序批式反应器的好氧颗粒污泥特性研究

对序批式反应器中好氧颗粒活性污泥的形成过程、处理性能和颗粒分布特性进行了研究。结果表明，不同操作条件下产生了结构形态不同的颗粒污泥，沉降时间是颗粒污泥形成的主要因素，有机负荷对颗粒污泥的结构有一定影响。颗粒污泥反应器对溶解性COD的去除率可达90％，对氨氮的去除率为24％。颗粒污泥在反应器中分布不均匀，反应器底部MLSS高达8g／L，SVI为34mL／g，随着反应器高度的增加则MLSS值降低、SVI值提高；此外较大的颗粒污泥聚集在反应器的底部，较小的颗粒污泥和絮体分布在反应器的中上部。     

强化生物脱氮分步进水型序批式反应器

介绍了分步进水型序批式反应器（SFSBR）工艺的运行方式、工艺特点、关键参数和研究进展,并分析了该工艺的应用前景。与传统SBR工艺相比,SFSBR反应阶段包含多个缺氧／厌氧-好氧子循环,并在各缺氧阶段始端进水,使进水中的有机物作为反硝化细菌碳源转化前一好氧阶段产生的硝态氮,提高了反硝化碳源补给率,强化了整个系统的生物脱氮能力。SFSBR工艺不仅适用于新建污水处理厂,而且适用于传统SBR工艺的改造和功能扩展,在实际工程中的推广应用可操作性强。     

不同工况下膜—SBR工艺的除污效能研究

将一体式膜生物反应器与序批式活性污泥法相结合而构建了M-SBR工艺.采用该工艺处理模拟生活污水,通过调节反应器的厌氧、好氧和缺氧时间比例,使系统分别按照A0-MSBR和AOA-MSBR的方式运行,考察了在相同操作条件下,系统对COD、氮、磷的去除效果.试验结果表明:AOA-MSBR工艺比A0-MSBR工艺具有更好的同步脱氮除磷效果,其对COD的平均去除率达到了98.5%,对氨氮的平均去除率达到了90.3%,对总氮的平均去除率达到了89.5%,对总磷的平均去除率为88.5%.     

用厌氧产氢反应器出水培养好氧颗粒污泥的研究

以厌氧产氢反应器出水为底物，在序批式反应器中研究了好氧颗粒污泥的培养过程。结果表明，以厌氧产氢反应器出水为底物，在60d内能够培养出粒径大、沉降性能优异且对污染物去除能力强的好氧颗粒污泥。在活性污泥的颗粒化过程中，伴随着污泥体积指数的减小。污泥的粒径和沉速增大，反应器内的污泥浓度增加，从而提高了反应器的处理效能。     

序批式复合反应器强化同步脱氮除磷

利用序批式复合反应器(SBHR)中同时存在的活性污泥和悬浮生物膜混合生物体系,进行了强化脱氮除磷的试验研究。连续稳定运行3个月后,系统对TN、TP和COD的平均去除率分别达到90%、95%和95%,处理效果稳定。该系统的悬浮生物膜与活性污泥的混合体系中生物种群具有多样化特征,所形成的微生物生态系统较稳定,抗外界干扰及恢复调节能力强;悬浮微生物体系能与水体形成复杂的整体螺旋上升、局部紊流的流态,有利于在空间形成有机污染物浓度梯度分布,使氧气和硝酸盐氮等电子受体和有机底物的传质效果良好。     

好氧MBR与序批式MBR处理生活污水的比较

比较了中试规模的好氧式膜生物反应器及序批式膜生物反应器处理生活污水的效果。结果表明，两者对COD及氨氮的去除效果相当，且都具有良好的抗冲击负荷能力；在总氮去除上，序批式膜生物反应器优于好氧式膜生物反应器；在稳定运行阶段，当好氧式膜生物反应器及序批式膜生物反应器处理同等水量时，过膜阻力增加率分别为1．68和1．03kPa／m。通过测定膜丝上多糖的含量分析了两者在膜污染速率上存在差异的原因，发现序批式膜生物反应器膜丝上的多糖含量要少于好氧式膜生物反应器。     

榨菜综合废水好氧生物处理工艺的选择试验

针对榨菜综合废水呈高盐、高氮磷、高有机物浓度的水质特征,对两级SBR与单级SBBR反应器处理榨菜废水的效能进行了研究.结果表明:在温度为20℃、有机负荷为1.0 kg-COD/(m3·d)、DO为5 ms/L、反应器运行工况为进水(0.25 h)/曝气(11 h)/沉淀(0.5 h)/排水(0.25 h)的条件下,SBBR反应器能够使榨菜综合废水达标排放,而两级SBR工艺则不适宜处理榨菜综合废水.     

好氧颗粒污泥技术用于味精废水处理的研究

以厌氧颗粒污泥为接种污泥,采用人工模拟废水在SBR反应器内培养好氧颗粒污泥,35 d后颗粒污泥成熟,反应器对COD和NH4+-N的去除率分别高于95%和99%。采用该反应器处理味精废水,当COD、NH4+-N的容积负荷分别为2.4、0.24 kg/(m3.d)时,对COD、NH4+-N和TN的去除率分别在90%、99%和85%左右,且颗粒污泥未出现解体的现象。以厌氧颗粒污泥为接种污泥、味精废水为进水,在与上述相同条件下培养好氧颗粒污泥,经过60 d的培养,反应器内的污泥以絮状污泥为主,该系统对COD、NH4+-N和TN的去除率分别为85%、99%和70%。     

Evaluation on the impacts of predators on biomass components and oxygen uptake in sequencing batch reactor and continuous systems

An expanded unified model for the biomass fractions, soluble-organic fractions, and oxygen-uptake rates considering extracellular polymeric substances (EPS), intracellular storage products (X_STO), and predators for activated sludge is used to study the impacts of predators on biomass components and oxygen uptake. The new model is applied to evaluate how predation affects the oxygen-uptake rate (OUR) and the different forms of biomass: active bacteria (X_H), X_EPS, and X_STO, under dynamic feast-and-famine and continuous conditions. For the dynamic conditions of a sequencing batch reactor (SBR), eliminating predators from the model increases X_H and X_EPS fractions significantly, and this causes the substantial increases in OUR and MLVSS once the famine period begins. An analysis of how the OUR is distributed among the several respiration processes shows that the predation of X_H is the most significant oxygen utilization rate process in the system under famine conditions of an SBR. Application of the model to simulate the long-term operation of an SBR indicates that predators reach their maximum fraction in the MLVSS (∼4% of MLVSS) at a solids retention time of about 13 days, but they are washed out at a solids retention time less than ∼3 days. Simulation for a continuous system indicates that predators take more time (about 800 h) to reach steady state and reach their maximum fraction (∼5.5%) at an SRT of ∼14 days. Comparison of SBR and continuous systems reveals that the predators have greater impact in the continuous system because the permanent near-famine condition accentuates predation processes.     

采用AOA模式在SBR中实现同步脱氮除磷

借助SBR反应器,通过采用厌氧/好氧/缺氧（AOA）的运行方式来实现同步脱氮除磷.结果表明,在好氧段补充一定量的碳源可以抑制好氧吸磷,进而在缺氧段实现反硝化除磷,从而达到了同步脱氮除磷的目的.最佳碳源投量为30～40 mg/L,补充碳源负荷为12.8～17.2 mgCOD/gMLSS;长期运行时系统的脱氮除磷性能稳定,对TN和PO4^3- -P的平均去除率分别可达85.5%、91.4%,同时NO2^- -N可以作为反硝化聚磷菌吸磷的电子受体;在一个SBR周期内,pH值呈规律性变化并和氮、磷的吸收/释放相关联,通过监测pH值可以初步判断磷释放、氨氮转化和磷吸收的终点.     

Coupling of sequencing batch reactor and mesh filtration: operational parameters and wastewater treatment performance

Wastewater treatment performance of the combined process of sequencing batch reactor (SBR) and mesh filtration bio-reactor was investigated with a synthetic wastewater. In this system, the filtration was performed only by the water level difference between the reactor and the effluent port, with the help of a sludge layer which accumulated on the mesh filter.

A half volume of the mixed liquor was filtrated for ca. 1 h, and the filtration time was not affected by the initial pressure within the range of 0.5–2.0 m-H₂O. Since the mesh filter could effectively reject the biomasses in the reactor, the effluents contained SS of less than 1 mg/L and BOD of less than 10 mg/L under continuous or intermittent aeration conditions. Nitrogen was also removed effectively with the adjustment of aeration time under the intermittent aeration conditions.

The results obtained in this work indicate that mesh filtration could be effectively combined with SBR and improve the performance of SBR.

In addition, it was shown that the performance of the mesh filtration such as filtration time and solids separation was influenced significantly by the saccharide content in the exocellular polymer of the activated sludge.     

Quantification of the shear stresses in a microbial granular sludge reactor

Since a certain level of hydrodynamic shear force is needed in the formation of microbial granules for wastewater treatment, a method for quantifying the shear stresses in a microbial granular sludge reactor is highly desirable. In this work a novel energy-dissipation-based model was established and validated to quantitatively describe the shear stresses in a granular sludge sequencing batch reactor (SBR). With this model, the shear stress at the solid–liquid interface in an SBR was estimated and the relative magnitudes of shear stresses induced by fluid, gas bubble and collision on granules were evaluated. The results demonstrate that the effect of reactor geometry on the global shear stress was significant. Both the shear stress at the microbial granule surface and the biomass-loss rate increased with an increase in biomass concentration in the SBR. The gas bubble and the collision were found to be the main source for the shear stress at the granule surface.     

Alternating anoxic feast/aerobic famine condition for improving granular sludge formation in sequencing batch airlift reactor at reduced aeration rate

In this study the influence of a pre-anoxic feast period on granular sludge formation in a sequencing batch airlift reactor is evaluated. Whereas a purely aerobic SBR was operated as a reference (reactor R2), another reactor (R1) was run with a reduced aeration rate and an alternating anoxic-aerobic cycle reinforced by nitrate feeding. The presence of pre-anoxic phase clearly improved the densification of aggregates and allowed granular sludge formation at reduced air flow rate (superficial air velocity (SAV) = 0.63 cm s⁻¹). A low sludge volume index (SVI₃₀ = 45 mL g⁻¹) and a high MLSS concentration (9–10 g L⁻¹) were obtained in the anoxic/aerobic system compared to more conventional results for the aerobic reactor. A granular sludge was observed in the anoxic/aerobic system whilst only flocs were observed in the aerobic reference even when operated at a high aeration rate (SAV = 2.83 cm s⁻¹). Nitrification was maintained efficiently in the anoxic/aerobic system even when organic loading rate (OLR) was increased up to 2.8 kg COD m⁻³ d⁻¹. In the contrary nitrification was unstable in the aerobic system and dropped at high OLR due to competition between autotrophic and heterotrophic growth. The presence of a pre-anoxic period positively affected granulation process via different mechanisms: enhancing heterotrophic growth/storage deeper in the internal anoxic layer of granule, reducing the competition between autotrophic and heterotrophic growth. These processes help to develop dense granular sludge at a moderate aeration rate. This tends to confirm that oxygen transfer is the most limiting factor for granulation at reduced aeration. Hence the use of an alternative electron acceptor (nitrate or nitrite) should be encouraged during feast period for reducing energy demand of the granular sludge process.     

Granulation of activated sludge in a pilot-scale sequencing batch reactor for the treatment of low-strength municipal wastewater

Aerobic granulation of activated sludge was achieved in a pilot-scale sequencing batch reactor (SBR) for the treatment of low-strength municipal wastewater (<200 mg L⁻¹ of COD, chemical oxygen demand). The volume exchange ratio and settling time of an SBR were found to be two key factors in the granulation of activated sludge grown on the low-strength municipal wastewater. After operation of 300 days, the mixed liquor suspended solids (MLSS) concentration in the SBR reached 9.5 g L⁻¹ and consisted of approximate 85% granular sludge. The average total COD removal efficiency kept at 90% and NH₄⁺-N was almost completely depleted (∼95%) after the formation of aerobic granules. The granules (with a diameter over 0.212 mm) had a diameter ranging from 0.2 to 0.8 mm and had good settling ability with a settling velocity of 18-40 m h⁻¹. Three bacterial morphologies of rod, coccus and filament coexisted in the granules. Mathematical modeling was performed to get insight into this pilot-scale granule-based reactor. The modified IWA activated sludge model No 3 (ASM3) was able to adequately describe the pilot-scale SBR dynamics during its cyclic operation.     

Application of multiway ICA for on-line process monitoring of a sequencing batch reactor

Multiway principal component analysis has been shown to be a powerful monitoring tool in many industrial batch processes. However, it has the shortcomings that all batch lengths should be equal, the measurement variables must be normally distributed and that future values of the current batch must be estimated to allow on-line monitoring. In this work, it is shown that multiway independent component analysis (MICA) can be used to overcome these drawbacks and obtain better monitoring performance. The on-line MICA monitoring of batch processes is based on a new unfolding method and independent component analysis (ICA). ICA provides better monitoring performance than PCA in cases with non-Gaussian data because it is not based on the assumption that the latent variables are normally distributed. The MICA algorithm does not require any estimation of future batch values and can also be applied to non-equal batch length data sets. This article describes the application of on-line MICA monitoring of a sequencing batch reactor (SBR). It is successfully applied to an 80L SBR for biological wastewater treatment, which is characterized by a variety of disturbance sources with non-Gaussian characteristics. The SBR poses an interesting challenge from the point of process monitoring characterized by non-stationary, batchwise, multiscale, and non-Gaussian characteristics. The results of the bench-scale SBR monitoring clearly showed the power and advantages of MICA monitoring in comparison to conventional monitoring methods.     

Evaluating sludge minimization caused by predation and viral infection based on the extended activated sludge model No. 2d

The Activated Sludge Model No. 2d (ASM2d) was extended to incorporate the processes of both predation and viral infection. The extended model was used to evaluate the contributions of predation and viral infection to sludge minimization in a sequencing batch reactor (SBR) system enriching polyphosphate-accumulating organisms (PAOs). Three individual decay processes formulated according to the general model rules were used in the extended model. The model was firstly calibrated and validated by different experimental results. It was used to evaluate the potential extent of predation and viral infection on sludge minimization. Simulations indicate that predation contributes roughly two times more to sludge minimization than viral infection in the SBR system enriching PAOs. The sensitivity analyses of the selected key parameters reveal that there are thresholds on both predation and viral infection rates, if they are too large a minimal sludge retention time is obtained and the effluent quality is deteriorating. Due to the thresholds, the contributions of predation and viral infection to sludge minimization are limited to a maximal extent of about 21% and 9%, respectively. However, it should be noted that the parameters concerning predation and viral infection were not calibrated separately by independent experiment in our study due to the lack of an effective method, especially for the parameters regarding viral infection. Therefore, it is essential to better evaluate these parameters in the future.     

Long-term formation of microbial products in a sequencing batch reactor

Activated sludge in a sequencing batch reactor (SBR) is subjected to alternating feast-and-famine conditions, which may result in the enhanced production of microbial products: extracellular polymeric substances (EPS), soluble microbial products (SMP), and internal storage products (X_STO). In this work, the long-term formation of these three microbial products by activated sludge in an SBR is investigated using an expanded unified model with a parallel experimental study. We also use the model to compare the impacts in an SBR to those in a continuous-flow activated sludge system. The model captures all experimental trends for all components with solids retention time (SRT) for global steady state and within a cycle. At an SRT of 20 days, the active microorganisms constitute about 28% of the mixed liquor volatile suspended solids (MLVSS); the remaining biomass is comprised of residual inert biomass (X_I) of 40%, EPS of 31%, and X_STO of ∼1%. The active biomass becomes a smaller fraction with the increasing SRT, while the inert biomass becomes increasingly dominant. For soluble components, effluent chemical oxygen demand (COD) is dominated by SMP, which varies to some degree in a cycle, peaking as external substrate becomes depleted. Within the SBR cycle, external substrate (S) declines strongly in the first part of the cycle, and SMP shows a small peak at the time of S depletion. X_STO is the only biomass component that varies significantly during the cycle. It peaks at the time that the input substrate (S) is depleted. Simulation for a continuous-flow activated sludge system and comparison with an SBR reveals that the constant “famine” conditions of the continuous system lead to lower EPS and X_STO, but higher MLVSS and X_I.