Effects of Coagulation and Ozonation Pretreatments on Biochemical Treatment of Fluid Catalytic Cracking Wastewater

Fluid catalytic cracking (FCC) salty wastewaters, containing quaternary ammonium compounds (QACs), are very difficult to treat by biochemical process. Anoxic/oxic (A/O) biochemical system, based on nitrification and denitrification reactions, was used to assess their possible biodegradation. Because of the negative effects of high salt concentration (3%), heavy metals and toxic organic matter on microorganisms’ activities, some techniques consisting of dilution, coagulation and flocculation, and ozonation pretreatments, were gradually tested to evaluate chemical oxygen demand (COD), ammonia-nitrogen (ammonia-N) and total nitrogen (TN) removal rates. In this process of FCC wastewater, starting with university-domesticated sludge, the ammonia-N and TN removal rates were worst. However, when using domesticated SBR’s sludge and operating with five-fold daily diluted influent (thus reducing salt concentration), the ammonia-N removal reached about 57% while the TN removal rate was less than 37% meaning an amelioration of the nitrification process. However, by reducing the dilution factors, these results were inflected after some days of operation, with ammonia-N removal decreasing and TN barely removed meaning a poor nitrification. Even by reducing heavy metals concentration with coagulation/flocculation process, the results never changed. Thereafter, by using ozonation pre-treatment to degrade the detected organic matter of di-tert-butylphenol and certain isoparaffins, COD, ammonia-N and TN removal rates reached 92%, 62% and 61%, respectively. These results showed that the activities of the microorganisms were increased, thus indicating a net denitrification and nitrification reactions improvement.

Study on Influencing Factors and Kinetics of Removal of Ammonia Nitrogen from High Salinity Wastewater by Sodium Hypochlorite Oxidation

The influencing factors and kinetics of oxidative degradation of ammonia nitrogen in high salinity wastewater by sodium hypochlorite oxidation( Na Cl O) were studied. The results showed that the degradation process of ammonia nitrogen by sodium hypochlorite accorded with a pseudo first-order kinetics model,and the influencing factors included Na Cl O dosage,initial concentration of ammonia nitrogen,salinity,temperature,and so on. When Na Cl O dosage was 0. 6%( MCl∶ MN= 13. 76),the reaction rate constant was up to 0. 015 75 min^(-1). The higher the initial concentration of ammonia nitrogen was,the worse the effect of oxidation reaction was. When the initial concentration did not exceed 45 mg/L,the effect on oxidation reaction rate constant increased with the increase of the initial concentration. Low salinity had no effect on ammonia nitrogen oxidation.When salinity was higher than 2. 0%,the inhibition effect on ammonia nitrogen oxidation would increase,and the reaction rate constant decreased obviously with the increase of salinity. The improvement of reaction temperature was beneficial to ammonia oxidation degradation. As temperature increased from 10 to 35 ℃,the reaction rate constant rose from 0. 00188 to 0. 01043 min^(-1).

Isolation and Identification of Ammonia Nitrogen Degradation Strains from Industrial Wastewater

Nine strains of ammonia nitrogen degradation strains from C1 to C9 were isolated from industrial wastewater to study their degradation and conversion of ammonia nitrogen. The results showed that C2 strain with a high degradation activiity of ammonia nitrogen, and the ammonia nitrogen degradation rate of the activated C2 strain was 93% within 24 h when the initial concentration of ammonia nitrogen was 200 mg/L under the conditions of inoculation 10%, temperature 35?C, pH 7.0, rotation 200 r/min. And C2 was identified as Bacillus amyloliquefaciens.

Treatment of coke plant wastewater by SND fixed biofilm hybrid system

In this article, coke plant wastewater was treated by a simultaneous nitrifying and denitrifying （SND） fixed biofilm hybrid system. The results showed that suitable parameters of the system were important for the performance of the bio-degradation system. The chemical oxygen demand （COD） removal efficiency in this system was satisfactory, higher than 94%, and ammonia nitrogen was higher than 95%. The effluent COD concentration could meet the discharge standard, except for very few situations. The results showed that a sufficient carbon source was important for making ammonia nitrogen concentration meet the discharge standard. Then the TiN removal efficiency in this system can be brought higher than 94%. Dissolved oxygen （DO） is very important to the performance of the SND bio-degradation system, and the suitable DO is about 3.5-4.0 mg/L at the forepart of reactor. In addition, the performance of the system was almost not affected by pH value. The results show that the system is feasible to treat coke plant wastewater.

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, BOD, 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 IBAC1 and 27 minutes in IBAC2, the O3-IBAC process achieved ammonia nitrogen removal efficiency of 91%. In addition, the removal efficiencies of COD, volatile hydrobenzenes, suspended solids, turbidity and petroleum-based micro-pollutants 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 IBAC1 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.

Experimental Research on Coke Wastewater Treatment by Hybrid Biological Reactor

Phase hybrid biological reactor (HBR) was used in treating coke wastewater by adding submerging fiber-ball fillers in suspended growth activated sludge.The optimum operation parameters for the highest performance were determined.It was found that the hybrid biological reactor worked well for the coke wastewater treatment in terms of Chemical Oxygen Demand (COD),NH+4-N and other refractory organic compounds removal efficiencies.Compared with conventional activated sludge system,the removal rate of COD and NH+4-N and the nitrating rate were higher and more stable in the hybrid biological reactor.COD of effluent was less than 75 mg/L and the removal rate of COD and NH+4-N could be up to 95.0% and 92.5% when COD of influent and NH+4-N were less than 700 mg/L and 300 mg/L,respectively.In this way,the quality of effluent concentration could reach the first class of integrated wastewater discharge standard (GB8978-1996)(COD ≤100 mg/L).

鸟粪石沉淀法处理高浓度氮磷废水研究进展

随着节能低碳理念的深入发展,鸟粪石沉淀法因其较高的氮磷回收效率和相对低能耗的优势,近年来成为高浓度氮磷废水处理和资源化利用的热点方向之一。系统地对国内外鸟粪石沉淀法处理污水的相关文献进行了梳理,从新兴处理对象及方案、回收反应器构型开发、低成本镁源开发、高效结晶、晶体分离提纯等方面,总结了相关研究成果。此外,结合环境毒理性、处理成本、综合资源化利用等角度对鸟粪石沉淀法的发展前景和趋势进行预判,为相关研究提供参考。

低氨氮质量浓度废水DPR-SNAD脱氮除磷效能研究

针对低氨氮废水单级自养脱氮系统副产物硝氮残留,有机物耐受能力差,以及缺乏除磷功能等问题,提出反硝化除磷(Denitrifying Phosphorus Removal,DPR)-单级自养脱氮(Simultaneous Partial Nitrification,Anaerobic Ammonium Oxidation and Denitrification,SNAD)组合处理技术,重点考察氨氮负荷对单级自养脱氮工艺(Single-stage Nitrogen Removal Using Anammox And Partial Nitritation,SNAP)系统、泥龄对DPR系统构建的影响,以及低氨氮废水DPR-SNAD组合处理系统的脱氮除磷效能与微生物种群。研究结果显示:采用氨氮质量浓度梯度递减方式,氨氮负荷为0.20 kg N/(m^(3)·d)的低氨氮质量浓度的SNAP系统构建时间为63 d,较负荷为0.05 kg N/(m^(3)·d)的系统缩短了37 d。泥龄对构建的DPR系统效能影响显著,泥龄为35 d的系统除磷脱氮效能较高,PO_(4)^(3-)-P、NO_(3)^(-)-N、COD去除率分别为86.25%、98.00%、92.00%,系统释磷、吸磷、反硝化脱氮速率分别达4.60 mg/(L·h)、4.13 mg/(L·h)、5.53 mg/(L·h)。DPR-SNAD组合处理系统的氨氮(NH_(4)^(+)-N)、总氮(Total Nitrogen,TN)、总磷(Total Phosphorus,TP)、化学需氧量(Chemical Oxygen Demand,COD)去除率分别为100%、98.64%、86.00%、93.30%。TN、TP去除率较对照组SNAP分别提高了19.20百分点和86.00百分点。16S rRNA高通量测序结果显示,组合系统脱氮除磷功能菌属主要有Rhodobacter、Candidatus_Brocadia、Nitrosomonas、Gemmobacter,SNAD系统中厌氧氨氧化菌(Anaerobic Ammonia Oxidation,AnAOB)相对丰度显著高于对照组SNAP系统,DPR促进SNAD提高了系统脱氮效能。

正渗透膜回收废水中氨氮的研究进展

综述了正渗透(FO)膜技术对废水中的氨氮回收的研究进展。重点介绍了其发展历史、工艺原理、应用现状,将应用现状分为膜制造和改性、膜与其它工艺的耦合工艺、提取液、膜污染、数学建模这五方面进行了综述。在此基础上,对正渗透膜技术的研究前景进行了展望。

生物增效技术促进炼油废水降氮效果分析

介绍了针对外排氨氮标准不断提升,炼油含盐废水处理装置出水氨氮控制难度增加,在一段时期常出现波动情况,投加硝化菌进行生物增效处理达标的生产试验。对试验过程和试验前后含盐污水处理装置进、出水数据进行分析,对照出水pH值与硝化系统的关系,找到了出水氨氮异常升高主要是污水处理系统碱度降低引起的根本原因。证明了投加硝化菌进行生物增效的方法可作为恢复污水生化系统快速建立硝化系统,恢复氨氮去除能力的有效应急手段。

成都假单胞菌处理畜禽养殖污水的效果研究

成都假单胞菌WD211是一株从养殖污水中筛选得到的具有良好脱氮性能、良好抗逆性的菌株。文章从畜禽养殖污水原液处理、模拟污水处理和微生物群落结构变化分析等方向对WD211菌污水处理效果进行了初步研究。研究结果表明,外源添加WD211菌对畜禽养殖污水的TN和NH_(4)^(+)-N的去除效率有明显提升,可达25.03%和27.30%,高于空白对照;外源添加WD211菌对畜禽养殖污水的NH_(4)^(+)-N的生化去除能力有促进作用,且这种促进作用在2%添加剂量时更为明显。模拟污水中WD211菌对COD、TN、NH_(4)^(+)-N的去除率分别为83.16%、28.35%、44.58%,仅积累少量的NO_(3)^(-)-N(0.907 mg/L)和NO_(2)^(-)-N(0.047 mg/L)。WD211菌在NH_(4)^(+)-N浓度较高的条件下能发挥较好的性能;外源添加WD211菌后,水样中假单胞菌属、类产碱菌属和副球菌属等脱氮相关菌属丰度上升。

含钒页岩酸浸提钒废水处置的研究进展

含钒页岩酸浸提钒过程中会产生两类废水:酸性废水以及氨氮废水。基于提钒废水的性质特点,评述了其处置的研究进展。处理酸性废水时,中和沉淀法操作简单,但存在重金属离子时还需进行二阶段处理;膜分离法避免了中和沉淀法产生污泥多的情况,但膜易结垢使得寿命较短;酸性废水循环主要是将其返回至前端的浸出过程,利用废水中的H+等,可明显节约成本。处理氨氮废水时,吹脱法简单高效,但废水氨氮浓度较高时还需要进行二次脱氮;磷酸铵镁结晶法不仅操作简便,其产物还可作为肥料使用,但其消耗药剂较多,这增加了成本;离子交换法虽运行成本低、效率高,但尚有吸附容量小、金属负载型树脂离子易洗脱等关键问题待解决;催化氧化法效率高且产物清洁,但其使用成本高以及反应稳定性差。最后,展望了提钒废水处置的方向与趋势。

外场强化生物与生态耦合工艺对生活污水氨氮处理适应性研究

为提高现有人工湿地对农村生活污水的净化效率、更好地为农村生活污水处理提供适宜可行的装置技术。以西南林业大学校园生活污水为模拟对象、传统生物生态耦合系统为基础,构建不同外场强化型生物与生态耦合工艺,探索施加磁场、电磁复合场、电场等外场强化作用对氨氮去除的影响。结果表明:经72 h的处理之后,BWR的氨氮平均出水浓度为14.14 mg/L、BWR-磁为9.79 mg/L、BWR-电磁为2.73 mg/L和BWR-电为2.79 mg/L,BWR-电磁的BWR-电的出水氨氮质量浓度可满足《城镇污水处理厂污染物排放标准》(GB18918—2002)一级A标准(5.0 mg/L);相比于BWR,磁场、电磁复合场、电场强化对氨氮的去除率分别了提高约17、41.83、42.85个百分点,立体与表面负荷削减量分别可提高7.27、19、18.92 mg/cm3与0.18、0.48、0.47 mg/cm2;变形菌门和硝化螺旋菌门相对丰度增加了8.29、14.40、13.83和0.31、1.24、0.50个百分点左右;电场能耗远低于传统污水厂的的平均能耗,电场与磁场相结合,实现了1+1>2,可有效解决碳氮比低的问题,在一定程度为人工湿地技术的改进提供了新的思路。

燃煤电厂氨氮废水电化学氧化处理工程实例

针对燃煤电厂高浓度氨氮废水处理的实际需求,设计研发了基于电化学氧化技术的氨氮废水处理系统,并应用于沿海某电厂。运行结果表明:系统能够处理该电厂全厂氨氮废水,对于氨氮浓度80~100 mg/L、氯离子浓度6000~8000 mg/L、pH不小于9.0的反应器进水,能够以过流处理的模式保证出水氨氮浓度小于1 mg/L且pH不小于6.0。系统出水含有较高浓度的余氯,可作为杀菌剂资源化回用至电厂冷却水系统,较原工艺减少经济成本119.93万元/年。该工程的顺利实施对同类废水的治理提供技术支持和借鉴参考。

常低温条件下氨氮质量浓度对厌氧消化处理轻工行业废水的影响

在升流式厌氧污泥床(Up-flow Anaerobic Sludge Blanket, UASB)中启动厌氧消化工艺,考查常低温(<25℃)条件下氨氮质量浓度对厌氧消化处理模拟轻工行业废水性能的影响。结果表明,间歇加泥并控制回流比为7.5的条件有利于厌氧消化工艺的启动,当氨氮质量浓度为400~1400 mg/L时,对厌氧消化性能基本无不利影响,且在400~800 mg/L之间时,会轻微促进厌氧消化性能,但较高的氨氮质量浓度会导致部分微生物死亡,促使胞外聚合物和溶解性微生物产物含量增大。此外,氨氮质量浓度的升高不利于氢营养型产甲烷古菌Methanobacterium的生长,其相对丰度从75.5%降低至6.3%,但有利于乙酸营养型产甲烷古菌Methanosaeta和兼性营养型产甲烷古菌Methanosarcina的增殖,二者的相对丰度分别从19.8%和1.7%增大至63.8%和29.1%。常低温条件下,厌氧消化工艺可以处理氨氮质量浓度为0~1400 mg/L的高COD的轻工行业废水,但优势产甲烷古菌会发生显著演替。

废水处理硝酸盐异化还原与厌氧氨氧化/反硝化耦合工艺构建

采用厌氧膨胀颗粒污泥床反应器(EGSB)处理含COD、氨氮和硝氮的模拟废水,旨在高浓度有机废水处理系统中快速构建厌氧氨氧化(Anammox)运行工艺。通过接种少量Anammox污泥和逐步提高氨氮浓度的操作方式,在连续运行58d后,系统成功启动Anammox反应,此时的总氮和COD去除率稳定在97%和98%以上。物料衡算显示,Anammox反应途径对氮的去除贡献逐渐增加,硝酸盐异化还原(DNRA)耦合Anammox和反硝化共同促进了系统的同步脱氮除碳。对微生物群落分析发现,Candidatus Kuenenia相对丰度由0.27%快速升高至35.87%,DNRA菌(Ignavibacterium、Thermogutta)及反硝化菌(Azospira、Gp3)在体系内共存。通过基因注释法,检测出了Anammox、DNRA、硝酸盐还原及亚硝酸盐还原关键基因。运行过程中,颗粒污泥颜色变红且粒径增大;胞外聚合物(EPS)分析表明多糖(PS)和蛋白质(PN)含量增加而PN/PS下降;三维荧光光谱发现腐殖酸类物质增多。研究结果为高浓度有机含氮废水高效处理提供了一种新的工艺途径。

臭氧+MVR+脱氨+MBR工艺对银粉加工废水的处理

银粉加工废水具有高盐、高COD_(Cr)和高氨氮等特点,对环境污染大,且处理难度大。针对某单位的银粉加工废水,采用臭氧催化氧化+MVR蒸发+氨氮吹脱+MBR生化组合工艺对其原有工艺进行改造。结果显示,废水出水水质COD为17 mg/L、氨氮为0.72 mg/L、TDS为601 mg/L、总氮为6.55 mg/L、pH为6~9,出水达到《四川省岷江、沱江流域水污染物排放标准》DB 51/2311-2016水质标准。采用臭氧催化氧化替代芬顿氧化,直接运行费用为71.12元/m~3,比芬顿单元降低157.88元/m~3,危险废物减少791.29 kg/d。该方法具有显著的环境效益和经济效益。

基质配置对潮汐流人工湿地处理稀土矿山含氨氮地表水效果的影响

人工湿地(Constructed Wetland,CW)可对稀土矿工业开采遗留的氨氮污染废水进行高效生态化处理。添加铁碳和生物炭材料构建四组潮汐流人工湿地,研究不同淹没空置比(F/D)条件下铁碳和生物炭添加方式及位置对湿地脱氮效果的影响。结果表明,控制F/D=6 h/6 h(水流淹没湿地床体6 h后排水空置6 h后下一批次进水),进水NH^(+)_(4)-N为40±2.37 mg/L,CW_(FeC2)(NO.2 Fe-C substrate Constructed Wetland)对NH^(+)_(4)-N有较好的脱氮效果,平均去除率86.44%±3.28%,最高去除率89.72%,CW_(B)(Biochar based Constructed Wetland)对总氮(TN)有较好的去除效果,最高去除率51.12%。高通量测序分析结果显示,生物炭基质湿地Alpha多样性指数各指标均大于铁碳基质湿地。具有固氮作用的变形菌门在CW FeC1和CW_(FeC2)中占比70%以上,在CW_(B)中占比40%以上,是最主要的脱氮菌群。在CW_(B)中发挥好氧硝化作用的硝化螺旋菌占比15%以上,酸杆菌门存在近10%,能适应酸性条件且具有一定脱氮作用。本实验的进行对稀土矿山含氨氮废水的生态化处理具有一定的参考应用价值,为相关领域填补空缺并提供一定的数据支持。

某存量农药化工废水处理的工程实例和运行分析

针对某存量农药化工废水水质复杂,氨氮浓度高,可生化性差的特点,采用“前芬顿氧化+氨氮吹脱+水解酸化+两级A/O+后芬顿氧化”的工艺进行处理。该工艺适应复杂的水质,而且处理效果稳定。实际运行数据表明,COD、氨氮、TP去除率分别达到92%和98%及96%以上,出水COD≤100 mg/L、ρ(NH_(3)-N)≤15 mg/L、ρ(TP)≤1mg/L,稳定达标排放。经成本核算,该处理项目运行成本为62.96元/t。该方法可为实际农药化工废水的有效处理提供参考。

核电厂非放射性生产废水处理方案研究

核电厂非放射性生产废水的来源及成分比较复杂,现有核电机组非放射性废水均是排入循环冷却水排水系统后经电厂总排放口排入海中,总排放口排水水质满足《污水综合排放标准》中的排放要求。随着国内环保要求的提高,部分地方环保部门提出废水中的二类污染物含量在排入循环冷却水排水前需满足《污水综合排放标准》中的排放要求,现有废水水质无法满足该要求。为解决上述问题,以CAP1000核电机组为例,通过对非放射性生产废水的组成及现有的处理情况进行分析,明确了超标废水来源主要为凝结水精处理系统树脂再生时排放的酸碱废水,废水中氨氮含量远高于排放标准要求。根据该废水的排放情况及水质特点,先对废水进行了高、低盐分类收集减量处理,然后针对氨氮超标的高盐废水提出了折点氯化法、吹脱+电解制氯氧化联合处理、膜脱氨3种处理方案,并对各方案进行了技术经济比较,为核电厂的非放射性生产废水处理的工艺设计提供参考。