应用及影响

由于硫酸盐还原的影响,普通高温UASB反应器处理亚硫酸盐纸浆厂排出的高硫酸盐难降解废水过程中甲烷菌活性受到了严重抑制.考虑到空气对硫化氢的吹脱和对硫化物的氧化作用可能减轻硫化物对甲烷菌的抑制,本研究在厌氧反应器中引入限量曝气措施.试验结果表明,反应器的运行稳定性和处理能力均得到大幅提高.在有机负荷提高到原来2倍的情况下,曝气后COD去除率仍有提高,从40%～50%提高到60%～70%.试验证明部分甲烷菌可以耐氧,而某些种类的水解酸化细菌则对不完全厌氧环境比较敏感.     

UASB的主要设计问题

介绍了ＵＡＳＢ的主要结构、外型尺寸、和三相分离器等方面的设计要点及经验参数。     

碱度对UASB处理淀粉废水影响的研究

通过UASB中试装置对淀粉废水处理工艺中不同碱度对UASB反应器中的碱度和酸化的影响的研究,论述了减少碱度投加的途径和酸化的预防与系统恢复.补充碱度可以防止酸化,使反应器处于良好运行状况.通过控制运行条件可以有效降低厌氧处理中碱度需求,在最大程度上降低厌氧处理运行费用.阐述了日常监测的方法,以及预防酸化的产生的途径.     

Conversion regular patterns of acetic acid, propionic acid and butyric acid in UASB reactor

On the basis of continuous tests and batch tests, conversion regular patterns of acetate, propionate and butyrate in activated sludge at different heights of the UASB reactor were conducted. Results indicated that the conversion capacity of the microbe is decided by the substrate characteristic when sole VFA is used as the only substrate. But when mixed substrates are used, the conversion regulations would have changed accordingly.Relationships of different substrates vary according to their locations. In the whole reactor, propionate‘s conversion is restrained by acetate and butyrate of high concentration. On the top and at the bottom of the reactor, conversion of acetate, but butyrate, is restrained by propionate. And in the midst, acetate‘s conversion is accelerated by propionate while that of butyrate is restrained. It is proved, based on the analysis of specific conversion rate, that the space distribution of the microbe is the main factor that affects substrates‘ conversion. The ethanol-type fermentation of the acidogenicophase is the optimal acid-type fermentation for the two-phase anaerobic process.     

Degradation of phenol in an upflow anaerobic sludge blanket(UASB) reactor at ambient temperatureKE

A synthetic wastewater containing phenol as sole substrate was treated in a 2.8 L upflow anaerobic sludge blanket(UASB) reactor at ambient temperature. The operation conditions and phenol removal efficiency were discussed, microbial population in the UASB sludge was identified based on DNA cloning, and pathway of anaerobic phenol degradation was proposed. Phenol in wastewater was degraded in an UASB reactor at loading rate up to 18 gCOD/(L·d), With a 1:1 recycle ratio, at 26(1℃, pH 7.0-7.5. An UASB reactor was able to remove 99% of phenol up to 1226 mg/L in wastewater with 24 h of hydraulic retention time(HRT). For HRT below 24 h, phenol degradation efficiency decreased with HRT, from 95.4% at 16 h to 93.8% at 12 h. It further deteriorated to 88.5% when HRT reached 8 h. When the concentration of influent phenol of the reactor was 1260 mg/L(corresponding COD 3000 mg/L), with the HRT decreasing(from 40 h to 4 h, corresponding COD loading increasing), the biomass yields tended to increase from 0.265 to 3.08 g/(L·d). While at 12 h of HRT, the biomass yield was lower. When HRT was 12 h, the methane yield was 0.308 L/(gCOD removed), which was the highest. Throughout the study, phenol was the sole organic substrate. The effluent contained only residual phenol without any detectable intermediates, such as benzoate, 4-hydrobenzoate or volatile fatty acids(VFAs). Based on DNA cloning analysis, the sludge was composed of five groups of microorganisms. Desulfotomaculum and Clostridium were likely responsible for the conversion of phenol to benzoate, which was further degraded by Syntrophus to acetate and H2/CO2. Methanogens lastly converted acetate and H2/CO2 to methane. The role of epsilon-Proteobacteria was, however, unsure.     

固定化甲烷八叠球菌(Methanosarcina)研究——厌氧颗粒污泥的形成

用实验室规模的UASB反应器处理豆制品废水培养厌氧颗粒污泥。通过对颗粒污泥形成过程中的产气率、进出水COD、水滞留期（HRT）、进出水挥发酸（乙酸、丙酸和丁酸）浓度、所产气体的甲烷含量等的变化分析和对颗粒污泥中优势产甲烷菌的扫描（SEM）和透射（TEM）电镜观察,阐明颗粒污泥的形成过程及特性。实验结果表明,消化器运转50d左右形成了颗粒污泥,厌氧颗粒污泥形成期间的平均产气率为5.3L/L·d,最高产气率达到了8.1L/L·d,进水和出水COD分别为3000～5500mg/L和800～3000mg/L,平均HRT为10.4h,平均出水乙酸、丙酸和丁酸浓度分别为264.1、519.8和104.6mg/L,所产气体的平均甲烷含量为60.6％,颗粒污泥为黑色,直径0.5～3.0mm不等,沉降速率为119.6m/h,其中的优势产甲烷菌为鬃毛甲烷菌（Methanosaeta）,而甲烷八叠球菌（Methanosarcina）存在甚少。     

垃圾焚烧发电厂垃圾渗滤液处理工艺的研究

通过对垃圾焚烧厂和垃圾填埋场垃圾渗滤液的特点比较 ,确定UASB反应器 CASS反应器复合工艺处理垃圾焚烧厂渗滤液 ,确定其最佳处理参数。结果表明 ,通过该系统处理后 ,CODCr总去除率达 98 1 % ,NH+ 4 N总去除率达96 3% ,取得较好的去除有机物和脱氮效果     

Kinetic of carbonaceous substrate in an upflow anaerobic sludge sludge blanket (UASB) reactor treating 2,4 dichlorophenol (2,4 DCP)

The performance of an upflow anaerobic sludge blanket (UASB) reactor treating 2,4 dichlorophenol (2,4 DCP) was evaluated at different hydraulic retention times (HRTs) using synthetic wastewater in order to obtain the growth substrate (glucose-COD) and 2,4 DCP removal kinetics. Treatment efficiencies of the UASB reactor were investigated at different hydraulic retention times (2-20 h) corresponding to a food to mass (F/M) ratio of 1.2-1.92 g-COD g(-1) VSS day(-1). A total of 65-83% COD removal efficiencies were obtained at HRTs of 2-20 h. In all, 83% and 99% 2,4 DCP removals were achieved at the same HRTs in the UASB reactor. Conventional Monod, Grau Second-order and Modified Stover-Kincannon models were applied to determine the substrate removal kinetics of the UASB reactor. The experimental data obtained from the kinetic models showed that the Monod kinetic model is more appropriate for correlating the substrate removals compared to the other models for the UASB reactor. The maximum specific substrate utilization rate (k) (mg-COD mg(-1) SS day(-1)), half-velocity concentration (K(s)) (mg COD l(-1)), growth yield coefficient (Y) (mg mg(-1)) and bacterial decay coefficient (b) (day(-1)) were 0.954 mg-COD mg(-1) SS day(-1), 560.29 mg-COD l(-1), 0.78 mg-SS g(-1)-COD, 0.093 day(-1) in the Conventional Monod kinetic model. The second-order kinetic coefficient (k(2)) was calculated as 0.26 day(-1) in the Grau reaction kinetic model. The maximum COD removal rate constant (U(max)) and saturation value (K(B)) were calculated as 7.502 mg CODl(-1)day(-1) and 34.56 mg l(-1)day(-1) in the Modified Stover-Kincannon Model. The (k)(mg-2,4 DCP mg(-1) SS day(-1)), (K(s)) (mg 2,4 DCPl(-1)), (Y) (mg SS mg(-1) 2,4 DCP) and (k(d)) (day(-1)) were 0.0041 mg-2,4 DCP mg(-1) SS day(-1), 2.06 mg-COD l(-1), 0.0017 mg-SS mg(-1) 2,4 DCP and 3.1 x 10(-5) day(-1) in the Conventional Monod kinetic model for 2,4 DCP degradation. The second-order kinetic coefficient (k(2)) was calculated as 0.30 day(-1) in the Grau reaction kinetic model. The maximum 2,4 DCP removal rate constant (U(max)) and saturation value (K(B)) were calculated as 0.01 mg COD l(-1) day(-1) and 9.8 x 10(-3) mg l(-1) day(-1) in the Modified Stover-Kincannon model.     

Determination of granule size distribution in a UASB reactor

Granular sludge is the key factor for an efficient operation of an upflow anaerobic sludge blanket (UASB) reactor. In order to monitor the granularity of anaerobic sludge, the determination of the granule size distribution is of vital importance. For this reason, several techniques have been proposed; however, they are either tedious, imprecise or expensive and hardly applicable in full-scale treatment plants. There was then the need for a simple and low-cost technique. This technique involves the determination of the settling velocities of a sludge sample and of extrapolating the corresponding diameters using a mathematical algorithm. In the proposed algorithm, the granules density was calculated, the flow regime was examined and finally the granule size distribution was obtained. Two very important correlations were suggested by the experimental results. The granule density and diameter were strongly correlated with the VSS/TSS ratio.     

生活污水的厌氧处理实验研究

利用UASB对生活污水的厌氧中试,使厌氧水力停留时间在8小时,处理效率达到80%,较大地降低了生活污水的吨水投资及直接运行费用.