Overview of key operation factors and strategies for improving fermentative volatile fatty acid production and product regulation from sewage sludge

In recent years,volatile fatty acid(VFA) production through anaerobic fermentation of sewage sludge,instead of methane production,has been regarded as a high-value and promising roadmap for sludge stabilization and resource recovery.This review first presents the effects of some essential factors that influence VFA production and composition.In the second part,we present an extensive analysis of conventional pretreatment and co-fermentation strategies ultimately addressed to improving VFA produc...     

碱性过硫酸钾消解测定城市污泥中总氮

城市污水处理厂污泥经风干粉碎后，用碱性过硫酸钾溶液在高压器皿中于124℃消解，取上清液以紫外分光光度法测定总氮。对11个污泥样品测定，相对标准差≤1．5％精密度较好。并用L-谷氨酸标准物加入11个溶液样品中作回收试验，回收率在94％～107％之间，准确度亦较好。     

Transport of Sewage Sludge in a Mixed Water Column

Sewage sludge from four publicly-owned treatment works was sampled and characterized in terms of parameters affecting transport at the 106-mile deep ocean disposal site as part of the US Environmental Protection Agency's site monitoring programme. Samples from treatment plants in Passaic Valley, Rahway, and Elizabeth, New Jersey and New York City were characterized in terms of dynamic size distribution, suspended solids and density. the transport characteristics of sludge particles were measured using a 2 metre computer-interfaced laboratory settling column. Experiments were conducted at constant salinity (35 ppt) while varying hydrodynamic mixing, sludge type and concentration using a modified factorial experimental design. Hydrodynamic power dissipation was varied so that the vertical dispersion and rms fluid shear rate ranged between 0-6 cm²S^-1 and 0-30s^-1 respectively. Results indicate that at least 80% of suspended sludge particles will eventually settle under mixed conditions. the average settling velocities ranged between 0.05-4.05 × 10^-3 cm ^s-1. Shear rates above 15 s^-1 inhibited sludge settling due to aggregate breakup and boundary effects, but at a lower shear rate, differential settling and fluid shear were the dominant transport mechanisms. Sludge dilution (1/500-1/5000) had a limited effect on the settling rate. Results from this study can be used to calibrate particle transport models to determine the fate of sludge disposed at an ocean disposal site.     

Use Impairments and Ecosystem Impacts of the New York Bight

The New York Bight is perhaps one of the most used and abused coastal areas in the world as a consequence of urbanization and the disposal of the waste of some 20 million people who reside by its shores and surrounding bays and estuaries. A variety of sources, including those associated with sewage wastes, industrial wastes, contaminated dredged material, urban runoff, and atmospheric fallout contaminate these coastal waters. Many of the stresses of excess population and industrialization as measured by pollutant loadings and ecosystem impacts can be crudely quantified in terms of use impairments-use impairments that have measurable social and economic relevance. Five broad categories of impairment attributed to pollution in the Bight that are causing significant losses of ecological, economic, or social values are: beach closures, unsafe seafoods, hazards to commercial and recreational navigation, loss of commercial and recreational fisheries, and declines in birds, mammals and turtles. These impairments are generally caused by floatable wastes, nutrients, toxicants, pathogens and habitat loss. Measures of such impairments are not standard, nor in many cases totally quantifiable. We have examined specific subsets of these impairments in terms of their spatial and temporal changes and as a first approximation determined the economic and social significance of these changes. the cost of these impaired uses of the Bight are measured in terms of billions of dollars annually for New York and New Jersey.     

Fate of herbicides and nonylphenol in soil–plant–water systems amended with contaminated sewage sludge

We studied the fate of sludge spiked with ¹⁴C-labelled diuron, glyphosate and nonylphenol applied to the soil by the way of contaminated sewage sludge in the soil-plant-water system. Here we show that the mineralization of the chemicals in mixture is reduced by 40–80% by comparison with a direct soil contamination. The persistence of the chemicals in soils is increased in the presence of sludge. We showed also that the chemicals present in the sludge are mobile and partly transferred to soil leachates and plant seedlings. These results allow postulating that these compounds may induce an ecotoxicological impact on the soil ecosystem.     

Membrane fouling controlled by coagulation/adsorption during direct sewage membrane filtration (DSMF) for organic matter concentration

Unlike the role of the membrane in a membrane bioreactor, which is designed to replace a sediment tank, direct sewage membrane filtration (DSMF), with the goal of concentrating organic matters, is proposed as a pretreatment process in a novel sewage treatment concept. The concept of membrane-based pretreatment is proposed to divide raw sewage into a concentrated part retaining most organics and a filtered part with less pollutant remaining, so that energy recovery and water reuse, respectively, could be realized by post-treatment. A pilot-scale experiment was carried out to verify the feasibility of coagulant/adsorbent addition for membrane fouling control, which has been the main issue during this DSMF process. The results showed that continuous coagulant addition successfully slowed down the increase in filtration resistance, with the resistance maintained below 1.0 × 10¹³ m^− 1 in the first 70 hr before a jump occurred. Furthermore, the adsorbent addition contributed to retarding the occurrence of the filtration resistance jump, achieving simultaneous fouling control and chemical oxygen demand (COD) concentration improvement. The final concentrated COD amounted to 7500 mg/L after 6 days of operation.     

从实用结果评估污水除油用浮选机的分选能力

为从生产实际使用结果比较不同浮选机的分选能力 ,提出以小型浮选试验研究得到的除油结果做为比较时的一个基础数据 ,同时考虑处理量、浮选工艺条件、水的温度等因素的影响 ,还应注意其抗冲击能力。在讨论时应注意所用含油量分析方法     

柴油机污染物排放后处理技术的研究进展

国内外柴油机主要排放物NOx和微粒的后处理技术的研究现状和最新技术发展动态表明，机内、机外处理技术的组合，是达到未来柴油机排放标准、实现大幅度降低柴油机污染物排放的趋势。分析了各种机外净化技术的特点和存在问题，阐述了燃油含硫量对柴油机排放后处理的影响。     

MBR污水处理技术在炼油污水中的应用

膜生物反应器（MBR）是膜技术和污水生物处理技术相结合的污水处理新工艺。金陵分公司污水处理场新建一座MBR处理装置，处理量为250t／h，自2005年11月正式投用，至今已连续运行一年的时间。该装置对炼油污水COD、油、硫、酚、氨氮、浊度的平均去除率分别稳定在80％、60％、100％、98％、90％、99％以上。为炼油污水回用创造了条件。     

石化企业外排污水水质自动监控系统应用分析

对石化企业外排污水水质自动监控系统进行了详细介绍。着重介绍系统的主体——在线监测仪器的性能、运行与维护、监测数据质控等情况，并分析系统运行四年多以来发现的问题及采取的应对措施。系统投运以来，运行稳定，达到了对外排污水实时监控的目的。