Pilot plant study on ozonation and biological activated carbon process for drinking water treatment

A study on advanced drinking water treatment was conducted in a pilot scale plant taking water from conventional treatment process. Ozonation-biological activated carbon process （O3-BAC） and granular activated carbon process （GAC） were evaluated based on the following parameters： CODMn, UV254, total organic carbon （TOC）, assimilable organic carbon （AOC） and biodegradable dissolved organic carbon （BDOC）. In this test, the average removal rates of CODMn, UV254 and TOC in O3-BAC were 18.2%, 9.0% and 10.2% higher on （AOC） than in GAC, respectively. Ozonation increased 19.3-57.6 μg Acetate-C/L in AOC-P17, 45.6-130.6 μg Acetate-C/L in AOC-NOX and 0.1-0.5 mg/L in BDOC with ozone doses of 2 8 mg/L. The optimum ozone dose for maximum AOC formation was 3 mgO3/L. BAC filtration was effective process to improve biostability.

Catalytic ozonation of phenol and oxalic acid with copper-loaded activated carbon

A novel heterogeneous catalytic ozonation process in water treatment was studied, with a copper-loaded activated carbon （Cu/AC） that was prepared by an incipient wetness impregnation method at low temperature and tested as a catalyst in the ozonation of phenol and oxalic acid. Cu/AC was characterized using XRD, BET and SEM techniques. Compared with ozonation alone, the presence of Cu/AC in the ozonation processes significantly improves the degradation of phenol or oxalic acid. With the introduction of the hydroxyl radical scavenger, i.e., turt-butanol alcohol （t-BuOH）, the degradation efficiency of both phenol and oxalic acid in the Cu/AC catalyzed ozonation process decreases by 22% at 30 min. This indicates that Cu/AC accelerates ozone decomposition into certain concentration of hydroxyl radicals. The amount of Cu（II ） produced during the reaction of Cu/AC-catalyzed ozonation of phenol or oxalic acid is very small, which shows that the two processes are both heterogeneous catalytic ozonation reactions.

Comparison Between Dielectric Barrier Discharge Plasma and Ozone Regenerations of Activated Carbon Exhausted with Pentachlorophenol

In this study, two regeneration methods （dielectric barrier discharge （DBD） plasma and ozone （03） regeneration） of saturated granular activated carbon （GAC） with pentachlorophe- nol （PCP） were compared. The results show that the two regeneration methods can eliminate contaminants from GAC and recover its adsorption properties to some extent. Comparing the DBD plasma with 03 regeneration, the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after 03 regeneration. 03 regeneration decreases the specific surface area of GAC and increases the acidic surface oxygen groups on the surface of GAC, which causes a decrease in PCP on GAC uptake. With increasing regeneration cy- cles, the regeneration efficiencies of the two methods decrease, but the decrease in the regeneration efficiencies of GAC after 03 regeneration is very obvious compared with that after DBD plasma regeneration. Furthermore, the equilibrium data were fitted by the Freundlich and Langmuir models using the non-linear regression technique, and all the adsorption equilibrium isotherms fit the Langmuir model fairly well, which demonstrates that the DBD plasma and ozone regeneration processes do not appear to modify the adsorption process, but to shift the equilibrium towards lower adsorption concentrations. Analyses of the weight loss of GAC show that 03 regeneration has a lower weight loss than DBD plasma regeneration.

Reclaimation of petroleum-based wastewater by noval ozone immobilized biological activated carbon process

Wastewater reclamation in the petroleum industries in Northern China is important because of the shortage of water resource. Conventional treatment technology used：in treating petroleum-based wastewater, namely the 3-phase biological process, typically removes COD, BODI grease, volatile hydrobenzenes, cyanides, sulfides and suspended solids. However, the process is often ineffective in ammonia-nitrogen removal, and thus the treated effluent quantity can＇ t meet the required standards for reuse. This paper investigated a novel ozone immobilized biological activated carbon（O3-IBAC） process for ammonia nitrogen removal from petroleum-based wastewater. Operated at a HRT （ Hydraulic Retention Time） of 15 minutes in IBACI and 27 minutes in IBAC2, the O3-IBAC process achieved ammonia nitrogen removal efficiency of 91%. In addition, the removal efficiencies 6f COD, volatile hydrobenzenes, suspended solids, turbidity and petroleum-based micropollutants were all above 90%. Competition between the autotrophs and heterotrophs was observed, which was indicated by an increase of ammonia nitrogen removal with a decrease of COD removal, and vise versa. Nitrite accumulation in IBACI followed by erobic shortcut denitrification in IBAC2 led to 28% of the Total Nitrogen removal efficiency. Pollutant reduction in＇ the IBAC process was achieved by a rapid physical adsorption and biodegradation on the activated carbon, which effectively retained the pollutants in the system despite the short hydraulic retention time.

Effect of ozone on the performance of a hybrid ceramic membrane-biological activated carbon process

Two hybrid processes including ozonation-ceramic membrane-biological activated carbon （BAC） （Process A） and ceramic membrane-BAC （Process B） were compared to treat polluted raw water. The performance of hybrid processes was evaluated with the removal efficiencies of turbidity, ammonia and organic matter. The results indicated that more than 99% of particle count was removed by both hybrid processes and ozonation had no significant effect on its removal. BAC filtration greatly improved the removal of ammonia. Increasing the dissolved oxygen to 30.0 mg/L could lead to a removal of ammonia with concentrations as high as 7.80 mg/L and 8.69 mg/L for Processes A and B, respectively. The average removal efficiencies of total organic carbon and ultraviolet absorbance at 254 nm （UV254, a parameter indicating organic matter with aromatic structure） were 49% and 52% for Process A, 51% and 48% for Process B, respectively. Some organic matter was oxidized by ozone and this resulted in reduced membrane fouling and increased membrane flux by 25%-30%. However, pre-ozonation altered the components of the raw water and affected the microorganisms in the BAC, which may impact the removals of organic matter and nitrite negatively.

Control of Bromate and THM Precursors Using Ozonation Combined System

Objective To investigate the feasibility of reducing THM precursors and controlling bromate taste and odor in drinking water taken from the Yellow River by an ozonation combined system. Methods The appropriate ozone dosage was determined, and then the changes of TOC, UV254 and THM formation potential （THMFP） in the combined system were evaluated. Results One mg/L ozone could effectively remove taste and odor and meet the maximum allowable bromate level in drinking water. The pre-ozonation increased THMFP, but the conventional treatment system could effectively reduce the odor. The bio-ceramic filter could partly reduce CHC13FP, but sometimes might increase CHCl2BrFP and CHClBr2FP. The biological activated carbon （BAC） filter could effectively reduce CHC13FP and CHCl2BrFP, but increase CHClBr2FP. Compared with other filters, the fresh activated carbon （FAC） filter performed better in reducing THMFP and even reduced CHClBr2FP. Conclusion The combined system can effectively reduce taste, odor, CHC13FP, and CHCl2BrFP and also bring bromate under control.

Catalytic ozonation of volatile organic compounds(ethyl acetate)at normal temperature

Catalytic treatments of VOCs at normal temperature can greatly reduce the cost and temperature of processing,and improve the safety factor in line with the requirements of green chemistry.Activated carbon fiber(ACF)was pretreated with 10%H_(2)SO_(4)by single factor optimization to increase specific surface area and pore volume obviously.The catalytic ozonation performance of ACF loaded with Au,Ag,Pt and Pd noble metals on ethyl acetate was investigated and Pd/ACF was selected as the optimal catalyst which had certain stability.Pd is uniformly distributed on the surface of ACF,and Palladium mainly exists in the form of Pd0 with a amount of Pd+2.The specific surface area of the catalysts gradually decreases as the loading increases.The activation energy of ethyl acetate calculated by Arrhenius equation is 113 kJ mol 1.With 1%Pd loading and the concentration ratio of ozone to ethyl acetate is 3:1,catalytic ozonation performance is maximized and the conversion rate of ethyl acetate reached to 60%in 3050℃Cat 15,00030,000 h^1.

活性炭负载TiO_(2)催化臭氧的造纸废水处理方法研究

造纸废水的处理一直是水利水电工程关注的重点项目。造纸废水中含有大量的污染物质,若是直接排放到环境中,将会对环境造成严重危害。为此,研究一种活性炭负载TiO_(2)催化臭氧的造纸废水处理方法尤为重要。基于此,从水利水电工程废水储蓄池中采集造纸废水水样,配制TiO_(2)催化剂,制备活性炭,将二者混合形成活性炭负载TiO_(2)催化剂;利用催化剂与臭氧充分接触后发生的氧化反应,去除废水中的有机污染物,从而完成造纸废水的处理。测试结果表明:活性炭负载TiO_(2)催化剂对各种污染物质具有很好的去除效果,且催化剂中TiO_(2)负载量越高,催化剂的去除率越高。随着时间的推移,BOD5逐渐降低,水体中的污染物逐渐被分解和消除,证明了所研究方法在造纸废水处理中的应用效果。

Characterization of bacterial community and iron corrosion in drinking water distribution systems with O3-biological activated carbon treatment

Bacterial community structure and iron corrosion were investigated for simulated drinking water distribution systems（DWDSs） composed of annular reactors incorporating three different treatments： ozone, biologically activated carbon and chlorination（O3-BAC-Cl2）;ozone and chlorination（O3-Cl2）; or chlorination alone（Cl2）. The lowest corrosion rate and iron release, along with more Fe3O4 formation, occurred in DWDSs with O3-BAC-Cl2 compared to those without a BAC filter. It was verified that O3-BAC influenced the bacterial community greatly to promote the relative advantage of nitrate-reducing bacteria（NRB）in DWDSs. Moreover, the advantaged NRB induced active Fe（III） reduction coupled to Fe（II） oxidation, enhancing Fe3O4 formation and inhibiting corrosion. In addition, O3-BAC pretreatment could reduce high-molecular-weight fractions of dissolved organic carbon effectively to promote iron particle aggregation and inhibit further iron release. Our findings indicated that the O3-BAC treatment, besides removing organic pollutants in water, was also a good approach for controlling cast iron corrosion and iron release in DWDSs.

Activated carbon enhanced ozonation of oxalate attributed to HO·oxidation in bulk solution and surface oxidation: Effect of activated carbon dosage and pH

Ozonation of oxalate in aqueous phase was performed with a commercial activated carbon（AC）in this work. The effect of AC dosage and solution pH on the contribution of hydroxyl radicals（HOU） in bulk solution and oxidation on the AC surface to the removal of oxalate was studied. We found that the removal of oxalate was reduced by tert-butyl alcohol（tBA） with low dosages of AC,while it was hardly affected by tBA when the AC dosage was greater than 0.3 g/L. tBA also inhibited ozone decomposition when the AC dosage was no more than 0.05 g/L, but it did not work when the AC dosage was no less than 0.1 g/L. These observations indicate that HOUin bulk solution and oxidation on the AC surface both contribute to the removal of oxalate. HOU oxidation in bulk solution is significant when the dosage of AC is low, whereas surface oxidation is dominant when the dosage of AC is high. The oxalate removal decreased with increasing pH of the solution with an AC dosage of 0.5 g/L. The degradation of oxalate occurs mainly through surface oxidation in acid and neutral solution, but through HOUoxidation in basic bulk solution. A mechanism involving both HOUoxidation in bulk solution and surface oxidation was proposed for AC enhanced ozonation of oxalate.

Disinfection byproduct formation from algal organic matters after ozonation or ozone combined with activated carbon treatment with subsequent chlorination

Algal organic matter(AOM),including extracellular organic matter(EOM)and intracellular organic matter(IOM)from algal blooms,is widely accepted as essential precursors of disinfection byproducts(DBPs).This study evaluated the effect of ozonation or ozone combined with activated carbon(O_(3)-AC)treatment on characteristic alternation and DBP formation with subsequent chlorination of Chlorella sp..The effects of p H and bromide concentration on DBP formation by ozonation or O_(3)-AC treatment were also investigated.Results showed that the potential formation of DBPs might be attributed to ozonation,but these DBP precursors could be further removed by activated carbon(AC)treatment.Moreover,the formation of target DBPs was controlled at acidic pH by alleviating the reactions between chlorine and AOM.Besides,the bromide substitution factor(BSF)value of trihalomethanes(THMs)from EOM and IOM remained constant after AC treatment.However,THM precursors could be significantly decreased by AC treatment.The above results indicated that O_(3)-AC was a feasible treatment method for algal-impacted water.

天津某净水厂引江水强化处理技术研究

天津某净水厂主水源为南水北调中线工程引江水,该水厂在常规工艺基础上增设预臭氧、后臭氧和活性炭强化工艺,以期进一步提升出水水质。建立小试试验装置,对以上各工艺强化常规工艺处理引江水的效果展开探讨。结果表明,絮凝剂PAC和FeCl_(3)的最佳投加量均为17 mg/L;在常规工艺基础上增设预臭氧或后臭氧工艺可以有效提升有机物的去除效果,增设活性炭工艺可同时提升浊度和有机物的去除效果,同时增设后臭氧和活性炭工艺强化去除浊度和有机物的作用最显著。预臭氧和后臭氧的最佳投加量均为1.0 mg/L,当原水中溴离子质量浓度高达150μg/L时,常规-后臭氧工艺、预臭氧-常规-后臭氧工艺中臭氧的投加量应调整为≤0.5 mg/L。

净水厂生物活性炭微生物解析和风险研究进展

系统梳理了活性炭表面存在的微生物类群和优势物种,其中原核生物中变形菌门和拟杆菌门常为其中的优势菌门,真核生物以原生动物和微型后生动物为主;并对某些优势菌群在污染物去除过程中的潜在功能进行了总结,大多数为好氧的化能有机异养微生物。还探讨了可能存在的风险微生物,水源性耐氯细菌病原体属于放线菌亚纲、芽孢杆菌纲和γ-变形菌纲;并归纳了影响微生物群落的因素,包括载体、水质条件、剩余臭氧和进水流向。研究结果有望为净水厂臭氧/生物活性炭工艺的精确调控提供理论依据和技术支撑。

臭氧活性炭工艺处理多种新污染物复合污染研究

以南方某流域水体可检出的SD、SMZ、HCB、马拉硫磷和BPA等新污染物为研究对象,进行复合新污染物共存的原水加标处理试验,研究预处理-常规处理-臭氧活性炭工艺处理效果。结果表明,SD、SMZ、BPA与COD_(Mn)均具有较好的相关性;生物预处理工艺对SD、SMZ、HCB、马拉硫磷和BPA去除率分别为23.97%、21.20%、6.08%、16.26%和23.76%,生物预处理最优停留时间是120min,最优气水比是1:2;常规处理工艺对SD、SMZ、HCB、马拉硫磷和BPA的去除率分别为18.02%、20.08%、23.02%、8.26%和16.53%,常规处理中SMZ和马拉硫磷的混凝剂最佳投加量为15mg/L,其余3种新污染物的混凝剂最佳投加量为20mg/L;深度处理工艺对SD、SMZ、HCB、马拉硫磷和BPA的去除率分别为49.13%、53.80%、60.20%、77.07%和71.50%,深度处理最佳臭氧投加量是3mg/L,最佳臭氧接触时间为24min,最优炭床停留时间是25min。试验工艺对复合新污染物具有良好的去除作用,对SD、SMZ、HCB、马拉硫磷和BPA的总去除率达到了69.86%、73.10%、73.65%、83.74%和82.72%,试验条件下出水的HCB、马拉硫磷和BPA满足《生活饮用水卫生标准》(GB5749-2022),出水的磺胺嘧啶和磺胺二甲嘧啶满足欧美发达国家的水质标准。

臭氧活性炭深度处理工艺中微生物泄漏防控的生产性试验研究

本研究以上海市某水厂臭氧活性炭深度处理工艺为研究对象,研究活性炭滤池微生物泄漏特征,并通过生产性试验优化臭氧和活性炭工艺防控微生物泄漏。优化前活性炭滤池出水中细菌、总大肠菌群和异养菌均有不同程度的泄漏,对应总数分别比进水时增加了8倍、7倍和21倍;将臭氧投加量控制在0.8 mg·L^(-1)以上,炭滤池反冲洗周期缩短至3 d,同时气冲和水冲时间减少至5 min+5 min,对于控制活性炭滤池微生物泄漏有较好的效果。

臭氧-活性炭深度处理在饮用水厂除嗅的应用

常规饮用水处理技术在水体嗅味问题处理中能力有限,研究分别采用活性炭吸附和臭氧氧化对水中土臭素、二甲基异莰醇、异佛尔酮、紫罗兰酮、柠檬醛等嗅味污染物进行实验。结果表明,在400 mg/L活性炭投加量下,去除效果依次为柠檬醛>土臭素>二甲基异莰醇>紫罗兰酮>异佛尔酮,去除率均在80.00%以上。在1 mg/L臭氧氧化条件下,去除效果依次为柠檬醛>异佛尔酮>紫罗兰酮>土臭素>二甲基异莰醇。将两种工艺应用到现场,在黄河下游某水厂改造新增臭氧-活性炭深度处理工艺,通过对不同工艺阶段以及常规水处理进行取样检测,分析有机污染物浓度和CODCr的变化情况。

In-situ sludge reduction based on Mn^(2+)-catalytic ozonation conditioning:Feasibility study and microbial mechanisms

To improve the sludge conditioning efficiency without increasing the ozone dose,an in-situ sludge reduction process based on Mn^(2+)-catalytic ozonation conditioning was proposed.Using ozone conditioning alone as a control,a lab-scale sequencing batch reactor coupled with ozonated sludge recycle was evaluated for its operating performance at an ozone dose of 75 mg O_(3)/g VSS and 1.5 mmol/L Mn^(2+)addition.The results showed a 39.4%reduction in MLSS and an observed sludge yield of 0.236 kg MLSS/kg COD for the O_(3)+Mn^(2+)group compared to the O_(3)group (15.3%and 0.292 kg MLSS/kg COD),accompanied by better COD,NH_(4)^(+)-N,TN and TP removal,improved effluent SS and limited impact on excess sludge properties.Subsequently,activity tests,BIOLOG ECO microplates and 16S rRNA sequencing were applied to elucidate the changing mechanisms of Mn^(2+)-catalytic ozonation related to microbial action:(1) Dehydrogenase activity reached a higher peak.(2) Microbial utilization of total carbon sources had an elevated effect,up to approximately 18%,and metabolic levels of six carbon sources were also increased,especially for sugars and amino acids most pronounced.(3) The abundance of Defluviicoccus under the phylum Proteobacteria was enhanced to 12.0%and dominated in the sludge,they had strong hydrolytic activity and metabolic capacity.Denitrifying bacteria of the genus Ferruginibacter also showed an abundance of 7.6%,they contributed to the solubilization and reduction of sludge biomass.These results could guide researchers to further reduce ozonation conditioning costs,improve sludge management and provide theoretical support.

颗粒活性炭三维电极臭氧体系降解布洛芬影响因素及机理研究

为了解决传统电催化臭氧(E-O_(3))工艺中传质效率低和难降解有机物的问题,在E-O_(3)工艺中引入了颗粒活性炭(GAC)粒子电极,建立三维E-O_(3)体系(E-O_(3)-GAC)。选取布洛芬(IBP)作为目标污染物,对比研究该体系氧化降解效率。结果表明,E-O_(3)-GAC体系氧化能力明显优于常规催化体系(电解(E)、活性炭吸附(GAC)、臭氧氧化(O_(3))、活性炭催化(O_(3)-GAC)、电催化臭氧(E-O_(3))),在40 min反应时间内,IBP降解率可达96.9%。同时,E-O_(3)-GAC体系的协同指数(SI)为2.97,表明电场和GAC具备较好的协同活化作用。E-O_(3)-GAC体系的最佳运行参数为:GAC浓度0.5 g/L,电流强度300 mA,O_(3)流速60 mL/min,初始溶液为酸性条件。一系列猝灭与表征实验表明,在E-O_(3)-GAC体系中,GAC和电场协同催化O_(3),明显提高羟基自由基(·OH)产量。GAC作为微粒电极,能够有效还原水溶液中O_(2)为H_(2)O_(2),与O_(3)反应生成·OH。外加电场对GAC提供保护作用,从而保持GAC催化活性的稳定。综上,E-O_(3)-GAC体系是一个高效、稳定的有机废水处理技术,有望在有机废水处理领域发挥优势。

臭氧-活性炭工艺在东营某水厂升级改造中的应用

东营市垦利区某水厂为提高供水水质,需对现状水厂进行升级改造。水厂总规模为6万m^(3)/d,拟建地块的吨水用地指标偏低,出水水质在执行国家现行的《生活饮用水卫生标准》(GB 5749—2022)基础上,要求浑浊度小于0.3 NTU。文章总结了该水厂处理工艺升级改造方案的比选、制定,详细介绍了臭氧-活性炭工艺在该项目中的设计及应用。该水厂臭氧-活性炭深度处理工艺的运行改善了水的色度、臭和味等感官指标,提高氨氮、亚硝酸盐、有机卤化物等耗氧指标的保障率,特别是当夏季水质恶化、水源含泥沙量较大时,可保障出水水质稳定,保证城市供水安全。

臭氧-活性炭与原位挖潜改造在水厂提标扩容工程中的应用

为响应江苏省政府办公厅关于加强城市基础设施建设和供水安全保障的文件精神,江苏某自来水厂根据原水及出水水质情况结合水厂现状制水工艺,采用了以去除有机物为主要目标的“臭氧-活性炭”深度处理工艺,并对水厂旧系统沉淀池及滤池进行原位挖潜改造。水厂提标扩容工程完成后,出水高锰酸盐指数、浑浊度和氨指标分别降低38.9%、42.1%和40.7%,水厂供水规模提升20%,运行效果达到设计预期,可为类似水厂提标扩容工程提供借鉴。