COST ANALYSIS OF WATER AND WASTE WATER TREATMENT PROCESSES IN DEVELOPING COUNTRIES1

ABSTRACT: Mathematical modeling techniques are used to develop predictive equations for cost of water and waste water treatment processes in developing countries utilizing socioeconomic, environmental, and technological indicators. Predictive equations are developed for each of the three regions (Africa, Asia, and Latin America) for construction, operation, and maintenance costs of slow sand filter, rapid sand filter, stabilization lagoon, aerated lagoon, activated sludge, and trickling filter. Data analysis indicated that cost of water treatment processes is a function of technological indicator (percentage of imported materials), population, and the design capacity. The variables which gave the best correlation for waste water treatment cost were population, design flow, and the percentage of imported waste water disposal materials.     

ACUTE RESIDUAL TOXICITY OF SEVERAL DISINFECTANTS IN DOMESTIC AND INDUSTRIAL WASTE WATER1

ABSTRACT: This study determined the acute toxicity of waste water disinfected with chlorine, bromine chloride, or ozone. The residual toxicity of effluent dechlorinated with sulfur dioxide was also tested. Toxicity tests were conducted with cyprinid, salmonid, and centrarchid fishes, as well as several species of fresh water macroinvertebrates. Residual chlorine exhibited the greatest toxicity of the disinfectants tested; dechlorination with sulfur dioxide effectively eliminated the toxicity of chlorinated effluent. Residual ozone produced mortality in test animals only under special conditions where subjects were exposed to effluent immediately after it was contacted with ozone, and chlorobrominated effluent was more toxic to salmonids than chlorinated effluent.     

WASTE WATER REUSE IN PHOENIX-HOW VIABLE IS IT?1

ABSTRACT: The Phoenix metropolitan area has a unique combination of circumstances which makes it one of the prime areas in the Nation for waste water reuse. Overriding all of these conditions is the long-term inadequacy of the existing water supplies. The Salt River Valley has a ground water overdraft of about 700,000 acre feet per year. To help alleviate this situation, the Corps of Engineers in conjunction with the MAG 208 is looking at ways to reuse a projected 2020 waste water flow of 340,000 acre feet per year. Reuse options identified include ground water recharge, agricultural irrigation, turf irrigation, recreational lakes, fish and wildlife habitats, and industrial cooling. These look nice on paper but before they can be implemented, some hard questions have to be answered, such as: How acceptable are local treatment plants when 15 years ago there was a major push to eliminate local plants; is the Phoenix area ready for reuse in urban areas; what are people willing to pay for water; who benefits if a city goes to ground water recharge; how much agriculture will be left in the area by 2020? These and other questions must be resolved if reuse is to become a viable option in water resource planning in the Phoenix area. Summary. Large scale reuse of waste water conforms with the national goal of better resource management through recycling. The Phoenix metropolitan area has a unique combination of circumstances which makes it one of the prime areas in the nation for waste water reuse. Some of the most notable conditions are: the existence of a large and rapidly growing urban area which is in the process of planning for future waste water management systems; the existence of agricultural areas which are projected to be farmed well into the future, and the existence of constructed and planned major recreational systems such as Indian Bend Wash which can use recycled waste water; the existence of extensive depleted ground water aquifers; the need for a dependable source for the cooling of the Palo Verde Nuclear reactors; and finally, overriding all of this, the long-term inadequacy of the existing water supplies. Given this, one would expect to find total reuse within the Phoenix metropolitan area. Reuse is taking place with irrigation and nuclear power cooling to the west but there is no long term plan which looks at the Valley as a whole and considers waste water as part of the Valley's water resources. The Corps 208 plan is looking at waste water in this manner but initial analysis shows that although reuse is technically feasible there are many financial, social, institutional, and political questions still to be answered. These include: determining the value of existing diminishing water sources and what people are willing to pay for the next source of water; are people willing to identify priority uses of water for the area so that water of varying quality is put to its highest and best use; will the present institutional boundaries remain to create water-rich and water-poor areas; and will legislation be forthcoming to simplify the complex surface and ground water laws that presently exist? The Corps 208 study will not be able to answer these questions, but the goal at the moment is to identify feasible reuse systems along with decisions the public, owners, agencies, and politicians must make to select and implement them. If some sort of logical process is not developed and public awareness not increased, the chance for a long-term plan to utilize waste water as a major element in the Phoenix area water resource picture, may be missed.     

WATER SUPPLY DILEMMAS OF GEOTHERMAL DEVELOPMENT IN THE IMPERIAL VALLEY OF CALIFORNIA1

Abstract: There are four known geothermal resource areas in the Imperial Valley that have a combined potential of over 4,000 megawatts of electrical energy for 25 years. Water resources available to support geothermal enerfy development are imprted Colorado River water, agricultural waste waters, Salton Sea water, and groundwater. In addtion, geothermal power plants can produce their own cooling water from steam condensate. Nevertheless, the relatively high water requirements of geothermal facilities along with a series of real and potential constraints may cause water supply dilemmas involving both the acquistion and use of cooling water. Important constraints are institutional policies, water supply costs, technical problems, and impacts upon the Salton Sea. These constranits and related dilemmas are examined in light of relevanty information on the valley's water resources, geothermal resources and energy technologies, cooling water requrements, and water supply options.     

SYSTEMS ENGINEERING AND WATER RESOURCES IN SOUTHERN NEVADA1

ABSTRACT The Las Vegas Valley in southern Nevada has provided ample opportunity for mission oriented water resources research, and, to some extent, application of those research results. Past studies of the ground-water systems have resulted in the construction of a direct electrical analog, two digital simulation models, a Hele-Shaw fluid analog, a linear programming model, and two dynamic programming models. The work accomplished has dealt with the problems of groundwater management, waste water reclamation and artificial recharge, and conjunctive use water management. The current study is attempting to integrate previous results and new work into a detailed and realistic conjunctive use water resource management model to achieve system efficiency under more than one criteria. The research team is interdisciplinary in nature and encompasses the physical and social sciences.     

WATER QUALITY AND MACROINVERTEBRATE POPULATIONS BEFORE AND AFTER A HAZARDOUS WASTE CLEANUP1

ABSTRACT: Water samples and macroinvertebrates were collected from Finley Creek, Indiana, both before and two years after the cleanup of a nearby hazardous waste site. Water quality constituents were compared between years. Below the disposal site higher concentrations of constituents were found before and after the cleanup. However, two years after the cleanup, an improvement of water quality was observed. Total dissolved solids decreased by 52% and macroinvertebrate taxa increased by 44%.     

WASTE WATER DISPOSAL THROUGH A COASTAL AQUIFER1

ABSTRACT: Feasibility of disposing treated sewage in wells sunk into a partially confined coastal limestone aquifer at Waimanalo in the island of Oahu was investigated using an electric analog model. Electric analog modeling was preferred over digital modeling because of ease with which tides could be generated at the ocean boundary in the form of sinusoidal waves. The results of model operation showed that high permeability, low storativity, and the presence of ocean render the Waimanalo aquifer highly suitable for the disposal of waste water in deep wells. Since the quality of water in the aquifer is already unsuitable for municipal, industrial, or agricultural use, waste water injection will not result in any loss of fresh water supply source to the island. It is also believed that the cost of waste water disposal through the aquifer will be considerably less than that through an ocean outfall. During model development it was discovered that electric analog models can help prepare certain graphs which can be useful for aquifer analysis without any further use of the model.     

COST REDUCTIONS DUE TO SEASONAL VARIATION IN MUNICIPAL WASTE WATER TREATMENT LEVELS1

ABSTRACT: Varying treatment levels to meet seasonal variation in assimilative capacity of streams can reduce total costs of treatment. A mathematical model of a Pennsylvania stream based on a theoretically sound approximation of the physical relationships underlying the distribution of DO in a river system was used to determine discharge constraints for an economic optimization model which produced estimates of sewage treatment cost savings. Increasing the number of flow periods during the year enhances cost reducing opportunities even when land application processes are considered. Also, the least cost treatment process for year around operation may not be the least costly under multiple flow period management.     

CITY OF TUCSON WASTE WATER EFFLUENT DELIVERY FACILITY1

ABSTRACT: The Tucson area is totally dependent on ground water, which is in increasingly short supply due to excessive overdrafts. Tucson area waste water treatment plants discharge material quantities of secondary effluent downstream, which is lost to evapotranspiration and recharge of the ground water basin. The city and the four large mining companies who share the common Santa Cruz basin ground water, recognized the common water supply problem and agreed to fund a feasibility study for mining process use of the effluent to partly alleviate the overdraft of ground water. The study analyzed the projected waste water effluent resources, potential mining company demand for waste water effluent and possible interface of an effluent delivery facility with the proposed Central Arizona Project. The effluent resources were analyzed with respect to potential demand. An optimum alignment was selected. An optimum system was detailed through design schematics, amortized cost and finance requirements, and an implementation schedule. It was concluded that a waste water effluent delivery facility could be implemented which would utilize reclaimed effluent in quantities approximating 35 percent of basin overdraft and which would provide revenue for full cost recovery over a 20 year operation period. The mining companies are studying the internal economic impacts of the project.     

IDENTIFICATION OF MONTHLY TRENDS IN URBAN WATER USE1

ABSTRACT: Monthly water use for the period 1960–1984 for the Columbus, Ohio, metropolitan area is analyzed to identify differential monthly trends in growth of water use. By associating water use activities with the identified trend months, inferences may be made as to the possible underlying causes of the observed trend in overall water use. Three methods were found useful in determining monthly trends: 1) regression analysis on the monthly percentage of annual use, 2) regression analysis on the monthly water use data itself, and 3) analysis of the slope of the monthly water use regression line. Agreement between the three methods is strong, but each provides some insight not found in the others. All three should be used in drawing final conclusions. For the case study, usage in the Winter months January-April has grown considerably relative to the other months, while the Summer-Fall months of June, August, September, and October show a relative decline. A possible explanation for the trend is aging of the distribution system, with consequent general leakage and increased water main breakage caused by freeze/thaw conditions. More research needs to be carried out linking water use activities to particular months or groups of months.     

CAPACITY EXPANSION PLANNING MODEL FOR WASTE WATER TREATMENT AND I/I CONTROL1

ABSTRACT: A dynamic programming model is presented for planning the optimal capacity expansion sequence of waste water treatment plants servicing sewerage systems with infiltration/inflow. The model employs a nonlinear deterministic demand function for waste water treatment plant capacity. Model output provides the optimal timing, size, and sequence for treatment plant capacity expansion projects and infiltration/inflow removal projects. An example problem is presented and solved.     

EMERGENCY WATER SUPPLIES FROM GROUND WATER IN HUMID REGIONS1

ABSTRACT: This paper focuses on the development and testing of a mathematical model of an emergency ground water supply operated principally during periods of low streamflow. The process of ground water withdrawal and recharge is simulated taking account of streamflow, water demand, evapotranspiration, natural and artificial recharge and increased evapotranspiration due to artificial recharge, ground water pumpage, and streamflow contribution to pumped water. The model determines whether natural recharge is possible in less time than the return period of drought and also whether artificial recharge is needed. By simulating operation over a long period of time, the model can examine different droughts of short and long duration and can test the operating rules for ground water storage development in an area. Submodels analyze the components of the operating process including ground water flow into the stream, seepage losses, stream portion of well discharge due to induced infiltration and recharge from rainfall or water spreading. The model has been tested for areas in the humid northeastern United States.     

WATER AND THE ENERGY CRISIS1

ABSTRACT: Water and energy are inextricably bound. Energy is consumed and sometimes produced by every form of water resources system. Opportunities for future development and production of energy resources abound as well as those for significant reductions in energy consumption through wise water development and management. Technological, political, social, economic and environmental factors interrelate in the energy-water mix. The role of the water resources planner will have to be expanded to include assessment of water-energy impacts in addition to traditional planning considerations. An energy conservation account may well have to be added to the dimensions of national economic development and environmental quality in water resources planning. Ways must be found to reduce amounts and rates of water used and energy consumed through new manufacturing processes, improved irrigation practices, better management, new or altered social-political-economic arrangements and other procedures. To do this will require setting priorities and making difficult management decisions. The water fraternity can play a major role in alleviating the energy crisis we now face.     

POTENTIAL BENEFITS AND COSTS OF INGROUND STORAGE OF IMPORTED WATER1

ABSTRACT: In the near future, groundwater storage of imported water may become increasingly important as sites for surface storage are less available. This article explores the potential economic costs and benefits of groundwater storage. The costs include capital outlays, maintenance costs, land costs, legal costs, energy costs, and opportunity costs. The benefits include land cost savings, prevention of subsidence, aquifer protection, and higher economic use of surface lands that might be covered by a reservoir.     

WATER SUPPLY FORECASTING IN REAL-TIME1

ABSTRACT: A strategy is developed for making seasonal water supply forecasts in real time. It links the traditional regression based forecasting techniques to real-time data acquired by systems such as the Soil Conservation Service SNOTEL and the U.S. Bureau of Reclamation Hydromet networks. The concept is based on interpolating between the forecast values obtained by using real-time data in the forecast equations that bracket the real time. Different interpolation procedures were examined and the procedure for calculating confidence intervals about the forecast estimates is developed. The entire conceptual procedure is demonstrated using data from the Reynolds Creek, Idaho, experimental watershed maintained by the USDA-ARS Northwest Watershed Research Center in Boise, Idaho.     

LAND USE FUNCTION IN WATER QUALITY MANAGEMENT1

ABSTRACT. The Nation has entered a new era of water quality management in which land use policy and regulation must assume an increasingly important role. The benefits of tertiary and advanced waste treatment may be offset by contradictory land use and pollution from land runoff. Unless land use planning and controls are included in water quality management, land-imposed constraints on water quality can be anticipated. Pollution from major types of land runoff are reviewed with respect to sources, effects, and control procedures. Emphasis is given to land use practices and controls. The crucial issue with regard to the latter is lack of land use policies at federal, state, and local levels. State legislation establishing guidelines and minimum standards for land use regulation by local government is required. The dependency of water quality on land use points to the fallacy of attempting to provide for comprehensive water pollution control outside the context of comprehensive land-water resource planning and management.     

RURAL RESIDENTIAL WATER DEMAND: AN ECONOMETRIC AND SIMULATION ANALYSIS1

ABSTRACT: This study proposes that demand management through pricing policies can be used in conjunction with supply management to solve water supply problems. Economic principles are shown to apply to rural residential water use. A demand function for water was developed based on cross-sectional water use data collected in Kentucky. Price was found to be a significant determinant of the quantity of water demanded. A constant price elasticity of -0.92 was found. The demand function was used in a simulation analysis to determine reservoir capacity needed to supply water needs of a rural community. The simulation revealed that price can significantly affect required reservoir storage.     

MUNICIPAL AND INDUSTRIAL WATER SUPPLY IN CIUDAD JUAREZ,MEXICO1

Rapid industrialization and population growth in the north Mexican desert city of Ciudad Juarez are placing a serious strain on the city's municipal water resources. Water deliveries and service area have more than doubled over the past decade, and plans for additional expansion are presently being implemented. This expansion is already contributing to water table declines and salinity increases in the Mexican portion of the Heuco Bolson, the sole source of water for the city. Continued mining of the limited fresh water reserves should produce serious water supply problems in the near future. New estimates of future water consumption incorporated into a digital aquifer simulation model indicate that these problems may show up much sooner than was anticipated in previous investigations. The results of this study point to the need to accelerate the gathering of basic data on alternative water resources. The problems faced by Cd. Juarez are illustrative of the kinds of difficulties likely to confront other rapidly developing cities of the arid zone.     

CONFLICTS IN ATTAINING NATIONAL GOALS FOR BOTH WATER QUALITY AND ENERGY PRODUCTION1

ABSTRACT: The “policy environment” is defined herein as the institutional setting in which planning is conducted and policy decisions are made with regard to meeting two of the Nation's high priority goals: water quality protection and energy independence. The simultaneous pursuit of these goals has resulted in numerous conflicts among the energy industry, environmentalists, and government. An analysis of selected energy development-water quality conflicts shows that these conflicts can be described in terms of one or more of the following policy environment characteristics: resource scarcity, sense of urgency, lack of experience, administrative complexity, uncertainty about future policies and regulations, technological complexity, and uncertainty about impacts. These characterics provide a useful framework for formulating potential strategies for the resolution of energy development-water quality conflicts.     

DETERMINISTIC MODELS FOR PREDICTING RESIDENTIAL WATER CONSUMPTION1

ABSTRACT: Forecasts of future urban water demand traditionally have been made by the projection of historic trends in per capita consumption and population. This paper outlines the use of two deterministic models to forecast the residential component of urban water demand. The models incorporate specific representation of the activities which result in water consumption at each residence. Predictions of water use can then be made by modeling the changes expected in the number of these activities and the consumption for each such activity.