Kinetics model of aerobic phase in hybrid anoxic-oxic process

Kinetics models of COD degradation,biomass growth of the anoxic-oxic ( A/O) system as well as NH3-N degradation in aerobic phase were presented according to the mass balance theory,reaction-diffusion theory and Fick law. Then these models were testified by comparson with experimental results. It is demonstrated that the variation trends of theoretical and experimental values for COD degradation and biomass growth are similar. The deviation rate between theoretical and experimental values is always under 20% even it increases along with the fluctuation of influent organic loading. In terms of NH3-N degradation,nitrification can also be well simulated by the model as the substrates of influent are sufficient. It indicates that the model can accurately reflect the reaction in hybrid A/O process. Models presented herein provide a theoretical basis for the design, operation and control of hybrid A/O process.

Real-time control of aerobic/anoxic digestion for waste activated sludge

Experiments were conducted to study the performance characters of aerobic/anoxic （A/ A） digestion of sludge at 30± 1 ℃, while the sludge retention time （SRT） was kept 16 d. The varia tions of oxidation reduction potential （Eh ） and pH were continuously monitored during the A/A di gestion and the conversions of ammonium and nitrate were investigated. Important features on both Eh and pH profiles were identified to develop process control strategy. Since the feature point on Eh profile where d2 Eh/dt^2 =0 is very stable during anoxic cycle, it can be used to determine the end of denitrification. The end of nitrification can be identified according to dpH/dt = 0. A real-time control strategy of A/A digestion of sludge was developed and tested with pH and Eh as control parameters. It is shown that the performance of the real-time control strategy is better than that of a fixed time control strategy. While the real time controlled A/A digestion system can achieve a similar volatile suspended solids （VSS） destruction efficiency of 35.2 % as a continuously aerated system, it im proves the supernatant quality in a shorter aeration time（7. 75 d for a 20 d period）.

Effect of Resistance Training,Aerobic Exercise Before Doula-Assisted Delivery on the Psychological Well-Being and Labor Duration of Parturients

Objective:To investigate the impact of resistance training and aerobic exercise before doula-assisted delivery on the psychological well-being and labor duration of parturients.Methods:105 cases of parturients who gave birth in our hospital from February 2021 to April 2023 were included in this study.The patients were divided into a control group of 52 cases and an observation group of 53 cases.The patients in the control group received no particular intervention before delivery and only received doula assistance.The patients in the observation group received resistance training,aerobic exercise,and doula assistance prior to giving birth.After delivery,the mothers were observed for 2 hours in the delivery room and then returned to the maternal and infant ward.The observation indicators of the two groups were compared.Results:In comparison to the control group,the observation group exhibited shorter durations in the first,second,and third stages of labor,as well as the total delivery time.Additionally,the amount of postpartum blood loss at 2 hours was smaller in the observation group.The rate of cesarean section was lower,and the rate of vaginal natural delivery was higher in the observation group.Following the intervention,both groups of postpartum women showed decreased SAS and SDS scores compared to before the intervention.Moreover,the observation group had lower scores than the control group.These differences were all statistically significant(P<0.05).Conclusion:Resistance training and aerobic exercise before doula-assisted delivery can effectively improve the psychological state of parturients,shorten labor duration,increase the rate of natural vaginal delivery,and reduce pain and postpartum hemorrhage.

Removal of nitrogen and phosphorus in a combined A^2/O-BAF system with a short aerobic SRT

A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter （A^2/O-BAF） combined system was carded out to treat wastewater with lower C/N and C/P ratios. The A^2/O process was operated in a short aerobic sludge retention time （SRT） for organic pollutants and phosphorus removal, and denitrification. The subsequent BAF process was mainly used for nitrification. The BAF effluent was partially returned to anoxic zone of the A^2/O process to provide electron acceptors for denitrification and anoxic P uptake. This unique system formed an environment for reproducing the denitdfying phosphate-accumulating organisms （DPAOs）. The ratio of DPAOs to phosphorus accumulating organisms （PAOs） could be maintained at 28% by optimizing the organic loads in the anaerobic zone and the nitrate loads into the anoxic zone in the A^2/O process. The aerobic phosphorus over-uptake and discharge of excess activated sludge was the main mechanism of phosphorus removal in the combined system. The aerobic SRT of the A^2/O process should meet the demands for the development of aerobic PAOs and the restraint on the nitrifiers growth, and the contact time in the aerobic zone of the A^2/O process should be longer than 30 min, which ensured efficient phosphorus removal in the combined system. The adequate BAF effluent return rates should be controlled with 1--4 mg/L nitrate nitrogen in the anoxic zone effluent of A^2/O process to achieve the optimal nitrogen and phosphorus removal efficiencies.

Aerobic N_2O emission for activated sludge acclimated under different aeration rates in the multiple anoxic and aerobic process

Nitrous oxide（N_2O） is a potent greenhouse gas that can be emitted during biological nitrogen removal. N_2O emission was examined in a multiple anoxic and aerobic process at the aeration rates of 600 m L/min sequencing batch reactor（SBRL） and 1200 m L/min（SBRH）.The nitrogen removal percentage was 89% in SBRLand 71% in SBRH, respectively. N_2O emission mainly occurred during the aerobic phase, and the N_2O emission factor was 10.1%in SBRLand 2.3% in SBRH, respectively. In all batch experiments, the N_2O emission potential was high in SBRLcompared with SBRH. In SBRL, with increasing aeration rates, the N_2O emission factor decreased during nitrification, while it increased during denitrification and simultaneous nitrification and denitrification（SND）. By contrast, in SBRHthe N_2O emission factor during nitrification, denitrification and SND was relatively low and changed little with increasing aeration rates. The microbial competition affected the N_2O emission during biological nitrogen removal.

A novel multistage anoxic/aerobic process with sludge regeneration zone (R-MAO) for advanced nitrogen removal from domestic sewage

To achieve advanced nitrogen removal from actual municipal sewage,a novel multistage anoxic/aerobic process with sludge regeneration zone(R-MAO)was developed.The reactor was used to treat actual domestic sewage and the nitrogen removal capacity of the sludge regeneration zone(R zone)was investigated during the long-term operation.The best performance was obtained at the R zone’s Oxidation-Reduction Potential(ORP)of-50±30 mV and hydraulic residence times(HRT)of 1.2 hr.The average effluent COD,TN,NH_(4)^(+)-N and NO_(3)^(−)-N of the R-MAO process were 18.0±2.3,7.5±0.6,1.0±0.5 and 4.6±0.4 mg/L,respectively,with the corresponding removal efficiency of COD,TN and NH_(4)^(+)-N were 92.9%±1.0%,84.1%±1.5% and 97.5%±1.1%.Compared to the sole MAO system,the TN removal efficiency of the R-MAO increased by 10.1%.Besides,under the optimal conditions,the contribution of the R zone in the R-MAO that removal COD,TN,NH_(4)^(+)-N and NO_(3)^(−)-N were 0.36,0.15,0.032 and 0.82 g/day.High-throughput sequencing results showed that uncultured_bacterium_f_Burkholderiaceae(5.20%),OLB8(1.04%)and Ottowia(1.03%)played an important role in denitrification in the R zone.This study provided effective guidance for the design and operation of the R-MAO process in domestic sewage treatment.

Effect of nitrate concentration on filamentous bulking under low level of dissolved oxygen in an airlift inner circular anoxic-aerobic incorporate reactor

This laboratory research investigated a possible cause of filamentous bulking under low level of dissolved oxygen conditions （dissolved oxygen value in aerobic zone maintained between 0.6-0.8 mgO2 /L） in an airlift inner-circular anoxic-aerobic reactor. During the operating period, it was observed that low nitrate concentrations affected sludge volume index significantly. Unlike the existing hypothesis, the batch tests indicated that filamentous bacteria （mainly Thiothrix sp.） could store nitrate temporarily under carbon restricted conditions. When nitrate concentration was below 4 mg/L, low levels of carbon substrates and dissolved oxygen in the aerobic zone stimulated the nitrate-storing capacity of filaments. When filamentous bacteria riched in nitrate reached the anoxic zone, where they were exposed to high levels of carbon but limited nitrate, they underwent denitrification. However, when nonfilamentous bacteria were exposed to similar conditions, denitrification was restrained due to their intrinsic nitrate limitation. Hence, in order to avoid filamentous bulking, the nitrate concentration in the return sludge （from aerobic zone to the anoxic zone） should be above 4 mg/L, or alternatively, the nitrate load in the anoxic zone should be kept at levels above 2.7 mg NO-3N/g SS.

一体化厌氧-变级数缺氧/好氧循环流污水处理装置中试研究

针对现有村镇污水处理技术与装备的不足,开发出适用于村镇污水处理的新型一体化厌氧-变级数缺氧/好氧循环流(A-(AO)_n)同步脱氮除磷、沉淀分离技术与装备,以长沙某污水提升泵站沉砂池的出水作为处理对象开展中试实验。对好氧区不同溶解氧、填料填充比和分区进水条件下装置污水处理效能的变化进行研究,结果表明:当好氧区溶解氧控制在1.5~2.0 mg/L,好氧区填料填充比为30%时,装置的脱氮除磷效果最佳。在不外加碳源且不投加化学除磷药剂的条件下,出水水质优于《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级A标准。高通量测序结果显示,好氧区投加悬浮球填料后,系统中微生物总量和多样性明显提高,为系统中发生同步硝化反硝化(SND)现象创造了条件。

好氧-缺氧序批式反应器去除布洛芬和非诺洛芬的效能研究

布洛芬和非诺洛芬由于其难降解及生物富集性,对水生生态系统和人类健康具有潜在的生态毒性和生物累积风险。探究好氧/缺氧悬浮序批式反应器(O/ASSBR)去除制药废水中化学需氧量(COD)、总氮(TN)及新型污染物布洛芬(IBU)和非诺洛芬(FENO)的效能。结果表明,在O/ASSBR水力停留时间(HRT)为24 h、好氧阶段和缺氧阶段溶解氧分别为2.0和0.4 mg/L,COD有机负荷为1.2~10 kg/m^(3)·d、氨氮(NH_(4)^(+)-N)负荷为4.3~6.3 g/m^(3)·d、IBU负荷为1.71~5.1 mg/m^(3)·d、FENO负荷为0.39~2.1 mg/m^(3)·d的运行条件下,废水中COD、NH_(4)^(+)-N、TN、IBU、FENO的去除率分别为87.74%~89.36%、76.52%~96.75%、69.92%~93.94%、90.01%和91.57%。对反应器中活性污泥生物群落分析表明:系统中主要是革兰氏阳性菌,其中假蕈状芽孢杆菌(Bacillus pseudomycoides)、赤红球菌(Rhodococcus rubber)和地中海弧菌(Vibrio mediterranei)3株菌株对IBU和FENO具有较高的抗性。上述研究表明,O/ASSBR生物系统中存在的功能微生物可以有效降解IBU和FENO等新兴有机污染物,因此O/ASSBR工艺在处理制药废水方面有很好的应用潜力。

废油漆桶清洗废水处理工程设计

根据废油漆桶清洗废水高pH值、高COD和悬浮物、可生化性较差的水质特点,设计采用加酸中和-气浮-混凝沉淀-臭氧氧化-水解酸化-缺氧-好氧-MBR组合工艺进行处理。工程运行结果表明,在进水COD、BOD_(5)、SS质量浓度分别为3750、900、450 mg/L,色度为420度时,相应出水分别为110、15、5 mg/L和15度,排水水质满足GB/T 19923—2005《城市污水再生利用工业用水水质》表1规定的洗涤用水标准。该工艺具有运行稳定,操作简单,投资及运行成本低且节约水资源等特点,实现了良好的经济效益和环境效益。

污水处理厂中“AAO+深度处理”工艺减污降碳研究

针对当前污水处理过程中的碳排放问题,设计“AAO(厌氧—缺氧—好氧)+深度处理”的污水处理工艺,并以某污水处理厂为例,将“AAO+深度处理”工艺应用其中,对污水处理效果进行分析,并对该项工艺的降碳和经济性进行探究。

生物脱氮除磷工艺厌氧/缺氧环境倒置效应

厌氧、缺氧环境是生物脱氮除磷工艺必不可少的重要组成部分，就该两种环境的先后顺序及其对工艺性能的影响进行机理研究。结果表明：常规工艺厌氧（Ａ１）／缺氧（Ａ２）／好氧（Ｏ）布置方式的合理性是值得再探讨的。把常规工艺的厌氧、缺氧环境倒置过来，即以缺氧（Ａ２）／厌氧（Ａ１）／好氧（Ｏ）方式运行可明显提高工艺的氮磷脱除效果。在同等条件下，Ａ２／Ａ１／Ｏ系统的出水Ｏｒｔｈｏ－Ｐ比常规Ａ１／Ａ２／Ｏ系统低５０％，而比反硝化速率却比后者高４０－５０％。

SBR法交替缺氧好氧模式下短程硝化效率的优化

采用SBR法以实际生活污水为研究对象,通过交替缺氧好氧的运行模式实现了短程硝化的快速启动.在不同的缺/好氧时间比条件下考察了短程硝化的启动时间、污染物处理效果以及氨利用速率的变化.结果表明,在缺氧/好氧时间比为1：1和2：1条件下,分别用了31,55d使得两系统的亚硝酸盐积累率达到90%,短程状态稳定.氨氮去除率达到95%以上,COD出水在50mg/L以下,总氮去除率提高20%,污染物的去除效率有所提高.由全程到短程的转变期间,系统氨利用速率分别提高了67.5%和89.8%,同时提高了短程硝化的效率.期间,污泥沉降性较好,污泥容积指数稳定在60~80m L/g.

SBR工艺交替硝化反硝化运行方式的可行性研究

将交替好氧、缺氧运行方式应用于间歇式污水处理系统(SBR工艺),分别在原水碱度充足和碱度不足情况下考察该运行方式的可行性.结果表明:原水碱度充足时,交替硝化反硝化的运行方式在处理效率上并没有体现出优势;原水碱度不足时,交替硝化反硝化与传统硝化反硝化相比,处理效率与出水水质明显提高,出水氨氮可以达到检测水平.当原水碱度的不足量低于所需碱度理论值的1 3时,采取交替硝化反硝化,无需额外补充碱度就可以达到原水碱度充足情况下的处理效率.如果原水碱度的不足量已超过1 3,采取交替硝化反硝化可最大限度节省额外投加碱度的量,降低处理成本,是一种理想的运行方式.

生物膜法A^2/O^2焦化废水处理系统缺氧反应器工艺特性

以焦化厂废水处理系统气浮设备出水为试验废水水源,在中试规模上研究了生物膜法A2/O2(厌氧/缺氧/好氧/好氧)系统中缺氧反应器的工艺特性和效果。缺氧反应器为以陶粒作填料的上流式滤池。研究结果表明,缺氧反硝化对去除焦化废水中COD有重要作用。反硝化菌可利用一些好氧微生物和厌氧微生物都难以降解的焦化废水中的有机物作碳源,反硝化反应器可去除进水中40%的COD。缺氧反硝化反应器进水碳氮质量比在5以上就可基本满足焦化废水反硝化对碳源的需求。稳定运行状况下的NO3--N容积负荷不大于0.24 kg/(m3.d)。缺氧反应器的水力停留时间不小于24 h。系统进水COD、NH3-N的质量浓度分别在1 000～2 200、200～400 mg/L范围内,对系统进水不进行稀释的条件下,水解酸化反应器HRT为20 h,缺氧反应器HRT为24 h,一级好氧反应器和二级好氧反应器HRT均为48 h,二级好氧反应器硝化液回流比为3时,生物膜法A2/O2系统处理出水的COD和NH3-N可以同时达到《污水综合排放标准》(GB8978-1996)中的一级排放标准。

不同持续时间健美操锻炼对大学女生执行功能影响的实验研究

目的:执行功能对于个体的健康发展具有核心作用,本实验探讨健美操锻炼对大学女生执行功能的改善作用,为采用体育锻炼手段改善执行功能提供理论和实践基础。对象与方法:以大学本科健美操公选课女生87名为研究对象,以中等运动强度按照干预持续时间不同分为常规教学组、持续锻炼6周组和持续锻炼12周组,使用Flanker任务、More-odd shifting任务和2-back任务分别测量被试实验前期、中期、后期执行功能的抑制、刷新和转换三个子功能的变化。结果:不同持续时间的健美操锻炼以及不同形式的健美操锻炼对执行功能整体(抑制、转换、刷新)具有显著性影响;常规教学组、持续锻炼6周组、持续锻炼12周组大学女生执行功能各子功能在实验前、中、后期均发生显著性变化;实验后,常规教学组、持续锻炼6周组、持续锻炼12周组大学女生执行功能各子功能存在组间差异。结论:持续一段时间的健美操锻炼可以提高大学女生的执行功能;锻炼持续时间是健美操锻炼影响大学女生执行功能发展的主要因素之一。

O/A式曝气生物滤池挂膜启动试验

目的研究两级串联O/A曝气生物滤池挂膜方法,及挂膜阶段曝气生物滤池对COD和NH4+-N的去除效果.方法采用复合式接种挂膜(接种挂膜+自然挂膜),好氧挂膜与缺氧挂膜同时进行,污泥闷曝7 d后,进水流速由1 m/h逐步增加到3 m/h,曝气量稳定在0.4 L/min,持续21 d.结果历时28 d,出水COD NH去除率为84.54%,NH4+-N去除率为52.95%.结论采用复合式接种挂膜启动快,微生物生长良好,与缺氧微生物相比,好氧微生物更易培养.

短程硝化反硝化去除高氨氮猪场废水中的氮

对比分析了运用缺氧／好氧SBR工艺处理2种COD／N不同的废水的脱氮效果，结果表明，2种废水的脱氮主要是通过短程硝化反硝化实现的，反应器中的NH4^+-N浓度和pH值是控制亚硝酸型硝化的重要因素，经过部分厌氧消化的废水由于保持了较高的COD／N，脱氮效果明显好于完全厌氧消化废水，NH4^+-N去除率达到98％以上，但出水反硝化不完全，投加乙酸钠后出水NOx^--N由100-120mg／L减少到10-20mg／L，乙酸钠投加量以275mg／L为宜．

缺氧/好氧比对连续流半亚硝化稳定性的影响

为研究不同缺氧好氧比对半亚硝化稳定性的影响,采用连续流反应器,在常温(22~25℃),DO(0.3~0.5mg/L)和FA协同作用下实现了全亚硝化后,转变进水为AO除磷二级出水,并逐步向半亚硝化过渡.在此过程中考察了不同缺氧好氧比(0:1、1:1、2:1和3:1)对半亚硝化稳定性的影响.结果表明,缺氧好氧比为0:1时,很难维持低NH_4^+-N(40~70mg/L)亚硝化的稳定,缺氧好氧比为1:1、2:1、3:1时均能维持稳定的半亚硝化效果,相比之下缺氧好氧比为3:1时更加节能;在缺氧好氧比0:1,1:1,2:1,和3:1的过程中,氨利用速率分别提高了29.57%、44.27%、45.23%、49.63%.在整个过程中污泥沉降性能良好,SVI在65~130m L/g.

水解酸化/AAO工艺的同步脱氮除磷及污泥减量研究

针对传统活性污泥法脱氮除磷效率低、污泥产量高的缺点，提出了水解酸化／缺氧-厌氧-好氧（HAAO）污水、污泥一体化处理工艺，研究了该工艺去除COD、氮、磷和污泥减量的效果及其主要影响因素。试验结果表明，在进水COD为286-425mg／L、NH4^＋ -N为36-58mg／L、PO4^3- -P为4-12mg／L、总水力停留时间为11．5h及无外加碳源和碱度的条件下，系统对COD、NH4^＋ -N、TN、PO4^3- -P的去除率分别可达95％、98％、84％、87％。好氧段的DO浓度、固体停留时间（SRT）和剩余污泥回流比对系统的运行效果有重要影响。将污水和剩余污泥同时进行水解酸化，既可有效地改善污水的可生化性，提高系统对碳源的利用效率，又可实现污泥的减量化，试验条件下系统的污泥减量率达56．5％。