活性污泥1号模型废水特性的测定研究

废水的水质特性是活性污泥数学模型研究和应用的重要方面。采用呼吸计量法及常规化学分析法对污水处理厂的废水特性进行了测定,通过研究发现,污水处理厂的曝气沉砂池出水中SS占总COD的比例平均为10．49％;Xs占总COD的比例平均为14．24％;S1占总COD的比例平均为5．52％。初沉池出水中Ss占总COD的平均比例为9．62％;Xs占总COD的比例平均为16．97％;S1占总COD的比例平均为11．38％。     

活性污泥中细微沙浓度的预测模型

悬浮在污泥混合液中的细微沙会导致活性污泥混合液挥发性悬浮固体与混合液悬浮固体比值（ratio of mixed liquor volatile suspended solids to mixed liquor suspended solids,MLVSS/MLSS）降低。通过向生化池进水中连续投加体积平均粒径分别为14、33、50、66和107 μm的石英砂,研究不同粒径细微沙对活性污泥MLVSS/MLSS的影响,探讨不同粒径细微沙的悬浮特性,构建活性污泥中细微沙浓度的预测模型,以为污水厂运行调控提供理论基础。研究结果表明,细微沙粒径越小,悬浮比（悬浮在污泥混合液中的细微沙占生化池进水中细微沙总量的比例）越大,悬浮比与细微沙粒径呈显著的相关关系。通过预测模型得到的细微沙浓度的预测值与实测值差异较小,说明构建的活性污泥中细微沙浓度的预测模型是合理的。污水厂可在维持活性污泥MLVSS稳定的条件下,结合活性污泥中细微沙的浓度,调控污泥MLSS,保证污水处理系统的稳定运行。     

Multicomponent activated sludge model for reactors in series with recycling

Multicomponent models containing both substrate and biomass have an advantage over conventional models in seeking better understanding of activated sludge systems. Such models are also useful in the characterisation of wastewater. Studies in recent years have shown that most of the soluble organic matter in the effluent of treatment systems consists of soluble microbial products that arise during biological treatment. In order to support experimental studies, mathematical models have also been developed to explain microbial product formation. In connection with the approaches in the literature, a mathematical model for estimating chemical oxygen demand in effluent in dispersed media has been developed in this study. The death–regeneration approach – an approach of multicomponent activated sludge models containing the formation of soluble inert organic matter with together carbon oxidation – was used. Because the differential equations developed for dispersed media have no analytical solutions, the system was represented with the in-series reactor approach, with the death–regeneration and hydrolysis concepts advised in the IAWPRC Task Group Model.     

Estimation of biodegradation parameters of phenolic compounds on activated sludge by respirometry

The bio-oxidation of phenol, catechol, resorcinol, m-cresol and 5-methylresorcinol on activated sludge was investigated by oxygen uptake measurements. In addition, the degradation of acetate with the same microbial population was studied. The substrate-dependent oxygen uptake data were analysed on the basis of the Michaelis-Menten kinetics. The extant kinetic parameters, the maximum rates of oxygen consumption and half-saturation constants for the processes with different substrates were determined. The simple respirometric approach also made it possible to determine the short-term oxygen demands of the substrates which formed 23-38% of the theoretical oxygen demand of the studied compounds.     

Assessing the diurnal variability of pharmaceutical and personal care products in a full-scale activated sludge plant

An intensive sampling campaign has been carried out in a municipal wastewater treatment plant (WWTP) to assess the dynamics of the influent pharmaceutical active compounds (PhAC) and musks. The mass loadings of these compounds in wastewater influents displayed contrasting diurnal variations depending on the compound. The musks and some groups of PhACs tended to follow a similar diurnal trend as compared to macropollutants, while the majority of PhACs followed either the opposite trend or no repeatable trend. The total musk loading to the WWTP was 0.74 ± 0.25 g d⁻¹, whereas the total PhAC mass loading was 84.7 ± 63.8 g d⁻¹. Unlike the PhACs, the musks displayed a high repeatability from one sampling day to the next. The range of PhAC loadings in the influent to WWTPs can vary several orders of magnitude from one day or week to the next, representing a challenge in obtaining data for steady-state modelling purposes.     

Effect of operational parameters on the removal of particulate chemical oxygen demand in the activated sludge process.

The removal of particulate material in the aeration basin of the activated sludge process is mainly attributed to bioflocculation and hydrolysis of particulate substrate. The bioflocculation process in the aeration tank of the activated sludge process occurs only under favorable conditions in the system, and several common operational parameters affect its performance. The principal objective of this research was to observe the effect of mixed liquor suspended solids, solids retention time (SRT), and extracellular polymer substances on the removal of particulate substrate by bioflocculation. A first-order particulate removal expression, based on flocculation, accurately described the removal rates for supernatant suspended solids and colloidal chemical oxygen demand. Based on the results presented in this investigation, a mixed liquor concentration of approximately 2200 mg/L, an SRT of at least 3 days, and a contact time of 30 minutes are needed for relatively complete removal of the particulate substrate in a plug-flow reactor.     

膜生物反应器中运行参数对污泥胞外聚合物的影响

研究了膜生物反应器(MBR)中曝气强度、有机负荷和污泥停留时间(SRT)与污泥胞外聚合物(EPS)变化的关系。实验结果表明,随着气水比由20增加至40,污泥EPS逐渐下降。当气水比＞35之后,EPS趋于稳定。随着有机负荷由0.129 kg COD/kg VSS·d减小至0.016 kg COD/kg VSS·d,附着型...     

循环式活性污泥法中好氧选择区的运行条件研究

研究了循环式活性污泥法好氧生物选择区的停留时间和整个系统中泥龄、污泥负荷、曝气时间等运行参数对选择区内微生物吸附性能的影响。结果表明 ,选择器停留时间 3 0 min,系统泥龄 9～ 15 d,曝气 2 h,污泥有机负荷为 0 .3 g CODCr/(g ML SS·d)左右时 ,选择器中微生物的吸附性能最优 ,可去除进水中 90以上的 CODCr。     

Effects of sludge properties on the thickening and dewatering of waste activated sludge.

The thickening and dewatering of waste activated sludge, from a pilot-scale submerged membrane bioreactor and two bench-scale, complete-mix activated sludge reactors (high-shear and low-shear aeration) treating the same municipal primary effluent, were investigated. Solids settling and compaction were measured using the diluted sludge volume index (DSVI) analysis and a batch centrifugation analysis, respectively. Elevated levels of filamentous microorganisms resulted in higher DSVI values and lower centrifuged pellet concentration. Elevated levels of nocardioform bacteria resulted in lower solids float concentrations, and higher colloidal material reduced solids recovery in batch flotation experiments. Sludge filterability, measured as time-to-filter, was shown to be a function of extracelluar polymeric substances and colloidal material, where higher levels of either reduced sludge filterability. Additional research is necessary to confirm these results using full- or demonstration-scale thickening and dewatering units.     

ASM No.2d模型模拟SBR工艺同步脱氮除磷效能

SBR工艺由于处理上的高效性和操作上的灵活性在世界范围的污水处理领域得到广泛应用.采用国际水质协会1999年提出的ASM No.2d模型,利用matlab作为程序开发工具编制计算模型,并利用该模型对一实验室规模SBR系统进行模拟.模拟过程中动力学和化学计量参数采用ASM No.2d给出的典型参数值,并结合实际SBR系统进行了修正.结果表明,该模型能够较好模拟SBR工艺同步脱氮除磷效能,说明应用ASM No.2d进行SBR系统的模拟能够对SBR系统的优化和控制起辅助作用.     

Improved computational model (AQUIFAS) for activated sludge, integrated fixed-film activated sludge, and moving-bed biofilm reactor systems, Part I: Semi-empirical model development

Research was undertaken to develop a model for activated sludge, integrated fixed-film activated sludge (IFAS), and moving-bed biofilm reactor (MBBR) systems. The model can operate with up to 12 cells (reactors) in series, with biofilm media incorporated to one or more cells, except the anaerobic cells. The process configuration can be any combination of anaerobic, anoxic, aerobic, post-anoxic with or without supplemental carbon, and reaeration; it can also include any combination of step feed and recycles, including recycles for mixed liquor, return activated sludge, nitrates, and membrane bioreactors. This paper presents the structure of the model. The model embeds a biofilm model into a multicell activated sludge model. The biofilm flux rates for organics, nutrients, and biomass can be computed by two methods--a semi-empirical model of the biofilm that is relatively simpler, or a diffusional model that is computationally intensive. The values of the kinetic parameters for the model were measured using pilot-scale activated sludge, IFAS, and MBBR systems. For the semiempirical version, a series of Monod equations were developed for chemical oxygen demand, ammonium-nitrogen, and oxidized-nitrogen fluxes to the biofilm. Within the equations, a second Monod expression is used to simulate the effect of changes in biofilm thickness and fraction nitrifiers in the biofilm. The biofilm flux model is then linked to the activated sludge model. The diffusional model and the verification of the models are presented in subsequent papers (Sen and Randall, 2008a, 2008b). The model can be used to quantify the amount of media and surface area required to achieve nitrification, identify the best locations for the media, and optimize the dissolved oxygen levels and nitrate recycle rates. Some of the advanced features include the ability to apply different media types and fill fractions in cells; quantify nitrification, denitrification, and biomass production in the biofilm and mixed liquor suspended solids; and perform dynamic simulations.     

活性污泥脱水性能与电化学阻抗谱参数的关联特性

为探究FeCl₃混凝调理过程中活性污泥脱水性能与电化学阻抗谱参数的关联关系,选取北京3座污水处理厂的剩余活性污泥,研究不同调理投药量下活性污泥的毛细吸水时间(CST)、比阻(SRF)、抽滤含水率、Zeta电位、电导率以及电化学阻抗等指标的变化,通过Pearson相关性分析讨论污泥脱水性能与阻抗谱参数(d_s/f_c)的相关性,并探讨d_s/f_c预测污泥脱水性能的可行性。实验结果表明,FeCl₃调理活性污泥的较适投加量为100 mg·g^-1;超过100 mg·g^-1时,活性污泥CST、SRF、抽滤含水率基本不再下降,Zeta电位却缓慢升高;电化学阻抗Z则随着投加量的增加而持续下降,且Nyquist图中高频区半圆面积减小,这表明电子更易转移、污泥更易导电。相关性分析表明,活性污泥的脱水性能均与d_s/f_c呈显著正相关(r > 0.639,p < 0.01);3种活性污泥CST、SRF、抽滤含水率分别与d_s/f_c的线性回归结果显示它们之间呈线性关系,且线性方程斜率为正值(R² > 0.921,p < 0.01)。上述研究结果表明,活性污泥的d_s/f_c参数可以作为指示脱水性能的潜在指标。本研究结果可为污泥减量化技术提供参考。     

Relative efficacy of intrinsic and extant parameters for modeling biodegradation of synthetic organic compounds in activated sludge: dynamic systems.

The utility of intrinsic and extant kinetic parameters for simulating the dynamic behavior of a biotreatment system coupled with a distributed, unstructured, balanced microbial growth model were evaluated against the observed response of test reactors to transient loads of synthetic organic compounds (SOCs). Biomass from a completely mixed activated-sludge (CMAS) system was tested in fed-batch reactors, while a sequencing batch reactor (SBR) was tested by measuring SOC concentrations during the fill and react period. Both the CMAS system and the SBR were acclimated to a feed containing biogenic substrates and several SOCs, and the transient loading tests were conducted with biogenic substrates along with one or more SOCs. Extant parameters more closely reflect the steady-state degradative capacity of activated-sludge biomass than intrinsic parameters and, hence, were expected to be better predictors of system performance. However, neither extant nor intrinsic parameters accurately predicted system response and neither parameter set was consistently superior to the other. Factors that may have contributed to the inability of the model to predict system response were identified and discussed. These factors included the role of abiotic processes in SOC removal, disparity in the bases used to evaluate parameter estimates (substrate mineralization) and reactor performance (substrate disappearance), inhibitory substrate interactions under the severe loading conditions of the SBR, changes in the physiological state of the biomass during the transient loading tests, and the presumed correlation between the competent biomass concentration and the influent SOC concentration.     

Simultaneous nitrification-denitrification and clarification in a pseudoliquified activated sludge system.

This paper describes results from a pilot study of a novel wastewater treatment technology, which incorporates nutrient removal and solids separation to a single step. The pseudoliquified activated sludge process pilot system was tested on grit removal effluent at flowrates of 29.4 to 54.7 m3/d, three different solid residence times (SRT) (15, 37, and 57 days), and over a temperature range of 12 to 28 degrees C. Despite wide fluctuations in the influent characteristics, the system performed reliably and consistently with respect to organics and total suspended solids (TSS) removals, achieving biochemical oxygen demand (BOD) and TSS reductions of > 96% and approximately 90%, respectively, with BOD5 and TSS concentrations as low as 3 mg/L. Although the system achieved average effluent ammonia concentrations of 2.7 to 3.2 mg/L, nitrification efficiency appeared to be hampered at low temperatures (< 15 degrees C). The system achieved tertiary effluent quality with denitrification efficiencies of 90 and 91% total nitrogen removal efficiency at a total hydraulic retention time of 4.8 hours and an SRT of 12 to 17 days. With ferric chloride addition, effluent phosphorous concentrations of 0.5 to 0.8 mg/L were achieved. Furthermore, because of operation at high biomass concentrations and relatively long biological SRTs, sludge yields were over 50% below typical values for activated sludge plants. The process was modeled using activated sludge model No. 2, as a two-stage system comprised an aerobic activated sludge system followed by an anoxic system. Model predictions for soluble BOD, ammonia, nitrates, and orthophosphates agreed well with experimental data.     

活性污泥系统优化设计对不确定性参数的灵敏度研究

在活性污泥系统优化设计模型参数不确定性分析的基础上,考察了进水负荷、生物动力学参数、曝气设备性能参数和二沉池浓缩常数变化对优化设计的影响。灵敏度分析结果表明,对优化设计影响较大的参数为：进水水量水质、与氧转移效率相关的校正参数以及二沉池的浓缩常数等。研究结果对于低灵敏度系统的设计,提高优化设计结果的工程实用性具有重要的意义。