臭氧氧化—包埋菌流化床生物处理组合工艺深度处理煤气化废水

采用臭氧氧化—包埋菌流化床生物处理组合工艺对煤气化废水进行深度处理。实验结果表明：当臭氧的质量浓度20 mg/L、臭氧进气流量1.5 L/min、臭氧通气时间30 min、包埋菌流化床水力停留时间24 h时,臭氧氧化工序的COD去除率达到30.0%~40.0%,总酚去除率达到100.0%;包埋菌流化床工序的COD去除率达到60.0%以上,氨氮的去除率大于95.0%;经组合工艺处理后,出水COD<60 mg/L,ρ（氨氮）<1.0 mg/L,ρ（总酚）未检出,色度小于50倍,达到GB8978—1996《污水综合排放标准》中的一级排放标准。     

High rate mesophilic, thermophilic, and temperature phased anaerobic digestion of waste activated sludge: a pilot scale study

The paper reports the findings of a two-year pilot scale experimental trial for the mesophilic (35°C), thermophilic (55°C) and temperature phased (65+55°C) anaerobic digestion of waste activated sludge. During the mesophilic and thermophilic runs, the reactor operated at an organic loading rate of 2.2 kgVS/m(3)d and a hydraulic retention time of 20 days. In the temperature phased run, the first reactor operated at an organic loading rate of 15 kgVS/m(3)d and a hydraulic retention time of 2 days while the second reactor operated at an organic loading rate of 2.2 kgVS/m(3)d and a hydraulic retention time of 18 days (20 days for the whole temperature phased system). The performance of the reactor improved with increases in temperature. The COD removal increased from 35% in mesophilic conditions, to 45% in thermophilic conditions, and 55% in the two stage temperature phased system. As a consequence, the specific biogas production increased from 0.33 to 0.45 and to 0.49 m(3)/kgVS(fed) at 35, 55, and 65+55°C, respectively. The extreme thermophilic reactor working at 65°C showed a high hydrolytic capability and a specific yield of 0.33 g COD (soluble) per gVS(fed). The effluent of the extreme thermophilic reactor showed an average concentration of soluble COD and volatile fatty acids of 20 and 9 g/l, respectively. Acetic and propionic acids were the main compounds found in the acids mixture. Because of the improved digestion efficiency, organic nitrogen and phosphorus were solubilised in the bulk. Their concentration, however, did not increase as expected because of the formation of salts of hydroxyapatite and struvite inside the reactor.     

Impact of Effluent Recirculation on Stabilization Pond Performance

This paper presents a test case for the effects of recirculation on stabilization pond performance. The BOD₅, COD, SS and Total Coliform removal at the intermediate treatment stages and the outlet of a stabilization pond treatment line, over a 2-year operational period (January 2000-December 2001), is described in detail and the effluent at different stages of treatment is compared to that of a conventional stabilization pond treatment line operating under similar conditions. The system consisted of four ponds in line—an anaerobic pond, followed by three individual ponds (Pond 1, Pond 2 and Pond 3). The effluent of the last pond (Pond 3) was recirculated back to the inlet of the first pond (Pond 1) at a discharge ratio 2:1 (recirculation:inflow). The overall BOD₅, COD, SS and Total Coliforms total reduction was 89%, 81%, 85% and 99.7%, respectively. The anaerobic pond proved to be the most efficient in removing COD and SS (57% and 68%, respectively) whereas Pond 1 achieved the most significant reduction in BOD₅ and Total Coliforms (69% and 86%, respectively). Although BOD₅ and COD were adequately reduced by the recirculating pond line, the SS concentration was high due to algae presence in the final effluent. Moreover, the Total Coliforms were insufficiently removed due to the reduced hydraulic retention time involved in this type of recirculation.     

Landfill leachate treatment using a rotating biological contactor and an upward-flow anaerobic sludge bed reactor

This paper describes the feasibility of an aerobic system (rotating biological contactor, RBC) and a biological anaerobic system (upward-flow anaerobic sludge bed reactor) at small scale for the treatment of a landfill leachate. In the first phase of the aerobic system study, a cyclic-batch RBC system was used to select perforated acetate discs among three different acetate disc configurations. These discs were chosen on the basis of high COD removal (65%) and biological stability. In the second phase, the RBC system (using four stages) was operated continuously at different hydraulic retention times (HRT), at different rotational speeds, and with varying organic concentrations of the influent leachate (2500-9000mgL(-1)). Forty percent of the total surface area of each perforated disc was submerged in the leachate. A COD removal of about 52% was obtained at an HRT of 24h and a rotational speed of 6rpm. For the anaerobic system, the reactor was evaluated with a volumetric organic load of 3273g-COD m(-3) day(-1) at an HRT of 54, 44, 39, 24 and 17h. At these conditions, the system reached COD removal efficiencies of 62%, 61%, 59%, 44% and 24%, respectively.     

Anaerobic treatment of effluents from an industrial polymers synthesis plant

The feasibility of the anaerobic treatment of an industrial polymer synthesis plant effluent was evaluated. The composition of the wastewater includes acrylates, styrene, detergents, a minor amount of silicates and a significant amount of ferric chloride. The average chemical oxygen demand (COD) corresponding is about 2000 mg/l. The anaerobic biodegradability of the effluent is shown and the toxicity effect on the populations of anaerobic bacteria is evaluated. The results of the anaerobic biodegradation assays show that 62% of the wastewater compounds, measured as COD, could be consumed. An upflow anaerobic sludge blanket (UASB) reactor was used in the evaluation, it has a diameter–height ratio of 1:7, and 4-liter volume. The inoculum was obtained from a UASB pilot plant that treats brewery wastewaters. At the beginning of the operation, the biomass showed an anaerobic activity of 0.58 gCOD/(gVSS×d), it decreased only 2.5% in the subsequent 4 months. After 35 days of continuous operation, the reactor was operated at different steady states for 140 days. The COD was maintained at 2200 mg/l in the feed. The results were: organic loading rate (OLR): 4.3 kg COD/(m³×d), hydraulic retention time: 12 h, superficial velocity: 1 m/h, average biogas productivity: 290 L CH₄/kg COD fed, biogas composition: 70–75% methane and a COD removal percentage >75%. ©     

Continuous high-solids anaerobic co-digestion of organic solid wastes under mesophilic conditions

With increasing concerns over the limited capacity of landfills, conservation of resources, and reduction of CO(2) emissions, high-solids (dry) anaerobic digestion of organic solid waste (OSW) is attracting a great deal of attention these days. In the present work, two dry anaerobic co-digestion systems fed with different mixtures of OSW were continuously operated under mesophilic conditions. Dewatered sludge cake was used as a main seeding source. In reactor (I), which was fed with food waste (FW) and paper waste (PW), hydraulic retention time (HRT) and solid content were controlled to find the maximum treatability. At a fixed solid content of 30% total solids (TS), stable performance was maintained up to an HRT decrease to 40 d. However, the stable performance was not sustained at 30 d HRT, and hence, HRT was increased to 40 d again. In further operation, instead of decreasing HRT, solid content was increased to 40% TS, which was found to be a better option to increase the treatability. The biogas production rate (BPR), CH(4) production yield (MPY) and VS reduction achieved in this condition were 5.0m(3)/m(3)/d, 0.25 m(3) CH(4)/g COD(added), and 80%, respectively. Reactor (II) was fed with FW and livestock waste (LW), and LW content was increased during the operation. Until a 40% LW content increase, reactor (II) exhibited a stable performance. A BPR of 1.7 m(3)/m(3)/d, MPY of 0.26 m(3) CH(4)/g COD(added), and VS reduction of 72% was achieved at 40% LW content. However, when the LW content was increased to 60%, there was a significant performance drop, which was attributed to free ammonia inhibition. The performances in these two reactors were comparable to the ones achieved in the conventional wet digestion and thermophilic dry digestion processes.     

流化床反应器处理高浓度含氟废水的效率和稳定性

采用小试规模的流化床反应器处理氟质量浓度为500~1 400 mg/L的模拟高浓度含氟废水。以氟化钙颗粒为晶种,以氯化钙溶液为沉淀剂（流量25 L/h）,考察了流化床连续运行过程中沉淀除氟的效率和稳定性。实验结果表明：氟化钙的沉淀反应在30.7 s内即可完成;在废水流量为11~23 L/h、反应pH为7.0~9.0、上升流速为0.005 9~0.013 0 m/s、钙与氟的摩尔比为0.85~1.00的条件下,出水清液中氟质量浓度低于10 mg/L,达到《污水综合排放标准》（GB 8978—1996）要求。连续运行过程中,流化床沉淀除氟高效稳定,操作条件范围较宽。流化床出水中细颗粒沉淀物的存在会导致氟浓度显著升高,应采取有效措施减少其产生或溢出,以保证沉淀除氟效率。     

Treatment of a high-strength sulphate-rich alkaline leachate using an anaerobic filter

The research looks at the feasibility of treating an alkaline sulphate-rich leachate arising from the co-disposal of municipal solid waste with cement kiln dust by means of an anaerobic filter (AF). This type of leachate with a high sulphate concentration is commonly prohibited for discharge to sewer and requires an on-site treatment solution. The AF used had a working volume of 4l and contained reticulated polyurethane foam as the biomass support material. The filters were operated over a 152 day experimental period during which the COD loading onto the filter was increased from 0.76 to 7.63kgCODm(-3)d(-1). In the early stages of operation at low loading, soluble sulphides accumulated that inhibited methanogenic activity. This was restored by dosing FeCl(3) to the reactor. The continued dosing allowed efficient COD removal of between 75% and 90% until the nominal retention time in the reactor was 3 days, at which point reactor performance declined significantly. The main mechanism for COD removal was by sulphate-reducing bacteria, which also resulted in up to 88% sulphate removal from the leachate. The average methane generation rate was 0.10lg(-1) COD removed. The results indicate the potential for using this approach as a pre-treatment that could significantly reduce the COD load to a second stage treatment process, but problems associated with the implementation of the technology at a larger scale have been identified.     

耦合光催化与生物处理4-氯酚废水

采用三相内循环式流化床光反应器和固定床生物反应器耦合处理4-氯酚(4-CP)废水。光反应器中采用粗孔硅胶负载的具有高活性和长寿命的TiO2为催化剂,处理效率高。废水的BOD5／COD及固定床生物反应器处理效果表明,4-CP为难生物降解物,光催化预处理能显著增强废水的可生化性。在单级耦合处理中,光催化预处理4h后进行生物处理,能达到最佳效率,但要完全矿化COD则需要延长预处理时间。光催化预处理为生物处理提供可降解性COD,后者却没有机会作用于前者。在多级耦合处理中,两者之间存在协同作用,使多级耦合处理效率大大提高。     

Enhanced anaerobic treatment of CSTR-digested effluent from chicken manure: The effect of ammonia inhibition

The effect of ammonia inhibition was evaluated during the enhanced anaerobic treatment of digested effluent from a 700 m³ chicken-manure continuous stirred tank reactor (CSTR). A 12.3 L internal circulation (IC) reactor inoculated with an anaerobic granular sludge and operated at 35 ± 1 °C was employed for the investigation. With a corresponding organic loading rate of 1.5-3.5 kg-COD/m³ d over a hydraulic retention time of 1.5 d, a maximum volumetric biogas production rate of 1.2 m³/m³ d and TCOD (total COD) removal efficiency ranging from 70% to 80% was achieved. However, the continual increase in the influent TAN content led to ammonia inhibition in the methanogenesis system. The SCOD/TAN (soluble COD/total ammonia nitrogen) ratio was presented to be the key controlling factor for the anaerobic treatment of semi-digested chicken manure, and further validation through shock loading and ammonia inhibition experiments was conducted. The threshold value of the SCOD/TAN ratio was determined to be 2.4 (corresponding to a TAN of 1250 mg/L) at an influent pH of 8.5-9.     

冷冻固定化硝化菌去除废水中氨氮的研究

采用聚乙烯醇(PVA)循环冷冻法制备固定化硝化菌颗粒,经活化后在颗粒填充率为9％的三相流化床中进行氨氮废水处理试验。处理低浓度氨氮有机废水(NH3-N质量浓度为75mg／L．COD约为400mg／L,水力停留时间为4h)时,NH3-N去除率约为90％,COD、TIN的去除率可达82％和60％左右;处理高浓度氨氮废水(NH3-N质量浓度450～500mg／L,水力停留时间为20h)时,NH3-N去除率在98％以上,氨氧化产物中NO2^--N质量分数在95％以上,为亚硝酸盐反硝化提供了有利条件。用该法制成的硝化菌颗粒寿命在3个月以上。     

SMBBR-AF-SMBBR组合工艺处理高氨氮农药废水

采用特异性移动床生物膜反应器(SMBBR)和厌氧生物滤池(AF)组合工艺处理高氨氮农药废水。考察了HRT、pH和DO等工艺条件对SMBBR-AF-SMBBR组合工艺运行稳定期COD和氨氮去除率的影响。试验结果表明,在进水COD为2 408~7 440 mg/L、ρ(NH_4~+-N)为160.21~433.84 mg/L、TN为208.27~537.65 mg/L、HRT为8d、pH为8.0、DO为4 mg/L的条件下,处理后出水平均COD为342 mg/L,COD去除率达92.3%;ρ(NH_4~+-N)小于4.0mg/L,氨氮平均去除率为89.2%;TN小于50 mg/L,平均TN去除达83.0%。出水各指标均优于原A2O工艺出水。     

Optimization of conventional Fenton and ultraviolet-assisted oxidation processes for the treatment of reverse osmosis retentate from a paper mill

According to current environmental legislation concerned with water scarcity, paper industry is being forced to adopt a zero liquid effluent policy. In consequence, reverse osmosis (RO) systems are being assessed as the final step of effluent treatment trains aiming to recover final wastewater and reuse it as process water. One of the most important drawbacks of these treatments is the production of a retentated stream, which is usually highly loaded with biorecalcitrant organic matter and inorganics; and this effluent must meet current legislation stringent constraints before being ultimately disposed. The treatment of biorefractory RO retentate from a paper mill by several promising advanced oxidation processes (AOPs) - conventional Fenton, photo-Fenton and photocatalysis - was optimized considering the effect and interaction of reaction parameters; particularly using response surface methodology (RSM) when appropriate (Fenton processes). The economical cost of these treatments was also comparatively assessed. Photo-Fenton process was able to totally remove the COD of the retentate, and resulted even operatively cheaper at high COD removal levels than conventional Fenton, which achieved an 80% reduction of the COD at best. In addition, although these optimal results were produced at pH=2.8, it was also tested that Fenton processes are able to achieve good COD reduction efficiencies (>60%) without adjusting the initial pH value, provided the natural pH of this wastewater was close to neutral. Finally, although TiO(2)-photocatalysis showed the least efficient and most expensive figures, it improved the biodegradability of the retentate, so its combination with a final biological step almost achieved the total removal of the COD.     

煤制乙二醇废水预处理装置的工业化调试

针对煤制乙二醇废水含高浓度硝酸盐氮的特点,设计了缺氧膨胀床(AEB)反应器预处理装置,并进行了工业化启动和调试运行,考察了其在反硝化连续流运行条件下的处理效果及工艺参数变化。结果表明,AEB反应器启动后,填料层生物膜挂膜快速且生长稳定。反应器在工业化调试阶段运行稳定,COD和TN的去除率和去除负荷较为稳定。在受到来水冲击后,AEB反应器处理效果稳定,出水可在短期内恢复正常。该技术的系统操控参数范围较广,易于工业化操控运行,在煤制乙二醇废水和其他含高浓度硝酸盐氮废水的处理中具有较大的推广价值。     

移动床生物膜反应器预处理含酚废水

采用两级移动床生物膜反应器（MBBR）预处理高挥发酚含量的石化厂汽提净化水,考察了HRT和DO对废水中挥发酚和COD去除效果的影响。实验结果表明：在两级MBBR总HRT为10 h、MBBR中部废水DO 为1~3 mg/L的条件下, 装置连续运行处理ρ（挥发酚）=110~201 mg/L、COD=644~1 827 mg/L、BOD₅/COD=0.15~0.69的废水,两级MBBR处理后出水平均ρ（挥发酚）为17.6 mg/L,挥发酚去除率达87.9%;平均COD为745 mg/L,COD去除率为32.7%;出水BOD₅/COD平均为0.68,表明经过两级MBBR处理后,废水的可生化性有所提高,有利于废水的后续生化处理。     

两相厌氧+A/O工艺处理腈纶和丙烯酰胺混合废水

采用两相厌氧+A/O工艺处理腈纶和丙烯酰胺混合废水。实验结果表明：在混合进水中V（腈纶废水）∶V（丙烯酰胺废水）=1、产酸反应器HRT为20 h、产甲烷反应器HRT为36 h、A/O池HRT为24 h、DO为4~5 mg/L、混凝池进水COD为（4 000±300） mg/L的条件下,总COD去除率为87%~89%,A/O池出水COD低于500 mg/L,出水达到GB 8978—1996《污水综合排放标准》中的三级标准;在混凝池进水BOD₅/COD为0.20~0.30的条件下,产甲烷反应器出水BOD₅/COD为0.55~0.65,说明两相厌氧可明显提高废水的可生化性。     

Fenton氧化-生物接触氧化工艺处理甲醛和乌洛托品废水

采用Fenton氧化一生物接触氧化工艺处理含甲醛和乌洛托品的模拟废水（简称废水）,在H2O2（体积分数30％）加入量2．5g／L、H2O2与Fe^2＋质量浓度比3．75、反应时间3h、不调节废水初始pH的Fenton氧化预处理最佳操作条件下,废水COD从1000mg／L左右降至300mg／L,COD去除率达72％。原废水完全无法直接进行生化处理,经Fenton氧化预处理后其BOD,／COD约为0．5,易于生化处理。Fenton氧化一生物接触氧化工艺处理废水,生物接触氧化停留时间为12h时,废水COD去除率高达94％,处理后出水COD小于70mg／L,处理效果很好。     

好氧颗粒污泥处理增塑剂生产废水

以SBR为反应器,利用好氧颗粒污泥处理增塑剂生产废水。实验结果表明:通过培养驯化后,好氧颗粒污泥对该废水具有较好的处理效果;好氧颗粒污泥对增塑剂生产废水中COD的去除率为78%,出水COD为62mg/L,接近于GB18918－2002《城镇污水处理厂污染物排放标准》中的一级B标准;出水中NH3-N未检出,TP为0.03mg/L,去除率分别达到100%和90%。     

用移动床生物膜反应器处理石化废水

采用悬浮填料移动床生物膜反应器处理石化废水,在水力停留时间大于6h、反应器填料投加率为50％的条件下,出水COD、NH3－N、SS、浊度等均达到国家排放标准,在水力停留时间大于8h时,能达到良好的硝化效果。     

EGSB出水回流对EGSB—SBR工艺处理果汁废水的影响

采用EGSB—SBR工艺处理实际果汁废水(COD 2 608~6 500 mg/L,p H 5.0~7.0)。在EGSB反应器成功启动及驯化完成的情况下,连续运行49 d。实验结果表明:第25天起,控制EGSB回流比为3.00∶1,EGSB反应器可在无须添加Na HCO3的条件下稳定运行,从而降低了废水处理成本;第25天起,平均进水COD,BOD5,SS分别为5 968,2 130,1 020 mg/L,平均出水COD,BOD5,SS分别降至131,11,50 mg/L,平均COD,BOD5,SS去除率分别为98%,99%,95%;组合工艺对该实际果汁废水具有良好的处理效果。