低氧下膜生物反应器强化脱氮除磷

利用城市污水对一体化膜生物反应器脱氮除磷的特性进行研究,研究结果表明,当控制反应器内溶解氧浓度为0.5 mg/L左右时,系统在有效地去除有机污染物的同时,可达到较高的氮、磷去除率.CODcr进水为342～1 500 mg/L,出水均在40 mg/L以下,去除率在90%以上;总磷(TP)进水为4.08～31.45 mg/L,出水均在0.5 mg/L以下,去除率平均为96%;进水总氮(TN)为30.55～91.34 mg/L,去除率平均在70%以上.     

铝氧化废水处理新工艺研究

铝氧化废水采用二级化学混凝沉淀+空气吹脱+二段水解酸化--接触氧化处理新工艺,废水中污染物指标CODcr、NH3-N、磷酸盐均能达标排放。在原水CODcr为4500mg/L、NH3-N为429mg/L、磷酸盐为532mg/L时,出水指标CODcr为65mg/L、NH3-N为7.6mg/L、磷酸盐为0.35mg/L。CODcr去除率为98.6%,NH3-N去除率为98.2%,磷酸盐去除率为99.9%。     

山地农村生活污水无动力处理

针对贵州山区地势落差的地形条件,我们设计了跌水生物接触氧化装置,结合氧化塘的工艺处理方式处理山地农村生活污水,通过三个月连续检验设备处理的农村生活污水,监测结果:CODcr、TN、TP的出水平均浓度为42 mg/L,4.0 mg/L和0.41 mg/L,平均去除率分别为79%、69%、78%。出水水质可达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级排放标准,污水处理设备依靠地势落差建造,实现无动力消耗运转。     

新型生态膜＋活性炭深度处理深圳某小区生活污水的研究

通过对新型生态膜反应器处理生活污水的试验研究,考察了不同水力停留时间（HRT）对反应器中去除CODer、NH,-N、TP污染物效果的影响。通过实验表明,在实际工况下,控制HRT为最佳工况状态,CODcr、NH3-N、TP的去除率分别达到80％、78％、65％以上,出水浓度可达到30mg／L、5mg／L、1mg／以下。出水水质达到国家标准《城镇污水处理厂污染物排放标准》（GB18918—2002）一级A标准要求。     

外置式中空纤维膜-生物反应器处理污水的研究

设计了可正/反运行的外置式膜-生物反应器(RMBR),研究了RMBR处理污水的工艺条件,讨论了膜面流速、添加粉末活性炭(PAC)等因素对临界膜通量、CODcr脱除率的影响.结果表明:在进水水质CODcr为312~584 mg/L,NH3-N为16~40 mg/L时,RMBR的出水水质达到CODcr<15 mg/L(脱除率>96.5%),NH3-N<1.53 mg/L(平均去除率>80%),浊度<0.17 NTU;添加PAC后出水水质CODcr<4.22 mg/L,临界循环比降低了10%~20%;对于已污染的膜,水反冲洗、碱浸泡后水反冲洗、碱浸泡 酸浸泡后水反冲洗可使膜通量恢复至新膜的47%,83%,94%;组件反置运行可使膜通量恢复约10%.     

自制粉煤灰陶粒填料处理城市污水

利用粉煤灰、黏土、脱水污泥和碳酸钙等原料制备粉煤灰陶粒。通过正交试验确定原料的最优配比,并对自制陶粒进行了性能表征,进一步利用自制曝气生物滤池装置,通过改变运行参数,测试了自制陶粒用作曝气生物滤池填料处理城市污水的效果。结果表明:自制陶粒填料各项性能都符合相关标准;化学需氧量(COD)、总氮(TN)去除率随着水力停留时间(HRT)的增加而增加,当HRT为4h时,总磷(TP)去除率达到最大;低温不利于TN、TP的去除,温度对COD去除率影响不大;当进水中的TN含量为30mg/L时,TN去除率最大。TP去除率随着进水中的TP含量的增加而增加,进水浓度对COD去除率影响不大。     

纳滤膜在北京阿苏卫填埋场渗滤液改扩建工程中的应用

在阿苏卫垃圾卫生填埋场渗滤液改扩建工程中,以膜生物反应器(MBR)的出水为研究对象,考察了在一定的pH、进水流量、操作压力下纳滤膜对CODcr、NH3-N和电导率的去除情况.结果表明:在设备初期运行阶段,在pH为7、操作压力为0.5 MPa时,纳滤膜对CODcr的去除率达75%;对NH3-N的去除率较低,出水的NH3-N值略低于进水;对电导率的平均去除率达55%.此外,还分析了纳滤膜的运行性能以及与原有反渗透处理工艺联合使用等问题.     

生化法治理PU合成革二甲胺污染技术研究

改良的A1O1／A2O2工艺和预处理方法,A1O1段COD污泥负荷为0．578kgCOD／kgMLSS．d,去碳效果达到70％;A2O2段,TN去除率为82％,NH3-N去除率90％．NH3-N污泥负荷为0．046kgNH3-N／kgMLSS．d;经生化后,二甲胺已经转化为氨氮,出水小于5mg／L。     

膜生物反应器脱氮除磷工艺处理城市污水的工程应用

为强化城市污水脱氮除磷,研发了厌氧/缺氧/好氧/缺氧-膜生物反应器(A2/O/A-MBR)新工艺,并建设了设计处理规模为2万m3/d实际工程.对该工程的长期监测表明,出水C()D、TN、NH4+-N和TP的平均浓度分别为20.6、6.67、1.05、0.19 mg/L,优于《城镇污水处理厂污染物排放标准》中的一级A标准...     

倒置A~2O-MBR工艺处理城市生活污水脱氮除磷中试研究

利用天津膜天膜科技股份有限公司生产的中空纤维帘式膜组件,并采用自行设计的MBR中试设备构建倒置A2 O-MBR工艺处理城市生活污水.结果表明,该工艺的产水COD、NH3—N、TN、TP平均值分别为22.23mg/L、1.89mg/L、14.96mg/L、0.38mg/L,去除率分别为91.49%、94.5%、63.4%、87.3%,出水浊度0.19NTU.出水主要水质指标在系统运行正常时可以达到《城镇污水厂污染物排放标准》(GB 18918—2002)一级A标准.一般情况下,出水水质可以保证符合一级B标准的要求.对于已污染的膜,采用复合碱性溶液浸泡循环清洗、碱性溶液和酸性溶液依次浸泡循环清洗两种方法可分别使跨膜压差由43kPa降至12kPa,73kPa降至25kPa,压差下降量分别为31kPa、48kPa,恢复产水.     

影响一体式平板膜生物反应器临界通量的因素

利用阶梯式通量递增法测定了一体式平板膜-生物反应器中的临界通量,对不同操作条件下测定值的差异进行了考察.通过正交试验设计,研究了曝气强度、污泥浓度(MLSS)和滤液COD(SCOD)三个因素分别在0.8,1.2,1.5 m3/h;10,20,30 g/L和50,100和150 mg/L水平下对临界通量测得值的影响.研究发现,污泥浓度和SCOD均对临界通量测得值呈负影响作用,而曝气强度则起正作用.随着污泥浓度和SCOD的增大,临界通量测得值是逐步减小的;而曝气强度的增大在一定程度上可以提高临界通量值.其中,临界通量测定值受SCOD的影响最大,MLSS次之,曝气强度最小.     

臭氧催化氧化-活性炭吸附处理DDNP废水

采用臭氧催化氧化-活性炭吸附方法处理DDNP废水,与单独臭氧氧化相比,催化剂的加入可以提高反应后期酸性环境下臭氧的氧化效率。试验选用Fe-活性炭催化组合,在曝气量为70 L/min,臭氧质量浓度为11.5mg/L的情况下处理500 mL废水,1 h后废水中COD、色度、硝基酚类化合物去除率分别达到72.6%、94.3%、80.6%;活性炭吸附处理臭氧催化氧化后DDNP废水可达到《兵器工业水污染排放标准》。当活性炭饱和导致水质超标时,采用臭氧对活性炭进行再生20 min,经反复10次试验,出水水质中COD稳定在131.47~152.96 mg/L,色度和硝基酚类化合物的含量低于排放标准,处理效果良好,具有可重复性。     

氧化石墨烯可见光催化能力的影响因素

为了验证氧化石墨烯的光催化能力,研究能增强其光催化效果的最佳条件,用改进的Hummer法制备了氧化石墨烯及分散液,通过扫描电镜、透射电镜、红外图谱、拉曼光谱以及荧光共聚焦光谱,对氧化石墨烯的微观形貌、成分、结构进行表征研究;在光照条件下降解亚甲基蓝验证其光催化能力,通过改变催化剂浓度、搅拌条件、曝气氧气浓度和外加电流,研究了四种条件对光催化能力的影响.在亚甲基蓝浓度为40 mg/L,氧化石墨烯浓度为20 mg/L,曝气量为2 L/min,氧气浓度为50%时,2 h可见光照射后亚甲基蓝降解率为62.9%,总去除率为89.9%;当不进行曝气处理,外加电流密度为1 m A/cm~2时,2 h可见光照射后亚甲基蓝降解率为53%,总去除率为87.9%.氧化石墨烯可以通过光催化产生羟基自由基降解污染物,通过改变条件来增加自由基含量可以提升催化效果.     

Wastewater treatment in a hybrid activated sludge baffled reactor

A novel hybrid activated sludge baffled reactor (HASBR), which contained both suspended and attached-growth biomass perfect mixing cells in series, was developed by installing standing and hanging baffles and introducing plastic brushes into a conventional activated sludge (CAS) reactor. It was used for the treatment of domestic wastewater. The effects on the operational performance of developing the suspended and attached-growth biomass and reactor configuration were investigated. The change of the flow regime from complete-mix to plug-flow, and the addition of plastic brushes as a support for biofilm, resulted in considerable improvements in the COD, nitrogen removal efficiency of domestic wastewater and sludge settling properties. In steady state, approximately 98+/-2% of the total COD and 98+/-2% of the ammonia of the influent were removed in the HASBR, when the influent wastewater concentration was 593+/-11 mg COD/L and 43+/-5 mg N/L, respectively, at a HRT of 10 h. These results were 93+/-3 and 6+/-3% for the CAS reactor, respectively. Approximately 90+/-7% of the total COD was removed in the HASBR, when the influent wastewater concentration was 654+/-16 mg COD/L at a 3h HRT, and in the organic loading rate (OLR) of 5.36kgCOD m(-3) day(-1). The result for the CAS reactor was 60+/-3%. Existing CAS plants can be upgraded by changing the reactor configuration and introducing biofilm support media into the aeration tank.     

A pilot scale bioreactor using EMMC for carbon and nitrogen removal

A pilot scale (100 l reactor) of an entrapped mixed microbial cell (EMMC) process was fabricated and tested for simultaneous removal of carbon and nitrogen. Process performance, operational stability, and maintenance requirements were all determined. Two sources of actual agricultural processing wastewater containing a high concentration of chemical oxygen demand (COD) (about 800–1,000 mg/l) and domestic sewage containing a low concentration of COD (about 150–200 mg/l) were investigated in this study. Various HRT (hydraulic retention time) and aeration schedules were operated. It was found that soluble COD (SCOD) and soluble total nitrogen (STN) could be removed in the range of 40–70% and 20–90%, respectively, for domestic sewage depending on the operational conditions provided. For agricultural processing wastewater, removal efficiencies of SCOD and STN are 89–91% and 60–75%, respectively, depending on the HRTs and aeration schedules applied. Economic evaluation for the application of domestic sewage was conducted. It was found that at an HRT of 6 h with 24 h of aeration it costs U.S.$1.75 for the treatment of 1,000 gal/day (3.8 m³/day). It is apparent that the EMMC process is technically feasible for simultaneous removal of carbon and nitrogen under the operation of an alternated schedule of the aeration in one single bioreactor. Ultimately, it can replace or upgrade the existing conventional wastewater treatment plant by combining the secondary and tertiary wastewater treatment plant in one bioreactor and provides simple maintenance and operation. This will also assist in providing the high quality of treated effluent meeting current and future environmental regulation for reuse. Electronic Publication     

Theoretical assessment of an ejector enhanced oil flooded compression cycle

Compressor loss and throttling loss are major thermodynamic losses in basic vapor compression cycle. For this reason, an ejector enhanced oil flooded compression cycle is proposed. To evaluate the performance, a mathematical model is established and the performance of this cycle with R32 as the working fluid is investigated. Furthermore, basic cycle, ejector enhanced basic cycle and oil flooded compression cycle have also been investigated. The comparison results show that the developed cycle has a maximum of 4.3% and 4% COP improvement at the evaporation temperature of −25 °C and the condensation temperature of 45 °C over the oil flooded compression cycle and the ejector enhanced basic cycle respectively. In addition, the effects of internal heat exchanger on the developed cycle are also studied. In comparison to the ejector enhanced basic cycle with 50% efficient internal heat exchanger, the COP improvement of the developed cycle rises up to a maximum of 8.5%. The results show that the proposed cycle has large potential applications for the ejector cycle enhancement.     

Bioremediation of phenols and polycyclic aromatic hydrocarbons in creosote contaminated soil using ex-situ landtreatment.

Soil from a former creosoting plant containing phenols and polycyclic aromatic hydrocarbons, was remediated using an ex-situ landtreatment process. Total 16 USEPA priority PAH and total phenol were reduced from 290 mg/kg and 40 mg/kg to < 200 mg/kg and 2 mg/kg, respectively. The bioremediation process involved soil mixing, aeration, and slow release fertilizer addition. The indigenous populations of PAH and phenol utilizing populations of microorganisms were shown to increase during the treatment process, indicating that biostimulation was effective. The most extensive degradation was apparent with the 2- and 3-ring PAH, with decreases of 97% and 82%, respectively. The higher molecular weight 3- and 4-ring PAH were degraded at slower rates, with reductions of 45% and 51%, respectively. Six-ring PAH were degraded the least with average reductions of < 35%. The residual concentrations of PAH and total phenol obtained in the study allowed the treated soil to be disposed of as low level contaminated landfill.     

Nitrogen removal in the bioreactor landfill system with intermittent aeration at the top of landfilled waste

High ammonia concentration of recycled landfill leachate makes it very difficult to treat. In this work, a vertical aerobic/anoxic/anaerobic lab-scale bioreactor landfill system, which was constructed by intermittent aeration at the top of landfilled waste, as a bioreactor for in situ nitrogen removal was investigated during waste stabilization. Intermittent aeration at the top of landfilled waste might stimulate the growth of nitrifying bacteria and denitrifying bacteria in the top and middle layers of waste. The nitrifying bacteria population for the landfill bioreactor with intermittent aeration system reached between 10(6) and 10(8) cells/dry g waste, although it decreased 2 orders of magnitude on day 30, due to the inhibitory effect of the acid environment and high organic matter in the landfilled waste. The denitrifying bacteria population increased by between 4 and 13 orders of magnitude compared with conventional anaerobic landfilled waste layers. Leachate NO(3)(-)-N concentration was very low in both two experimental landfill reactors. After 105 days operation, leachate NH(4)(+)-N and TN concentrations for the landfill reactor with intermittent aeration system dropped to 186 and 289 mg/l, respectively, while they were still kept above 1000 mg/l for the landfill reactor without intermittent aerobic system. In addition, there is an increase in the rate of waste stabilization as well as an increase of 12% in the total waste settlement for the landfill reactor with intermittent aeration system.     

铁碳微电解预处理印染废水的强化技术研究

采用铁、碳材料组成微电池电解处理工业印染废水,考察了铁、碳材料的用量比、pH值等因素对印染废水处理效果的影响。试验结果表明：m（铁）：m（碳）：1：4、pH3．5时效果最好。在此基础上,以6m3／（m3·min）的通气量进行强化曝气可进一步增强催化效果,当印染废水COD浓度为2000mg／L时,其去除率可达92．5％。     

Experimental validation of a prototype ejector designed to reduce throttling losses encountered in transcritical R744 system operation

This study presents experimental results obtained from a transcritical R744 system using a refrigerant ejector. The results were compared to that of a conventional system with an expansion valve. For the test conditions considered, the cooling capacity and COP simultaneously improved by up to 8% and 7%, respectively. Experiments were analyzed to quantitatively assess the effects on system performance as a result of changes in basic ejector dimensions such as motive nozzle and diffuser sizing. Small angles of 5° yielded best results for the static pressure recovery of the high-speed two-phase flow entering the diffuser. Experiments confirmed that like in a conventional transcritical R744 system with expansion valve, the high-side pressure control integrated into the ejector could be used to maximize the system performance. Numerical simulation results helped identifying this basic trend. Due to difficulties in the ejector throat pressure measurements, a more practical performance metric was introduced in order to quantify overall ejector efficiencies. According to this definition, the prototype ejector was able to recover up to 14.5% of the throttling losses.