Radiation transmission through a composite pure water layer of uniform and depth-dependent extinction characteristics

The paper describes the calculation of the beam solar radiation transmission across the uniform salinity upper convecting zone (UCZ) and the salinity stratified gradient zone (GZ), when the extinction coefficient is not only wavelength but also salinity-concentration dependent, assuming that the effect of scattering to be negligible. The results are useful in determining the effects of dissolved salt ions on pure water transmission, at least according to the existing measured data in the literature.     

Stability analysis of double-diffusive solar ponds with non-constant temperature and salinity gradients

In this communication, the stability of the double-diffusive solar ponds with non-uniform temperature and salinity gradients has been investigated. This is a further generalization of our approach to this problem initiated in Ref. [7]. Using a stochastic approach, the linearized system of basic equations of motion is reduced to a single integro-differential equation. For convective motion, this equation reduces to a time-independent Schrödinger equation for a particle moving in a potential field ƒ(Z) characterized by the non-uniform temperature and salinity gradients. This equation can, in general, be solved (exactly or approximately depending on the form of the gradient profile) by methods commonly used in quantum mechanics.

In the Appendix, we show that, for a quadratic gradient profile, the above equation has an analytical solution similar to that obtained by Zangrando using numerical computations.     

Wastewater reuse and exposure to Legionella organisms

Eight hundred and fifty-two (852) blood sera were drawn in 1980 and 1981 from populations residing in 30 agricultural settlements (having a total population of 16,240). These sera were tested for the presence of antibodies against 15 different antigens of Legionella species (L. pneumophila serogroups 1–8 and seven other Legionella, i.e. bozemanii, gormanii, micdadei, jordanis, dumoffii, longbeacheae and oakridgensis). The results indicate a significant (P < 0.02) excess in the percentage of sera positive for L. pneumophila (serogroups 1–8) among sewage and non-sewage irrigation and fish pond workers as compared to the control group (4.5% vs 1.5%). For the other Legionella species, there was no difference among the above groups. The isolation of L. pneumophila serogroup 4 and five organisms resembling Legionella spp from one oxidation pond used for irrigation strengthens the seroepidemiological findings.     

渠塘供水模式下灌区信息管理系统的设计

以引大灌区为对象研究了渠塘供水模式下灌区信息管理系统的设计。该设计以充分利用渠塘联控调水模式、最大限度提高灌区水资源的利用率为目标,由监测子系统提供塘群、渠系水情等实时信息,基于B/S结构的信息管理系统将完成动态配水、GIS查询等功能,实现对塘水、渠水的信息化管理和调度,突出渠塘供水模式的特色,充分发挥塘的二次调蓄功能。     

基于ExcelVBA实现山塘堰上水头计算的自动化

分析山塘综合整治工程中堰上水头计算现状,针对存在的问题,提出将Excel的二次开发工具VBA语言应用于堰上水头计算。编写计算程序、将可视化窗口作为用户操作界面,实现山塘综合整治工程堰上水头计算的自动化。将本程序应用于山塘实例,结果表明该程序可实现堰上水头计算的自动、准确、高效进行。     

Improving Water Supply Outlook in Korea with Ensemble Streamflow Prediction

Abstract

The purpose of this study is to propose an alternative forecasting approach for improving the current water supply outlook in Korea. Using a rainfall-runoff model, the existing technique for the water supply outlook in Korea produces monthly low, average, and high runoff forecasts. The proposed technique is called Ensemble Streamflow Prediction (ESP), and is currently implemented by the National Weather Service in the U.S.A. ESP appears particularly valid in Korea where the historical rainfall record is much more comprehensive than the historical streamflow record. This study applies ESP to runoff forecasting for a river basin in Korea to examine its applicability. An ensemble of one-month ahead runoff forecasts at the Gongju gauging station in the Keum River basin, Korea, was generated for each month. The resulting ESP forecasts were compared with the corresponding observed runoff data as well as the existing forecasts. Although this study is limited to one case study, the following conclusions can be made: (1) the ESP technique dominates the existing forecasting techniques in terms of both systematic and random errors; and (2) ESP is more accurate when high flows occur.     

石嘴山氧化塘净化能力预测

本文的主要目的是预测石嘴山氧化塘在不同面积及水深情况下的净化能力。采用Wehner-Wilhelm设计方法,从预测的结果来看一、三方案净化效果最好,方案二可以满足现有污水量的处理要求。预测结果为氧化塘现在和将来的运行提供参考。最后,通过方案比较建议适时采取不同的方案。     

An analysis of cascade‐aerated facultative waste stabilisation ponds in the United Kingdom

This paper examines the performance of cascade‐aerated facultative ponds in a waste stabilisation pond (WSP) installation in the United Kingdom. The pond system is privately owned and treats wastewater from a conference centre with a population equivalent between 20 and 40. A snapshot analysis investigates the removal efficiency of BOD, COD, SS, FC and nutrients. Further, the oxygen supply through ‘flow form’ cascades is examined, and the DO concentrations, surface loads and retention times are discussed. The results show a very high removal of BOD, COD and SS; and nutrient removal is satisfactory. An unusual finding is that the FC removal efficiency is almost two log units better than for a common maturation pond. This is possibly attributable to the high cascade flow, where wastewater is exposed to the damaging effects of sunlight (photo‐oxidation).     

Rural industrialization and environmental disamenities: the case of the Bendel cement company,Okpella Bendel state (Nigeria)

This paper attempts a comparative analysis of the economic and non‐economic damage of rural industrialization to the environment of a poor community in a developing country. The major finding is that rural industrialization is more directly and strongly associated with environmental disamenities than with economic loss. A policy implication of this is that the package of rural industrialization strategy in developing nations must transcend conventional compensation schemes. The package must include programmes to provide for alternative sources of water, say, and an adequate health care delivery, where the disamenities caused are in the forms of polluting natural sources of water supply and/or increasing health hazards.     

凤眼莲净化含镍废水的研究

本文介绍了实验室条件下凤眼莲对含镍废水的净化功能及镍对凤眼莲生长的影响。所得结果为:(1)在含镍浓度为1～10毫克/升的废水中,20天内凤眼莲的除镍率为41～69%;(2)凤眼莲具有积累镍的能力,其根部的镍积累量远大于茎、叶内的积累量;(3)废水中的COD>100毫克/对凤眼莲的生长及除镍效果均有明显的促进作用;(4)当含镍浓度为1～5毫克/升时,凤眼莲的生长和正常条件差异不大。当镍浓度大于10毫克/升时,凤眼莲的生长受抑制,幼叶色黄,老叶枯死,表明凤眼莲对镍的耐性较弱。作者认为,在自然氧化塘内种植凤眼莲,可以扩大氧化塘的净化功能,对利用氧化塘处理日趋复杂的城市污水及工业废水有重要意义。