给水预臭氧化与预氯化对比试验研究

通过常规给水处理工艺预臭氧化和预氯化对比试验,研究了预臭氧化工艺对水中浊度、氮氮和CODMn的去除效果,对三卤甲烷生成的影响,及其致突变活性的变化。结果表明预臭氧化工艺沉淀池和滤池出水浊度均低于预氯化工艺,其对有机物的去除效果明显优于预氯化工艺,对CODMn的总去除率达53.4%,并能有效去除原水中大量的三卤甲烷前体物,而在致突变活性方面预臭氧化工艺滤后水更安全可靠。同时试验得到在原水CODMn为5-6 mg/L条件下臭氧最佳投加量为1-1.2 mg/L。     

河北应急水源工艺适应性研究与工艺优化

南水北调的应急工程是从河北四水库调水进京,为了保证净水厂运行稳定,进行了适应性研究,并采用层次优化法对中试工艺进行选优。结果表明:第九水厂工艺运行方案为采用粉末活性炭预处理(20mg/L),混凝剂投加量为20～25mg/L;当原水藻类较高时可采用"氯+粉末活性炭"联合预处理方式;在剑水蚤数量较多时,建议砂滤池和炭池的反冲洗水不回收。第三水厂、田村山水厂采用混凝—沉淀—过滤—O3—炭池工艺,主臭氧投加量为0.5～1.5mg/L,混凝剂投加量为20～25mg/L。剑水蚤数量较少时,混凝沉淀能够将其去除,或通过主臭氧将剑水蚤杀死去除。在调水过程中,应跟踪原水MIB的变化,并加强活性炭出水的臭味检测,适时调整工艺运行参数。     

臭氧-生物活性炭滤池运行及水厂成本变化研究

处理规模10万m3/d的杭州南星水厂是钱塘江水源水厂首座采用臭氧-生物活性炭工艺(O3-BAC)进行深度处理的水厂.通过对O3-BAC处理效果的各影响因素进行生产性研究,确定适宜的余臭氧浓度为0.15～0.25 mg/L,BAC滤池水力负荷可大于设计值10 m3/(m2·h),运行周期设定为10 d左右,加臭氧有助于提高O3-BAC对CODMn的去除效果,同时推断在秋冬季水温较低(7～16℃)的情况下,BAC滤池的生物挂膜时间为运行后101～105 d.原水CODMn＜4.59 mg/L时,采用常规处理即可将出水CODMn控制在2 mg/L以下.实施臭氧预处理和O3-BAC深度处理后,水厂总运行成本增加0.199元/m3.     

饮用水臭氧应用安全性研究

对预臭氧、臭氧—生物活性炭等技术与常规水处理工艺联用中有机物去除效果、消毒副产物THMFP的消除等进行了研究。结果表明:采用适量臭氧(如1mg/L)预氧化,可有效提高混凝过程中有机物去除率;THMFP从常规处理的116μg/L降至78μg/L(1mg/LO3)。与预臭氧强化混凝联用的臭氧—生物活性炭工艺能进一步降低DOC和THMFP。研究发现:溴酸盐随着臭氧含量呈现起伏变化,溴酸盐相关前驱物不易分离去除。两次臭氧投加(预臭氧和主臭氧)均导致溴酸盐、AOC和甲醛升高;其含量可分别在后续的混凝过滤及生物活性炭过程中得到控制,仅AOC含量较原水和常规工艺出水有所升高。     

臭氧—活性炭—超滤组合工艺处理石油微污染水的试验研究

采用臭氧-活性炭-超滤(O3-GAC-UF)处理石油微污染水,研究该组合工艺对水中石油污染物的去除效果.结果表明,当原水油含量为4 mg/L左右时,在臭氧投加量约为4 mg/L、反应时间为12 min、活性炭停留时间为12 min条件下,超滤出水油含量为0.027 mg/L,对色度、浊度和CODMn的去除率均接近100%,UV254从0.117 cm-1降低为0.004 cm-1,并且随着处理水量的增加,系统运行稳定.臭氧-活性炭-超滤工艺可以作为处理石油微污染水的一种有效方法.     

深圳水源水藻类去除中试研究

采用正交试验和单因素试验设计方法,考察预O3、PAC、PAM和主O3投量对藻类去除的影响程度.中试结果表明,在深圳夏季高藻季节,当原水藻密度小于2×107个/L时,预O3、PAC、PAM和主O3投量分别为1 mg/L、1.5 mg/L、0.05 mg/L和2 mg/L可保障炭滤出水藻密度在105个/L(深圳市生活饮用水水质目标)范围内;当原水藻密度增加到2×107个/L以上(3.5×107个/L以下)时,可通过加大投药量,即预O3、PAC、PAM和主O3投量分别为1.8mg/L以上、2 mg/L、0.07 mg/L和2.5 mg/L,达到上述炭滤出水藻密度水平.     

粉末活性炭技术处理水中臭味物质的应用研究

随着水资源日益紧缺、水质恶化,原水臭味问题成为我国给水厂迫切关注的水质问题.经过对B市地表水水源突发臭味问题进行分析,确定2-MIB为水体主要致臭物质.通过臭氧、高锰酸钾预氧化和粉末活性炭对水中2-MIB的去除试验,发现粉末活性炭对其处理效果最佳.原水投加粉末活性炭与现有水厂常规处理 活性炭工艺构成解决臭味问题的双重技术保障.通过实验室吸附试验和中试确定了粉末活性炭投加点位置和投加量等技术参数.在加强滤池反冲洗及部分回流水排放的条件下,原水2-MIB浓度达到100 ng/L时,投加15 mg/L粉末活性炭、20 mg/L聚氯化铝时,可将出厂水2-MIB控制在10 ng/L以下.     

臭氧—平板陶瓷膜新型净水工艺中试研究

为应对饮用水源受到的有机物和氨氮的复合污染,对混凝—臭氧/陶瓷膜—活性炭池新型净水工艺进行中试研究。结果表明,臭氧可以在线控制膜污染,臭氧投加量2mg/L,间歇提高臭氧投加量至5mg/L时,陶瓷膜跨膜压差在通量100L/(m2·h)下运行5d后增长小于2kPa。臭氧促进了陶瓷膜对颗粒物的去除,投加臭氧时膜出水中大于2μm粒径的颗粒数低于10个/mL。新型净水工艺能有效去除受污染原水中的有机物和氨氮,工艺对UV254的去除率为65%~95%,CODMn去除率为71%~98%,出水CODMn低于0.5mg/L;原水氨氮3.5mg/L时,工艺出水氨氮0.1mg/L,且无亚硝态氮积累,氨氮基本转化为硝态氮。此外,新型净水工艺对卤乙酸生成势的去除率高于85%,大大提高了工艺出水的安全性。实现了传统工艺与深度处理工艺的叠加集成,对水厂升级改造具有重要意义。     

河北应急水源的预臭氧化工艺研究

南水北调的应急工程是从河北四水库调水进京,四水库水源水质与密云水库水质相差较大.为了保证河北水进京后水厂工艺运行的稳定性,根据水厂现行工艺(混凝-沉淀-煤砂过滤-活性炭过滤)增加预臭氧在河北黄壁庄水库进行适应性研究.试验结果表明:在投加臭氧1.5～2.6 mg/L后炭出水基本无味;试验条件为:臭氧浓度0.4 mg/L,接触时间8 min时,预臭氧能够将剑水蚤杀死去除;预臭氧后系统对有机物去除效果较好,且沉后藻类去除率达到80%以上,煤滤池出水藻类低于2万个/L;中试系统煤滤池出水和炭滤池出水溴酸盐浓度均小于5 μg/L,因此臭氧氧化后不存在溴酸盐副产物超标的风险.同时,建议在河北水进京前测定水中MIB浓度,适时调整臭氧投加量,在有必要的情况下考虑增加粉末活性炭预吸附.     

吴淞江微污染水源水处理工艺的比较研究

采用预臭氧生物活性炭滤池、生物接触预氧化、PAC吸附预处理三种工艺对吴淞江微污染水源水处理进行研究;常温下,臭氧投加量2 mg/L,预臭氧生物活性炭滤池对氨氮的去除率维持在70%以上,出水NH3-N约1 mg/L,CODMn平均去除率34.16%;生物接触预氧化对氨氮去除率可达80%以上,但CODMn平均去除率只有7.6%;PAC对色度及臭味有良好的去除效果,但对其他物质去除率较低.三种工艺相比,作为水厂改造或备用应急方案,预臭氧生物活性炭滤池为最佳选择.     

ANAMMOX工艺在生活污水深度处理中的应用研究

随着水环境质量的恶化,高能低耗的污水深度处理技术成为当前研究热点,尤其是对于低C/N比的城市生活污水脱氮技术的研究。试验以城市生活污水的二级出水为研究对象,采用ANAMMOX下向流生物滤池,当二级出水NH3-N=15-35mg/L,CODCr=25-45mg/L,TOC=9-12mg/L,水温=25-28℃时,ANAMMOX下向流生物滤池脱氨率达80%-100%,不仅适用于处理高氨废水,也可用于城市生活污水深度处理中。试验发现pH可以用来指示ANAMMOX反应的进行,同时也可以用来指示ANAMMOX反应进程的快慢。试验中还发现,厌氧氨氧化反应速率与NO2--N含量有关,原水中NO2--N含量的增多有利于ANAMMOX工艺处理效果。     

Nitrite oxidation inhibition by hydroxylamine: experimental and model evaluation.

A proposed approach for biological nitrogen removal significantly reduces cost by reducing biomass production and carbon requirements via inhibition of nitrite oxidation (NO2- to NO3-). Batch experiments were conducted to examine the effect of hydroxylamine (HM) on nitrite oxidizers, ammonia oxidizers, and nitrite reducers. Hydroxylamine effect experiments were done at initial pH values of 7.4-8.4, nitrogen concentrations of 100 mg N/L, biomass concentrations of 100-400 mg VSS/L and HM dosages up to 43 mg/L. Nitrite oxidizer activity was completely inhibited by HM at dosages of 7.0 and 8.9 mg/L for pH values of 8.4 and 7.6, respectively. Relatively low HM concentrations (0.35-5.5 mg/L) can be used to completely inhibit nitrite oxidation, but do not significantly affect ammonia oxidizers and nitrite reducers. A model developed to describe the effect of pH on nitrite oxidation rate fits the data well (R2 = 0.89) with values for Vmax of 0.372 (mg N/mg VSS-hr), pH* of 7.72, and the inhibition constant Kh of 0.154. Incorporation of HM inhibition into the model provided a good fit to relative nitrite oxidation rate as a function of undissociated HM concentration (R2 = 0.80, Vmax = 0.028 mg N/mg VSS-hr, pH = 7.89, Kh = 0.302, a = 0.195, and Ki= 0.277 mg/L).     

Denitrification of nitrate-contaminated groundwater using a simple immobilized activated sludge bioreactor

A simple anaerobic-activated sludge system, in which microorganisms are immobilized by a novel functional carrier, was used for removing nitrate in groundwater. The operating conditions, including hydraulic retention time (HRT), C/N ratio, temperature and NO(3)(-)-N loading concentration were investigated. The NO(3)(-)-N concentration, residual chemical oxygen demand (COD) and nitrite accumulation were used as indicators to assess the water quality of the effluent. The anaerobic biomass loading capacity in the carrier was 12.8 g/L and the denitrifying Pseudomonas sp. and Rhodocyclaceae bacterium were dominant among the immobilized microorganisms in the anaerobic-activated sludge. Under operating conditions of HRT= 1.5 h, C/N= 2-3 and T= 16.8-20 °C, the removal efficiency of NO(3)(-)-N exceeded 93%, corresponding to a relatively high denitrification rate of 0.73 kg NO(3)(-)-N m(-3) d(-1), when the NO(3)(-)-N loading concentration was 50 mg/L. The NO(3)(-)-N concentration of the effluent always met regulatory criteria for drinking water (<10 mg/L) in the main developed and developing countries. The effluent COD was also below 10 mg/L. Although some nitrite accumulated (0-1.77 mg/L) during the operating period, it can be decreased through adjusting the operating pH and HRT. The immobilized activated sludge system may be useful for the removal of nitrate from groundwater.     

采用活性炭强化常规处理原水突发油类污染的研究

中试研究表明,常规处理(混凝—沉淀—过滤)可以将含油约为10mg/L的原水处理达标,并且除油率不受混凝剂投加量的影响。油污染浓度为7.2～18mg/L的原水经混凝沉淀去除的效率基本相同。20mg/L的油污染仅通过常规处理无法达标,需采用投加粉末活性炭(PAC)的强化混凝或颗粒活性炭(GAC)的强化过滤,即投加40mg/L的PAC,或在过滤阶段铺40cmGAC层的炭砂滤柱。KMnO4和Cl2的预氧化对除油效果无影响。     

Simultaneous biological removal of sulphide and nitrate by autotrophic denitrification in an activated sludge system.

The feasibility of an autotrophic denitrification process in an activated sludge reactor, using sulphide as the electron donor, was tested for simultaneous denitrification and sulphide removal. The reactor was operated at nitrate (N) to sulphide (S) ratios between 0.5 and 0.9 to evaluate their effect on the N-removal efficiency, the S-removal efficiency and the product formation during anoxic oxidation of sulphide. One hundred per cent removal of both nitrate and sulphide was achieved at a NLR of 7.96 mmol N-L(-1) x d(-1) (111.44 mg NO3- -N x L(-1) x d(-1)) and at a N/S ratio of 0.89 with complete oxidation of sulphide to sulphate. The oxygen level in the reactor (10%) was found to influence the N-removal efficiency by inhibiting the denitrification process. Moreover, chemical (or biological) oxidation of sulphide with oxygen occurred, resulting in a loss of the electron donor. FISH analysis was carried out to study the microbial population in the system.     

Treatment of landfill leachate by a pilot-scale modified Ludzack-Ettinger and sulfur-utilizing denitrification process.

Nitrogen removal efficiency of a pilot-scale system consisted of Modified Ludzack-Ettinger (MLE) followed by sulfur-utilizing denitrification (SUDNR) process was evaluated with a landfill leachate. For SUDNR, a down-flow mode sulfur packed bed reactor (SPBR) filled with sulfur and limestone particles was used. Although total nitrogen removal efficiency of the MLE process was about 80% at the recycle ratio of 4, effluent contained 350-450 mg/L NO(3-)-N. Up to a loading rate of 1.2 kg NO(3-)-N/m3-day, the SPBR could achieve complete removal of nitrate, and nitrate removal rate was kept to that level even at higher loading rate. When a COD/N ratio of MLE process was maintained at 2 instead of 4, more organics with molecular weight less than 500 were utilized for heterotrophic denitrification although denitrification was not complete with the lack of electron donors. Clogging in the SPBR, mainly by the accumulation of nitrogen gas in the pores, could easily be removed by introducing the effluent in an upward direction for 1 min at 1 hr intervals. The proposed treatment system could achieve nitrate free effluent with a slight increase in chemical cost. Furthermore, depending on further COD removal requirement after biological treatment, the proposed treatment system can be an economical solution.     

催化二氧化氯氧化处理难降解废水特性研究

在二氧化氯化学氧化和催化氧化体系对比试验的基础上,探讨了催化二氧化氯氧化的过程与催化特性。试验结果表明:二氧化氯化学氧化处理CODCr为3 500 mg/L的配制难降解废水时, 最佳反应pH为6-8、氧化剂用量为1 000 mg ClO2/L,反应时间为60 min,CODCr去除率可达50%左右;而采用催化二氧化氯氧化处理配制废水时,最佳反应pH为2左右,氧化剂经济用量为800 mg ClO2/L,反应时间为45-60 min,CODCr去除率可达80%以上,去除1 kgCODCr氧化荆费用为3.7元, 废水可生化性得到很大的提高,表明催化二氧化氟氧化法是一种新型高效的难降解废水处理技术。     

Model experiments on improving nitrogen removal in laboratory scale subsurface constructed wetlands by enhancing the anaerobic ammonia oxidation.

Anaerobic ammonia oxidation (Anammox) has been identified as a new general process-strategy for nitrogen removal in wastewater treatment. In order to evaluate the role and effects of the Anammox process in wetlands, laboratory-scale model experiments were performed with planted fixed bed reactors. A reactor (planted with Juncus effusus) was fed with synthetic wastewater containing 150-200 mg L(-1) NH4+ and 75-480 mg L(-1) NO2(-). Under these operating conditions, the plants were affected by the high ammonia and nitrite concentrations and the nitrogen removal rate fell within the same range of 45-49 mg N d(-1) (equivalent to 0.64-0.70 g Nm(-2)d(-1)) as already reported by other authors. In order to stimulate the rate of nitrogen conversion, the planted reactor was inoculated with Anammox biomass. As a result, the rate of nitrogen removal was increased 4-5-fold and the toxic effects on the plants also disappeared. The results show that, in principle, subsurface flow wetlands can also function as an "Anammox bioreactor". However, the design of a complete process for the treatment of waters with a high ammonia load and, in particular, the realisation of simple technical solutions for partial nitrification have still to be developed.     

利用缺氧反硝化降解硝基苯的试验

首先在(35±0.1)℃水温条件下,采用静态试验装置测定硝基苯缺氧反硝化的pH值以及理论COD质量浓度与NOx--N(包括NO3--N和NO2--N)质量浓度的比值w,然后参考这些参数,利用动态试验装置(水温为35℃左右)研究NO2--N质量浓度对硝基苯降解的影响和反硝化处理硝基苯废水的实际运行效果。结果表明:6.0~8.0范围内的pH值和NO2--N质量浓度对硝基苯缺氧反硝化去除效果都没有显著影响;在硝基苯质量浓度不超过60 mg/L、w约为0.23的情况下,废水中的硝基苯能得到有效降解。     

Simultaneous nitrification and de-nitrification in MBR.

Experiments have been carried out to get an understanding of the effect of DO, C/N ratio and pH on the performance of a bench scale membrane bioreactor (MBR) in simultaneous nitrification and denitrification. It was found that under the conditions of MLSS in the range of 8000-9000 mg/L and temperature of water in the MBR of 24 degrees C, influent COD and NH3-N in the range of 523-700 mg/L and 17.24-24 mg/L respectively, the removals of COD, NH3-N and TN were 98%, 99% and 60%; 96.5%, 0,98% and 75%; 96%, 95% and 92%; 90%,70% and 60% respectively at DO of 6, 3, 1 and 0.5 mg/L. It was also found that the changes in C/N ratio and pH in a certain range have a slight effect on COD removal but have significant influence on the removal of NH3-N and TN. The results showed that only under the conditions that each ecological factor was maintained relatively steadily, simultaneous nitrification and de-nitrification proceeded smoothly. It was found that when C/N ratio was 30, the influent pH 7.2, the temperature of water in MBR 24 degrees C and DO 1 mg/L, as optimum conditions, the removals of COD, NH3-N and TN were 96%, 95% and 92% respectively. In addition, mechanism research on simultaneous nitrification and de-nitrification in MBR has been conducted as well.