缺氧/好氧比对连续流半亚硝化稳定性的影响

为研究不同缺氧好氧比对半亚硝化稳定性的影响,采用连续流反应器,在常温(22~25 ℃),DO(0.3~0.5mg/L)和FA协同作用下实现了全亚硝化后,转变进水为AO除磷二级出水,并逐步向半亚硝化过渡.在此过程中考察了不同缺氧好氧比(0:1、1:1、2:1和3:1)对半亚硝化稳定性的影响.结果表明,缺氧好氧比为0:1时,很难维持低NH₄⁺-N(40~70mg/L)亚硝化的稳定,缺氧好氧比为1:1、2:1、3:1时均能维持稳定的半亚硝化效果,相比之下缺氧好氧比为3:1时更加节能;在缺氧好氧比0:1,1:1,2:1,和3:1的过程中,氨利用速率分别提高了29.57%、44.27%、45.23%、49.63%.在整个过程中污泥沉降性能良好,SVI在65~130mL/g.     

Occurrence and behavior of pharmaceuticals in sewage treatment plants in eastern China

The occurrence and removal efficiency of seven pharmaceuticals (norfloxacin, trimethoprim, roxithromycin, sulfamethoxazole, ibuprofen, diclofenac and carbamazepine) were determined in three sewage treatment plants (STPs) with anaerobic/anoxic/oxic, anoxic/oxic and oxidation ditches processes in Xuzhou City, Eastern China. The results showed that seven pharmaceuticals were detected in the influent samples with concentrations ranging from 93 to 2540 ng·L⁻¹. The removal of these substances among the three different STPs varied from 36 to 84%, with the highest performance obtained by the wastewater treatment works with tertiary treatment (sand filtration). Most of the compounds were removed effectively during biologic treatment while sand filtration treatment also made a contribution to the total elimination of most pharmaceuticals. The efficiency comparison of the three sewage treatment processes showed that the STP which employed anaerobic/anoxic/oxic was more effective to remove pharmaceuticals than the oxidation ditches and anoxic/oxic.     

不同好氧/缺氧时长联合分区排泥优化生活污水短程硝化反硝化除磷颗粒系统运行

采用生活污水接种人工配水下成熟短程硝化反硝化除磷颗粒,通过不同好氧/缺氧时长联合分区排泥优化调控短程硝化反硝化除磷系统运行.结果表明,调控好氧/缺氧时长联合分区排泥可实现系统的稳定运行.后期稳定期出水COD浓度在50mg·L^-1以下,出水TN浓度低于15mg·L^-1,TN去除率达83%左右并保持平稳,出水P浓度均在0.5mg·L^-1以下,平均去除率为93.72%.同时,分区排泥（70%顶部污泥和30%底部污泥）可作为筛选微生物的途径,维持了良好的亚硝化和除磷性能,使粒径分布更为集中,并保证氨氧化菌（ammonia oxidizing bacteria,AOB）和反硝化聚磷菌（denitrifying phosphate accumulating organisms,DPAOs）的生长优势.缺氧时长的增加提高了缺氧异养菌的生长速率,使得缺氧异养菌分泌出更多的EPS,确保了颗粒污泥性状的改善和后续维持稳定.     

Biological removal of selenate in saline wastewater by activated sludge under alternating anoxic/oxic conditions

Removal of selenate in saline wastewater by activated sludge was examined. Sequencing batch reactor was operated under alternating anoxic/oxic conditions. Above 97% removal of soluble selenium (Se) was achieved continuously. Major Se removal mechanism varied depending on the length of aeration period. Various Se-reducing bacteria likely contributed to coordinately to Se removal. Selenium (Se)-containing industrial wastewater is often coupled with notable salinity. However, limited studies have examined biological treatment of Se-containing wastewater under high salinity conditions. In this study, a sequencing batch reactor (SBR) inoculated with activated sludge was applied to treat selenate in synthetic saline wastewater (3% w/v NaCl) supplemented with lactate as the carbon source. Start-up of the SBR was performed with addition of 1–5 mM of selenate under oxygen-limiting conditions, which succeeded in removing more than 99% of the soluble Se. Then, the treatment of 1 mM Se with cycle duration of 3 days was carried out under alternating anoxic/oxic conditions by adding aeration period after oxygen-limiting period. Although the SBR maintained soluble Se removal of above 97%, considerable amount of solid Se remained in the effluent as suspended solids and total Se removal fluctuated between about 40 and 80%. Surprisingly, the mass balance calculation found a considerable decrease of Se accumulated in the SBR when the aeration period was prolonged to 7 h, indicating very efficient Se biovolatilization. Furthermore, microbial community analysis suggested that various Se-reducing bacteria coordinately contributed to the removal of Se in the SBR and main contributors varied depending on the operational conditions. This study will offer implications for practical biological treatment of selenium in saline wastewater.     

AEB反应器反硝化处理高浓度硝酸盐废水

采用缺氧膨胀床(AEB)反应器处理高浓度硝酸盐废水,研究了反应器的快速启动和挂膜特性,以及在反硝化连续流运行条件下对废水的处理效果。实验结果表明:采用自然挂膜方式,填料层从下至上生物膜厚度逐渐增加;AEB的快速启动8 d可完成,COD去除率由44.9%升至92.3%,NO_3~--N去除率由39.8%升至98.4%;稳定运行阶段(进水COD 4 628～5 548 mg/L、ρ(NO_3~--N) 1 339～1 505 mg/L),COD去除率稳定在95%左右,NO_3~--N去除率稳定在98%～99%,COD和NO_3~--N的容积负荷去除量最高可达27.8 kg/(m~3·d)和7.3 kg/(m~3·d)。     

倒置A^2／O工艺出水指标预测和评价方法的研究

研究了用一种简单的静态物理模型取代复杂的数学动态模型,实现对实际污水处理效果的实时预测及评价的方法。应用国际水协（IWA）GPS-X模拟软件中的ASM2d模型,建立了不同进水水质和不同运行参数条件下倒置A^2／O工艺出水TSS、COD、TN、NH4^＋-N、TP和溶解性磷酸盐浓度的数据库,结果表明,该数据库可以对倒置A^2／O工艺出水指标进行预测。以预测的出水指标和实际出水指标之间的差值为指标因素,采用专家打分法确定指标权重,通过对指标的分级界定建立因素指标的隶属函数,最后运用模糊综合评判的方法实现了对倒置A^2／O工艺处理效果的评价,建立了倒置A^2／O工艺处理效果的数学模型。     

超声波强化剩余活性污泥缺氧/好氧消化的研究

试验选取超声波声能密度,超声时间、超声间隔3个因素没计正交实验,研究了超声波对城市污水剩余活性污泥(WAS)的缺氧/好氧消化的作用.结果表明,经超声辐照的WAS缺氧/好氧消化9天后,MLVSS去除率最高达50.9%,比未经超声辐照的提高了14.4%.对实验结果的分析表明,超声波强化WAS的缺氧/好氧消化的最佧参数为:超...     

Control of membrane fouling during hyperhaline municipal wastewater treatment using a pilot-scale anoxic/aerobic-membrane bioreactor system

Membrane fouling limits the effects of long-term stable operation of membrane bioreactor (MBR). Control of membrane fouling can extend the membrane life and reduce water treatment cost effectively. A pilot scale anoxic/aerobic-membrane bioreactor (A/O-MBR, 40 L/hr) was used to treat the hyperhaline municipal sewage from a processing zone of Tianjin, China. Impact factors including mixed liquid sludge suspension (MLSS), sludge viscosity (μup), microorganisms, extracellular polymeric substances (EPS), aeration intensity and suction/suspended time on membrane fouling and pollution control were studied. The relationships among various factors associated with membrane fouling were analyzed. Results showed that there was a positive correlation among MLSS, sludge viscosity and trans-membrane pressure (TMP). Considering water treatment efficiency and stable operation of the membrane module, MLSS of 5 g/L was suggested for the process. There was a same trend among EPS, sludge viscosity and TMP. Numbers and species of microorganisms affected membrane fouling. Either too high or too low aeration intensity was not conducive to membrane fouling control. Aeration intensity of 1.0 m³/hr (gas/water ratio of 25:1) is suggested for the process. A long suction time caused a rapid increase in membrane resistance. However, long suspended time cannot prevent the increase of membrane resistance effectively even though a suspended time was necessary for scale off particles from the membrane surface. The suction/suspended time of 12 min/3 min was selected for the process. The interaction of various environmental factors and operation conditions must be considered synthetically.     

Simulation studt on effects of different A/O parut o. s of oxidation ditches on nitrogen removal

采用3种不同曝气模式的模拟氧化沟分别形成2、4、7个缺氧-好氧（A/O）分区,研究了3种工况下氧化沟的脱氮方式和脱氮效果.结果表明,在好氧缺氧区体积比例相同的条件下,A/O分区越多,则好氧区平均DO浓度越小,硝化菌活性越低,在2、7个4、A/O分区的3种工况下的硝化菌活性分别为4.80、和3.73mg·g·h4.65-1-1;A/O分区少,则每一分区的缺氧段和好氧段长,进水后反硝化菌利用的有机物就多,在好氧区中的有机物就少,用于硝化的DO量多,从而硝化和脱氮效果好.试验中3种工况的总氮平均去除率分别为60.14%、47.93%、57%,出水总氮平均浓度分别为17.01、22.17和27.92mg·L-1.在氧化沟工艺中,氮的去除途径主要是缺氧反硝化及同步硝化反硝化（SND）.分区多,则主要通过同步硝化反硝化脱氮;分区少,则以缺氧反硝化脱氮为主,这是由于碳源限制致使同步硝化反硝化的脱氮效率比缺氧反硝化低.     

厌氧、缺氧、好氧环境下富磷剩余污泥的释磷机制

以采用A/O生物强化除磷工艺水质净化厂排出的富磷剩余污泥为研究对象,利用棕色消化瓶设计3组释磷试验,讨论厌氧、缺氧、好氧环境下富磷剩余污泥消化释磷的机制. 结果表明:富磷剩余污泥在厌氧和缺氧环境下均有明显的释磷现象,平均释磷速率分别为1.614和0.998 mg/(L·d);厌氧和缺氧环境下释磷量与聚β-羟基丁酸(PHB)之间的计量关系比较表明,释磷过程中包含有明显的微生物释磷机制,同时还存在着物理化学方面引起的释磷机制,硝酸盐抑制剩余污泥中磷的释放主要是通过影响其微生物学机制完成的.