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.     

Constructed Wetland Treatment of Nitrates: Removal Effectiveness and Cost Efficiency

A constructed wetland (CW) was strategically placed to treat nitrates in groundwater as part of a watershed‐based farmer engagement process. Using stream water quality data collected before and after installation, this CW was found to reduce stream concentrations of nitrogen from nitrate (NO₃‐N) during the growing season by about 0.14 mg/l at mean streamflow, a 17% reduction. Based upon realistic ecological and economic assumptions, about 80 kg of NO₃‐N were removed annually by the CW at a cost of around US$30/kg. This per unit cost is at the low range of small wastewater treatment plant costs for nitrates, but higher than the costs of reduced fertilizer application.     

A SYSTEMS STUDY OF FUTURE GROUNDWATER DEVELOPMENT COSTS IN THE CHICAGO REGION1

The cost of developing groundwater resources in northeastern Illinois from 198cL2020 is estimated for the purpose of providing a basis for comparing alternative sources. Demands for each township in the study area are estimated at 10-year increments and are satisfied, where the supply is sufficient, in such a way as to minimize the cost subject to constraints on supply. Sources of water are two shallow aquifers with known potential yields and a series of deep aquifers treated as a single unit and modeled on a digital computer. For each township the costs of wells, pumps, power and rehabilitation is estimated for each aquifer on a per million gallons of water per day basis. In addition the cost of groundwater treatment necessary to raise the quality to that of treated Lake Michigan water is considered. Raw water costs are found to vary from 2 to 14 cents per 1000 gallons depending upon the depth to the deep aquifer water. Treated water costs vary from 22 to 53 cents per 1000 gallons, the lower costs applying to the largest users because of the economy of scale. It is found that with proper distribution of pumpage there is sufficient water in storage in the deep aquifers to meet groundwater demands through 2020.     

Controlling groundwater pumping online

Groundwater over-pumping is a major problem in several countries around the globe. Since controlling groundwater pumping through water flow meters is hardly feasible, the surrogate is to control electricity usage. This paper presents a framework to restrict groundwater pumping by implementing an annual individual electricity quota without interfering with the electricity pricing policy. The system could be monitored online through prepaid electricity meters. This provides low transaction costs of individual monitoring of users compared to the prohibitive costs of water flow metering and monitoring. The public groundwater managers' intervention is thus required to determine the water and electricity quota and watch the electricity use online. The proposed framework opens the door to the establishment of formal groundwater markets among users at very low transaction costs. A cost–benefit analysis over a 25-year period is used to evaluate the cost of non-action and compare it to the prepaid electricity quota framework in the Batinah coastal area of Oman. Results show that the damage cost to the community, if no active policy is implemented, amounts to (−$288) million. On the other hand, the implementation of a prepaid electricity quota with an online management system would result in a net present benefit of $199 million.     

Wellhead treatment costs for groundwater contaminated with pesticides: A preliminary analysis for pineapple in Hawaii

In Hawaii, trace concentrations of pesticides used in the production of pineapple were found in the groundwater supplies of Mililani Town in the Pearl Harbor Basin on the island of Oahu. Groundwater serves as the major source of drinking water and residents pay for wellhead treatment of the contaminated water, via their monthly water bill. The agricultural chemical users within the Pearl Harbor Basin do not include these wellhead treatment costs in their production costs. The agricultural industry benefits from using pesticides but does not pay the entire societal cost of using these chemicals. In this study we evaluate the specific financial cost of wellhead treatment, and not the economic value of groundwater. While wellhead treatment costs could conceivably be shared by several parties, this study focuses on the financial impact of the pineapple industry alone. This study factors annual wellhead treatment costs into annual pineapple production costs to measure the effect on annual financial return from pineapple production. Wellhead treatment costs are calculated from the existing granulated activated carbon (GAC) water treatment facility for Millilani Wells I and II. Pineapple production costs are estimated from previous cost of production studies. The inclusion of wellhead treatment costs produces different production-cost results, depending on the scale of analysis. At the local scale, the Mililani wellhead treatment costs can be factored into the production costs of the pineapple fields, which were probably responsible for contamination of the Mililani Wells, without causing a deficit in economic return. At the larger regional scale, however, the return from all of the pineapple grown in the Pearl Harbor Basin can not sustain the cost of wellhead treatmentfor the entire water supply of the basin. Recommendations point to the prevention of groundwater contamination as more cost-effective measure than wellhead treatment.     

剩余污泥经臭氧破解后其中碳、氮和磷的变化

在臭氧对污泥进行减量的过程中,针对臭氧作用后污泥中碳、氮和磷数量的变化,对污水处理厂的剩余污泥进行了不同累计时间的臭氧作用研究,结果表明经臭氧破解后污泥中的TN没有较大改变,污泥中的TP最终呈减少趋势,破解液中的COD虽有所增加,但破解液回流到生物系统中反而可以补充反硝化过程中有机碳的不足,从而促进污水生物处理的脱氮除磷作用,臭氧的引入不仅可以减少污水处理厂的运行成本,同时可为城镇污水处理厂全面升级改造提供一定的参考。     

Review of submarine groundwater discharge (SGD) in coastal zones of the Southeast and Gulf Coast regions of the United States with management implications

Groundwater serves as the primary drinking water source for over half of the coastal populations of the Southeast and Gulf Coast regions, two of the fastest growing regions in the United States. Increased demand for this resource has exceeded sustainable yields in many areas and induced saltwater intrusion of coastal aquifers. A process associated with coastal groundwater, submarine groundwater discharge (SGD), has been documented as a source of subsurface fluids to coastal ocean environments throughout the Southeast and Gulf Coast regions and is potentially a significant contributor to nearshore water and geochemical budgets (i.e., nutrients, carbon, trace metals) in many coastal regions. The importance of groundwater as a drinking water source for coastal populations and the influences of submarine groundwater discharge to the coastal ocean warrant increased research and management of this resource. This paper highlights findings from recent SGD studies on three hydrogeologically different continental margins (Onslow Bay, NC, southern Florida, and the Louisiana margin), provides background on the common methods of assessing SGD, and suggests a regional management plan for coastal groundwater resources. Suggested strategies call for assessments of SGD in areas of potentially significant discharge, development of new monitoring networks, and the incorporation of a regional coastal groundwater resources council.     

ECONOMIC DESIGN OF CENTRAL WATER SUPPLY SYSTEMS FOR MEDIUM SIZED TOWNS1

ABSTRACT. Adequate and good-quality water supply for medium sized towns is costly when there are insufficient quantity and low quality of groundwater or surface water. In a central water supply system serving a number of towns, the economies of scale may permit a sufficient and good-quality supply at lesser rates. Such a system has the flexibility of supplying rural population through small service lines. The system may be an interbasin or intrabasin conveyance depending on the location of a suitable water source and the economics of the supply network. Seven cost elements are pertinent to the optimum or least-cost design of network consisting of pipelines and pumping stations. The relevant cost functions are based on the available data gathered from various sources. Water conveyance costs are calculated for various flow rates, pipeline diameters, flow variabilities, static heads, and interest rates, thus providing a measure of sensitivity of the conveyance cost to such variations. The economies of scale, the sensitivity of optimum unit conveyance costs, and variations in unit costs with change in cost functions are useful in making a feasibility study for a proposed conveyance system.     

Costs of the electrochemical oxidation of wastewaters: a comparison with ozonation and Fenton oxidation processes

In the work described here the technical and economic feasibilities of three Advanced Oxidation Processes (AOPs) have been studied: Conductive-Diamond Electrochemical Oxidation (CDEO), Ozonation and Fenton oxidation. The comparison was made by assessing the three technologies with synthetic wastewaters polluted with different types of organic compounds and also with actual wastes (from olive oil mills and from a fine-chemical manufacturing plant). All three technologies were able to treat the wastes, but very different results were obtained in terms of efficiency and mineralization. Only CDEO could achieve complete mineralization of the pollutants for all the wastes. However, the efficiencies were found to depend on the concentration of pollutant (mass transfer control of the oxidation rate). Results obtained in the oxidation with ozone (at pH 12) or by Fenton's reagent were found to depend on the nature of the pollutants, and significant concentrations of oxidation-refractory compounds were usually accumulated during the treatment. Within the discharge limits that all of the technologies can reach, the economic analysis shows that the operating cost of Fenton oxidation is lower than either CDEO or ozonation, although CD\EO can compete satisfactorily with the Fenton process in the treatment of several kinds of wastes. Likewise, the investment cost for the ozonation process seems to be higher than either CDEO or Fenton oxidation, regardless of the pollutant treated.     

THE EFFICIENCY OF WATER PRICING: A RATE OF RETURN ANALYSIS FOR MUNICIPAL WATER DEPARTMENTS1

ABSTRACT: The rate of return on invested capital can be used as a guide to resource allocation by municipal water departments (MWD's) in the same way it is used in the private sector. To achieve economic efficiency, the target rate of return for MWD's should be the market rate of return as an approximation to the opportunity cost of capital. The actual internal rate of return for a sample of 30 California MWD's for the period 1970-1982 is calculated for this study. The operating internal rate of return varies across the sample MWD's from less than 2 percent to 14 percent. If 10 percent is taken as the opportunity cost of capital, 25 of the 30 MWD's were inefficient; i.e., earned less than 10 percent. Half the sample earned less than 5 percent. An examination of potential causes of low rates of return shows that low average water prices are the primary reason for the low rates of return. For efficient operation, MWD's should set a target rate of return equal to the opportunity cost of capital and adjust water prices so as to achieve that target.     

COST EFFECTIVE OPERATION OF URBAN WATER SUPPLY SYSTEM USING DYNAMIC PROGRAMMING1

ABSTRACT: Efficient operation of a city water supply system is an important goal of all municipalities. Efficient operation should result in minimum operation cost through reduction in total energy use and/ or reduction in on-peak energy consumption. An optimization model was designed for operating the water supply systems of cities using groundwater. The Newton-Raphson pipe network was used for network analysis and a dynamic programming optimization algorithm was used for determining a schedule for pump operation in the pipe network system. The model is most suitable for use in small cities with up to 45,000 in population, but with large-scale disintegration techniques may also be used for larger cities. The savings in operation costs are a function of energy cost and energy use pattern and water use pattern in the area.     

IMPLEMENTATION OF AN OPTIMIZATION MODEL FOR OPERATION OF A METROPOLITAN RESERVOIR SYSTEM1

ABSTRACT: A deterministic dynamic programming optimization model with a refining sectioning search procedure is developed and implemented to find least cost withdrawal and release patterns for water supple from a multiple reservoir system serving a metropolitan area. Applications are made to teh four reservoir system operated by the city of Dallas, Texas. A realistic cost structure, including nonlinear power consumption, block rate unit power costs, and flow dependent power consumption for intracity water distribution, is utilized. Applications are made to find least cost operating patterns and, as well, by inclusion of a water loss penalty function, supply patterns which will reduce evaporation water losses for the Dallas system.     

Estimating the economic burden from illnesses associated with recreational coastal water pollution--a case study in Orange County, California

A cost-of-illness framework was applied to health and income data to quantify the health burden from illnesses associated with exposure to polluted recreational marine waters. Using data on illness severity due to exposure to polluted coastal water and estimates of mean annual salaries and medical costs (adjusted to 2001 values) for residents of Orange County, California, we estimated that the economic burden per gastrointestinal illness (GI) amounts to 36.58 dollars, the burden per acute respiratory disease is 76.76 dollars, the burden per ear ailment is 37.86 dollars, and the burden per eye ailment is 27.31 dollars. These costs can become a substantial public health burden when millions of exposures per year to polluted coastal waters result in hundreds of thousands of illnesses. For example, exposures to polluted waters at Orange County's Newport and Huntington Beaches were estimated to generate an average of 36,778 GI episodes per year. At this GI illness rate, one can also expect that approximately 38,000 more illness episodes occurred per year of other types, including respiratory, eye, and ear infections. The combination of excess illnesses associated with coastal water pollution resulted in a cumulative public health burden of 3.3 million dollars per year for these two beaches. This paper introduces a public health cost variable that can be applied in cost-benefit analyses when evaluating pollution abatement strategies.     

A binational, supply-side evaluation for managing water quality and invasive fouling species on California's coastal boats

Integrated solutions are needed for sustainable management of risks posed by recreational boats to coastal water quality and ecosystems. Fouling organisms roughen vessel hull surfaces, creating friction that slows sailboats and increases fuel consumption by powerboats. Hull fouling control strategies for recreational boats that are stored in the water may include antifouling hull paints, newer alternative hull coatings, periodic in-water hull cleaning, and excluding propagules by surrounding the boat with a slip liner or raising it above water on a lift. Copper discharged to harbor waters from antifouling paints via passive leaching and in-water hull cleaning may elevate dissolved copper levels above government standards. Invasive species carried among boat-hull fouling organisms may be introduced as boats move among coastal areas. Some of these species tolerate copper in antifouling paints and copper-polluted harbor waters. Policy development must consider supply-side capacity, as well as economic and environmental sustainability, in managing these issues. This paper presents a supply-side evaluation useful in developing policies to co-manage water quality and invasive species risks for recreational boats navigating along the coasts of California, the Baja California peninsula and California's Sacramento-San Joaquin Delta. Supply-side perspectives on services, materials, costs, and boat owner behaviors, such as residence and travel patterns, awareness of hull-coating choices and selection of hull coatings, are determined. Analyses include evaluation of risks, risk management capacity and costs, and role of education in risk management. The issues raised are broadly applicable, as they are appearing on research and policy agendas in diverse coastal areas.     

Coming to the table: collaborative governance and groundwater decision-making in coastal California

Collaborative governance is on the rise in the United States. This management approach brings together state and non-state actors for environmental decision-making, and it is frequently used in California for decisions regarding local groundwater management. This study examines groundwater decision-making groups and practices in a central California coastal community to understand whether groups meet specific collaborative governance criteria and whether and why certain subsets of the population are excluded from groundwater decision-making practices. It also identifies actions for better group inclusion. We find that small farmers, the Hispanic/Latino community, and the general public are often excluded from groundwater decision-making groups and practices due to unawareness, mistrust, and insufficient resources. Education and awareness as well as incentives could help increase inclusion. This study provides insights into more equitable groundwater decision-making groups and practices, and also calls for more critical examination of the current stakeholder approach to decision-making.     

RECIRCULATING WELLS: GROUND WATER REMEDIATION AND PROTECTION OF SURFACE WATER RESOURCES1

ABSTRACT: Several chlorinated solvent plumes threaten the sole‐source aquifer underlying the Massachusetts Military Reservation at the western end of Cape Cod. Sensitive surface water features including ponds, cranberry bogs, and coastal wetlands are hydraulically connected to the aquifer. For one of the plumes (CS‐10 the original remedy of 120 extraction and reinjection wells has the potential for significant disruption of surface water hydrology, through the localized drawdown and mounding of the water table. Recirculating wells with in‐well air stripping offer a cost‐effective alternative to conventional pump‐and‐treat technology that does not adversely affect the configuration of the water table. Pilot testing of a two well system, pumping 300 gpm, showed a capture radius of > 200 feet per well, in‐well trichloroethylene (TCE) removal efficiencies of 92 to 98 percent per recirculation cycle, an average of three recirculation cycles within the capture zone, and no measurable effect on water table elevations at any point within the recirculation/treatment zone. During 120 days of operation, the mean concentration of TCE in the treatment zone was reduced by 83 percent, from 1,111 μg/l to 184 μg/l. Full‐scale design projections indicate that 60 wells at an average spacing of 160 feet, having an aggregate recirculation 11 MGD, can contain the CS‐b plume without ground water extraction or adverse hydraulic effects on surface water resources. The estimated capital costs for such a system are about $7 million, and annual operations‐and‐maintenance costs should be about $1.4 million, 40 percent of those associated with a pump and treat system over a 20‐year period.     

Farm-level irrigation and the marginal cost of water use: evidence from Georgia

We create a proxy for the cost of irrigation water in Georgia from a sample of Georgia irrigators by investigating the marginal cost of pumping groundwater. We then combine this proxy with agronomic and climatic variables to estimate the response of agricultural water use to differences in the marginal cost of irrigation. The results show that pumping costs are a significant determinant of water use, and imply that agricultural water use would be moderately affected by institutional changes that would explicitly price water.     

CAPITAL COST OF RURAL WATER DISTRIBUTION SYSTEMS1

ABSTRACT: The cost of water service to rural residents is very high compared to urban areas. This is true even after subsidization by Farmers Home Administration (FmHA) loans and grants. Capital cost data on 44 projects financed by the Ohio office of the FmHA during the period August 1968 to January 1977 are used to derive cost equations for 26 components of rural water distribution systems. These components represent 92 percent of the capital cost of the pipeline distribution systems studied. The data can be used to economically design rural water supply systems from a capital cost viewpoint. More data are needed on operation and maintenance costs as well as central and cluster well costs before totally economic system designs can be undertaken.     

INEQUITIES FOR SMALL FOOD PROCESSING PLANTS RESULTING FROM LIQUID WASTE TREATMENT REGULATIONS1

ABSTRACT: The cost of the liquid wast treatment measures required to meet federal as well as typical state and local regulations was examined for dairy processing plants of various sizes. Federal effluent standards were found to produce higher estimated capital costs per unit of raw material for smaller plants, even with relaxed requirements for smaller plants. State regulations limiting the effluent BOD₅- concentration were also found to result in inequitable costs for smaller processors. These inequities result from economies of scale and not such factors as level of process technology employed or amount of waste produced per unit of raw material. In contrast, applying an example sewer surcharge formula did not produce inequities from economies of scale.     

Cost effective policies for alternative distributions of stochastic water pollution

This study investigates the role for cost effective coastal water management with regard to different assumptions of probability distributions (normal and lognormal) of pollutant transports to coastal waters. The analytical results indicate a difference in costs for a given probability of achieving a certain pollutant load target whether a normal or lognormal distribution is assumed. For low standard deviations and confidence intervals, the normal distribution implies a lower cost while the opposite is true for relatively high standard deviations and confidence intervals. The associated cost effective charges and permit prices are higher for lognormal distributions than for normal distributions at relatively high confidence intervals and probabilities of achieving the target. An application to Himmerfj?rden--an estuary south of Stockholm, Sweden--shows that the minimum costs of achieving a 50 per cent reduction in nitrogen load to the coast varies more for a lognormal than normal probability distribution. At high coefficient of variation and chosen probability of achieving the target, the minimum cost under a lognormal assumption can be three times as high as for a normal distribution.