ECONOMIC FRAMEWORK FOR FLOOD AND SEDIMENT CONTROL WITH DETENTION BASINS1

ABSTRACT: A framework for combining economic factors and the hydrolo of detention basins is provided. The general development of economic production functions for water quality (sediment) and flood control is discussed. Example production functions are generated to compare water quality (sediment control only) and flood control. For the given example, the design of a detention basin for downstream sediment control is economically unwarranted. When compared to on-site detention facilities, regional detention structures appear to be more practical from an economic standpoint for water quality control. Since sediment was the only water quality parameter assessed, it is entirely possible that the design of a detention basin for water quality control would be justified if the effects of all pollutants of concern could be quantified. Policy aspects of detention facilities that relate to the economics of water quality control are also discussed.     

DESIGN OF A DIVERSION SYSTEM TO MANAGE THE FIRST FLUSH1

ABSTRACT: To manage the first flush of storm runoff in urbanized areas, a diversion box and detention basin system has been proposed for a new storm sewer system or for retrofitting an existing system. A software package for a personal computer has been developed to facilitate the analysis and design of the system. Hydrographs and pollutographs are generated at the inlet and outlet of the diversion box and the detention basin. The peak outflow and peak pollutant concentrations are compared with the allowable outflow and pollutant concentration for urban stormwater quantity and quality management. The model is developed for both analysis and design purposes.     

Long-Term Effects on Soil of the Disposal of Olive Mill Waste Waters (OMW)

Disposal of untreated olive mill waste waters (OMW) is a serious environmental problem in many Mediterranean countries. The aim of this work was to assess whether changes in soil properties have occurred due to direct disposal of raw OMW on soil and in evaporation ponds, and to investigate the potential fate and transport of pollutants after olive oil production had ceased. The results clearly showed that uncontrolled OMW disposal is a significant source of pollution to surface soil and waters. Disposal of OMW on soil greatly increased electrical conductivity (EC), available phosphorous (P), exchangeable potassium (K) and magnesium (Mg), organic matter, polyphenols, total and inorganic nitrogen (N), and available micronutrients mainly in surface soil layers. The presence of a high content of clay and carbonates in soil act as barriers and prevent downward transport of pollutants. Residual levels of total carbon (C), polyphenols, total and inorganic N, exchangeable K⁺, available P, iron (Fe), and copper (Cu) were also elevated even 8 years after mill closure. The long term disposal of OMW highlights the need to establish soil quality standards for soil parameters in order to identify soils affected by the disposal of OMW.     

Efficiency of locally available filter media on fluoride and phosphate removal for household water treatment system

Since conventional water treatment is not affordable in developing countries,looking for locally available and alternative treatment options is mandatory.Removal of fluoride and phosphate can be achieved by designing appropriate filtration media from different materials such as sand,calcined clay,pumice,scoria and bone char.This study was designed to determine the removal efficiency of these locally available filter media with respect to detention time and pH.The filtration apparatuses(tank)were filled separately with stone,gravel with grain size 0.6-4.75 mm and 40 cm deep,sand(ES=0.15-0.35 mm and UC=1.5-3),calcined clay,pumice,scoria and bone char with grain size 0.25-0.5 inch.Water samples were prepared using glass bottles with fluoride concentrations of 6 and 8 mg/l and phosphate concentration of 4 mg/1.Laboratory analysis was carried out before and after filtration to determine the removal efficiency of each medium.It was found that the highest removal of fluoride was achieved by bone char(89.65%),followed by pumice(82.4%).However,bone char has rather increased the concentration of phosphate by 63.8%.Sand was the most efficient media to remove phosphate,managing to remove by 70%.Therefore,it is an attractive option to use these locally available,environmental friendly and appropriate technologies for efficient removal of both fluorine and phosphate at the household or community water treatment level.     

池塘水体氨氧化细菌季节变化及其与环境影响因子相关性分析

以氨氧化细菌(AOB)的氨单加氧酶amoA基因为分子标记,调查了湖北省公安县崇湖渔场草鱼池塘水体AOB季节变化,并分析了AOB丰度与主要环境因子的相关性.结果表明,池塘表、底层水体AOB amoA基因拷贝数均呈相似的季节变动规律,即夏季显著高于春、秋两季(p0.05),而春、秋两季间无显著差异(p0.05);相同季节池塘表、底层水体AOB amoA基因拷贝数无显著性差异(p0.05).表、底层水体AOB amoA基因拷贝数均与温度、总磷呈显著正相关;与溶解氧呈显著负相关.此外,表层AOB amoA基因拷贝数与总有机碳呈极显著负相关.主成分分析将8个环境因子划分为3个主成分.表层第一主成分为水温、溶解氧、氨氮与总磷,第二主成分为硝态氮与总有机碳,第三主成分为总氮与亚硝态氮;底层第一主成分为水温、溶解氧、氨氮、总磷与总有机碳,第二主成分为硝态氮与亚硝态氮,第三主成分为总氮.     

招远市黄金尾矿库生态工程技术研究与实践

招远市现有黄金尾矿库不仅占用大量土地资源,对周围的空气、土壤、水体造成污染,破坏周围的生态环境,而且存在安全隐患,严重制约了当地经济社会的可持续发展.针对不同类型黄金尾矿库的特点,建立了漫溢型生态景观园、高台型生态休闲园、坝坡型风景防护林地、沟夼型生产园地等4种黄金尾矿库生态工程模式.通过生态工程示范区建设,将尾矿库改造成城镇景观绿地、生产园地,解决了黄金尾矿库的生态环境问题.     

室内人员疏散时间快速预测模型研究

为准确快速估算室内人员疏散时间,基于传统Togawa模型,提出1种基于出口处人员流动速率的室内人员疏散时间快速预测模型,并利用Pathfinder软件模拟某房间人员疏散过程,对比快速预测模型与传统Togawa经验公式计算结果.结果表明:快速预测模型计算量少,可获得更多更精确人员疏散信息.研究结果可为室内人员疏散提供理论...     

串联氧化塘中氮、磷去除的容积分配效应的研究

在人工模拟条件下,串联厌氧 好氧塘在总容积相同,不同的容积分配的情况下,污水中的氮、磷去除效率不同,存在最佳容积分配比：V_厌/V_总约为0.27。在最佳容积分配比处,COD、氮、磷的去除率可分别提高11.4％、26.0％、51.6％。随着负荷、污水C/N比、温度、光照时间等因素的变化,氮磷去除呈一定的变化规律。说明了串联厌氧 好氧塘氮、磷去除的容积分配效应是客观存在的,合理的容积分配对氮、磷去除尤其重要     

PENN STATE URBAN RUNOFF MODEL TO PINPOINT FLOOD PEAK SOURCE LOCATION1

ABSTRACT: The Penn State Urban Runoff Model, developed in 1976, is described in this paper. Aside from locating infiltration and detention basin operation in an unconventional manner, the model includes a peak flow presentation table which identifies watershed subareas chiefly responsible for the occurrence of flooding conditions at certain points in the watershed. The results of a case study on an urban drainage basin in the Philadelphia area is discussed, and preferred sites for retention ponds are suggested. The simplicity of the Penn State model is pointed out and computer run costs between 10 and 20 percent of the corresponding cards for HEC-I and SWMM are cited.     

TRACE ELEMENTS IN NORTHERN GREAT PLAINS STRIP MINE AND LIVESTOCK IMPOUNDMENT WATER1

ABSTRACT: The water from 32 strip mine water impoundments and nine livestock watering ponds in North Dakota, South Dakota, and Wyoming were analyzed for trace elements. Because of the high concentrations of trace elements in coal and bentonite clay, the possibility exists for these elements to dissolve or be suspended in the water. Strip mine ponds were not significantly higher in trace element concentrations compared to livestock ponds. All but one of the 41 ponds sampled contained elemental concentrations that would be detrimental for livestock use or aquatic life use. Cadmium and lead were the elements most frequently in excess of water quality crieria. Lead was found in the study ponds about 35 times the median concentration of North American rivers. Manganese concentrations were found to exceed iron in many ponds, which is unusual in natural waters. The potential for detrimental concentrations of trace elements in pond water must be evaluated when designing land use management plans for ponds intended to be used by livestock or aquatic life.