Effect of Salinity Variations on the Performance of Activated Sludge System

To investigate the influence of salinity variations on the performance of activated sludge systems, treating domestic wastewater. Methods The completely mixed reactor was used and operated in a batch-wise mode. The activated sludge taken from the Gaobeidian Wastewater Treatment Plant was used as a seeding sludge. Total organic carbon (TOC), oxygen uptake rate (OUR) and suspended solids (SS) were used as parameters to characterize the performance of the treatment systems. TOC was measured using a TOC-analyzer (TOC-5000, Japan). The OUR value was measured with a dissolved oxygen meter (YSI model-58). SS was measured gravimetrically. Results The TOC removal efficiency and the OUR value of activated sludge were not deteriorated when the NaCl shock concentration was less than 0.5 g/L. However, when the NaCl shock concentrations were up to 10g/L and 20 g/L, the OUR of activated sludge was reduced by 35% and TOC removal efficiency was dropped by 30%, compared with the control experiment without NaCl shock loading. Conclusion The effect of NaCl shock loading on the activated sludge wastewater treatment system is dependant upon the NaCl concentrations and the degree of influence can be inferred through the change of substrate utilization rate at different shock NaCl loadings.

Optimizing Conditions of Enhancing Granule Sludge Concentration and Performance

An expanded granular sludge bed （EGSB） reactor was adopted to study the influence factors and rule of enhancing granular sludge concentration and performance. The experiment was performed at 33 ℃, pH 6.0-8.0 with continuous flow by adding proper quantity of nutritional trace elements. The results show that SLR was the key of steady operation of EGSB reactor. The increment of the granular sludge was influenced by volume loading rate （VLR）, liquid up-flow velocity and sludge loading rate （SLR）. Concentration of granular sludge increased rapidly when liquid up-flow velocity was over 0.94 m · h^-1 with SLR being at 1.0-2.0 d ^-1. With the propriety parameters： liquid up-flow velocity 2.52 m · h^-1, SLR 1.0-2.2 d^-1 and VLR 8.2-13.1 kg · m ^3 · d^-1, 23 days＇ continuous operation resulted in an increment by over 80% of granular sludge concentration in the EGSB reactor, plus good granular sludge property.

Application of Heterogenous Catalysis with TiO2 Photo Irradiated by Sunlight and Latter Activated Sludge System for the Reduction of Vinasse Organic Load

Vinasse is the main residue generated during alcohol, sugar and blue rum production by fermentation process. This residue is effluent that could cause serious environmental pollution due to high organic load when is not treated adequately. The aim of this work consists of evaluating the efficiency and application of heterogeneous photocatalysis with TiO2, followed by a biological treatment (activated sludge system) to reduce organic load in the referred effluent. Complete factorial designs indicated the best experimental conditions subsequent to photacatalytic and biological treatments providing a reduction of non-purgeable organic carbon (NPOC) as a variable response. After the photocatalytic process, the sample from the best experiment condition was treated by a biological process in order to verify the degradation efficiency of the effluent organic matter studied according to the hybrid system (Advanced Oxidation Process—Acti- vated Sludge System). This system, which presented more efficiency, had a photochemical treatment of 180 minutes carried out in aerated solutions, pH 9 and effluent in natura, while the biological treatment was performed at pH 8 and sludge concentration of 5 gL–1. The reduction of biochemical oxygen demand (BOD) was >80%.

Study on Limited Filamentous Sludge Bulking Test in A/O Activated Sludge Process

[Objective] This study aimed to make use of the limited filamentous sludge bulking characteristics to purify water quality and save energy. [Method] The effects of dissolved oxygen （DO） on sludge bulking were explored by changing the DO con- centration in the aerobiotic pool of NO system from the low load （0.25 kg COD/（kg MLSS.d）） and the medium to high load （0.55 kgCOD/（kg MLSSod））. [Result] In the NO activated sludge system, when the sludge load was 0.25 kg COD/（kg MLSS.d）, DO=1.5 mg/L, the sludge index was at around 250, while when the sludge load- ing was 0.55 kg COD/（kg MLSS.d）, DO=1.5 mg/L, the sludge index was close to 300, occurring the limited filamentous bulking. The bulked sludge still showed high removal rates to COD, SS, nitrogen and phosphorus. [Conclusion] It could improve the oxygen transfer rate and reduce the aeration rate at low DO conditions to achieve energy-saving.

Performance evaluation of up-flow anaerobic sludge blanket(UASB) reactor for treatment of paper mill wastewater

The present study deals with the performance evaluation of the UASB reactor under varied organic loading rate(OLR) for the treatment of paper mill wastewater. The sludge granulation process started after 120 days from the start-up period. Sludge granules size was found to be 0 8 mm at OLR of 1 72 kgCOD/(m 3·d), which reached maximum size of about 1 0 to 1 2 mm at OLR of 2 1 kgCOD/(m 3·d). At the end of initial OLR of 1 0 kgCOD/(m 3·d) the VSS concentration was 12 86 gVSS/L, which got increased to 38 05 gVSS/L at the end of an OLR 2 1 kgCOD/(m 3·d). Most of the times VFA recorded were well within the limit of VFA reported in anaerobic fermentation process. Many times the pH observed was between 6 5 and 7 8, which is more favorable for any anaerobic process. It is also found that pH within the reactor increases along with the height of reactor. The total maximum biogas production was found to be 0 40 L/gCOD removals at OLR of 2 1 kgCOD/(m 3·d) and the maximum BOD removal at this stage was observed to be 90%.

基于NS2的改进O-LOAD路由的设计与实现

针对目前LOAD路由存在的个别节点能量消耗过快导致整个网络瘫痪以及路由请求频繁的问题,提出改进OLOAD路由协议,加入能量模型作为路由代价之一并且设计备用路由,当活跃路由失效时,更新备用路由为活跃路由。经过NS2平台对O-LOAD路由进行仿真,结果证明O-LOAD路由具备高数据投递率和低路由开销的优点,同时有效延长了网络的生存时间。

Process Adaption of a Small WWTP Operated at Low Loading Conditions for Substantial Energy Savings

The very long tradition of the activated sludge treatment model within the water industry has demonstrated very versatile possibilities to adopt the operation mode for different enhancements. By looking into other treatment models within the activated sludge family it is possible to find alternatives for the operation. This paper concentrates on the possibilities to improve even small WWTP with respect to energy savings. The small plant in Northern Sweden, called Rosvik WWTP, is given as an example. Some important findings related to the intermittent aeration mode may be summarized as follows: 1) An energy savings for the operation of the small WWTP with respect to aeration needs that resulted in a decrease of the energy power supply by more than 35%, as compared with the previous operation based on continuous aeration;2) The up to date effluent levels with respect to the main pollutants have remained at very good levels in 2020, P-level averages 0.16 mg P/l versus consent level < 0.5 mg P/l;COD-level 40 versus < 70 mg/l and BOD7 9 versus < 15 mg/l;3) Sometimes, also improved sludge settling characteristics have been observed, thus providing improved discharge figures;4) The potential to develop an enhanced biological phosphorus removal. There are however some needed conditions to accomplish these improvements: 1) Reliable on-line probes for both oxygen control, SS-concentration control and optionally also for nitrogen control;2) A flexible automation system that allows the needed process modifications to take place;3) And finally, very important dedicated and competent plant operators, with the needed curiosity for operation improvements.

Process Adaption and Modifications of a Nutrient Removing Wastewater Treatment Plant in Sri Lanka Operated at Low Loading Conditions

The Sri Lankan national water authority, that is The National Water Supply and Drainage Board (NWS&DB) has taken a new wastewater treatment plant into operation at Ja Ela, North of Colombo. The plant has been in operation since September 2011. In April 2012, it was concluded how a test of the aeration efficiency and a performance test should be carried out. The tests have been based on the actual loading of the plant and the analysis results from the daily process control. The evaluation of the aeration efficiency is not reported in this paper. The paper presents the overall performance of the water treatment part of the plant during start-up conditions, from fall 2011 through the first five months of 2012. The results from the operation are found in Table 1. An important circumstance at the plant is the current very low loading in comparison with the design load. This fact has resulted in an introduction of an intermittent mode of the aeration (nitrification) reactor. Based on operation figures, during more than a month (May 2012), it has been possible to give a realistic assessment of the overall performance. The most striking results are summarized as follows: 1) The intermittent operation has enabled an energy efficient operation of the plant. By the introduction of the intermittent aeration, the energy consumption has been reduced by around 75%, compared with the continuous operation mode;2) The plant performance during the intermittent operation has been improved with respect to virtually all important pollution variables. The most striking improvement is the discharge total P level, reflecting that a substantial enhanced biological phosphorus removal takes. The typical discharge levels found during May 2012, were compared with the earlier obtained values. It is important to underline that the loading on the plant has slightly increased during May as compared with the previous operation period.

330 MW机组煤粉锅炉耦合油污泥低负荷燃烧数值模拟与试验研究

针对含油污泥的无害化处置问题,提出预处理后送入煤粉锅炉与煤粉耦合燃烧的技术路线,在330 MW机组四角切圆锅炉上做了改造,并进行了含油污泥的热重分析及含油污泥入炉后的数值模拟,开展了油污泥入炉低负荷稳燃试验。结果表明:含油污泥具有易着火且热值接近动力煤的特点,可提高锅炉低负荷稳燃能力;含油污泥入炉后火焰中心略微下移,排放的烟气NO_(x)量有所降低;锅炉最低稳燃负荷率可低至20.00%,对应燃烧器层炉膛温度上升30~50℃,煤粉燃烧器火检信号更稳定,飞灰含碳量从4.79%降至3.80%,证明了油污泥对低负荷工况下煤粉燃烧的促进作用;120 MW负荷下含油污泥入炉后,锅炉效率提高约0.23百分点,可降低供电煤耗率约0.7 g/(k W·h),含油污泥热值可替代标准煤约3.7 t/h,节能效果显著。

连续流中氮负荷对好氧颗粒污泥稳定性的影响

考察了连续流反应器中好氧颗粒污泥(AGS)处理无机高氨氮废水的脱氮性能及稳定性。接种成熟AGS启动连续流反应器,运行第1~55 d内进水氮负荷由初始时的1.0 kg/(m~3·d)逐步升至4.0 kg/(m~3·d),第56~125 d内氮负荷逐步降至1.4 kg/(m~3·d),第126~145 d氮负荷再次升至2.0 kg/(m~3·d)。前75 d内观察到明显的AGS破碎及流失现象,且颗粒平均粒径不断减小;虽然多次补充接种AGS可维持系统的稳定性,但前80 d内颗粒的污泥容积指数(SVI)、胞外聚合物(EPS)及比耗氧速率(SOUR)剧烈波动。其中,第91~109 d反应器原位闲置。系统重新运行后,AGS的理化指标逐渐趋于稳定。前45 d内AGS对氨氮去除率逐渐升至98%以上;46~75 d内AGS对氨氮去除率迅速降至50%后又回升至99%以上;总无机氮去除率基本维持为35%~45%。考察了连续流反应器对污泥选择性筛分的效果,利用高通量测序分析污泥菌群组成变化。结果表明,当沉淀池中挡板深度为27 cm时,反应器对污泥截留率在98%以上,出水污泥粒径多为0~0.30 mm。与刚接种AGS相比,运行145 d时AGS中的硝化细菌属(Nitrosomonas)相对丰度明显增大,而反硝化细菌属(unclassified_Bacteria、Thauera、Truepera等)的相对丰度略有降低。

低强度超声波对高负荷厌氧氨氧化EGSB反应器运行性能的影响

研究了低强度超声波对厌氧氨氧化EGSB反应器处理无机高氨氮废水的影响,考察了超声波处理对反应器脱氮性能、厌氧氨氧化颗粒污泥特征、胞外聚合物以及微生物菌群的变化情况。结果表明,低强度超声波可提高厌氧氨氧化反应器脱氮效能,在进水氮负荷为6.03kg N/(m^(3)·d)时,总氮去除率提高了11.40%,抵抗氮负荷冲击能力也得到了增强。周期性超声波辐照后,颗粒污泥粒径维持在1.0~1.5mm,有利于改善传质效率,提升厌氧氨氧化颗粒污泥活性和减少颗粒漂浮。污泥EPS总量有显著增加,其中紧密结合型胞外聚合物(TB-EPS)增加较为明显,有助于维持颗粒污泥的结构稳定性。污泥表面官能团种类不变,但羟基、羧基、氨基等基团有所增多。颗粒污泥的比厌氧氨氧化活性提高了33.2%,通过简化的Gompertz方程模型发现超声组的厌氧氨氧化菌生长速率(0.0127d^(-1))高于对照组(0.0107d^(-1))。高通量测序显示,超声波促进了厌氧氨氧化菌及其共生菌,其中Candidatus Brocadia提升了22.03%。同时严重抑制了部分反硝化细菌,使厌氧氨氧化菌的底物和生存空间更加充足。

不同负荷条件对好氧污泥颗粒化的影响

采用R1、R2两组SBR反应器,以好氧絮状污泥为接种污泥,通过添加PFS(聚合硫酸铁)作为颗粒污泥造粒晶核及改变各反应器进水有机负荷,力求快速培养出AGS(好氧颗粒污泥)。研究表明,控制R1有机负荷为1.5~4.5 kgCOD_(Cr)/(m^(3)·d),在第17天时AGS培养成功,其中值粒径为412μm;培养过程中PN(蛋白质)分泌量最高达112.69 mg/g,PN的大量分泌更利于AGS的培养;培养成功的AGS(17~28 d)对COD_(Cr)、TN、TP的去除率分别为93%~94%、70%~72%、91%~93%。而控制R2有机负荷为4~6.5 kgCOD_(Cr)/(m^(3)·d),培养期间进水有机负荷过高,AGS培养失败;在培养过程中PS(多糖)分泌量最高达90.93 mg/g,PS的大量分泌易引发污泥膨胀。

基于高负荷活性污泥法城市污水碳捕获研究进展

首先综述了HRAS工艺特点,对溶解氧(DO)、污泥龄(SRT)等工艺参数对碳捕获效率的影响进行了总结;其次阐明了工艺碳重定向路径与碳捕获机理;然后介绍了化学强化高负荷活性污泥法(CEHRAS)等组合工艺的研究进展;最后提出了急需解决的问题并阐述了未来的发展前景。

氮负荷对好氧颗粒污泥处理无机废水脱氮性能及稳定性的影响

本研究考察了无机废水中氮负荷对好氧颗粒污泥(AGS)稳定性的影响。接种储存的AGS启动序批式反应器(SBR),采用好氧-(缺氧+外加碳源)-好氧交替运行模式,在运行过程中逐步将氮负荷由0.3 kg N/(m^(3)·d)提升至0.6 kg N/(m^(3)·d)。前40 d内,进水氮负荷为0.3 kg N/(m^(3)·d),30 min污泥容积指数(SVI_(30))在30~45 mL/g范围内波动,硝化菌比耗氧速率(SOURN)呈减小趋势(13.50~8.10 mg O_(2)/(g SS·h))。41~70 d内,逐渐将进水氮负荷提升至0.6 kg N/(m^(3)·d),在氮负荷冲击下,部分AGS破碎。随着絮体污泥大量排出及破碎颗粒的生长,系统在第104 d完成重新造粒,AGS的平均粒径为1.4 mm。144 d后,AGS的理化性质趋于稳定,污泥浓度稳定在8600~9060 mg/L,颗粒化率保持在95%以上。139 d后,AGS对氨氮和总无机氮的去除率分别为90%和80%以上,由于游离亚硝酸(FNA)对亚硝酸盐氧化菌的抑制作用,脱氮途径逐渐转变为短程硝化反硝化。氮负荷提升后,硝化菌如Nitrosomonas(0.2%~12.1%)和反硝化细菌如Thauera(10.4%~21.6%)的相对丰度明显提高,表现出较传统工艺更强的脱氮性能。

不同负荷梯度对污水厂活性污泥的产酸性能分析

活性污泥发酵产酸有利于实现污泥资源化利用。文中以污水厂活性污泥为研究对象,在污水厂现场采用半连续碱性发酵方法,探究了先低梯度再高梯度长周期提负荷过程中污泥的产酸性能。结果表明:低梯度提负荷运行阶段,第112 d污泥的酸化率达到最大值,且乙酸占比为71.67%,游离氨(FA)质量浓度为(208±39)mg/L,低于250 mg/L,对微生物无抑制性。在高梯度提负荷阶段,第192 d污泥的水解率提高至41%,丁酸与戊酸的占比增加,FA质量浓度逐渐升高至450 mg/L时产酸性能下降。低梯度的优势菌Guggenheimella(24.88%)演变为高梯度的unclassified_Clostridiales(37.08%)。此外,当负荷为3250 mg TSS/(L·d)时,挥发性脂肪酸(VFAs)达到最大值(3339 mg COD_(Cr)/L)。经过50 d的稳定运行,污泥的产酸率为(606±30)mg COD_(Cr)/(g VSS)。合适的负荷梯度有助于污泥中有机物在碱性条件下(pH值=10.0±0.05)长期稳定连续生成VFAs。

河道淤泥气泡混合轻质土动力特性及本构模型研究

河道淤泥气泡混合轻质土(FMLSS)是一种较新颖的疏浚淤泥在工程领域废物再利用方式。利用室内动三轴试验分析了不同的围压、含水率、水泥掺入量和气泡含量条件下FMLSS动应力应变骨干曲线的变化规律。结果表明,FMLSS动应力应变骨干曲线呈现先线性增加然后逐渐趋稳的规律,符合双曲线模型;相比围压、含水率和气泡含量的影响,水泥掺入量对FMLSS动应力应变关系的影响更显著。考虑到FMLSS力学性质的复杂性,对原有Hardin-Drnevich模型进行改进,提出修正系数k及其函数表达,再由拟合曲线反推求出k值并对其变化规律进行分析,发现k值随围压、水泥掺入量和气泡含量的增加而减小,随含水率的增加而增大。根据拟合结果对k值函数中的待定系数进一步优化,最后建立起符合FMLSS动力特性的修正Hardin-Drnevich模型,为其稳定分析、灾变预测及工程应用提供支撑。

生物炭改良曝气折流式人工湿地对生活污水的降解效果

为探究生物炭对折流式人工湿地的改良效果,明确生物炭在折流式人工湿地中的最佳应用方法,构建了生物炭曝气折流式人工湿地。通过小试实验考察了添加污泥生物炭对湿地处理生活污水中污染物效果的影响,研究了不同曝气时间和水力负荷条件下,湿地对污染物去除效果的变化,并确定合适运行参数。结果表明:添加污泥生物炭对折流式人工湿地净化污水有显著改良作用,对COD、NH_(4)^(+)-N、TN和TP的平均去除率分别提高了5.41%、5.31%、12.16%、25.46%;随着曝气时间增加,COD、NH_(4)^(+)-N的去除率增加,而TN和TP的去除率先升高后降低,适当的曝气时间才是高效去除污染物的关键;随着水力负荷增加,COD、NH_(4)^(+)-N、TN、TP的去除效果均下降;在曝气条件为0.5 L/min,4 h/d,水力负荷为0.37 m^(3)/(m^(2)·d)时,污泥生物炭改良的曝气折流式人工湿对污染物的去除效果最佳。因此,添加污泥生物炭能够实现折流式人工湿地对污染物的高效去除,将其用作湿地基质具有广阔应用前景,对人工湿地去除生活污水的工程应用具有一定参考价值。

污泥负荷对反硝化过程动力学和亚硝酸盐积累能力的探究

为提高短程反硝化耦合厌氧氨氧化(PD/Anammox)工艺处理负荷,探究负荷对反硝化中氮转化途径的影响。在批次试验中探究不同污泥负荷对反硝化过程中动力学和亚硝酸盐积累能力的影响,并通过改变连续试验中的污泥负荷,共同探究其对短程反硝化过程的影响。在批次试验中,随着污泥负荷增高,NO_(2)^(-)-N及NO_(3)^(-)-N的反应速率都降低,但NO_(2)^(-)-N积累能力增强,亚硝酸盐积累率(NAR)最高达72.47%;在低污泥负荷下反应加快,同时也促进了NO_(2)^(-)-N还原速率,NAR降低至56.46%。在连续试验中,通过缩短HRT增大污泥负荷,反应器短程反硝化能力提升,NAR从26.86%提升至45.62%,污泥活性增加,反硝化活性试验中NAR达90.24%。污泥颗粒化结构明显,粒径和胞外聚合物含量增加。短期批次和长期连续试验结果表明,提升污泥负荷是提高反硝化过程中短程反硝化能力的有效策略。

反硝化颗粒污泥处理电镀废水中硝态氮的中试研究

采用絮状污泥培育的反硝化颗粒污泥处理实际电镀废水中的硝态氮,通过逐步提升反硝化负荷,培养反硝化颗粒污泥,以评估该污泥的脱氮效果及其性状变化,进而探索其在电镀废水脱氮处理中的实际应用潜力。试验结果显示,在进水COD的质量浓度为400~520 mg/L,NO_(3)^(-)-N的质量浓度为50~100 mg/L,NO2--N的质量浓度为0.2~2.3 mg/L,pH值为6.5~7.2,反应器溶解氧的质量浓度小于0.2 mg/L,上升流速为2~6 m/h的条件下,当脱氮负荷提升至3.4 kg[NO_(3)^(-)-N]/(m^(3)·d)时,硝态氮的去除率高达95%以上,且Δρ(COD)/Δρ(NO_(3)^(-)-N)平均值仅为3.85∶1。系统稳定运行时间长达30 d,处理后出水中NO_(3)^(-)-N的质量浓度低于5 mg/L。此外,处理电镀废水后,反硝化颗粒污泥中的钙、铜、镍、铁含量均有显著上升。同时,成熟的颗粒污泥的VSS/SS值明显降低,颗粒污泥的粒径主要集中在1.0~2.8 mm范围内。反硝化颗粒污泥在处理电镀废水时展现出脱氮负荷高、出水NO_(3)^(-)-N浓度低、Δρ(COD)/Δρ(NO_(3)^(-)-N)低以及脱氮效果稳定等特点,可显著提高处理电镀废水NO_(3)^(-)-N的效率。

水玻璃基淤泥固化土力学性质试验研究

为解决淤泥固化及其资源化利用的问题,以宁波地区淤泥为研究对象,利用水玻璃基淤泥固化剂制备固化土,通过室内试验、固化机理分析和现场试验研究固化土的力学性质。室内试验给出了无侧限抗压强度和压缩模量随固化剂掺入比改变的规律,并指出存在最佳掺入比为7%;固化机理分析表明随着固化剂掺入比增加,固化土颗粒由鳞片状或条块状向团块状变化,团块体积呈增大趋势,固化土孔隙率小幅增大,中值孔径亦小幅增大,固化土由黏性土向粉土化转变;现场试验取心土样无侧限抗压强度约为室内试验值的70%。结果表明,水玻璃基淤泥固化剂加固淤泥土方案切实可行。