Potential impacts of on-site greywater reuse in landscape irrigation

This study investigated the effects of irrigation with different types of waters on soil, plants, and public health. The test plant was ryegrass grown in 12 planters filled with sandy loam soil and irrigated with three types of waters (4 planters for each type): freshwater, raw domestic light greywater (GW), and treated domestic light GW. The sodium adsorption ratio (SAR), EC, pH and alkalinity of the three types of irrigation waters did not differ significantly, suggesting that raw or treated light GW should not exhibit negative effects. Concentrations of anionic and cationic surfactants in the freshwater and the treated GW were about the same, while their concentrations in the raw GW were higher. Surfactant levels in the three drainage water types were low. Some accumulation of surfactants occurred in planters irrigated with raw and treated GW. The COD of the drainage water of planters irrigated with raw GW was higher than the COD of other two drainage water types. Although raw and treated GW contained faecal coliforms, they were hardly detected in the drainage waters. All plants did not show any signs of stress. This may be due to the fact that the GW originated mainly from showers and washbasins.     

创新机制 突出重点 努力实现农田水利基本建设新跨越

<正>近年,湖北省认真贯彻落实党中央、国务院有关工作部署,大力开展农田水利基本建设并取得显著成效,农田水利基本建设实现了力度大于往年、资金多于往年、各项措施优于往年、综合效益好于往年的总目标。主要采取了五项措施:     

Aeration effect on the efficiency of swine manure treatment in a trickling filter packed with organic materials.

Effect of aeration rate on the removal of organic matter and nitrogen and on the formation of NH3, N2O and N2 was studied for an extensive biofiltration system packed with an organic media, which was used to treat pig manure. The results show high removal of BOD5 and TSS (99 and > or = 98%), independently of the four aeration rate tested (3.4-34 m3/m2 x h). Aeration rate > or = 4.4 m/h resulted in high ammonia stripping during start-up (> or = 1.0 kg NH3-N/m3 of swine manure treated), while using 3.4 m/h only 0.3 kg NH3-N/m3 were stripped. Complete nitrification was achieved after day 100 of operation, except in the biofilter with the lowest aeration rate. Simultaneous denitrification established in all the biofilters. Applying an aeration rate of 9.4 m/h up to 1.2 kg nitrogen was removed in the form of N2 for each m3 of swine manure treated. Contrary to the expectations, N2 formation and release increased with the aeration rate. This particular behaviour seems to be related to the punctual accumulation of water layers inside the biofilters, caused by the air force flowing in the opposite direction to the water flux. N2O production was quite similar in all biofilters (between 0.25-0.36 kg N2O-N/m3 of swine manure treated).     

如何做好灌区工程施工质量监理工作

根据灌区工程工期短、线路长的特点,提出监理关键是要抓好开工前的准备工作,同时在施工过程中要加强检查,以达到控制工程质量的目的。指出完工后要及时验收,确保工程安全投入使用。     

Modernization of irrigation systems in Spain: review and analysis for decision making

Abstract

This article presents a method for analyzing the economic feasibility of modernizing irrigation systems. By using substitution relationships between two variables, one can determine irrigation performance and farm profit ?above which modernization would be justified from an economic point of view; ?and also the investments and energy consumption up to which modernization could be considered cost-effective. By means of representative average values, this method is applied to the now widespread conversion from surface irrigation to drip irrigation in Spain. Two conclusions are drawn. First, modernization may, in some instances, be justified only if more productive crop patterns are implemented. Second, saving water is a cheaper option than using an alternative resource only under certain conditions.     

Solar disinfection for the post-treatment of greywater by means of a continuous flow reactor

SODIS (solar disinfection) is a low-cost alternative for water decontamination. The method is based on the exposure of water, contained in PET bottles, to direct sunlight, and mainly its UV-A and infrared components. The present research studied SODIS as a low cost alternative for the inactivation of Escherichia coli (E. coli) in treated greywater, aiming at its reuse for more noble applications. Experiments were performed in (i) batch mode (2 L PET-bottles), testing the effect of turbidity on system efficiency and, (ii) in a continuous pilot-scale reactor prototype (51 L, using interconnected 2 L-PET bottles), testing hydraulic retention times (HRT) of 18 and 24 h. Samples were exposed to an average solar radiation intensity of 518 W/m2. The results obtained indicate that the SODIS system has potential for total coliforms and E. coli inactivation in the pre-treated greywater, reaching 2.1 log units E. coli inactivation in batch experiments for low turbidity samples (21 NTU), and > 2 log units inactivation of total coliforms (and E. coli, when present) for the 24 h HRT-continuous prototype. The continuous flow prototype needs more testing and structural improvements to cope with the difficulties posed by algae growth, as they complicate maintaining conditions of constant flow and make frequent maintenance inevitable.     

The beneficial effects of storage on the quality of wastewater for irrigation: a case study in Sicily.

Although the main function of reservoirs in agriculture is to allow the storage and temporal shifting of large volumes of waters, further benefits emerge from their application in wastewater reuse systems. In fact, as observed in several other studies carried out on such complex natural systems, the storage period, under proper conditions, can lead to a significant improvement of the water quality for irrigation thanks to concurrent physical, chemical and biological processes. In order to investigate the reservoir dynamics, an experimental research was carried out in a farm reservoir (volume of 11,000 m3, maximum depth of 6.3 m and mean depth of about 5 m), receiving treated wastewater and subject to scheduled highly variable input to volume ratios, in order to observe the broadest range of behaviour responses. Specifically, over a monitoring period lasted 4 months, the reservoir was operated as a standard batch reactor in the first and third phases and as a continuous flow reactor in the second one. Based on correlation analysis between the chemical, physical and biological water parameters and operational ones, a new operative index is proposed which integrates the morphological characteristics of the tank and the management ones, and shows a significant correlation with the qualitative characteristics of the stored water.     

Microbiological quality of reclaimed water used for golf courses' irrigation.

Microbial quality of reclaimed water used for irrigation in two golf courses located in the southern Iberian Peninsula (Spain and Portugal) was evaluated. Bacterial indicators for faecal pollution (total and faecal coliforms, Escherichia coli and enterococci) were tested by membrane filtration using appropriate selective media. In addition, somatic E. coli bacteriophages, enteric viruses (entero-, hepatitis A and rota-) and Legionella pneumophila were also analysed. The results obtained showed that all wastewater treatment processes reduced adequately the number of indicator microorganisms although a significant correlation between pathogenic and indicator microorganisms tested was not found. L. pneumophila was detected by PCR but not confirmed by culture. Survival experiments of pathogenic microorganisms in aerosols and irrigated turf are conducted to determine the health hazards for the golf practice and to propose a microbial standard for wastewater used for irrigation of golf courses.     

Effect of irrigation water quality on organic matter, Cd and Cu mobility in soils of Central Mexico.

Untreated wastewater has been used for irrigation since 1912 at the Irrigation District 03, Central Mexico. Accumulated heavy metals are dominantly bound to the organic soil fraction. In a field study we evaluated the effect of wastewater irrigation on the quality of soil organic matter and the amount of water extractable Cu and Cd. In a column experiment we tested if water treatment affects the leaching of both metals and dissolved organic carbon (DOC) out of soils that have been irrigated for more than 90 years with untreated wastewater. The field study shows that long term irrigation increases the mineralizable carbon fraction and the DOC concentrations. The water extractable Cu and Cd concentrations also increase and correlate with DOC. In the column leachates the Cu concentrations also correlate with DOC, the Cd concentrations correlate with the sum of cations, chloride and DOC concentrations. Water treatment reduced Cd leaching, but it did have no substantial effect on Cu leaching.     

水质有机污染损失的经济计量模型

运用污染损失率函数和有机污染物衰减方程建立数学模型,把污染损失与污染物浓度、污染物降解时间联系在一起,突出了污染损失随着有机物衰减而发生的变化,并用福州市的工业废水有机污染物排放情况验证模型。     

The use of buffer zones to protect water quality: A review

It is popularly accepted that vegetated buffer zones are effective in removing water pollutants from surface runoff. However, there is a paucity of detailed information about establishing and maintaining buffer zones under different conditions, particularly in large catchments with diverse land uses. This paper reviews information on the application and effectiveness of vegetated buffer zones, and seeks to provide guidelines on their use for water quality control.Investigations into the use of buffer zones are grouped here into three major categories: studies of runoff plots or confined field areas; studies of operational forestry catchments; and studies of agricultural catchments. The degree of effectiveness of buffer zones for water pollution control in all these categories is generally attributed either to physical properties of the buffer zones (such as width, slope, vegetative cover, or soil type) or to the type of pollutant encountered. However, it is clear that although buffer zones have been shown to work well under small scale, experimental conditions, they lack success for water quality control on a broad catchment basis.In this respect, it is important that runoff must enter a buffer zone as shallow, overland flow in order to be slowed or detained, and that excessively channelised runoff will pass through a buffer zone unhindered. Buffer zones positioned close to sources of surface water pollution are therefore more likely to succeed in controlling water quality.It is suggested that although buffer zones are capable of removing pollutants from surface runoff, the proximity of buffer zones to sources of pollution is more important to their effectiveness than has been generally recognised. In view of this, the successful use of buffer zones for water quality control would require that they be comprehensively arranged along streams and around pollution sources in a catchment, and therefore that a large proportion of catchment area be set aside for this purpose. The real value of buffer zones in any situation would rest not only on their ability to control water quality, but on a number of other benefits and costs associated with maintaining large areas of natural vegetation.     

上海市供水水质现状和2012年供水水质达标步骤与措施

上海市地处长江和太湖流域下游,水源水质较差;采用常规处理工艺,取用长江水源的供水水质基本达标,取用黄浦江水源的供水中耗氧量、臭和味等指标的达标率低;目前上海市正在抓紧建设长江口青草沙水源地原水工程,至2012年上海饮用水水源60%取自长江,40%取自黄浦江。取用黄浦江水源的净水厂在2012年前将采用深度处理工艺提高供水水质;同时,上海市正着力研究长江水源的净水工艺,进一步解决上海市供水水质的臭和味问题。     

基于水分-品质响应关系的特色经济作物节水调质高效灌溉

摘要：传统的非充分灌溉理论主要基于水分生产函数考虑产量损失最小或总产量及效益最佳,较少考虑水分-品 质响应关系及其对节水效益的影响。针对此问题,本文归纳了节水调质高效灌溉的生理学、生物学和工程学基 础,探讨了水分-品质响应关系的研究进展与存在的问题。在此基础上,针对特色经济作物构建了基于水分-品质 响应关系的节水调质高效灌溉理论,提出了节水调质高效灌溉的实施思路,阐述了节水调质高效灌溉需要解决的 几个重要科学问题。以期能为充分挖掘作物生理节水潜力,大幅度提高作物水分利用效率和实现节水、丰产、优 质、高效的     

Design of a combined observer-controller for irrigation canals

Using a linear distributed model of open-channel flow, the canal operation problem was formulated as an optimal control problem, and an algorithm for the gate opening in the presence of unknown external disturbances (changes in flow rate demands) was derived by solving the algebraic Riccati equation. An observer was designed to estimate the values for depth of flow and flow rates at the intermediate nodes based upon measured values of depth at the upstream and downstream ends of a pool. Considering an example, the changes in depths and gate opening obtained from the linearized model were compared with the results obtained from the nonlinear hydrodynamic equations. For an external disturbance of 20% of the initial flow rate in the pool, the difference between the two models in predicting the variation in the upstream and downstream water surface elevations and the change in the upstream gate opening was insignificant.     

公共灌溉管理体制现代化--将来可持续灌溉的重点

对于大型灌区来说,其最终目标是以最少的国家财政支出,通过改善服务水平来不断提高农业耕作的收益率.但是,大型灌区内部的官僚体制和配水系统的不灵活性使其很难按照市场的变化和利润优势进行快速反应.因此,必须通过综合系统的现代化,即通过将现有的体制结构和灌溉配水系统进行变革,使其按照需水要求提供可持续的、高效的配水服务来进一步提高收益率.这种按照需水要求提供配水服务的体制变革主要包括削弱政府在管理和财政上的作用、进行权利分散、提高部门责任感以及经济自立.通过提高用水效率来减少支出,扩大收入.用水户协会的成立已经证明其在现代化改造和用水户参与方面是行之有效的,因此,应将其包括在决策制定过程中的各个环节.同时鼓励扩大水委员会或用水户联合会.在时机成熟时转让灌溉管理权,且灌溉管理权的转让应提前做好规划,按照中长期进程加以实施.同时还可以鼓励和开展公私合作伙伴(PPP).建立PPP的主要目的就是成立"第三专业机构"来改善管理,加强合作.     

Removal of nitrogen in different wetland filter materials: use of stable nitrogen isotopes to determine factors controlling denitrification and DNRA.

Laboratory incubations with varying O2 and NO3 concentrations were performed with a range of filter materials used in constructed wetlands (CWs). The study included material sampled from functioning CWs as well as raw materials subjected to laboratory pre-incubation. 15N-tracer techniques were used to assess the rates of denitrification versus dissimilatory nitrate reduction to ammonium (DNRA), and the relative role of nitrification versus denitrification in producing N2O. The N2O/(N2 + N2O) product ratio was assessed for the different materials. Sand, shell sand, and peat sustained high rates of denitrification. Raw light-weight aggregates (LWA) had a very low rate, while in LWA sampled from a functioning CW, the rate was similar to the one found in the other materials. The N2O/(N2 + N2O) ratio was very low for sand, shell sand and LWA from functioning CWs, but very high for raw LWA. The ratio was intermediate but variable for peat. The N2O produced by nitrification accounted for a significant percentage of the N2O accumulated during the incubation, but was dependent on the initial oxygen concentration. DNRA was significant only for shell sand taken from a functioning CW, suggesting that the establishment of active DNRA is a slower process than the establishment of a denitrifying flora.     

改性天然矿物滤料在农村饮水降氟中的应用

一、高氟水危害及除氟方法 我国是世界上饮水型地方性氟中毒流行最广、危害最严重的国家之一.地方性氟中毒是人体在高氟区的特定地理环境中,从外界长期摄入超过生理需要量的氟积存于骨骼系统引起的一种慢性地方病.     

Using on-farm sedimentation ponds to improve microbial quality of irrigation water in urban vegetable farming in Ghana.

This paper presents an assessment of the potential of using on-farm ponds to reduce levels of microbial contamination in wastewater--contaminated irrigation water. The study involved observations on the use of ponds in urban agriculture in Kumasi, Ghana, and more than 300 irrigation water samples were taken for physico-chemical and microbial laboratory analysis. The study shows that while on-farm ponds are commonly used, their potential to remove pathogens through sedimentation has not been fully optimized. Two-thirds of helminth eggs were in the sediments and careful collection of irrigation water without disturbing sediments reduced helminth eggs in irrigation water by about 70%. Helminth eggs reduced from about 5 to less than 1 egg per litre in three days in both dry and wet seasons while thermotolerant coliforms took six days in the dry season to reduce from about 8 to 4 log units per 100 ml, to meet the WHO guidelines. For optimal pathogen removal, better pond designs, farmers' training on collection of water with minimal disturbance and any other means to enhance sedimentation and pathogen die-off can be essential components of a multiple-barrier approach complementing farm-based measures like simple filtration techniques, better irrigation methods and post-harvest contamination.     

滴灌系统叠片过滤器离散型流道结构水力性能试验及内部流场模拟

为获得叠片流道内部水流流动特性,解决叠片过滤器水头损失较大的弊端,通过室内试验对比了传统叠片过滤器和具有离散型流道结构的叠片过滤器在不同流量下的水头损失,并采用Fluent19.0对清水条件下2种不同流道结构叠片过滤器内部流场分布规律进行数值模拟。结果表明:流道内部流量模拟值与试验设定值最大相对误差为4.8%;随着流量的增大,传统叠片过滤器产生的水头损失更为明显,与传统叠片过滤器相比,离散型流道叠片过滤器产生的水头损失在最大流量下降幅为20.8%;对不同流道进行内部流场分析,得出同一流量下离散型流道的平均过流断面面积大于直线型流道,过流断面面积越大,则流速越小,水头损失也越小,离散型流道内部局部水头损失占主导地位,凸台的离散排列降低了沿程水头损失。研究结果可为叠片流道的设计和结构优化提供参考。