乌鲁木齐城市小区雨水收集回用系统设计建议——以晨光-佳苑为例

运用城市小区雨水资源收集回用系统成为了城市节约水资源新的途径。分析了乌鲁木齐晨光-佳苑住宅小区原有雨水收集回用状况,建议采用雨水入渗技术,对原有设计系统进行改造,增加新的雨水收集回用系统,探讨改造小区雨水收集回用系统的可行性,提出完善新增雨水收集回用系统的建议。     

国外雨水资源利用研究对我国“海绵城市”研究的启示CSSCI

"海绵城市"建设是我国应对城市雨水问题的新举措,目的是改善城市水文环境,促进城市雨水资源的可持续利用。国外尤其是发达国家已进行了多年的雨水利用理论研究与实践。对相关研究成果进行梳理并加以借鉴,将有助于促进我国"海绵城市"建设。通过文献分析法检索了世界知名出版社和数据库的相关论文,对国外近年来雨水资源利用的主要研究成果进行了总结和分类。结果表明,国外的雨水资源利用在雨水采集系统、技术应用、风险评价、社会学研究、低影响开发与最佳管理实践等领域取得了丰富的成果,在研究深度、广度和尺度上对我国的相关研究具有启发性。我国的"海绵城市"研究应吸收国外的优秀成果并与中国的城市特点相结合,全方位、系统性地开展研究和实践,为全国范围内的推广应用提供科学依据。     

典型雨水收集处理系统的生命周期评价

生命周期评价是一种对全过程资源消耗和环境影响进行分析与评价的方法,利用生命周期评价法对雨水收集处理方法进行评估分析对低影响开发雨水系统构建具有重要意义。根据《海绵城市建设技术指南—低影响开发雨水系统构建》的要求,对3种低影响开发雨水系统技术展开了生命周期评价。结果表明,绿色屋顶原材料最为环保,污染物排放最小;雨水花园产生的综合环境影响最小,水体污染物减排效应最为显著,环保优势较为明显;透水路面会对环境产生较大的负荷,应考虑环保材料、改进工艺等手段降低化石能源的消耗,从而减少雨水收集系统对环境所造成的负面影响。     

成都市雨水分布特征及其利用潜力分析

雨水是一种可供人类使用的宝贵淡水资源。为缓解成都水资源供需矛盾,有效利用雨水资源,本文针对成都市的降雨情况,分析了降雨年内分布特征、雨水水质特点和雨水利用潜力,给出了雨水收集、利用的相应措施,可为城市雨水利用工程规划与建设提供科学参考。     

雨水资源与雨水资源的评价

本文论述了雨水资源和目前世界各地雨水利用的概况,提出了家庭用水和农业用水雨水资源评价的计算方法。     

炼油企业初期雨水收集和处理

炼油企业初期雨水流经装置设备和场地路面时受到污染,未经处理排放后,将会对水体造成污染,由于设计和管理原因,实际操作中初期雨水并没有妥善处理。文章提出了相关的初期雨水量的计算方法、并提出了一种可靠的初期雨水收集处理系统,以实现初期雨水的规范处理。     

重庆市河堰村景观改变对水环境的影响

为了研究农村景观改变对水环境的影响,选取重庆市河堰村为研究对象,运用SWMM水文模拟软件,分析了研究区域的景观变迁与水量、水质变化的相互关系;通过访谈当地居民,分析了土地利用与景观变化对水环境的影响机制。认为(1)散点状的居民点分布模式与"村村通公路,户户通水泥"的农村道路建设以及庭院硬质化导致农村不透水表面面积迅速增加,缩短了雨水汇流时间并加速了污染物向水体的转移。(2)山体开发和现代农田水利工程的建设,如水库、山坪塘和排灌沟渠等的建设导致水体自净能力降低,加重了水体污染。(3)地表硬质化与河床沟渠化加速了水过程从而加速水环境的破坏。(4)人水关系由"我"、"你"变成"我"、"它",农民在卫生意识上升的同时缺乏相应的环保意识。     

城市生态休闲绿地建设研究

城市生态休闲绿地不同于城市绿地,主要包括其中的城市公园绿地和其他绿地。结合市民平时主要在居住地附近散步、节假日喜欢到郊区游憩的休闲活动特点,把生态休闲绿地分为日常短时休闲绿地和节假日长时休闲绿地。在城市生态休闲绿地建设中,应重点建设日常短时休闲绿地,配套开发节假日长时休闲绿地,完善城市公共绿地的休闲设施,增强城市公共绿地的大众性,提高专有绿地的开放性。     

澳大利亚的雨水净化设备

介绍了澳大利亚CDS公司的雨水净化设备结构、原理和应用效果。     

化工企业初期雨水污染防治

化工企业厂区初期雨水径流含有各种跑、冒、滴、漏的化学品或油品,为有效防止其对周围土壤和水体污染,本文根据化工项目初期雨水的水质、水量特点,提出了相应的收集和处理办法.     

MODELING WATER BALANCE WITH THE ERHYM MODEL ON SOUTH TEXAS RANGELANDS1

ABSTRACT: Understanding the hydrologic processes of rangeland plant communities is essential to determine if water augmentation through shrub management is feasible. Vegetation manipulation studies are costly, difficult to accurately replicate, and often require more than 10 years to determine treatment effect on the water budget. If properly applied, hydrologic simulation models are an attractive alternative for assessing vegetation manipulation practices. The ERHYM-II model was evaluated to determine if it was capable of simulating the water balance for honey mesquite shrub clusters, grass interspaces, and bare soil in south Texas. The simulated water budget was within 2 percent of the measured evapotranspiration for the shrub clusters and grass interspaces. The model underestimated the number of runoff events and overestimated runoff volume for the grass interspace and shrub clusters. Simulated runoff was overestimated by approximately twofold for the grass interspace and threefold for the shrub clusters. Although simulated runoff was substantially overestimated, observed and simulated runoff only accounted for 3 to 6 percent of annual rainfall for the grass and shrub dominated areas, respectively. Simulated evapotranspiration was underestimated by 18 percent and soil water content was overestimated by 82 percent for the bare soil. The model underestimated evapotranspiration for the bare soil as a result of restricting evaporative losses to the first soil layer. Based on our analysis, the ERHYM-II model has the potential for simulating the annual water balance for semiarid rangeland plant communities where runoff and deep drainage are limited components of the water balance.     

SIZING SMALL STORMWATER PUMP STATIONS1

ABSTRACT: Design of a stormwater pump station is a complicated procedure because of the large number of parameters that are involved. Even the most basic pump station serving a small catchment requires a computationally intensive iterative evaluation. However, the design problem consists primarily of finding the combination of temporary storage and pump capacity that accommodates runoff of the selected recurrence interval for the least cost. A procedure is developed for rapidly obtaining the needed relation between storage volume and discharge for small pump stations where a constant outflow can be assumed and the inflow hydro-graph can be represented using the modified rational method with rainfall given by a widely-used intensity-duration equation. Accepting the limitations of the modified rational method and the simplifications applied to pump station operation, the procedure provides an uncomplicated way of rapidly finding the stormwater runoff volume that needs to be temporarily stored for given values of pump discharge and activation water level (or, equivalently, activation storage volume). Ultimate determination of temporary runoff storage will depend on an economic analysis of the trade-off between storage volume and pump capacity.     

PEAKING STORAGE TANKS FOR WATER SUPPLY SYSTEMS1

ABSTRACT: Construction of a “peaking storage tank” may reduce the operational cost of municipal water in the availability of a time-of-use energy rate. A peaking storage tank is used for storing water that is pumped from wells or other sources of supply during off-peak periods when energy costs are less for use during periods of on-peak water demand. The optimal size of a peaking storage tank is that which results in the minimum total cost, which includes both the storage construction cost and the cost of operation of the pumps. The operational cost for a given time-of-use rate is determined by help of a pipe network simulation model solved by the Newton-Raphson technique and a dynamic programming optimization model. A more simplified method is also introduced. Analyses show that low off-peak energy costs make the construction of peaking storage tanks economically attractive and reduce on-peak energy use, which results in electrical load leveling.     

Energy and exergy analysis of a heat storage tank with a novel eutectic phase change material layer of a solar heater system

Solar energy is one of the most important renewable energy sources, but it is not available every time and every season. Thus, storing of solar energy is important. One of the popular methods of heat storage is use of phase change materials (PCMs) which have large thermal energy storage capacity. In this study, the heat storage tank in a domestic solar water heating system was chosen as control volume. The experiments were performed in the province of Elaz?g, Turkey, in November when solar radiation was weak due to cloudy sky. The heat storage tank of the system was modified to fill PCM between insulation and hot water part. A few PCMs which are Potassium Fluoride, Lithium Metaborate Dihydrate, Strontium Hydroxide Octahydrate, Barium Hydroxide Octahydrate, Aluminum Ammonium Sulfate, and Sodium Hydrogen Phosphate were analyzed to proper operating conditions using a Differential Scanning Calorimeter (DSC) and the best PCM was obtained with the Aluminum Ammonium Sulfate and Sodium Hydrogen Phosphate mixture. Thus, eutectic PCM was obtained and used in a heat storage tank of the solar water heating system. Energy and exergy analysis of heat storage tank was performed with and without the PCM. Energy and exergy analysis has shown that the heat storage tank with the PCM is more efficient than without the PCM and the maximum exergy efficiency was obtained as 22% with the heat storage tank with the PCM.     

Optimisation of rainwater tank design from large roofs: A case study in Melbourne, Australia

Rainwater tanks for larger roof areas need optimisation of tank size, which is often not carried out before installation of these tanks. This paper presents a case study of rainwater tank evaluation and design for large roof areas, located in Melbourne, Australia, based on observed daily rainfall data representing three different climatic regimes (i.e. dry average, and wet years). With the aim of developing a comprehensive Decision Support Tool for the performance analysis and design of rainwater tanks, a simple spreadsheet based daily water balance model is developed using daily rainfall data, contributing roof area, rainfall loss factor, available storage volume, tank overflow and irrigation water demand. In this case study, two (185 m³ and 110 m³) underground rainwater tanks are considered. Using the developed model, effectiveness of each tank under different climatic scenarios are assessed. The analysis shows that both the tanks are quite effective in wet and average years, however less effective in dry years. A payback period analysis of the tanks is preformed which reveals that the total construction cost of the tanks can be recovered within 15-21 years time depending on tank size, climatic conditions and future water price increase rates. For the tanks, a relationship between water price increase rates and payback periods is developed. The study highlights the need for detailed optimisation and financial analysis for large rainwater tanks to maximise the benefits.     

STRATIFICATION OF VARIABILITY IN RUNOFF AND SEDIMENT YIELD BASED ON VEGETATION CHARACTERISTICS1

ABSTRACT: Runoff and sediment yield were collected from 100 plots during simulated rainfalls (100 mm/hr for 15 minutes) at antecedent soil moisture conditions. A clustering technique was used to stratify the variability of a single data set within a sagebrush‐grass community into four groups based on vegetation life form and amount of cover. The four cluster groups were grass, grass/shrub, shrub, and forb/grass and were found to be significantly different in plant height, surface roughness, soil bulk density, and soil organic matter. Stepwise multiple regression analyses were performed on the single data set and each cluster group. Results for individual groups resulted in more robust predictive equations for runoff (r²= 0.65–0.73) and sediment yield (r²= 0.37–0.91) than for equations developed from the single data set (r²= 0.56 for runoff and r²= 0.27 for sediment yield). The standard errors of the cluster group regression equations were also improved in three of the four group equations for both runoff and sediment yield compared to the single data set. Runoff was found to be significantly less (p >0.01) in the forb/grass group compared with other vegetation cluster groups, but this was influenced by four plots that produced little or no runoff. Sediment yield was not found to be significantly different among any cluster groups. Discriminant analysis was then used to identify important variables and develop a model to classify plots into one of the four cluster groups. The discriminant model could be incorporated into rangeland hydrology and erosion models. The percentage cover of grasses, shrubs, litter, and bare ground effectively stratified about 12 percent of the variation observed in runoff and 26 percent of the variability for sediment yield as determined by r².     

Aerating grasslands: effects on runoff and phosphorus losses from applied broiler litter

Aeration has been promoted as improving infiltration of rainfall and extending grass or forage productivity, but research on the impact of this practice on P losses from grasslands has had mixed results. We designed a study to determine at the field scale, using a paired watershed approach, the impact of slit aeration on runoff volume and P losses in runoff from fescue (Festuca arundinacea Schreb.)/bermudagrass (Cynodon dactylon L.) hay fields fertilized with broiler litter. Three pairs of 0.8-ha fields, each with similar soils (Typic Kanhapludults, Aquic Hapludults, and Aquultic Hapludalfs), were fertilized with broiler litter and monitored under similar management from 1995 through 1998, then one field in each pair received aeration treatment from 2001 through 2003. In the field with mostly well-drained soils, grassland aeration reduced surface runoff volume and mass losses of dissolved reactive P (DRP) in runoff by approximately 35%. In contrast, when poorly drained soils dominated, grassland aeration increased runoff volume (4.8 mm/runoff event) and mass losses of DRP and total P (0.25 kg TP ha-1 per runoff event). This implies that aeration of well-drained soils in the top poultry-producing counties of Georgia (0.2 million ha) could decrease dissolved phosphorus losses by more than 500 Mg P each year. This is not the case if soils are poorly drained.     

Overland flow model for asphalt oil spills

Along the asphalt production line, the hot asphalt oil needs to undergo a cooling process that involves temporary storage in a tank. Safety is always a concern as to what if the tank is ruptured. Scenario studies of asphalt oil spills are required when designing the layout and open space for such a cooling process in the refinery yard. Applying the laminar flow theory to an asphalt oil spill, this paper presents an overland flow model to calculate the possible range of spread. The major parameters used in this model include fluid viscosity, ground slope, hydraulic conveyance, and asphalt oil volume. As a simplified model for a quasi-steady state flow condition, a hot asphalt oil spill for a typical case in a refinery yard can run approximately 400 to 600 feet before the asphalt mass cools down and becomes solid-like.     

Demonstration of methods to reduce E. coli runoff from dairy manure application sites

Contamination by bacteria is a leading cause of impairment in U.S. waters, particularly in areas of livestock agriculture. We evaluated the effectiveness of several practices in reducing Escherichia coli levels in runoff from fields receiving liquid dairy (Bos taurus) manure. Runoff trials were conducted on replicated hay and silage corn (Zea mays L.) plots using simulated rainfall. Levels of E. coli in runoff were approximately 10(4) to 10(6) organisms per 100 mL, representing a significant pollution potential. Practices tested were: manure storage, delay between manure application and rainfall, manure incorporation by tillage, and increased hayland vegetation height. Storage of manure for 30 d or more consistently and dramatically lowered E. coli counts in our experiments, with longer storage providing greater reductions. Manure E. coli declined by > 99% after approximately 90 d of storage. On average, levels of E. coli in runoff were 97% lower from plots receiving 30-d-old and > 99% lower from plots receiving 90-d-old manure than from plots where fresh manure was applied. Runoff from hayland and cornland plots where manure was applied 3 d before rainfall contained approximately 50% fewer E. coli than did runoff from plots that received manure 1 d before rainfall. Hayland vegetation height alone did not significantly affect E. coli levels in runoff, but interactions with rainfall delay and manure age were observed. Manure incorporation alone did not significantly affect E. coli levels in cornland plot runoff, but incorporation could reduce bacteria export by reducing field runoff and interaction with rainfall delay was observed. Extended storage that avoids additions of fresh manure, combined with application several days before runoff, incorporation on tilled land, and higher vegetation on hayland at application could substantially reduce microorganism loading from agricultural land.