Combined process of sequencing batch reactor activated sludge process and constructed wetland for domestic wastewater treatment

By combining sequencing batch reactor (SBR) activated sludge process and constructed wetland (CW), this study is to achieve the domestic wastewater treatment. Our purpose was to determine the optimum operating parameters of the combined process. The process involved advantages and shortages of SBR and CW. Under normal temperature, the 3rd cycle (SBR’s operation cycle is 8 h: inflow for 1 h, limited aeration for 3 h, sediment for 1 h, outflow for 1 h, and idling for 2 h; CW’s hydraulic retention time (HRT) is 24.8 h and hydraulic loading is 24.5 m3/m2 d) was the best cyclic mode. The effluents can meet the standard GB/T18921-2002: "The reuse of urban recycling water: water quality standard for scenic environment use". In the 3rd cycle, the efficiency of CW was the maximum, and energy consumption of SBR was the minimum. Under the condition of low dissolved oxygen, the removing efficiency of chemical oxygen demand (COD) and ammonia was not affected obviously. Simultaneously, nitrification and denitrification phenomena occured and phosphorus was absorbed obviously.

Production of Poly-b-hydroxybutyrate by Activated Sludge in Sequencing Batch Reactor under Aerobic Conditions

In order to improve poly-β-hydroxybutyrate（PHB） production in activated sludge, the anaerobic/aerobic alternative operating sequencing batch reactor（SBR） process was applied in this paper to accumulate PHB. Effects of nutritional conditions and carbon concentration on PHB accumulation were studied. Results indicated that PHB accumulation reached the highest level and accounted for 11.2 % under anaerobic condition for phosphate limitation and 20.84 % under aerobic condition for nitrogen and phosphate limitation of mixed liquor suspended solid（MLSS）, respectively. In addition, 4 g/L was proved to be the optimum carbon concentration in both anaerobic and aerobic experiments, and the PHB accumulation reached 17.1 %（anaerobic, phosphorus limitation） and 60.4 %（aerobic, nitrogen and phosphorus limitation） of MLSS, respectively. PHB could be successfully extracted with sodium hypochlorite and chloroform method from the activated sludge. In addition, the infrared spectrum showed that the PHB sample extracted was of high purity.

Effect of Sludge Retention Time on Nitrite Accumulation in Real-time Control Biological Nitrogen Removal Sequencing Batch Reactor

In this study,four sequencing batch reactors(SBR),with the sludge retention time(SRT)of 5,10,20 and 40 d,were used to treat domestic wastewater,and the effect of SRT on nitrite accumulation in the biological nitrogen removal SBR was investigated.The real-time control strategy based on online parameters,such as pH,dissolved oxygen(DO)and oxidation reduction potential(ORP),was used to regulate the nitrite accumulation in SBR. The model-based simulation and experimental results showed that with the increase of SRT,longer time was needed to achieve high level of nitritation.In addition,the nitrite accumulation rate(NAR)was higher when the SRT was relatively shorter during a 112-day operation.When the SRT was 5 d,the system was unstable with the mixed liquor suspended solids(MLSS)decreased day after day.When the SRT was 40 d,the nitrification process was significantly inhibited.SRT of 10 to 20 d was more suitable in this study.The real-time control strategy combined with SRT control in SBR is an effective method for biological nitrogen removal via nitrite from wastewater.

Impact of salinity on treatment of saline wastewater by sequencing batch biofilm reactor process

High salinity industrial wastewater is difficult to treat using biological treatment system because of the high concentrations of salt.The potential of a sequencing batch biofilm reactor(SBBR)process in treating synthetic high salinity wastewater was evaluated at laboratory scale during a 110-day operation.The reactor was operated in a 12 h cycle,and each cycle consisted of 0.25 h influent addition,8 h aeration,3 h anoxic reaction,0.5 h sedimentation and 0.25 h effluent withdrawal.Gradual increase in salinity gradient was applied during the acclimatization period.The acclimated SBBR system was demonstrated to be an effective process to remove organic compounds and ammonia nitrogen under high salinity conditions with chemical oxygen demand(COD)and ammonia nitrogen(NH3-N)removal efficiencies of 88% and 80%,respectively.The microscopic examination indicated that rather than rotifers or vorticella,the zoogloea,filamentous fungus mingled with a small quantity of swimming infusorians were dominant bacteria in SBBR system.The removal efficiencies close to 80% in COD and 75% in NH3-N were achieved at an organic loading rate(OLR)of 0.96 kg COD/(m3·d),pH of 7.0,salinity of 14 g/L and NH3-N of 30 mg/L.

Effect of inorganic carbon on anaerobic ammonium oxidation enriched in sequencing batch reactor

The present lab-scale research reveals the enrichment of anaerobic ammonium oxidation microorganism from methanogenic anaerobic granular sludge and the effect of inorganic carbon(sodium bicarbonate)on anaerobic ammonium oxidation.The enrichment of anammox bacteria was carried out in a 7.0-L sequencing batch reactor(SBR)and the effect of bicarbonate on anammox was conducted in a 3.0-L SBR.Research results,especially the biomass,showed first signs of anammox activity after 54 d cultivation with synthetic wast...

Removal of Pharmaceutically Active Compounds in Sequencing Batch Reactor

Biological treatment efficiency of six pharmaceutical compounds （acetazolamide, metronidazole, opipramol, piracetam, salicylamide and tinidazole） was evaluated using lab-scale Sequencing Batch Reactor （SBR）. Comparative biological degradation processes of two types of activated sludge from municipal and pharmaceutical industry sewage treatment plants were examined. Three different organic loadings （0.05 g COD/g MLSS.d, 0.1 g COD/g MLSS.d and 0.2 g COD/g MLSS-d） and reaction time on the efficiency of Active Pharmaceutical Ingredient （API） decomposition were examined. Chemical oxygen demand, non-purgeable organic carbon as well as ammonium nitrogen contents were monitored by standard methods. Percentage of API decomposition was analysed by High Performance Liquid Chromatography （HPLC）. The overall API removal efficiency was strictly dependent on the type of activated sludge origin. The main biodegradation products were identified using HPLC-MS,1H NMR and 13C NMR methods as e.g. （{4-[3-（5H-dibenzo[b,f]azepin-5-yl]piperazin-l-yl}methanamine） and （2-amino-1,3,4-thiadiazol-5-sulfonamide） for opipramol and acetazolamide respectively.

Effect of Deionization on Activated Sludge Characteristics: A Case Study of Activated Sludge Culture with Tap Water and Distilled Water

Activated sludge dewaterability and settleability properties are of prime importance in sludge treatment and disposal. Herein, we have experimentally examined the effect of deionization on activated sludge characteristics taking a case study of activated sludge inoculated in tap water and distilled water. The quality of the effluent, both distilled water and tap water were analyzed to determine the characteristics of activated sludge. Results indicated the increasing of the sludge volume index from 51.67 ml/g to 146.9 ml/g leading to the sludge bulking for sludge inoculated in distilled water. The Capillary Suction Time (CST) of sludge cultivated in distilled water varied from 23.1 to 38.4 s, which suggests poor dewaterability. These are due to the growth of some filamentous bacteria in distilled water system. These have further confirmed by light microscope images that showed a significant difference between the sludge systems cultivated in tap water and those grown in distilled water. The present work indeed advances our understanding of activated sludge treatment and would serve as a handy reference for researchers or scholars who want to deal with sewage water treatment.

Molecular characterization of bacterial community in aerobic granular sludge stressed by pentachlorophenol

To characterize the effects of pentachlorophenol (PCP) on the performance and microbial community of aerobic granular sludge in sequencing batch reactor (SBR), the web-based terminal restriction fragment length polymorphism (T-RFLP) and real-time PCR (RT- PCR) techniques were used to explore the bacterial community structure. When PCP increased from 0 to 50 mg/L, the COD removal rate changed little, while the ammonia removal rate dropped from 100% to 64.9%. The results of molecular characterization showed t...

Oxygen Transfer and Hydrodynamics in a Flexible Fibre Biofilm Reactor for Wastewater Treatment

A flexible fibre biofilm reactor was developed for treatment of organic wastewaters.The hydrodynamic characteristics and mass transfer coefficients of oxygen were studied and compared with those of the conventional activated sludge processes.Tracer experiments were performed to obtain the residence time distributions of the reactors.The results indicated that both reactors could be treated as mixed flow reactors.The effects of flow rates of water and air on the overall mass transfer coefficient of oxygen were investigated,and the correlations between the mass transfer coefficient and the ratio of flow rates were obtained.Compared to the conventional activated sludge reactor,the mass transfer coefficients in the flexible fibre reactor were similar to but slightly lower,and less sensitive to the variation in the ratio of flow rates.It indicated that the fibre packing in the reactor hindered the oxygen transfer to some extent.

Effect of high-strength ammonia nitrogen acclimation on sludge activity in sequencing batch reactor

The effect of high-strength ammonia nitrogen acclimation on sludge activity in sequencing batch reactor （SBR） was investigated. Two batch experiments, RUN1 and RUN2, were conducted with the influent ammonia nitrogen concentrations 60 and 500 mg/L, respectively. The sludges inoculated from RUN1 and RUN2 were used to treat a series of influent with ammonia nitrogen concentrations of 59, 232, 368, 604 and 1152 mg/L. It is found that the activated sludge acclimated to higher ammonia nitrogen concentrations revealed higher COD and NH 4 ＋ -N removal efficiencies, and slower DHA decrease. The results confirmed that the activities of the bacteria in activated sludge in SBR were inhibited by high-strength ammonia nitrogen, whereas the activated sludge acclimated to high-strength ammonia nitrogen showed substantial resistance to inhibition by influents containing high levels of ammonia nitrogen.

The key role of inoculated sludge in fast start-up of sequencing batch reactor for the domestication of aerobic granular sludge

Two types of inoculated sludges, granular sludge that had been stored at-20°C and activated sludge, were investigated for the domestication of aerobic granular sludges(AGSs in sequencing batch reactors(SBRs). The results showed that using the stored granular sludge as inoculation sludge could effectively shorten the domestication time of AGS and yielded mature granular sludge after 22 days of operation. The AGS domesticated by stored granular sludge had better biomass and sedimentation properties; its MLSS and SVI reached8.55 g/L and 35.27 mL/g, respectively. The removal efficiencies for chemical oxygen demand(COD), ammonium nitrogen(NH_4^+-N) and total phosphorus(TP) reached 90.76%, 97.39% and 96.40%, respectively. By contrast, 54 days were needed to obtain mature granules using activated sludge. The microbial community structure was probed by using scanning electron microscopy(SEM) and high-throughput sequencing. The results showed that the diversity of the microbial community in mature granules was reduced when stored granular sludge rather than activated sludge was employed as inoculation sludge, and the dominant microbes were changed. The dominant species in mature granules domesticated using stored granular sludge were Zoogloea, Acidovorax and Tolumonas at the genus classification level, while the dominant species were Zoogloea and TM7-genera in granules developed from activated sludge.

Process evaluation of an alternating aerobic-anoxic process applied in a sequencing batch reactor for nitrogen removal

In order to improve the nitrogen removal efficiency and save operational cost,the feasibility of the alternating aerobic-anoxic process(AAA process)applied in a sequencing batch reactor(SBR)system for nitrogen removal was investigated.Under sufficient influent alkalinity,the AAA process did not have an advantage over one aerobic-anoxic(OAA)cycle on treatment efficiency because microorganisms had an adaptive stage at the alternating aerobic-anoxic transition,which would prolong the total cycling time.On the contrary,the AAA process made the system control more complicated.Under deficient influent alkalinity,when compared to OAA,the AAA process improved treatment efficiency and effluent quality with NH4+-N in the effluent below the detection limit.In the nitrification,the average stoichiometric ratio between alka-linity consumption and ammonia oxidation is calculated to be 7.07 mg CaCO_(3)/mg NH4+-N.In the denitrification,the aver-age stoichiometric ratio between alkalinity production and N_(3)^(−)-N reduction is about 3.57 mg CaCO(3)/mg NO_(3)^(−)-N.As a result,half of the alkalinity previously consumed during the aerobic nitrification was recovered during the subsequent anoxic denitrification period.That was why the higher treat-ment efficiency in the AAA process was achieved without the supplement of bicarbonate alkalinity.If the lack of alkalinity in the influent was less than 1/3 of that needed,there is no need for external alkalinity addition and treatment efficiency was the same as that under sufficient influent alkalinity.Even if the lack of alkalinity in the influent was more than 1/3 of that needed,the AAA process was an optimal strategy because it reduced the external alkalinity addition and saved on operational cost.

Carbon Footprint Analyses of Wastewater Treatment Systems in Puducherry

Carbon footprint analysis is a method to quantify the life cycle Greenhouse Gases (GHGs) emissions and identify the measure to reduce climate change impacts. The Intergovernmental Panel on Climate Change (IPCC) has identified that the global warming and climate change which is one of the most important issues in the domain of environment are caused by the excessive emission of Greenhouse Gases (GHG) mainly constituting Carbon dioxide (CO2), Methane (CH4) and Nitrous oxide (N2O). The municipal wastewater treatment plant receives wastewater for treatment and finally discharges the treated effluent. The emissions of GHG during the treatment of wastewater as well as during the treatment process of sludge and also for energy generation are known to be on-site GHG emissions. Off-site GHG emissions are generated due to transportation and disposal of sludge, off-site energy and chemical production. In Puducherry, the municipal wastewater is being treated using oxidation ponds, Upflow Anaerobic Sludge Blanket (UASB) and Sequencing Batch Reactor (SBR). Wastewater treatment using Sequencing Batch Reactor (SBR) technology is one of the state-of-the art wastewater management systems. In this technology equalization, biological treatment and secondary clarification are performed in a single reactor in a time control sequence. The emissions of GHG from the Oxidation ponds of 12.5 MLD, UASB reactor of 2.5 MLD and SBR of 17 MLD were assessed based on the IPCC guidelines and the total emissions of GHG in terms of equivalent of CO2 were compared. The performance of the SBR is more efficient and the emissions of GHG are less than the emissions in the UASB as well as in oxidation ponds. The emission of GHG in SBR is about 60% of the existing treatment systems of oxidation ponds and UASB thus a reduction of 40% GHG emission could be achieved.

大肠杆菌高密度发酵制药废水处理工艺设计实例

大肠杆菌高密度发酵制药的废水包括发酵产生的工艺废水和清洗、冷却产生的低污染废水,前者水量小但污染物含量高,后者量大但污染物含量低。分析比较吹脱法、折点加氯法、生物法、离子交换法和化学沉淀法,确定对污染性强的工艺废水采用化学沉淀法、活性污泥法相结合的处理工艺,先MAP沉淀除氨脱磷,再用低污染废水10倍稀释后进行SBR生化处理,达标排放。MAP沉淀除氨脱磷药剂选用氯化镁和磷酸氢二钠,pH值9.5,投药比采用n(Mg^(2+))∶n(NH_(4)^(+))∶n(PO_(4)^(3-))=1.2∶1∶1,氨氮去除率达83%,COD Cr的去除率达19%,稀释10倍后氮磷含量符合SBR生化处理要求。该工艺污水综合处理成本约为51.8元/m^(3),但处理量小,污水处理总费用约为88元/d,综合费用低,且副产物MAP可用作肥料。

侧流与主流磷回收工艺对比及调控因子分析

从污水中回收磷是缓解磷资源危机的有效途径,目前,污水处理厂常用的磷回收工艺主要为从剩余污泥中回收磷的侧流工艺,存在工艺复杂、回收效率低等问题.以生物膜为主体的主流磷回收工艺可实现磷的同步去除与富集,工艺简单且高效,因此更具发展前景.两种工艺在运行原理及模式上存在显著差异,因此对两者的调控措施不尽相同.本文分别以A^(2)O工艺和生物膜序批式反应器工艺为代表,对比了侧流和主流磷回收工艺在运行原理及模式上的异同,并以聚磷菌的代谢机理为基础,总结了温度、pH值、水力停留时间、溶解氧、碳源和蓄磷量等调控因子对两种工艺产生的影响,并阐述了其差异化机制,以期为生物膜磷回收工艺的进一步发展提供参考.

持续负荷冲击下AnSBBR运行性能及群落结构响应

以厌氧序批式生物膜反应器(AnSBBR)处理葡萄酒生产废水,考察反应器在持续负荷冲击下的运行特性及群落结构响应.结果显示,持续负荷冲击的前13d(29~41d),反应器运行稳定;因逐渐增加的氢分压和挥发性脂肪酸(VFAs),到56d时系统稳定性降低(VFA/TA=0.72),乙酸比产甲烷活性(SMA)降低46.2%,但氢利用速率(HUR)增加69.2%,辅酶F420浓度增加11.9%.在42d时仅外层的Slime-EPS浓度明显增加(34.1%);在56d时TB-EPS和LB-EPS浓度增加61.3%和62.8%,其PN/PS比值增加197.8%和126.0%,负荷冲击诱导EPS分泌大量的应急性蛋白类产物,其电活性物质提高了系统的电子传递活性(35.5%).Illumina MiSeq显示,负荷冲击下Desulfovibrio、Ruminococcus和Geobacter等产酸菌丰度降低,而Methanobacterium丰度由32.2%增至50.9%.生物膜系统通过逐级EPS分泌和强化还原CO_(2)产甲烷来响应持续负荷冲击的影响.

3株高效石油降解菌对SBR处理含油废水的强化作用

研究了3株不同高效石油降解菌株用于序批式活性污泥法(SBR)处理含油废水的效果。结果表明,投加菌液苍白杆菌FP1、假单胞菌X1、红平红球菌KB1的SBR,COD平均去除率分别为90.8%、92.8%、98.2%;石油类物质平均去除率分别为79.1%、80.0%、92.8%;NH_(4)^(+)-N平均去除率分别为87.5%、91.4%、94.7%;TP平均去除率分别为23.8%、30.9%、44.4%。与未投加石油降解菌相比,投加石油降解菌株能显著提高SBR对含油废水中各污染物的去除效率,同时系统运行稳定,耐冲击负荷能力高。实验结果还表明在SBR中投加Fe Cl3利用化学除磷协助生物除磷可提高系统对TP的去除率,同时提高活性污泥的絮凝沉降性能,增加系统内活性生物量。该研究为生物强化SBR处理含油废水的工艺设计与设备运行提供了参考,石油降解菌强化SBR技术有望应用于含油废水生物处理。

Effects of activated sludge flocs and pellets seeds on aerobic granule properties

Aerobic granules seeded with activated sludge flocs and pellets （obtained from activated sludge flocs） were cultivated in two sequencing batch reactors and their characteristics were compared. Compared with granules seeded with activated sludge flocs, those seeded with pellets had shorter start-up time, larger diameter, better chemical oxygen demand removal efficiency, and higher hydrophobicity, suspended solid concentration, and Mg 2＋ content. The different inocula led the granule surface with different microbial morphologies, but did not result in different distribution patterns of extracellular polymeric substances and cells. The anaerobic bacterium Anoxybacillus sp. was detected in the granules seeded with pellets. These results highlighted the advantage of pellet over activated sludge floc as the seed for aerobic granulation and wastewater treatment.

城市污水处理不同序批式活性污泥法的工艺特点和功能差异分析

城市污水处理是保障城市环境卫生和健康的重要环节,而序批式活性污泥法作为一种常用的污水处理技术,具有灵活、高效、适应性强的特点。然而,不同的序批式活性污泥法在工艺特点、功能差异、优缺点以及应用场景上存在差异。因此,对这些技术进行深入研究和比较,对于选择适合的污水处理工艺具有重要意义。

污泥减量化的高浓度废水作为碳源的原位生化处理

为了实现污泥减量化和弥补污水处理厂污水碳源不足,本文调查了臭氧与机械耦合工艺破解剩余污泥的溶解效率和产生高浓度污水的特性,使用序批式活性污泥反应器(SBR)进一步调查高浓度废水和碳源较低的市政污水混合共同生化处理的可行性以及出水水质。实验结果表明,臭氧与机械耦合工艺可释放出大量有机物污染物,在最佳臭氧投加量100 mg O_(3)/g MLSS、搅拌速度800 r/min时,混合泥水的MLSS由7500.0 mg/L下降到3851.2 mg/L,污泥的溶解效率为48.7%,其溶解性化学需氧量(SCOD)、总磷(TP)、总氮(TN)和氨氮(NH_(4)^(+)-N)分别由原来的28.0、0.8、11.0、2.0 mg/L增加到3086.0、24.5、144.3、48.8 mg/L。将这样高浓度污水视为碳源,回到系统,与低浓度的市政污水10:1的体积加以混合,其水质分别为COD:500.0 mg/L、TP:6.0 mg/L、TN:60.0 mg/L和NH_(4)^(+)-N:51.0 mg/L,经过好氧生化反应后,出水水质可达到COD:33.7 mg/L、TP:1.4 mg/L、TN:14.6 mg/L和NH_(4)^(+)-N:2.2 mg/L,去除率分别为93.3%、76.7%、75.7%和95.7%,从而说明,臭氧与机械搅拌耦合破解污泥的高浓度废水,不仅可以实现城市污水厂污泥减量化,而且还可以作为碳源,促进污水的有效处理,是未来污水厂污泥减量化自身消纳的一个重要发展方向。