污水处理过程中除磷加药智能控制系统及应用研究

应用基于化学除磷模型和在线传感器的智能控制系统对污水处理厂的药剂投加量进行优化控制,以达到污水处理厂一级A总磷排放标准。以广州市某污水处理厂为例,设计了除磷加药智能控制系统的控制策略,拟合出化学除磷公式,以表征智能除磷系统的应用效果。结果表明,在一般城市生活污水的总磷浓度条件下,可以节约除磷药剂量40%~50%,2~3年便可回收控制系统的建设成本。污水处理厂采用该除磷加药智能控制系统后,可以实现在出水水质稳定达标的前提下降低加药量的目标。     

利用正磷酸盐连续监测设备调节铁盐投加量的研究

针对进水水质、水量变化导致的出水总磷浓度不稳定的情况,在污水处理厂使用正磷酸盐连续监测设备,及时准确地监测混凝池进水中的正磷酸盐浓度,以此来调节化学除磷试剂在生物反应池和混凝池的投加量,可以达到稳定出水总磷浓度、最大限度地减少化学除磷试剂消耗量的目的,实际运行效果良好。     

城市污水厂化学除磷精确控制技术研究与工程示范

针对污水处理厂化学除磷加药基本无自动控制系统,普遍采用固定加药量,导致过量投加化学除磷药剂的状况,研究了投药量系数β与出水总磷的关系、化学除磷加药量预测模型、药剂投加反馈调节系统,以实现化学除磷精确控制。结果表明,在β值为2.0、3.83、3.80和3.02时,聚合硫酸铁(PFS)、液态聚合氯化铝铁(LPAFC)、聚合氯化铝(PAC)、聚合硅酸铝铁(PAFSI)的除磷率分别达到78.99%、75.61%、70.03%和60.11%;在北京市吴家村污水处理厂建立了集RTU(远程终端控制系统,用于采集进出口污水的在线总磷值)、计算机分析、PLC控制加药变频器和专家后反馈的化学除磷精确控制系统,示范工程运行一个月约节约投药量20%。     

化学除磷对城镇污水厂活性污泥系统的影响

为降低城镇污水处理厂出水磷含量,在生物除磷的基础上辅以化学除磷。化学除磷剂的投加会生成化学污泥而导致污泥量的增加,且化学污泥若进入生化系统会对污泥活性带来负面影响。以石家庄市桥东污水处理厂为例,从多个角度分析了化学除磷剂对生化系统的影响及其成因,并提出了有效解决措施。     

后置沉淀化学除磷工艺的优化控制研究

目前,化学除磷在污水处理厂被广泛采用。通过小试和中试,对后置沉淀化学除磷工艺的优化控制进行研究。首先通过烧杯试验考察了加药量、加药位置和不同药剂对除磷效果的影响,为优化控制设定工艺参数,然后采用中试AAO系统对比了恒量加药和优化控制的除磷效果。中试结果表明,恒量加药的出水磷浓度波动较大,而经优化控制后的出水正磷浓度稳定维持在0.3mg/L以下,并减少药剂用量约18.9%。因此,对后置沉淀化学除磷工艺进行优化控制,能够在保证出水总磷浓度稳定达标的同时减少加药量。     

数学模拟技术对MBR工艺的模拟与优化

采用BioWin软件建立了北京某污水处理厂MBR工艺模拟模型,利用污水厂实际运行数据和实验室对污水中各种有机组分的检测结果校正了模型并调整了模型参数.模型运行结果与出水检测指标的验证结果表明,所建立的模型能较好地反映该污水厂的实际运行状况.针对出水中氮、磷达不到GB 18918-2002一级A标准的问题,利用BioWin软件从调整运行参数、改变工艺流程及改造池体尺寸3个方面对现有工艺进行了模拟优化,提出了对现有工艺的改造方案.     

污水处理厂脱氮除磷潜力分析评价体系的应用

脱氮除磷的碳源需求分析是污水处理厂升级改造难度评估和工艺对策设计的关键。介绍了一种在综合考虑脱氮和除磷碳源需求的基础上,同步评估污水处理厂脱氮除磷难度(DNR)的方法,并采用上海市19座城镇污水处理厂的实际运行数据对该方法进行可靠性分析与应用研究。统计分析结果表明,DNR指数与出水TN和TP浓度在0. 01水平上显著正相关,其相关系数明显高于碳氮比和碳磷比。根据DNR指数的分级结果,一级A标准下脱氮除磷难度较高、中等和较低的污水处理厂分别有3、11和5座,且大部分污水处理厂碳源需求中脱氮需求占比更高。DNR指数能够科学客观地反映污水处理厂的脱氮除磷难度,并能进一步应用于污水处理厂的分级管理、不同排放标准下的碳源供给分析和运行优化中。     

污水处理厂奥贝尔氧化沟工艺运行参数探讨

介绍了奥贝尔氧化沟工艺运行的基本原理和参数并结合天津市西青开发区大寺污水处理厂调试及运行的实际情况,对奥贝尔工艺运行参数进行系统的确定,得出该污水处理厂出水完全满足GB 18918-2002<城镇污水处理厂污染物排放标准>一级B标准并对脱氮除磷效果进行探讨.     

枣庄市污水处理厂脱氮除磷改造工程

枣庄市污水处理厂实际处理水量为6×104 m3/d,采用T型氧化沟工艺.由于建厂较早,当初选择的工艺技术参数没有考虑到污水脱氮除磷的需要,致使出水总氮、总磷超标.该厂对氧化沟自控系统进行升级改造,并针对性地增设了部分设备和工艺设施.改造后出水水质达到《城镇污水处理厂污染物排放标准》( GB 18918-2002)的一级B标准并实现再生水回用.     

低C/N值城市污水处理厂出水达标的运行条件优化

某污水处理厂采用微曝气氧化沟和化学除磷微絮凝过滤工艺,进水为低C/N值城市污水,出水水质执行《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级A标准,针对实际出水TN和TP浓度超标的问题,进行了一系列的工艺调整试验研究。结果表明,在不改变构筑物、不增加投资的条件下,通过采取曝气沉砂池停曝、投加外碳源、氧化沟低氧曝气、关闭内回流、优化化学除磷药剂等措施,可以实现出水水质的稳定达标,其中对TN和TP的平均去除率分别可达到65%和88%。     

ASM2d在污水处理中的研究与应用

介绍了描述脱氮除磷动态过程的活性污泥数学模型No．2d（ASM2d）的内容及应用ASM2d进行污水处理分析的模拟过程，并应用基于ASM2d开发的模拟程序ASM2G对某污水厂进行了模拟分析，通过参数校正，最后得到的二沉池出水模拟结果与实测结果符合较好（误差〈10％），说明ASM2d能较好地反映污水处理的实际运行状况，可用于模拟污水处理、预测出水水质及作辅助工艺设计的平台。     

Calibration of denitrifying activity of polyphosphate accumulating organisms in an extended ASM2d model

This paper presents the results of an experimental study for the modelling and calibration of denitrifying activity of polyphosphate accumulating organisms (PAOs) in full-scale WWTPs that incorporate simultaneous nitrogen and phosphorus removal. The convenience of using different yields under aerobic and anoxic conditions for modelling biological phosphorus removal processes with the ASM2d has been demonstrated. Thus, parameter η_PAO in the model is given a physical meaning and represents the fraction of PAOs that are able to follow the DPAO metabolism. Using stoichiometric relationships, which are based on assumed biochemical pathways, the anoxic yields considered in the extended ASM2d can be obtained as a function of their respective aerobic yields. Thus, this modification does not mean an extra calibration effort to obtain the new parameters. In this work, an off-line calibration methodology has been applied to validate the model, where general relationships among stoichiometric parameters are proposed to avoid increasing the number of parameters to calibrate. The results have been validated through a UCT scheme pilot plant that is fed with municipal wastewater. The good concordance obtained between experimental and simulated values validates the use of anoxic yields as well as the calibration methodology. Deterministic modelling approaches, together with off-line calibration methodologies, are proposed to assist in decision-making about further process optimization in biological phosphate removal, since parameter values obtained by off-line calibration give valuable information about the activated sludge process such as the amount of DPAOs in the system.     

Assessment of the nutrient removal performance in integrated constructed wetlands with the self-organizing map

The self-organizing map (SOM) model was applied to predict outflow nutrient concentrations for integrated constructed wetlands (ICWs) treating farmyard runoff. The SOM showed that the outflow ammonia-nitrogen concentrations were strongly correlated with water temperature and salt concentrations, indicating that ammonia-nitrogen removal is effective at low salt concentrations and comparatively high temperatures in ICWs. Soluble reactive phosphorus removal was predominantly affected by salt and dissolved oxygen concentrations. In addition, pH and temperature were weakly correlated with soluble reactive phosphorus removal, suggesting that soluble reactive phosphorus was easily removed within ICWs, if salt concentrations were low, and dissolved oxygen, temperature and pH values were high. The SOM model performed very well in predicting the nutrient concentrations with water quality variables such as temperature, conductivity and dissolved oxygen, which can be measured cost-effectively. The results indicate that the SOM model was an appropriate approach to monitor wastewater treatment processes in ICWs.     

Calibration and validation of an ASM3-based steady-state model for activated sludge systems--part II: Prediction of phosphorus removal

An ASM3-based steady-state model which can be used for estimating the average nitrogen-removal, sludge-production and phosphorus-removal rates of different biological phosphorus-removing systems (AAO, UCT, intermittent processes) is developed. It considers the wastewater composition, the oxygen and nitrate input in the anaerobic compartment and the interaction between biological phosphorus removal and denitrification for different operating conditions. The model is calibrated and validated with data from a number of long-term pilot and full-scale experiments for Swiss municipal wastewater. The steady-state model is adequate for a comparison of different BPR process configurations or for a first estimation of the nutrient-removal efficiency. It allows the plant performance and key parameters to be determined very quickly. Excel spreadsheets of the model for different flow schemes are available from the corresponding author.     

Metabolic modelling of full-scale biological nitrogen and phosphorus removing wwtp's.

This paper evaluates the experiences with modelling full-scale biological phosphorus and nitrogen removing wastewater treatment plants. For the simulation, we used a metabolic phosphorus model integrated in ASM2d, further referred to as TUDP-model. It was found that the metabolic model for bio-P removal can be applied for modelling full-scale wwtp's, without extensive parameter adjustments. A stepwise modelling approach was proposed. Only three specific parameters were calibrated. Two parameters, the inert fraction in the influent and the actual anoxic sludge fraction will need calibration for all systems. Parameter sensitivity analyses showed that the sensitivity of operational data, often considered as known input data, is high. The model kinetics were found less sensitive. This will in general be the case for all low-loaded wwtp's recorded in their pseudo-steady state. Based on mass balance calculations, operational data and measurements were evaluated. Since all terms on a phosphorus balance can be measured, errors in operational data (e.g. SRT and flow rates) become very apparent in P-removal models (ASM2d, TUDP). We suggest using the P-balance in general for wwtp modelling, as a check on data consistency. This study showed that considering operational data per definition as known input data is not justified. Therefore, operational data should be evaluated, or considered in model calibration over the use of kinetic and stoichiometric parameters.     

污泥焚烧灰分磷回收潜力分析及其市场前景

磷资源不可替代又不能再生。现代工业攫取磷矿大多用于磷肥生产,通过作物收获的粮食、蔬菜以及饲养畜禽肉类进入人体,而随食物进入人体的大多数磷(90%)会随排泄物进入污水(无粪尿返田情况)。尽管最终进入污水中的磷占开采磷矿的比例很小(<5%),但这是人类除动物粪便与作物秸秆外唯一可能实现磷人工循环的位点,相对于转移进作物中的磷来说该比例超过1/4。因此,在废弃粪尿返田之原生态习惯的情况下,从污水处理过程中回收磷则显得非常重要。目前从污水处理过程中回收磷存在许多方式与产品,而与污泥焚烧灰分相关的磷回收程度最高,可达90%。为此,首先基于全球磷资源危机与我国磷流向及其估算,揭示磷回收的必要性和急迫性。然后,对与污泥焚烧相关的灰分磷回收技术以及潜在应用进行总结和分析。最后,根据肥效实验与成本估算,认定灰分再生磷肥比传统矿石磷肥具有潜在市场前景,特别是它的可持续意义。     

ASM2d模型改良及在DE型氧化沟中的应用

对国际水质污染与控制协会(IAWQ)推出的活性污泥2d号模型(ASM2d)进行优化,使之能够模拟含有菌胶团的污水处理工艺。使用改良后的ASM2d模型模拟并分析了有机物、氮和磷在DE型双沟式氧化沟中的降解过程,发现优化后模型能够较好地拟合这些物质的降解过程。依据所建立的模型计算出各组分在DE型氧化沟中1个周期4个阶段的转化速率,该结果有助于深入分析有机物、氮及磷不同形态之间的转化规律。     

Growth and nutrient uptake of green alga, Scenedesmus dimorphus, under a wide range of nitrogen/phosphorus ratio—II. Kinetic model

A new kinetic model of algal growth and nutrient (nitrogen and phosphorus) uptake was proposed. In this model, algal cells were conceptually divided based on algal nitrogen content into two components of the functional substance and the storage substance. Specific algal growth rate, nitrogen uptake rate and phosphorus uptake rate were expressed by using four state variables of available nitrogen and phosphorus concentrations in the medium and algal nitrogen and phosphorus contents. The values of parameters used in the model equations were estimated applying them to the results of a chemostat culture experiment using Scenedesmus dimorphus. The outline of the overall processes of algal growth and nutrient uptake was found to be explained by this model and the model equations with the estimated parameters could reproduce the experimental results to a considerable extent.     

折流曝气生物滤池除磷效能的研究

针对城市污水处理中曝气生物滤池容易堵塞,除磷效果不好等问题,对折流曝气生物滤池(BBAF)的运行条件,除磷效能进行了研究;为提高其除磷效果,研究适于BBAF反应器的除磷方法,对其除磷机理进行了深入研究。