Growth kinetics of the filamentous microorganism Sphaerotilus natans in a model system of a food industry wastewater

Bulking by Sphaerotilus natans has been attributed to several factors such as low dissolved oxygen in the aeration basin, wastes with high C:N ratios and phosphorus limitation; however, the occurrence of bulking has been reported in fruit, vegetable, meat and poultry wastewaters in which the ratio C:N is variable.Growth of S. natans was analyzed in a model system of a food industry wastewater (potato processing waste) that was characterized by HPLC determining that citric acid was the most important identified component. The effect of several carbon sources on S. natans growth was also studied; different C:N ratios were tested in a continuous culture system (chemostat). This strain grew in a mineral medium with citric acid as a sole carbon source, in spite of the contradictory results found in literature. Chemostat studies showed that the medium was carbon-limited when C:N ratios <19 mgCOD (mgN-NH₃)⁻¹. Monod kinetic growth coefficients, determined for this strain in chemostat were: maximum specific growth rate, μ_max=0.301 h⁻¹; Monod constant, K_S=4.6 mgCOD l⁻¹; true biomass growth yield, Y^T_X/S=0.490 mgVSS (mgCOD)⁻¹; endogenous decay rate, k_d=0.011 h⁻¹ and maintenance coefficient, m_S=0.022 mgCOD (mgVSS)⁻¹ h⁻¹. The obtained parameters were compared with literature data and the effect of glucose and citric acid as carbon sources was discussed; these parameters are useful in modeling the growth of S. natans in potato processing wastewaters (or in other effluents under carbon-limiting conditions) especially when citrate is the main component and can be used to control filamentous bulking by metabolic or kinetic selection.     

高效产酸发酵反应器处理医药原料废水

以高效产酸发酵反应器作为高浓度医药原料废水的二段厌氧生物处理的产酸装置,通过中试研究获得了反应器运行过程的COD容积负荷,水力停留时间、进水COD浓度,搅拌速度等参数及与COD去除率的关系,为实际工程设计及运行提供了依据。     

The effects of food waste disposers on the wastewater system: a practical study

Domestic food waste disposers (FWDs) have recently come to prominence as a possible alternative for disposal of organic waste, to reduce the quantities of this type of waste sent to landfill. There has been little research undertaken on the potential effects of food waste on the wastewater system, and it is believed no previous practical studies have been undertaken in the United Kingdom. In this study, food waste was ground in an FWD and analysed for chemical oxygen demand (COD), biological oxygen demand (BOD), ammonia, total nitrogen, total phosphorus, total suspended solids and rapidly settleable solids to determine their effects on the wastewater system. The largest impacts were on COD, BOD and suspended solids, compared with the amounts of these determinands that currently arrive at sewage treatment works (STW). Experiments using settled samples showed that a relatively high proportion of nitrogen, phosphorus, COD and BOD would pass through to secondary treatment at the STW.     

Anaerobic treatment of wastewater containing fatty acids in upflow reactors

An extended summary is presented of a Dr.Sc. Thesis in which the results of a study on anaerobic treatment of wastewater containing fatty acids have been reported. This study, concerning the technological features of this process in upflow reactors, was aimed at the following subjects :

• - the dynamics of the fluid flow in the reactor;

• - the dynamic behaviour of the sludge particles in the reactor;

• - the kinetics of the conversion of the fatty acids and of the formation of the products (mainly biogas and anaerobic sludge); and

• - the separation of the gas and the sludge from the treated water.

From the results obtained in experiments on lab-scale and (semi) technical scale, a quantitative model for the operation of the reactor has been derived. This model can be used for scaling-up purposes and for optimisation of the process performance.     

污泥固态好氧发酵成套设备的开发

采用自行研发的好氧动态发酵系统对城市污水处理厂的脱水污泥进行处理,研究了污泥好氧发酵处理过程中温度、含水率、供氧量等参数的变化规律。结果表明,污泥好氧发酵过程可以实现顺利升温并在55℃以上维持48h,有效地降低了物料的含水率,去除了病原菌、寄生虫卵和大肠杆菌,达到了污泥减量化、稳定化、无害化、资源化的目的。     

Performance characteristics of the anaerobic baffled reactor

An anaerobic sludge blanket process, termed the anaerobic baffled reactor (ABR), has been developed and shows promise for industrial wastewater treatment. It combines the advantages of high stability and reliability with a high void volume. The risk of clogging and sludge bed expansion with resulting high microbial losses is reduced and there is no need for special gas collection or biological solids separation systems. Organic loadings as high as 36 g COD l^?1day^?1 have been achieved with COD removal rates of more than 24 g COD l^?1 day^?1 and methane production rates exceeding 6 volumes per day per unit volume of reactor. The hypothesis, that the ABR may be adequately modeled as a fixed-film reactor, has been supported. Therefore, a unified approach, based on fundamentals of bacterial kinetics and mass transport, appears useful for modeling this and similar systems. Pilot plant studies are necessary to determine the scaling factors of the system as well as the overall efficiency and costs.     

Fuzzy control of disturbances in a wastewater treatment process

This paper describes a real-time process control scheme to cope with the problem of input disturbances in wastewater treatment processes, based on a fuzzy inferential control system. This can detect the presence of a dangerous input conditions whenever either organic overload or inhibitory/toxic compounds are present in the raw wastewater. Based on this diagnosis, a set of fuzzy rules are implemented to divert the process flow and bring the system back into a safe state. The control system was designed and tested using a pilot plant, to which a toxic disturbance was applied. Its behaviour with and without fuzzy control are compared, and the process reliability improvement in the controlled case is demonstrated.     

上海青浦污水处理厂污泥好氧发酵新技术应用

对上海市青浦区城镇污水处理厂污泥工程设计进行了介绍,包括污泥量的估算、污泥处置出路的选择、污泥处理工艺确定及工程经济技术指标等。经比选后,青浦区城镇污水处理厂污泥主要处置方式为园林绿化用土。污泥处理方法采用好氧发酵处理工艺。最后具体介绍了工程设计,包括物料流程和配套设备。     

Battery industry wastewater: Pb removal and produced sludge

The process of neutralization with NaOH, in the presence of Fe(III) salt, of sulphuric acid battery industry wastewater seems to be more suitable than any other process for Pb removal because at the same time, it allows the exploitation of the scavenger action of Fe(III), which is often present in the same wastewater and precipitates as hydroxides. In order to optimize sludge production, a laboratory research study has been carried out to minimize the quantity of Fe(III) to be added. All aspects concerning the chemistry of wastewater have been taken into consideration step by step and discussed. As a result, a process which requires the addition of Fe(III) so that an Fe/Pb ratio, both expressed as ppm, of the order of 0.5 is achieved. The process has been applied to two artificial solutions, characterized by a content of H₂SO₄ of 1000 and 5000 ppm, respectively, and by 10 ppm of Pb, as well as to five samples of wastewater. The proposed process takes about 1 h to perform: 30 min for neutralization up to pH 8.5–9.5 and Fe(III) addition and 30 min for correction in the 9–9.5 pH range and for flocculation with the help of a polyelectrolyte. The Pb concentration of the treated effluent is below 0.2 ppm. Conditions for Pb removal using only NaOH or Na₂CO₃ have also been considered.     

对污水深度处理滤池工艺设计的探讨

首先介绍和分析了重力式滤池两种流向 (上向流式和下向流式 )的过滤机理 ,并从多方面阐明了污水深度处理宜采用上向流式滤池的观点 .其次 ,对上向流滤池的运行特性进行了分析 ,从而得出冲洗工序对滤后水质有影响的结论 .最后还介绍了上向流滤池的应用实例及其工艺设计参数 .     

有机废水厌氧发酵产酸的试验研究

利用厌氧污泥对有机废水进行了发酵产酸试验，考察了一次进料、多次进料和调节系统pH值为酸性等培养方式对系统产酸效果的影响，并确定了产乙酸效果最佳时的pH值。结果表明，在进水COD约为25000mg／L、温度为（36±1）℃、控制系统pH值在4．0—4．5的条件下，采用多次进料的培养方式，厌氧污泥的产酸效果较好，乙酸为主要末端发酵产物，且pH=4．3时系统的产乙酸效果最佳。     

Influence of wastewater treatment on sludge production and processing

The challenge of stricter wastewater standards is resulting in configuration changes to wastewater treatment. As facilities upgrade, the type of sludge produced is changing, with growing quantities of secondary and chemical sludge at the expense of primary sludge. It is already understood that secondary sludge is harder to treat than its primary equivalent; therefore, increasing the quantity of this type of sludge will have detrimental impacts downstream. As legislation tightens further, extended aeration times may be required during processing to remove more nutrients. Work has shown that extended aeration further exacerbates the treatability of secondary sludge. This paper explains how tightening wastewater legislation fundamentally alters the nature of the sludge produced, and how these alterations impact further processing, especially with respect to sludge production and type; sludge energy content; performance of anaerobic digestion and dewatering, and potential for thermal energy recovery.     

干式厌氧发酵反应器的中试研究

采用一种新型卧式推流干式厌氧发酵系统用于猪粪、秸秆和污泥处理中试研究。试验阶段干式厌氧发酵系统表现出较好的稳定性,运行效果良好。新型卧式推流干式厌氧反应器能够有效解决传热和传质差的问题。当进料含水率为80%、回流比为50%时,出料含水率为84%～88%,有机质含量为60%～70%,酸碱比基本维持在0. 1～0. 3。干式厌氧发酵系统的最佳有机负荷为4. 8 kg/(m³·d),有机物降解率为40%～50%,容积产气率可达2～3 m³/(m³·d)。猪粪与秸秆协同厌氧发酵的效果好于猪粪、秸秆单一物料,因为猪粪与秸秆混合可以将进料的C/N值控制在厌氧发酵的最佳范围(20～30)。猪粪和秸秆混合发酵系统中,C/N值的提高使得氨氮浓度呈下降趋势,这在一定程度上避免了系统出现氨抑制的情况。     

Economic evaluation of alternative wastewater treatment plant options for pulp and paper industry

Excessive water consumption in pulp and paper industry results in high amount of wastewater. Pollutant characteristics of the wastewater vary depending on the processes used in production and the quality of paper produced. However, in general, high organic material and suspended solid contents are considered as major pollutants of pulp and paper industry effluents. The major pollutant characteristics of pulp and paper industry effluents in Turkey were surveyed and means of major pollutant concentrations, which were grouped in three different pollution grades (low, moderate and high strength effluents), and flow rates within 3000 to 10,000 m³/day range with 1000 m³/day steps were used as design parameters. Ninety-six treatment plants were designed using twelve flow schemes which were combinations of physical treatment, chemical treatment, aerobic and anaerobic biological processes. Detailed comparative cost analysis which includes investment, operation, maintenance and rehabilitation costs was prepared to determine optimum treatment processes for each pollution grade. The most economic and technically optimal treatment processes were found as extended aeration activated sludge process for low strength effluents, extended aeration activated sludge process or UASB followed by an aeration basin for medium strength effluents, and UASB followed by an aeration basin or UASB followed by the conventional activated sludge process for high strength effluents.     

The effects of organic toxicants on methane production and hydrogen gas levels during the anaerobic digestion of waste activated sludge

Batch serum bottle assays were conducted to examine the response of the anaerobic digestion process to inhibition induced by the pulse addition of four organic toxicants [chloroform, bromoethanesulfonic acid (BES), trichloroacetic acid (TCAA) and formaldehyde]. The impact that increasing levels of inhibition of methane production had on hydrogen response and volatile fatty acid (VFA) accumulation were examined. All of the toxicants, with the exception of formaldehyde, appeared to elicit similar hydrogen response patterns and VFA accumulations for similar levels of inhibition. Results indicate that both the hydrogen and acetate catabolizing methanogenic populations were inhibited to approximately the same extent by chloroform, BES, and TCAA. Severe inhibition of methane production (>70% reduction of methane produced compared to controls) resulted in a rapid accumulation of hydrogen in the gaseous headspace. When inhibition was less severe, hydrogen accumulated to levels only slightly above controls. Based on these preliminary results, there appears to be some limits on the potential of using hydrogen as an early warning indicator of process upset. Results do indicate, however, that monitoring hydrogen in consert with conventional process indicators should improve digester monitoring and may provide more rapid indication of process upsets due to toxic shocks.     

厌氧生物滤池在PTA废水处理中的应用

为了提高现有PTA废水处理装置的处理能力,保障外排水质满足《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级B标准,某石化企业新建了厌氧生物滤池以预处理PTA废水。经过一段时间的运行表明,高浓度PTA废水经过厌氧预处理后,下一级纯氧曝气池的负荷降低,沉淀池出水COD<60 mg/L,达到了排放标准。介绍了厌氧生物滤池的处理效果、运行影响因素及开车阶段存在的问题等。     

厌氧/好氧/生物滤池工艺处理牛仔服漂洗废水

采用厌氧折流板反应池／改良接触氧化池／生物滤池工艺处理牛仔服漂洗废水,运行结果表明,厌氧折流板反应池和接触氧化池的容积负荷分别达到1．05kgCOD／（m^3&#183;d）和0．52kgCOD／（m^3&#183;d）。当进水COD、BOD5、SS、色度和硫化物的浓度分别为667．5mg／L、220．3mg／L、396．2mg／L、580倍和38．4mg／L时,出水相应指标的浓度分别为46．8mg／L、8．1mg／L、42．2mg／L、30倍和0．2mg／L,可实现牛仔服漂洗废水长期稳定达标排放。     

国家标准《食品工业洁净用房建筑技术规范》解读

介绍了该规范的主要内容,包括工厂平面布置、洁净用房分级和环境参数、对工艺设计的要求、通风与净化空调、给水排水等.对强制性条文进行了重点解读.     

A septic tank‐UASB combined system for domestic wastewater treatment: a pilot test

A 250 L and a 550 L pilot scale Up‐Flow Anaerobic Sludge Blanket (UASB) reactors having different reactor height were fed septic tank effluents and operated at ambient temperatures of 0°C to 30°C. Both UASB reactors were fed intermittently at least 8 times per Hydraulic Retention Time (HRT) and the performance was monitored at 4d and 1d HRT. The removal efficiencies of Total Suspended Solid (TSS) and Total Chemical Oxygen Demand (COD_t) were about 59–68% and 54–59%, respectively, for both reactors at both HRT. The TSS and CODt removal efficiencies of Septic tank – UASB combined system were above 80% for both HRTs tested. The average biogas yields were almost same at 4d and 1d HRT, representing 31(±3)% of influent CODt. The nitrogen and phosphorous removal efficiency was an average 20–30%. The tested system can become a suitable low cost yet effective option.     

变速生物滤池处理城市污水的效能研究

对采用酶促填料的变速生物滤池处理城市污水进行了生产性试验研究，考察了水力停留时间（HRT）和温度的影响。结果表明，常温、填料层厚度分别为1．5m和2．0m、填料层HRT分别＞3．5h和4．9h、相应的滤池HRT＞9．7h时，滤池能有效地去除水中有机物和悬浮物。