Synthesis and characterization of T-type zeolite membrane on a porous mullite tube

Although the scope for water recycling was examined in two reports in 1977–1978, it was not until the Environment Protection Authorities had been established in most of the states in the early 1990s that water authorities began making substantial use of treated wastewater, using recycled water on land as a component of meeting newly imposed discharge limits from sewage treatment plants. The period of nation-wide drought in 2001–2003 led to increased interest in the use of recycled water as a means of substituting it for drinking quality water where that standard was not required. The Australian Academy of Technological Sciences and Engineering published an extensive review of water recycling in Australia in March 2004, outlining progress to 2003 and identifying 24 issues that needed to be addressed. Developments since then are discussed, including an intergovernmental agreement between the Australian Government and most of the States and Territories on a National Water Initiative, and the generation by the mainland States of new strategies which aim to reduce per capita demand for water and increase the use of recycled water, stormwater and rainwater in Australia's capital cities.     

Adsorption characteristics of construction waste for heavy metals from urban stormwater runoff☆

Stormwater runoff has become an important source of surface water pollution. Bioretention, a low impact devel-opment measure in urban stormwater management, has been proven to be effective in the removal of pol utants from stormwater runoff, with appropriate bioretention media. In this study, construction wastes were selected as bioretention media to remove heavy metals from stormwater runoff. Static and dynamic adsorption batch exper-iments were carried out to investigate the adsorption of heavy metals in simulated stormwater runoff system with construction wastes in different particle sizes. The experimental results show that the pseudo-second-order kinetic model characterizes the adsorption process and the adsorption equilibrium data are wel described by Freundlich isotherm model. The construction wastes used can remove heavy metals from stormwater runoff effectively, with their average removal rates al more than 90%. The particle size of construction wastes greatly influences the equilibrium time, rate and adsorption capacity for heavy metals.     

化学酸洗去除钢铁氧化皮清洁生产的途径

汽车制造用钢材采用化学酸洗去除氧化皮。介绍了酸洗工艺及生产过程中废水、废气、废渣等污染物产生的来源。钢铁酸洗实施清洁生产,使用替代工艺,优化工艺规范,加强工艺管理,从而控制污染。配合末端治理,回收利用废酸液。     

A mixed integer optimisation approach for integrated water resources management

In areas lacking substantial freshwater resources, the utilisation of alternative water sources, such as desalinated seawater and reclaimed water, is a sustainable alternative option. This paper presents an optimisation approach for the integrated management of water resources, including desalinated seawater, wastewater and reclaimed water, for insular water deficient areas. The proposed mixed integer linear programming (MILP) model takes into account the subdivided regions on the island, the subsequent localised needs for water use (including water quality) and wastewater production, as well as geographical aspects. In addition, the integration of potable and non-potable water systems is considered. The optimal water management decisions, including the location of desalination, wastewater treatment, and reclamation plants, as well as the conveyance infrastructure for desalinated water, wastewater and reclaimed water, are obtained by minimising the annualised total capital and operating costs. Finally, the proposed approach is applied to two Greek islands: Syros and Paros-Antiparos, for case study and scenario analysis.     

Mineralogy and geochemistry of Greek and Chinese coal fly ash

In this paper the mineralogy and geochemistry of Greek and Chinese coal fly ash are examined. Annual production of fly ash in China is around 160 Mt while in Greece lignite fly ash accounts around 10 Mt. Even though the mineralogical and chemical composition of the fly ashes coming from these two countries differs, there are common questions on the utilization of this material. The variation of the Greek fly ash’ chemical composition, from Ca-poor to Ca-rich fly ash, has resulted to applications such as dam construction, use in cement and possibly in concrete and road construction. The Chinese fly ash, which is rich in mullite, is broadly applied for brick making.     

THE USE OF NONLINEAR PROGRAMMING TO OPTIMAL WATER ALLOCATION

Environmental protection, shortage of fresh-water and rising costs for wastewater treatment are all convincing motives for reducing fresh-water consumption and wastewater discharge of the chemical, petrochemical, petroleum refining and other process industries. Maximizing water reuse, regeneration re-use, and regeneration recycling within the chemical plant, as well as optimal distribution of waste streams for end-of-pipe treatment can reduce fresh-water usage and wastewater discharge, while they are also significant in shrinking capital investment in wastewater treatment systems.

Optimal assignment and design of water consuming, regenerating, and treatment systems is a complicated task that can be mathematically formulated as mixed integer non-linear programming (MINLP). In the present article the superstructure based 'Cover and Eliminate' approach with NLP is applied with the tools of the GAMS/M1NOS/CONOPT package and compared to previous results. After introducing the problem in the context of chemical process synthesis, a mathematical model is described and the use of the methodology is explained. Experience with the use of GAMS is discussed. Several case studies are solved including basic examples from the literature and their variants.

The main conclusion is that the application of the mathematical programming for the optimal water allocation problem is essential owing to the broad variety of the specification opportunities. The complex nature of re-use, regeneration re-use, and recycling with multiple pollutants and multiple treatment processes cannot be simultaneously taken into account by conceptual approaches. It is also shown that the assumption on the independency of contamination rates, generally applied in earlier works, are not necessarily valid; and the NLP approach can deal with the more reliable specifications.     

Adsorption characteristics of a novel ceramsite for heavy metal removal from stormwater runoff

Urban sediments have rapidly increased in recent years around the world,and their effective management has become an important problem.To remove heavy metals from stormwater runoff and use sediments as a resource,a novel ceramsite was developed using sewer pipe sediments(SPS),river bed sediments(RBS),urban water supply treatment sludge(WSTS),and wastewater treatment plant excess sludge(WWTS).The optimal composition was determined based on the Brunauer–Emmett–Teller specific surface area and an orthogonal test design.The adsorption characteristics of the novel ceramsite for dissolved heavy metals(Cu~(2+)and Cd~(2+)) were investigated through adsorption isotherms and kinetic experiments at(25±1)℃.Both Cu~(2+) and Cd~(2+) were effectively removed by the novel ceramsite,and their equilibrium adsorption was 4.96 mg·g~(-1) and 3.84 mg·g~(-1),respectively.Langmuir isotherms and a pseudo-first-order kinetic equation described the adsorption process better than other techniques.Characterization analysis of the ceramsite composition before and after heavy metal adsorption showed that the Cu~(2+) and Cd~(2+) contents in the ceramsite increased after adsorption.The results revealed that adsorption is both a physical and chemical process,and that ceramsite can be used as a bioretention medium to remove heavy metals from stormwater runoff while simultaneously converting problematic urban sediments into a resource.     

给水处理除藻技术最新进展

我国地表水源富营养化日趋严重,进而导致严重的藻类污染。藻类及其副产物的污染不仅给传统净水工艺带来了诸多不利影响,增加了水处理难度,而且使得供水安全难以保证。文章对饮用水中藻类去除技术进行了具体的论述,并系统分析各技术去除效果、局限性,展望了藻类去除技术发展前景。指出目前控制饮用水中藻类污染必须将水源污染的综合治理、开发高效低廉的新工艺结合起来。     

Greek lignites as additives for controlling filtration properties of water–bentonite suspensions at high temperatures

The effectiveness of Greek lignites to control the filtration characteristics of water–bentonite suspensions and to minimize formation damage at high temperatures was studied. Twenty-six lignite samples from various peat/lignite deposits in Greece were used together with a commercial lignite product. The contents of humic and fulvic acids, humins, oxygen, ash and the cation exchange capacity of lignite samples were examined with respect to fluid loss of these suspensions. The results show that most samples provided very good filtration control of the water–bentonite suspensions after exposure to 177 °C with some being superior to the commercial product. Better performance was observed after addition of 3% w/v lignite. Total humic and fulvic acids as percentage of dry lignite matter and the organic matter as lignite percentage showed a weak inverse correlation with the fluid loss volumes.     

某工业园区污水厂的工艺诊断及水质优化研究

针对某工业园区污水厂出水TN超标问题,对工业园区和污水厂存在的问题进行了分析,提出源头冲击管控、推流器角度改造、进水余氯控制、跌水富氧控制、回流硝化液DO控制、外加碳源优选的6大优化措施。采取以上措施进行改造后,污水厂出水TN稳定达标,出水水质达到GB 18918—2002《城镇污水处理厂污染物排放标准》中的一级A标准。     

Integrated Environmental Protection Reduces Water Pollution

In the manufacture of chemical products, undesirable residues are also produced. These frequently occur as polluted wastewater that leads to the formation of sewage sludge after end-of-pipe treatment. Effective reduction of these substances is an important aim of industrial environmental protection. Taking the example of chemical production, the author shows how this aim can be achieved by production-integrated environmental protection. The paper outlines the technical measures involved in this approach, the result that they bring and the inherent limitations. The associated cost criteria are also discussed. The two concepts of end-of-pipe technology and production-integrated environmental protection are compared.     

Impacts of a marine fish farm in Argolikos Gulf (Greece) on the water column and the sediment

The aim of this study was the qualitative and quantitative assessment of impacts on the physicochemical characteristics of the water column and the sediment caused by an intensive marine fish farm. The study area was the Plateia Island which is located in an open seawater area in the outer part of Argolikos Gulf (Northeastern Peloponnese, Greece). The particular plant has been in operation since 1988, producing about 350-400 tons per year of Gilthead seabream (Sparus auratus) and European seabass (Dicentrarchus labrax). The samples were taken on a three-season period started in August 2001 and ended in May 2002. During this study, the main physical and geochemical parameters on the water column and the sediment were investigated. Specifically, the parameters that were measured included: ammonium-nitrogen, phosphate and suspended solids in the water column and organic matter, organic carbon, and phosphorus (total and inorganic) in the sediment samples. The conclusions drawn from this work clearly verify that the most important impacts, mainly identified as increased nutrients and organics concentrations both in the water column and the sediment, were realized at the stations closest to the farm. These concentrations gradually decreased with increasing distance from the cages. The peak values in most of the parameters measured were obtained during summer or spring. However, it has to be mentioned that although the measured concentrations clearly depict the influence of the fish farm especially on the sediment, their values were, in general, considerably lower than those reported in relative studies in Greek fish farms.     

大型水处理装置生产管理与全自动化控制

针对云天化安宁草铺水厂工艺特点,研究开发大型水处理装置生产管理与控制全自动化控制系统。利用水处理装置生产管理方法与经验,应用过程控制技术,结合现有的自动化仪表与设备,将全自动化控制系统用于大、中型水处理生产过程控制与运行管理。     

Fatty acid composition of capsicum oils by gas liquid chromatography

The fatty acid composition of oils extracted from various parts (pericarp, seeds and stem) of the fruit ofCapsicum and from samples of Greek red pepper itself were obtained by gas liquid chromatography. Samples from three different varieties ofCapsicum annuum, cultivated in the region of Almopia, Greece, were taken from two crops (1967, 1968) and examined. The results are discussed. No characteristic differences in fatty acid composition of the corresponding samples of the parts ofCapsicum fruit of the three Greek varieties were noticed and there was no difference between the two crops. However, considerable differences in fatty acid composition between Greek and American varieties were observed, probably due to climatic conditions. Presented at the Association of Greek Chemists Meeting, Athens, 1970.     

反渗透技术在钢铁工业废水处理和回用中的应用

针对原水水质情况和环保要求，确定采用反渗透膜技术处理该废水，介绍了系统工艺流程及主要设备，详细说明了反渗透膜技术处理钢铁工业废水的应用经验及效果。通过观察电导、产水量、压差的变化，分析了膜污染的成因，提出了清洗方案，并对反渗透系统的运行管理问题进行了论述。结果表明，酸-碱-酸的清洗方案对反渗透膜污染具有很好的控制效果。     

Corrosion resistance of stainless steels in chloride containing supercritical water oxidation system

As the science and process applications of supercritical water (SCW) and supercritical water oxidation (SCWO) become more thoroughly understood, it is logical to envision the use of the SCWO process by diverse industries and public wastewater and sludge generators. This technology can be adapted to accomplish either pre or end-of-pipe wastewater treatment. There is a need to destroy both military and civilian hazardous waste, and urgency, mandated by public concern over traditional waste handling methodologies, to identify safe and efficient alternative technologies. By capitalizing on the properties of water above its critical point, 374 °C and 22.4 MPa for pure water, this technology provides rapid and complete oxidation with high destruction efficiencies at typical operating temperatures. Nevertheless, corrosion of the materials of fabrication is a serious concern. While iron-based alloys and nickel-based alloys are generally considered important for service applications, results from laboratory and pilot-scale SCWO systems presently in operation indicate that they will not withstand some aggressive feeds. Significant weight loss and localized effects, including stress corrosion cracking (SCC) and dealloying, are seen in chlorinated environments. This work assesses the corrosion characteristics of iron-based stainless steels exposed to high supercritical temperatures in a chlorinated military waste containing salts.     

流动电流混凝投药控制系统的运行管理

介绍流动电流混凝投药控制系统在某水厂的实际运行情况，并总结了一些运行管理的体会．认为正确设定流动电流值、按实际生产情况选择运行模式、加强设备的日常维护和保养是保证投药系统自动化的有效途径．并提出一些改进建议，可供SCD在水厂中应用参考。     

Effect of time and rate of nitrogen application on cotton

Field studies were conducted in nine cotton production areas of Greece, for 15 successive years, to detective the optimum time and rate of N fertilizer application for maximum yields and better fibre characteristics of cotton (Gossypium hirsutum). Two to five rates of N fertilizer (60–180 kg N/ha) were applied: before sowing, when the plants had 3–4 leaves and 20 days later. The yield of cotton increased in most of the cases by N fertilization, but not significantly to both N rates and time of application. Under Greek conditions - limited growing season and low precipitation in spring - the split application of N fertilizers, compared to a single presowing application did not differ, as regards its effect on yield and fibre quality of cotton. Split application of fertilizers, supplementary to that applied at sowing could be of significance, when N plant demands are high and in addition there is a risk for excessive plant growth or for leaching losses. In the case of high N fertilizers rates, the split application must be preferred.     

Ozone Plant Operations Under Drought Conditions

The Metropolitan Water District of Southern California (Metropolitan) owns and operates five potable water treatment plants. Currently four of the treatment plants utilize ozone as the primary disinfectant. The Metropolitan ozone contactors are over-under baffled and include 10 chambers, an afterbay, and an effluent channel. Ozone is generally added in either the first countercurrent gas/liquid flow chamber (Chamber 1) or the first and second (co-current gas/liquid flow) chambers. Disinfection credit is received from ozone residuals in Chambers 2 through 6. An ozone destruct system collects and destroys ozone off-gases from Chambers 1 through 9 and an ozone quenching system is used to minimize dissolved ozone from leaving the contactors. Severe drought in California, and resulting water supply limitations, have created significant operational issues ranging from reduced plant flows to source water changes and water quality challenges. The combination of reduced flow and different source water conditions resulted in the ozone systems being operated occasionally under unfamiliar conditions. This article discusses some of the challenges faced in operating the ozone plants at low flows and low ozone production rates. Further, water quality issues required prudent management of operations to meet regulatory requirements. From the lessons learned, several recommendations are offered in preparation for similar conditions in the future.     

Farmer adoption of improved nitrogen management technologies in rice farming: technical constraints and opportunities for improvement

Generally, agricultural research is conducted under the controlled conditions of research stations which, in many cases, do not represent farmers'circumstances. Thus, several technologies do not perform well in farmers' fields and so are not adopted by farmers. Many technical factors and management practices constrain the adoption of improved technologies including efficient N management techniques: (a) poor water control; (b) low plant population; (c) partial nutrient application; (d) insufficient weed control; (e) untimely sowing, transplanting, weeding, and/or harvesting; and (f) poor postharvest processing. Unless farmers improve many, if not all, of these conditions, they cannot reap the full benefits of modern rice varieties and related production technologies. In addition, soil-related constraints such as high spatial and temporal variability in nutrient status, nutrient imbalance, poor drainage, soil degradation (salinity, alkalinity, acidity), and subsoil compaction lessen the effectiveness of nutrient management techniques. Similarly, climatic factors such as variable and unpredictable rainfall, drought, flood, low radiation, and extremes in temperature affect crop growth and nutrient use in rice systems. Most of these factors are beyond farmers' control. Stress-tolerant rice varieties and improved management practices are being developed and evaluated on rice farms to tackle soil and climatic constraints, especially in rainfed lowland rice systems. Two of the management strategies rely on better N placement techniques and use of controlled-release fertilizers to improve nutrient use efficiency in rainfed lowlands. Some tools for site-specific N management in rice include chlorophyll meter and leaf color chart which are being evaluated on farmers' fields. Another strategy is the integrated nutrient management to enhance crop nutrition and minimize fertilizer costs. Adequate farmer training is needed to receive, process, and effectively exploit improved rice varieties and related information, knowledge, and technologies.