Comparison of a sMBR and a CASP system for wastewater reclamation and re-use

The performance of a submerged membrane bioreactor (sMBR) for municipal wastewater reclamation and re-use was compared with that of a current classic activated sludge process (CASP). The average chemical oxygen demand (COD) of CASP effluent was 75 mg/l, while the average COD of sMBR filtrate was 15 mg/l. In general, COD removal was above 98%. However, the best results were obtained at a sludge rentention time (SRT) of 50 days. The total phosphorus (TP) content of the filtrate decreased to a level <1 mg/l under aerobic conditions in which aeration occurred continuously. It was shown that the filtrate TP and orthoposphate (Orto-P) concentrations increased dramatically during the periods of intermittent aeration because phosphorus is released under anoxic conditions. In the CASP effluent, the average TP and Orto-P were 7.9 mg/l and 7.1 mg/l, respectively. The filtrate was free of suspended solids (SS) and total coliform bacteria. The effluent SS in the CASP was 40 mg/l. The turbidity removal in the sMBR reached almost 99%, i.e. generally less than 1 NTU, while the average turbidity of the CASP effluent was almost 15 NTU. The removal of ammonium nitrogen (NH₄⁺-N) in the sMBR was almost 99.8%. In addition, the nitrate concentration in the filtrate decreased to 2.4 mg/l under both aerobic & anoxic conditions. It was shown that both nitrification and denitrification could be successfully reduced through intermittent aeration. Average total Kjeldehl nitrogen (TKN) and NH₄⁺-N in the CASP effluent were 30.2 mg/l and 20 mg/l, respectively, i.e. the nitrification efficiency was 42.9%, and the denitrification value was not available. When these results are compared with those in the CASP, it indicated that the sMBR could be successfully used for reclamation and re-use of municipal wastewater.     

自养脱氮工艺有机物去除段与硝化段精确分离的实现与实时控制

为了实现城市污水处理过程中的节能降耗,提出了三段式城市污水自养脱氮工艺,阐述了除有机物SBR在整套工艺中的重要地位,探讨了不同曝气量与污泥浓度条件下,除有机物SBR中有机物的去除特征与规律。结果表明,在不同的曝气量及污泥浓度条件下,COD降解结束前NO₂^--N与NO₃^--N的浓度均低于0.1 mg·L^-1,反应器进入COD难降解阶段后,NO₂^--N与NO₃^--N的浓度快速提高,可以认为在除有机物SBR内有机物的去除和硝化过程是分步进行的,即先进行有机物的去除,而后进行硝化过程。DO曲线与pH曲线的突越点与除有机物过程的终点始终保持一致,可将其作为实时控制参数监测有机物的去除终点,对好氧曝气过程进行实时控制。     

生活污水最佳污泥负荷确定研究

污泥负荷（ Ns）是指单位质量的活性污泥在单位时间内所去除的有机污染物的量,单位kgCOD/（ kgMLSS·d）。利用泰州市紫光水业污水处理厂初沉池出水和曝气池的活性污泥制作一定浓度的污泥混合液,并在0.1~0.3 kgCOD/（ kgMLSS·d）污泥负荷中选择5个实验点,改变停留时间进行好氧生化反应,分别测COD, TP, NH3-N, TN的去除率,讨论不同污泥负荷不同停留时间对污水处理效果的影响,综合考虑污泥沉降性能和去除污水COD和脱氮除磷的效果,确定最佳污泥负荷为0.20 kgCOD/（ kgMLSS·d）。     

多点进水改良型复合A2/O处理低C/N污水

以低C/N比城市生活污水为研究对象,重点考查了改良A²/O工艺的脱氮除磷性能。原水按一定比例分配给厌氧池和缺氧池,以合理分配厌氧释磷和缺氧反硝化所需的碳源;在好氧池和缺氧池中分别投加填料,以稳定系统的硝化和反硝化效果,提高系统的脱氮性能;厌氧池和缺氧池出水都直接进入好氧池。在进水COD/TN平均为5.54,HRT为11 h,SRT为15 d,MLSS为3000～4000 mg·L^-1,污泥回流比为50%条件下,通过三种不同进水分配比以及三种混合液回流比的对比试验研究,得到系统最佳进水分配比5:5,对分配脱氮和除磷所需碳源更加合理;而混合液回流比为200%,过高会破坏缺氧池的溶解氧环境,过低又会导致缺氧池反硝化作用不能充分发挥。在最优工况下COD、NH₃-N、TN和TP出水水质分别为29.7、0.1、11.8和0.42 mg·L^-1,平均去除率分别达到87.8%、99.7%、72.4%和91.3%,出水优于国家GB 18918-2002一级A排放标准,并且在缺氧池中发生了明显的反硝化除磷现象。     

AOA/生物接触氧化法处理城市污水试验研究

研究建立在传统絮凝吸附强化-级处理基础上的AOA与生物接触氧化法组合形成-体化工艺处理城市生活污水的效果.结果表明,在最优工况下,即进水体积流量Q=1.0m~3·d~(-1)、吸附池F/M=2.8kgCOD·kg~(-1)MLSS·d~(-1)、吸附池HRT=1.5h时,-体化装置对污染物的总体去除效果最好,此时装置对SS、COD、NHM_4~(-1)-N、TN和TP的去除率分别为84.12%、86.37%、74.18%、75.23%和42.68%,去除效果稳定可靠.     

Simultaneous organic and nutrient removal from municipal wastewater by BSACNR process

Biological nutrient removal was investigated under a biological synthetic activated ceramic nutrient removal (BSACNR) process. Tests were made to establish whether organic compounds and nutrients (N, P) from municipal wastewater were eliminated effectively in a lab-scale BSACNR process by increasing the hydraulic retention time (HRT) from 4 hr to 10 hr. In the system, synthetic activated ceramic (SAC) media were packed in each reactor for attached growth of both nitrifying bacteria and denitrifying bacteria; the sludge of the clarifier was returned to the anaerobic reactor to release phosphate. In this configuration, nitrification, denitrification and phosphorus removal could be performed at their respective conditions. The influent was synthetic wastewater, and the mean concentration of COD, NH⁺ ₄ -N and T-P in the influent was about 200 mg/L, 20 mg/L and 8 mg/L, respectively. At a total HRT of the system of 4-10 hr, the system worked successfully obtaining the removal of COD, NH⁺ ₄-N, T-N and T-P: 90.5-97.5%, 72.9-94.4%, 56.5-73.7% and 36.0-61.1%, respectively. The results of this research show that a biological synthetic activated ceramic nutrient removal (BSACNR) process packed with SAC media could be applicable for treatment of organic and nutrient from municipal wastewater.     

CAST工艺改良对系统强化除磷性能的影响

传统CAST工艺广泛应用于国内各种规模城镇污水处理厂,单凭生物法难以达到城市污水排放一级A标准。采用改良的CAST工艺,在传统CAST工艺基础上引入主反应区独立的搅拌时序,并在实际规模的污水处理厂进行工程示范。通过两阶段的试验,逐步缩短曝气时间延长缺氧搅拌时间,优化聚磷菌的代谢环境,增强聚磷菌的竞争优势。经过改良后的CAST工艺TP去除率达到89.1%,较传统CAST工艺提高了22%,出水TP稳定达到一级A标准。静态试验结果表明改良后的工艺反硝化聚磷菌的比例有所增加, 吸收相似文献   

回流比对分段进水A2/O工艺脱氮除磷影响的小试研究

针对上海某污水厂实际运行中的问题,通过小试试验考察不同混合液回流比、污泥回流比及进水流量分配对分段进水A2/O工艺影响,以期提高其脱氮除磷效果。结果表明,混合液回流比对COD、TP和NH3-N的去除效果影响较小,对TN的影响较大,系统的混合液回流比维持在200％较为合适;污泥回流比对系统整体功能的发挥影响很大,污泥回流...     

Removal of nitrogen from wastewater for reusing to boiler feed-water by an anaerobic/aerobic/membrane bioreactor

The innovative process anaerobic/aerobic/membrane bioreactor (A/O/MBR) was developed to enhance pre-denitrification without the energy consumption of the recirculation pump for reusing wastewater to boiler feed-water. The performance of this bioreactor was investigated. Firstly, the septic tank wastewater with low ratio of COD/TN was disposed by a dynamic membrane bioreactor (DMBR). It was found that, although the high concentration of NO₂⁻–N in the effluent implied the potential ability of DMBR to realize shortcut nitrification and denitrification, the effluent of single DMBR was difficult to reach the criteria of reusing to boiler feed-water. Then, the process A/O/DMBR in disposing the septic tank wastewater was studied. The results indicated that this process not only accomplished the removal of 91.5% COD, 90.3% NH₄⁺–N and 60.2% TN, but also successfully realized pre-denitrification without additional recirculation pump. At last, based on the A/O/DMBR, a pilot plant A/O/MBR was built to dispose the municipal raw sewage. In the stable operation period, the average removal efficiencies for COD, NH₄⁺–N, TP and turbidity reached 90%, 95%, 70% and 99%, respectively. During the tested HRT run of 9.0 h, the effluent of COD, NH₄⁺–N, TP and turbidity was about 10 mg/L, 3 mg/L, below 1 mg/L and 1.2 NTU, respectively, which reached the criteria of the boiler feed-water in China.     

AAO-BAF反硝化除磷系统的二次启动特性

利用厌氧/缺氧/好氧工艺与曝气生物滤池组成的双污泥强化反硝化除磷系统（AAO-BAF）处理生活污水,通过对比污染物的去除性能,分析了该系统除污染物性能的恢复情况。试验用反硝化除磷污泥在室温下放置了1个月。试验期间比较了两种启动方式,AAO反应器中厌氧、缺氧和好氧区的容积比（V_r）分别为2：5：2和2：6：1,记为1^#和2^#。试验结果表明,系统去除有机物和氨氮的性能基本没有恶化。第17 d,两种启动方式得到的TN和PO₄^3--P的去除率分别达到了约75%和92%;去除单位NO^-₃-N吸收的PO₄^3--P量也由试验初的0.5 mg PO₄^3--P·（mg NO^-₃^-N）^-1增加到了1.5 mg PO₄^3--P·（mg NO^-₃-N）^-1 左右。试验结果显示,AAO-BAF系统更适宜采用有利于除磷性能和污泥沉降性能快速恢复的方式1（1^#）进行二次启动。     

A study of A2/O process in El-Berka WWTP by replacing the anaerobic selector with UASB and adopting a hybrid system in the oxic zone

ABSTRACT

A multistage system comprising an upflow anaerobic sludge blanket (UASB) followed by anoxic unit and then oxic activated sludge (AS) with biofilm is studied in El-Berka WWTP, Egypt. Different organic loading wastewaters of chemical oxygen demand (COD) less than 500 mg/L till 3000 mg/L are tested during the study. The hydraulic retention time (HRT) varies for each loading from 7.5 to 10 to 15 h. The UASB reactor accomplishes the removal efficiency of 50%–70% of influent COD. The overall system performs the removal efficiency of 95% of influent COD and NH₄-N. Also, the results are verified by a modified mathematical model.     

Effect of limited artificial aeration on constructed wetland treatment of domestic wastewater

To study the effect of limited artificial aeration on domestic wastewater treatment in the constructed wetlands (CWs), four pilot-scale horizontal subsurface flow CWs were operated from October 2006 to September 2007. The types of the four units include aerated and planted CW (APCW), planted CW (PCW), aerated CW (ACW) and CW, and all the units have the identical dimensions of 3 m in length, 0.7 m in width and 1 m in depth. The automated aeration was activated when the oxygen concentrations in the units were lower than 0.2 mg/L and ceased when the oxygen concentrations in the CWs were higher than 0.6 mg/L. More stable alkaline pH values were found in aeration units than that in the non-aeration units. APCW, in which the removal efficiencies of BOD, NH₄⁺-N and TN were 94.4% (16.7 g BOD d^− 1 m^− 2), 89.1% (4.54 g NH₄⁺-N d^− 1 m^− 2), and 86.0%( 4.99 g TN d^− 1 m^− 2) respectively, was more effective at pollutant removal than the other three units. There were no significant differences in TP removal between the aeration units and non-aeration units. Less surface area is needed due to high removal efficiency in APCW and the additional cost of operation is quite little. The results from this experiment indicated that limited artificial aeration in constructed wetlands is a cost-effective method for treating domestic wastewater.     

水解反硝化工艺强化脱氮处理

碳源对脱氮除磷都具有重要的作用,碳源不足会导致脱氮效果降低,出水TN水质不达标。为解决碳源不足造成的脱氮能力差的问题,本试验采用水解反硝化脱氮工艺,将水解酸化与反硝化脱氮过程相结合,取代缺氧反硝化,有效地解决了碳源不足所导致的脱氮效果差的问题。利用水解反硝化脱氮工艺处理城市污水,出水NH₄⁺-N、TN和COD都满足一级A标准,去除率分别为98.0%、69.4%和82.7%,比同期污水处理厂AAO工艺的TN去除率高出17.5%。在BOD₅/TN为3～5的条件下,水解池中污泥的比反硝化速率为缺氧池污泥的1.2～1.7倍,并且去除相同的N所需要的碳源较少,在碳氮比为3:1、3.5:1、4:1和5:1时去除单位N水解池可分别节省59.5%、52.2%、19.9%和23.1%的COD,有效地解决了脱氮过程中碳源不足问题。     

倒置A~2/O-动态膜生物反应器活性污泥培养和启动实验研究

活性污泥性能是倒置A2/O-动态膜生物反应器工艺稳定运行的关键因素,研究了活性污泥培养和反应器启动阶段,考察了活性污泥性能及对污染物的去除效果。结果表明,好氧池活性污泥MLSS由3 460 mg/L增加至6 100 mg/L,粒径d50由27.8μm增至59.8μm,活性污泥培养阶段,COD、NH3-N和TP去除率分别达到85.7%,97%,87%;反应器启动阶段,COD、NH3-N和TP去除率分别达到91.9%,99%,96.5%。     

污泥浓度对MBR净化效果影响试验研究

在不排泥条件下,膜生物反应器(MBR)内的污泥浓度MLSS和MLVSS都随时间不断累积,而反映污泥活性的MLVSS/MLSS则不断减少。研究中发现,MLSS对MBR运行效果影响显著:TN的去除率随污泥浓度增加而增加,而COD的去除率随MLSS的增加先降后升,TP的去除率则先升后降,且二者均在污泥浓度6500 mg/L时达到极值,NH3-N的去除效果则随着污泥负荷的增加呈降低趋势。     

连续流状态下好氧颗粒污泥培养及其脱氮除磷性能研究

在上流式污泥床好氧颗粒污泥反应器中,以厌氧颗粒污泥为接种泥．采用人工配制的模拟废水为进水的条件下,成功培养出具有同步脱氮除磷的好氧颗粒污泥。颗粒污泥粒径在0．5~2mm,颗粒污泥沉淀速度在29～58m／h。MLSS为3077---4103mg／L。当COD的进水容积负荷为4．8kg／（m3·d）时,去除率高达96％以上。氨氮进水在160mg／L时,去除率达97％以上,出水氨氮在5mg／L以下。对总磷的去除率在22％-37％。主要是因为亚硝态氮浓度、COD／TN比和TN／TP比等对聚磷菌除磷有影响。     

Effects of operational parameters on aeration on/off time in an intermittent aeration membrane bioreactor

This study was performed to evaluate the operational parameters on aeration on/off time in an intermittent aeration membrane bioreactor for wastewater treatment. The membrane bioreactor has 5.5 L of effective working volume including a microfiber membrane. The influent wastewater contained 133mg/L of BOD, 195 mg/L COD, 98 mg/L SS, 30 mg/L total nitrogen, and 3.8 mg/L total phosphorous. Operational conditions related to aeration on/off time were 8.8 h HRT, 10 LMH flux, 10 L/min air flow, and 6300 mg/L MLSS. For 2 h/cycle, aeration on/off time was operated for 12 cycles in three variations: 60/60 min, 50/70 min (I), and 40/80 min. Suction on/off time was 10/2 min, 8/2 min, and 8/2 min, respectively, but also 50/70 min (II) when aeration on/off time was operated at 8300 mg/L MLSS. The BOD removal efficiency rate of this process was higher than 97% regardless of the aeration on/off time distribution. To get higher than 82% total nitrogen removal efficiency rate, aeration off time in the reactor needs to be more than 70 min. The specific denitrification rate was 2.68 mgNO₃-N/gMv/h at 40/80 min on/off aeration times, which was 2.6 times more than at 60/60 min, and 1.4 times more than at 50/70 min (I) for 6300 mg/L MLSS. The specific nitrification rate was 1.96 mgNH₄-N/gMv/h at on/off aeration times of 50/70 min, 1.4 times less than at 40/80 min, but was ineffective for nitrification. Microbial activity was affected only a little by variation in aeration on/off time, though oxygen demand was reduced by aeration off time and allowed microbial concentration to increased. EPS (extracellular polymeric substance) per unit of microorganisms increased with aeration off time.     

Achieving partial nitrification in a novel six basins alternately operating activated sludge process treating domestic wastewater

A novel technology was developed to achieve partial nitrification at moderately low DO and short HRT, which would save the aeration cost and have the capacity to treat a wide range of low-strength real wastewater. The process enables a relatively stable whereas nitrite accumulation rate (NO₂-AR) was stabilized over 94% in the last aerobic basin on average of each phase through a combination of short HRT and low DO level. Low DO did not produce sludge with poorer settleability. The morphology and internal structure of the granular sludge was observed by using a scanning electron microscope (SEM) analysis during a long-term operation. The images indicated that thick clusters of spherical cells and small rod-shaped cells (NOB and AOB are rod-shaped to spherical cells) were the dominant population structure, rather than filamentous and other bacteria under a combination of low DO and short HRT, which gives a good indication of nitrite accumulation achievement. MPN method was used to correlate AOB numbers with nutrient removal. It showed that an ammonia-oxidizing bacterium (AOB) was the dominant nitrifying bacteria, whereas high NO₂-AR was achieved at AOB number of 5.33×10⁸ cell/g MLSS. Higher pollutant removal efficiency of 86.2%, 98% and 96.1%, for TN, NH ₄ ⁺ -N, and TP, respectively, was achieved by a novel six basin activated sludge process (SBASP) at low DO level and low C/N ratio which were approximately equal to the complete nitrification-denitrification with the addition of sodium acetate (NaAc) at normal DO level of (1.5–2.5 mg/L).     

碳氮比对AAO泥水回流工艺处理焦化废水的影响

采用AAO泥水回流工艺处理焦化废水,研究了进水碳氮比（C／N）对COD、氨氮及TN去除率的影响。研究表明,进水碳氮比（C/N）在12—25范围内,厌氧滤池COD去除率和氨化率分别达到37％和30％;缺氧进水碳氮比（C／N）控制在5．3-11．9范围内,MO泥水回流系统去除COD与氨氮效果的影响不明显,平均去除率分别为89．6％和95．2％;缺氧进水碳氮比（C/N）控制在7．5～8．6范围内,系统具有较好的TN去除率,平均值为72．2％。出水COD和NH3-N均能够达到污水综合排放标准中的二级标准。     

溶解氧浓度对连续流活性污泥工艺反硝化除磷的影响

引言 随着水体富营养化问题的日渐突出,污水处理技术逐渐从单一去除有机物为目的的阶段进入既要去除有机物又要脱氮除磷的深度处理阶段[1].