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Managing Wastewater in Coastal Urban Areas 1 Introduction Although significant progress has been made in improving the nation's water quality over the past 20 years, many coastal areas continue to suffer from persistent water-quality problems and can expect to encounter new problems in the future. Today's coastal water-quality policies do not provide adequate protection from some types of problems, and in some cases are overprotective for other types of problems. A rethinking of these policies is required if the nation hopes to continue to maintain and improve coastal water quality while keeping pace with coastal population growth. Around the nation, much of the debate over how to protect and improve coastal waters has focused on urban wastewater and stormwater management. This debate has been fueled by a series of events, some of which have not been demonstrated to be associated with wastewater and stormwater discharges. These events include the mass dolphin deaths that occurred along the Atlantic coast in the summer of 1987, followed by the wash-up of medical wastes along the same coasts in the summer of 1988. Also in 1988, the presidential campaign brought the debate over cleanup strategies for Boston Harbor into the national spotlight. Soon thereafter, the projected $2.4 billion expenditure for upgrades in treatment in San Diego also drew national interest. Brief histories of the San Diego and Boston wastewater management programs and related controversies appear as ''case histories" at the end of this chapter. More recently, reports of coral reef die-off in the Florida Keys have fueled interest in wastewater management issues. While each of these situations is unique in the types of problems faced and in the degree of relevance of urban wastewater management, they highlight the
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Managing Wastewater in Coastal Urban Areas need for improved understanding of the impact of human activities and better strategies for preventing and mitigating problems in the coastal environment. The management of wastewater and stormwater in coastal urban areas is inextricably linked to overall coastal management objectives. While wastewater and stormwater management constitute an immense enterprise, they take place in the context of a multitude of other human activities and natural processes within the coastal zone. In addition, there are many difficult tradeoffs associated with the array of options available for wastewater and stormwater management. This report, as was requested of the National Research Council by the U.S. Environmental Protection Agency at the direction of Congress, examines issues relevant to wastewater management in coastal urban areas. These issues include environmental objectives, policies, and regulations; technology; management techniques; systems analysis and design; and environmental modeling. The National Research Council was not asked to review past policies or decisions. Instead, it was directed to identify opportunities for improving the current system through which coastal urban wastewater and stormwater are managed. The report addresses marine and estuarine areas in particular and does not consider the Great Lakes. STRESSES ON THE COASTAL ENVIRONMENT Most coastal water-quality problems result from human activities associated with populations concentrated along the coasts and from land-use practices throughout coastal watersheds. As the U.S. population grows, it is becoming increasingly urbanized and concentrated along the coasts. In 1990, at least 37 percent of the total U.S. population, or approximately 93 million persons, resided in coastal counties, mostly in urban areas (NOAA 1990a). Population growth in coastal areas is expected to continue more rapidly than in other parts of the nation well into the future. As shown in Figure 1.1, coastal areas are the most densely populated in the United States, rivaled only by the Great Lakes region. More than 1,400 municipal wastewater treatment plants provide service to these coastal populations and discharge approximately 10 billion gallons of treated effluent per day. Approximately 85 percent of this effluent is discharged into bays and estuaries rather than the open ocean (EPA 1992a). More than 100 municipalities serving approximately 16 million persons have combined sanitary and stormwater sewers that overflow at approximately 1,800 points along the coast. In addition to municipal dischargers, approximately 1,300 industrial facilities are permitted to discharge about 11.3 billion gallons per day of treated industrial wastewater and spent cooling water to marine waters (EPA 1992a).
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Managing Wastewater in Coastal Urban Areas FIGURE 1.1 Distribution of population in the United States by region. The total quantity of direct discharges to coastal waters (bays, estuaries, and the open ocean) from municipal and industrial facilities does not tell the whole story. Coastal systems receive inputs from a variety of other sources. Urban, industrial, and agricultural runoff, as well as pollutants discharged into rivers upstream of coastal areas, have all been recognized as significant sources of pollutants to marine waters. In general, the volume of runoff and amount of debris and contaminants in runoff increases with increasing urbanization and suburbanization. Scientists are only now realizing the importance of the deposition of pollutants from the atmosphere into water bodies and, in some areas, the potential significance of infiltration of contaminated ground water into coastal waters. Although relatively limited in areal extent, one of the most insidious sources of contamination to the marine environment is that of existing contaminated sediments. In addition to these direct and indirect inputs of potentially harmful constituents into coastal waters, other human activities can cause stress to marine systems. For example, overfishing, destruction of spawning habitats, and reduction in freshwater flows have all been implicated in the depletion of fishstocks that has taken place around the country. Boating traffic, shipping, dredging and filling, oil and gas development, spills of oil and other
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Managing Wastewater in Coastal Urban Areas hazardous materials, and introductions of nonindigenous species have all been associated with the degradation of coastal environments. Natural events such as hurricanes can cause major perturbations in the coastal zone. It is not only important, but imperative, that the entire range of factors that may have an impact on coastal environmental quality be considered when strategies for protection are developed. WASTEWATER AND STORMWATER MANAGEMENT Among the myriad of factors that affect coastal environmental quality, the management of wastewater and stormwater are perhaps the two most critical considerations. Without appropriate control measures, these activities have the potential to wreak serious harm on the coastal environment. As with any other activity that takes place in the environment, the potential for harm depends on the magnitude of the insult, where it occurs, and the characteristics of the stress. Constituents and Impacts Municipal wastewater comes from a variety of sources including households, schools, offices, hospitals, and commercial and industrial facilities. Stormwater runoff comes from streets, parking lots, roofs, lawns, commercial and industrial developments, construction sites, farmland, forests, and a number of other settings. While wastewater and stormwater contain a wide variety of constituents, these constituents generally can be described using several characterizations: solids; suspended and dissolved substances that exert a biochemical oxygen demand (BOD) in natural waters; nutrients; pathogens; organic chemicals; metals; oil and grease; and plastics and floatables. Some constituents may fall into more than one of these categories. For example, metals, organics, and pathogens in wastewater are often associated with suspended solids; and organics can be a component of BOD. In general, each of these categories of constituents can have an adverse effect in the marine (as well as land and air) environment if present in sufficient concentrations. Table 1.1 provides an overview of these categories, examples of the types of constituents, and a summary of the possible impacts associated with the marine environment. The primary concern associated with BOD is, as the name implies, the depletion of oxygen as organic wastewater constituents degrade in the environment. Oxygen depletion associated with BOD can be a serious problem in lakes, rivers, estuaries, and other enclosed water bodies having limited exchange. In most open coastal areas, however, oxygen depletion due to BOD from wastewater is limited and not important. Oxygen depletion in these waters usually results from excess nutrient concentrations, which cause overgrowth of algae. This
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Managing Wastewater in Coastal Urban Areas TABLE 1.1 Wastewater and Stormwater Constituent Characterizations and the Associated Impacts in the Marine Environment Characterizations Examples Associated Impacts in the Marine Environment Solids Particulate matter ranging from large items to fine particles Most of the larger sized particles will be removed in treatment process. Fine particles remaining in wastewater effluent may be associated with toxic organics, metals, and pathogens. Solids discharged in shallow and nearshore areas, particularly from runoff, may cause excessive turbidity, shading of seagrasses, and sedimentation. Biochemical Oxygen Demand (BOD) Oxygen demanded (or required) for the biodegradation of organic matter In shallow or enclosed aquatic systems, excessive BOD can cause hypoxia and anoxia and suffocate living resources. Nutrients Nitrogen Phosphorus Iron Silica Excessive levels of nutrients increase primary production. At adverse levels, impacts include nuisance algal blooms, dieback of coral and seagrasses, and local- and regional-scale eutrophication. Eutrophication can lead to hypoxia and anoxia, which suffocate living resources. Pathogens Salmonella Shigella Campylobacter Enteroviruses Hepatitis E virus and A virus Gastrointestinal viruses Vibrio species Exposure to human pathogens via contact with contaminated water or consumption of contaminated shellfish can result in infection and disease.
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Managing Wastewater in Coastal Urban Areas Toxic Organic Chemicals Chlorinated pesticides Other halogenated organics Polyaromatic hydrocarbons Surfactants Toxic organics dissolved or suspended in the water column or accumulated in sediments can result in an array of adverse effects on marine organisms. Many of these compounds are suspected carcinogens and/or reproductive toxicants. They can concentrate in the tissue of fish and shellfish, which may then be consumed by humans. The bioaccumulative effects of these compounds on wildlife are potentially serious (e.g., DDT and the near extinction of the Brown Pelican in the early 1970s). Metals Arsenic Cadmium Chromium Copper Lead Mercury Silver Tin Metals, depending on their form, can be toxic to various marine organisms and humans. Elevated concentrations of metals may be found in shellfish taken from areas where there are highly contaminated sediments. Plastics and Floatables Fishing line Condoms Tampon applicators Oil and grease Other floating trash and debris While the problem most associated with plastics and floatables is aesthetic offense, these materials can also pose severe hazards to marine wildlife. Fish and other marine animals can become entangled in debris or eat it mistaking it for food. Oil and grease can inhibit natural reaeration processes and exacerbate hypoxic and anoxic conditions.
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Managing Wastewater in Coastal Urban Areas overgrowth leads to hypoxia and sometimes anoxia and other associated adverse effects. In freshwater dominated systems, for example, at the head of an estuary, phosphorus controls primary production, and in saltwater dominated systems in temperate zones, nitrogen is the controlling factor. In the tropics and semi-tropics, phosphorus may be the controlling factor. In mixed systems, such as in the middle of an estuarine mixing zone, both constituents would be of concern. In general, oxygen depletion associated with BOD occurs on a relatively localized scale (it can be controlled by ocean outfalls that achieve high initial dilution), while oxygen depletion and related effects associated with nutrient enrichment are secondary effects that may occur over much larger areas and usually result from a multitude of sources. Pathogens are microorganisms that can cause disease in humans and are found in wastewater, stormwater, and urban runoff. They include bacteria, viruses and protozoa, and are most often associated with gastrointestinal illnesses and hepatitis. Individuals can be exposed to these organisms through contact with contaminated recreational water and consumption of contaminated shellfish. Disease associated with the consumption of contaminated shellfish result primarily from the ingestion of raw or inadequately cooked clams, mussels, and oysters. Toxic organics can cause adverse effects in aquatic organisms and humans. Many of these compounds are synthetic chemicals such as pesticides or solvents. Some, such as polychlorinated biphenyls (PCBs), are slow to degrade to innocuous forms, while others degrade relatively rapidly. Metals, like the toxic organics, can also cause an array of adverse effects in aquatic organisms and humans. They may be present in different chemical forms that have widely varying toxicity. The term solids refers to particles in wastewater that may consist of a mixture of organic and inorganic material. It can refer to everything from gravel to submicroscopic organic colloids. Solids in wastewater are either readily settleable and can be removed in the primary treatment process, or they tend to remain suspended and require more advanced treatment for removal. Toxic organic chemicals, metals, and pathogens often are associated with solids in wastewater and stormwater. Plastics and floatables are materials that cause aesthetic offense and can harm wildlife. Sometimes these items (e.g., condoms) can wend their way through an entire treatment plant; however, almost all trash and debris are deposited in coastal waters by wind, CSOs, runoff, ships, recreational boaters, and other users of the shore. Anticipated National-Level Priorities for Constituents of Concern In the collective judgement of the Committee, in general, a wastewater constituent may be considered to be of high concern if it poses significant
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Managing Wastewater in Coastal Urban Areas TABLE 1.2 Anticipated National-Level Priorities for Constituents of Concern Priority Pollutant Groups Examples High Nutrients Nitrogen Pathogens Enteric viruses Toxic organic chemicals PAHs Intermediate Selected trace metals Lead Other hazardous materials Oil, chlorine Plastics and floatables Beach trash, oil, and grease Low Biochemical oxygen demand (BOD) Solids NOTE: Within each priority group the order of listing does not indicate further ranking. risk to human health or ecosystems (e.g., if it contaminates fish, shellfish and wildlife, causes eutrophication, or otherwise damages marine plant and animal communities) well beyond points of discharge and is not under demonstrable control. A wastewater constituent may be generally considered to be of lower concern if it causes only local impact or is under demonstrable control. In general, it may be anticipated that national-level priorities for wastewater constituents in coastal urban areas over the next several decades will be as summarized in Table 1.2. It is noted, however, that the relative importance of various constituents will likely differ at the local and regional levels depending on site-specific circumstances. Treatment Technologies and Other Management Techniques More than 1,400 municipal wastewater treatment plants provide service to the coastal population, discharging 10 billion gallons of treated to $500 per million gallons of treated effluent, the national expenditure effluent a day. At an estimated operating cost ranging from $300 to operate these plants is between $1.1 billion and $1.8 billion per year. Wastewater is collected and conveyed to treatment plants in sanitary sewers. In some older cities, especially in the northeast, most stormwater and wastewater share a common collection system. During storms, the collection system can become overloaded, which may result in the overflow of a mixture of sewage and stormwater into nearby waterways. These events are called combined sewer overflows (CSOs). Treatment technologies make use of physical, chemical, and biological processes to remove constituents from wastewater. Techniques range from
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Managing Wastewater in Coastal Urban Areas simple screening and settling operations to sophisticated biological, chemical, and mechanical operations that can produce water clean enough to reuse. As a general rule, the quality of treated water increases with more sophisticated technologies, as do costs, land-area requirements, energy requirements, and the amount of sludge produced. While treatment systems and levels of treatment have dominated the debate over wastewater management in coastal urban areas, a number of other factors in managing wastewater are also of considerable importance. As with any program for managing wastes, the most desirable tactic is to eliminate the production of the waste in the first place. While the complete elimination of waste is obviously not possible in the case of sewage, there are several approaches that can reduce the discharge of some constituents and decrease the volume of water discharged. Phosphate detergent bans in several inland regions of the United States have resulted in significant reductions in phosphorus levels entering treatment plants. Water conservation saves on a scarce natural resource in arid regions and can, in some cases, reduce the volume of water, although not the mass of pollutants, requiring treatment. Major reductions in contaminants from industrial dischargers have been achieved in areas where wastewater treatment agencies have instituted pretreatment requirements. An array of best management practices is available to reduce the volume and improve the quality of urban and agricultural runoff. Improved management practices (e.g., optimization of pesticide application rates and timing) prevent pollutants from getting into runoff. Public education can play a pivotal role in changing behaviors that can lead to local water-quality improvement, such as appropriate methods for disposal of used automobile oil. Other techniques, such as structural controls, are available to slow runoff, allow more water to percolate into the ground, and filter out contaminants. In addition, weirs, moveable dams, and detention areas can provide storage capacity in storm and combined sewer systems which can reduce the frequency and volume of CSOs. The location and mechanism of a wastewater discharge plays an important role in determining the extent of impact on marine resources. Contaminant concentrations build up in shallow and/or enclosed systems, whereas deep currents in open systems tend to disperse and flush away discharged material more rapidly. Open-ocean discharges through multiport diffusers are diluted rapidly. Finally, an important feature of any wastewater and stormwater management system is a monitoring and research program. Monitoring provides information on how well the system is working and where problems may arise; and research can lead to improved methods. It is through monitoring and research efforts that new and improved approaches for managing wastewater and stormwater are developed.
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Managing Wastewater in Coastal Urban Areas The Role of Government Numerous agencies at all levels of government have been established to protect the coastal environment from these many stresses and to maintain its desirability as a human habitat; each has its own particular mandate to protect some aspect of the coastal zone and its uses. Human expectations for the coastal environment are diverse and often conflicting. The rich array of uses, needs, and objectives for coastal resources is reflected in the wide variety of institutions established to steward these resources. At the federal level, the Environmental Protection Agency (EPA) holds the greatest responsibility for regulating the quality of the coastal environment. The EPA is responsible for regulating discharges to the coastal environment under the Clean Water Act and the Ocean Dumping Act and for cooperating in the administration of the Coastal Zone Management Act. Under the Clean Water Act, the EPA is responsible for conducting research to ascertain the best and most effective forms of pollution controls. The National Oceanic and Atmospheric Administration (NOAA) has diverse responsibilities for coastal management. Within NOAA, the Office of Ocean and Coastal Resource Management is charged to assist states in implementing the Coastal Zone Management Act, including implementing new provisions relating to nonpoint source pollution. Since enactment of the federal Coastal Zone Management Act in 1972, 29 states covering more than 90 percent of the nation's shoreline have developed coastal management strategies meeting the requirements of the law. An important element of this system is the requirement that federal actions be consistent with state planning processes. NOAA's National Ocean Service monitors the nation's coastlines for pollution trends, assists the Coast Guard in protecting marine resources during spills of oil and other hazardous materials, and manages National Marine Sanctuaries. NOAA's National Marine Fisheries Service monitors marine animal populations, is responsible for implementing the Endangered Species Act in the marine environment, and holds federal authority over fishstock management. In addition, as trustee for numerous marine resources, NOAA is responsible for conducting research and developing knowledge about coastal areas, which is useful to managers. NOAA recently has taken an active role in litigating recovery of damages and developing and implementing marine resource restoration projects. The Food and Drug Administration is responsible for seafood safety. The Army Corps of Engineers has authority over engineering projects and dredge and fill operations in the coastal zone. The Coast Guard is responsible for regulating traffic in coastal waters and coordinating response to oil spills from ships as well as other spills of hazardous materials to coastal
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Managing Wastewater in Coastal Urban Areas waters. Several other federal agencies also have interests in coastal urban areas. For example, the National Park Service is the steward for several coastal and marine parks, and the Fish and Wildlife Service oversees coastal and marine wildlife refuges. Local and regional government agencies plan, construct, own, and operate the public infrastructure to collect, treat, and dispose of municipal wastewater and stormwater. Usually the day-to-day funding and management of these facilities is provided under the authority of a multiple service government such as a city, or a single purpose entity such as a wastewater management agency. Many other agencies and governmental bodies at the state, regional, and local levels also concern themselves with coastal environmental management. These institutions include state legislatures, city councils, county agencies, port authorities, state water and environmental agencies, public health departments, state and regional park services, regional councils of government, and others. The Role of the Public A large number of nongovernmental organizations are concerned with the coastal environment. Among these, the most visible are interest groups that represent the views of different sectors of the public. Public interest groups provide a voice for the wide range of expectations that members of the public hold for their coastal environment. They are organized locally, regionally, and nationally. These groups may advocate policy changes to protect the environment; save certain animal species; enhance sport fishing, hunting of waterfowl, and recreational boating opportunities; or protect divers, surfers, and swimmers. In addition, a multitude of other organizations represent those who have a business or professional interest in the coastal environment. Within the regulated community, commercial fishing, shipping, and other business interests have organized themselves so that their voice is heard in government. Agencies responsible for managing wastewater and stormwater have organized themselves to share information and advocate policies that are protective of the environment while being cost effective for their rate payers. There is, as well, a growing body of environmental professionals, including scientists, engineers, policy analysts, and managers, who may work for any of these organizations, for the government, industry, or academia, and/or as consultants. These professionals have formed organizations that often speak on behalf of the professional community. In addition, they are often sought to provide advice and guidance. Although the many groups mentioned above do not always speak on behalf of the entire public or community that they represent, their role in defining the issues and establishing policy is extremely important.
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Managing Wastewater in Coastal Urban Areas ranging from aquatic toxicology to resource economics and environmental engineering must be involved. The experience prior to the 1972 amendments to the Clean Water Act suggests that efforts to manage wastewater on the basis of integrated regional planning were inadequate to meet emerging national objectives for clean water. As a result, the idea of mandatory technology controls became the hallmark of the 1972 act. In retrospect, it appears that the failure of the integrated planning approach can be attributed to a series of extraneous, but important, factors. Since 1972, many of these problems have been overcome. Therefore, it can be supposed that integrated planning is now more likely to be successful. For example, since 1972 a mandatory permit system that provides a means to apply specific control requirements to particular dischargers has been developed, enforcement mechanisms that have the capacity to compel correction of or provide adequate punishment for violations of legal requirements have been established, scientific capacity has advanced such that it is now possible to develop relatively accurate predictive models and allocate pollution reduction obligations in a more rational manner, and public expectations and support for clean water objectives have grown considerably, allowing for the development of the political will to allocate more adequate resources to cleaning up and protecting the nation's water resources. Fundamental to an integrated approach are the concepts that control strategies should be driven by an assessment of the priority risks and that risk decisions should place the burden of control on harmful activities. Finally, the implementation of an integrated system should be based in the recognition that coastal management issues will never be completely solved. They require a dynamic approach that first addresses problems that are easily solved or that present the largest opportunity to reduce risk and then moves to address the next highest priority problems. As for any type of management system, feedback is required to help identify successes and failures, identify new issues, make progress on known problems, and indicate where and what improvements can be made. In the case of integrated coastal management, monitoring, research, and public involvement should provide feedback on the management system. CASE HISTORIES Boston Boston Harbor and the major rivers leading into it—the Charles, Mystic, and Neponset—have been used for the disposal of sewage wastes for
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Managing Wastewater in Coastal Urban Areas hundreds of years. The backbone of the present collection and transport system was a combined sewer system completed in 1904 which provided for the discharge of millions of gallons per day of untreated sewage into the harbor. Over the next four decades it became obvious that these untreated discharges presented public health risks for swimmers and shellfish consumers and were causing severe aesthetic problems. To correct these problems, two primary treatment plants that removed about half the total suspended solids (TSS) and about a quarter of the biochemical oxygen demand (BOD) were built—one on Nut Island built in 1952 and having an average daily flow of 110 million gallons per day (MGD), the other on Deer Island built in 1968 and having an average daily flow of 280 MGD. However, the digested sludge produced by these primary treatment plants, approximately 50 tons per day, was also discharged into the harbor until December of 1991. During wet weather, the wastewater system's hydraulic capacity was exceeded causing combined sewage and stormwater to overflow into the harbor through 88 overflow pipes. The discharge from combined sewer overflows (CSOs) would occur approximately 60 times a year, dumping billions of gallons per year of combined wastewater into the harbor and causing frequent closings of nearby shellfish beds and bathing beaches. Figure 1.5 provides a map of the Boston region and includes the location of the Massachusetts Water Resources Authority's wastewater and CSO discharge points. The Metropolitan District Commission (MDC), the state agency responsible for managing water and wastewater treatment in the Boston metropolitan area until 1984, suffered from insufficient funding to maintain and upgrade the treatment plants. The result was equipment breakdowns, which in turn resulted in the further release of raw and partially treated sewage. The 1972 Clean Water Act mandated an upgrade to secondary treatment (85 percent removal of both TSS and BOD) for all wastewater discharges by 1977. In 1979, the MDC applied for a waiver from secondary treatment as provided by the 1977 Clean Water Act. The MDC proposed a seven-mile outfall to discharge primary effluent into Massachusetts Bay, cessation of sludge discharge into the harbor, and CSO abatement. The MDC studies on water quality determined that the impact of the discharge of primary effluent was acceptable and concluded that secondary treatment would not be cost effective. In June 1983, the EPA denied the waiver, primarily because of concerns about maintaining the dissolved oxygen standard in the bay and protecting the balanced indigenous population of marine life. The EPA also concluded that secondary treatment would result in fewer water-quality exceedences of priority pollutants, one-tenth the loadings of toxics to the sediments around the outfall, and a smaller area of sediment enrichment around the outfall. The MDC modified its waiver request by extending the outfall 9.2 miles into Massachusetts Bay to provide better dilution. The
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Managing Wastewater in Coastal Urban Areas FIGURE 1.5 CSO and effluent outfall discharge locations in Boston Harbor. (Reprinted, by permission, from the Massachusetts Water Resources Authority.) MDC's application was denied by the EPA again in March 1985. By this time, federal and state grants for construction of sewage treatment facilities were being phased out so that today 90 percent of the costs of the project are borne by the local communities. The MDC took no action to secure federal construction grants for the project prior to 1985. Since 1987, Congress has appropriated $280 million specifically for the Boston Harbor Project. An additional $170 million of State Revolving Fund loans have been earmarked for the project. To date, the combined congressional appropriations and State Revolving Fund loans amount to about 8 percent of the total projected cost of the project. During the impasse over the need for secondary treatment, two law suits were filed. In 1982, the city of Quincy filed a civil law suit against MDC, and in 1983, the Conservation Law Foundation (CLF), a public interest group, filed a suit against MDC for alleged violations of the Clean Water
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Managing Wastewater in Coastal Urban Areas Act and against the EPA for failing to bring Boston into compliance with the act. Under pressure from the EPA and the CLF, the state legislature replaced the MDC with an independent authority having control of the regional water and sewer services. The Massachusetts Water Resources Authority (MWRA) was created in December 1984; and in December 1985, the court ordered it to comply with the standards of the Clean Water Act. In 1991, the MWRA, the EPA, the CLF and the court designed a schedule for construction. It included constructing a land-based sludge processing facility to end the discharge of sludge in 1991, constructing a new 1,270 MGD primary treatment plant on Deer Island with a longer outfall by 1995, and constructing a 1,080 MGD secondary treatment plant and solving the problem of CSOs by 1999. The new outfall was selected by MWRA to be 9.5 miles long, including a 6,600-foot-long multiport diffuser—the longest single-leg diffuser in the world—terminating in a depth of water just over 100 feet. Figure 1.6 shows the location of the proposed outfall in Massachusetts Bay. FIGURE 1.6 Location of proposed outfall in Massachusetts Bay. (Reprinted, by permission, from the Massachusetts Water Resources Authority.)
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Managing Wastewater in Coastal Urban Areas Over the last several years, the MWRA's industrial pretreatment and source reduction programs have significantly reduced the levels of organics and heavy metals in the wastewater. Improvements to the treatment capacity of the existing plants and more efficient use of storage in the system have decreased CSO flows to the harbor, which has reduced bacterial contamination of the harbor to the lowest levels in 50 years. The disposal of sludge into the harbor has ceased, and sludge is now being converted to fertilizer pellets. The outfall and primary treatment plant are under construction, and the first portion of the secondary treatment plant is designed. Plans for CSO treatment are under way. These technical improvements in the wastewater treatment facilities, when complete, are expected to significantly improve the water quality of Boston Harbor. Recently, the proposed placement of the new outfall, 9.5 miles east of Boston into Massachusetts Bay, has caused substantial controversy in Cape Cod. Concerned about space limitations on Deer Island, integration with other wastewater construction activities, and large increases in sewer rates, in February 1992 the MWRA proposed to pause the construction program after completion of 500 MGD of the secondary plant (sufficient for most dry weather flows) to determine how to best set priorities concerning construction of CSO abatement facilities, the remaining 500 MGD of secondary treatment capacity (needed to treat peak dry weather flows and wet weather flows), and potential additional levels of treatment such as nutrient removal. The MWRA dropped this proposal approximately 5 months later, however it still remains a controversy. In addition, residents of Cape Cod have questioned the sufficiency of secondary treatment to protect Massachusetts Bay. They expressed concern that the discharge would cause nitrogen enrichment of the waters of Cape Cod Bay 35 miles away, resulting in nuisance algal blooms and threatening the endangered North Atlantic right whale and humpback whale. Although the EPA has concluded that such problems will not occur, some Cape Cod groups and others have proposed that the outfall not be built and that the discharge remain in Boston Harbor. There are also concerns within the region that MWRA will retreat from its commitment to secondary treatment following the completion of the outfall and primary treatment plant. Some civil engineers from the Massachusetts Institute of Technology, including a member of the Committee on Wastewater Management for Coastal Urban Areas, have conducted studies showing that average annual flows in Boston are substantially less than those for which the new treatment plant is designed. They suggest that the new primary treatment plant could be retrofitted for chemically-enhanced primary treatment which would reduce the subsequent BOD loading to the new secondary treatment plant. State and federal requirements could then be met, they propose, by building a biological secondary treatment half the size of the proposed facility. They
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Managing Wastewater in Coastal Urban Areas also argue that with the higher efficiency achieved in the primary treatment plant using chemically enhanced treatment, a portion of the primary treatment plant can be designated to treat wet weather flows, thereby reducing the need for deep tunnel storage capacity to control CSOs. Furthermore, they state that the space saved on Deer Island by reducing the size of the secondary treatment plant would then be available for the construction of nitrogen removal facilities, if needed in the future. They estimate that about $200 million could be saved by building a smaller secondary treatment plant and that several hundred million dollars more could potentially be saved by reducing the capacity of the deep tunnel storage capacity (Harleman et al. 1993). The MWRA is currently funding the MIT civil engineers' studies to further evaluate their claims. MWRA has not, however, presented any such proposals to EPA for consideration. Amid the many controversies, the court-ordered schedule of construction for Boston continues on schedule along with research studies to better understand the environmental processes within Massachusetts Bay. San Diego The existing San Diego Metropolitan Sewerage System (SDMSS) was designed and built in the early 1960s to solve water quality problems in San Diego Bay. The creation of the SDMSS involved the consolidation of wastewater from 10 separate communities, previously discharged into the bay or surf zone, into a new primary treatment system at Point Loma with a two and a half mile long, 200-foot deep outfall. The current Point Loma Treatment plant processes between 175 and 185 million gallons of sewage generated each day by more than 1.7 million persons in San Diego and 15 other surrounding cities and sewer districts. During dry weather, an additional 10 to 13 million gallons per day of wastewater from Tijuana is treated at the Point Loma plant. Sludge from the Point Loma treatment plant is dried on Fiesta Island in Mission Bay, a heavily used recreational area, and composted for use in soil conditioners or, as a last resort, disposed of in landfills. Stormwater and wastewater collection systems are completely separate in the San Diego region. Figure 1.7 provides a map of the existing San Diego system. San Diego applied for a 301(h) waiver from the secondary treatment requirement for its ocean discharge in 1979, for which it obtained tentative approval from the Environmental Protection Agency (EPA) in 1981. In 1983, San Diego submitted a revised waiver application that included revised flow projections as well as plans for treatment of sewage from Tijuana, Mexico. Also in 1983, the State Water Resources Control Board revised the California Ocean Plan to require body-contact bacteriological standards for all kelp beds. Although the Point Loma outfall discharges 6,000 feet be-
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Managing Wastewater in Coastal Urban Areas FIGURE 1.7 Locations of San Diego's major wastewater and sludge management facilities. (Reprinted, by permission, from the Clean Water Program for Greater San Diego.)
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Managing Wastewater in Coastal Urban Areas yond the nearest kelp bed in the area, at times, ocean currents carry the plume into the kelp beds and bacteriologic standards are exceeded. Based on field studies indicating that Point Loma discharges were not adversely affecting divers or the kelp beds, San Diego requested that the Regional Water Quality Control Board exclude or dedesignate the Point Loma kelp beds from the body-contact bacteriological standards requirement. Between 1979 and 1992, San Diego made several improvements in its treatment system. The initial upgrade from primary to chemically enhanced primary treatment increased the solids removal efficiency from about 55 percent to between 75 and 80 percent in 1988. During this period, San Diego's flow increased from 120 to 185 million gallons per day; thus the total quantity of suspended solids discharged did not change significantly. Currently, tests are being run under court order to determine if the Point Loma treatment plant's removal efficiency can be improved. In 1986, the EPA tentatively denied both the 1979 and 1983 waiver applications because of the lack of compliance with the California Ocean Plan bacteriological standards in a portion of the kelp beds and interference with the propagation and protection of a balanced indigenous population of bottom-dwelling organisms and fish populations in the vicinity of the Point Loma outfall. In the same year, the Regional Water Quality Control Board indicated that it would recommend against San Diego's prior request to dedesignate the kelp beds as a recreational area that must meet body-contact standards because no alternate standards had been developed to protect divers in the Point Loma kelp beds. Thus in 1987, after two public hearings, the San Diego City Council voted to withdraw the waiver applications and to come into compliance with the Clean Water Act by converting Point Loma to a biological secondary treatment plant. Faced with a water shortage and strong public support, the council also committed to developing an extensive water reclamation and reuse program. The San Diego Clean Water Program was established to carry out these goals. Following San Diego's withdrawal of its waiver application, the EPA filed suit against the city for more than 20,000 violations of the Clean Water Act and California Ocean Plan. Approximately 3,000 of these alleged violations were raw sewage spills from San Diego's collection system. Between 1987 and 1990, San Diego developed a plan to come into compliance that included upgrading the collection system to prevent spills, complying with bacterial standards in the kelp beds, upgrading the Point Loma plant to secondary treatment, building a second secondary treatment plant, and constructing six water reclamation plants. In 1990, the cost of the plan was estimated to be approximately $2.4 billion which is expected to result in rate payments around $360 per household per year. By January 1990, the EPA and San Diego entered into a consent decree
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Managing Wastewater in Coastal Urban Areas that put San Diego's plan on a legally enforceable schedule for compliance. However, the federal judge whose approval of the consent decree was also required was troubled by local scientists' contention that secondary treatment would be costly and fail to achieve marked environmental benefits. Following two 1991 hearings on the consent decree and the EPA lawsuit against San Diego, the court found that ''the city has been in violation of the Clean Water Act almost continuously since the statute was enacted in 1972" (United States and State of California v. San Diego, No. 88-1101-B[IEG], slip op. at 6 [S.D. Cal. April 18, 1991]). The judge was particularly concerned by the frequency of sewage spills from the collection system, which occurred about once a week. With respect to environmental harm, the court found that the community of organisms in the sediments around the outfall were not adversely affected by the discharge. However, the court also found that the exceedence of bacteriological standards in the Point Loma kelp beds may have adversely affected the marine environment and that viruses in the sewage imperiled divers. (In a later decision, the judge ruled that San Diego could meet bacteriological standards in the kelp beds by extending the outfall rather than by disinfecting the effluent. The extension, which will result in a 4.5-mile-long outfall terminating in water 320-feet-deep, is currently under construction.) San Diego was fined $3 million for its violations and given the option of paying only $0.5 million and enacting a water conservation ordinance and spending at least $2.5 million on water conservation projects. Finally, the judge deferred his decision on the consent decree until early 1993 which he has since extended until mid-1993. In the interim, he instructed San Diego to conduct tests at the Point Loma plant to determine if it could improve the solids removal efficiency of the chemically enhanced primary treatment process, to complete a master plan for reuse of treated effluent, and to continue all other efforts as if the decree were in effect. Although the opportunity to apply for a new waiver expired in 1982, in his 1990 and 1991 rulings, the judge has indicated that, since he lacks jurisdiction over the waiver process, his rulings do not affect any rights San Diego might have to reapply for a waiver. In September 1992, the judge modified his interim order, pending the May 1993 hearing on entry into the consent decree, to allow San Diego to proceed with a scaled-down program termed the "consumers' alternative" and granted the city a 19-month extension on all secondary treatment and reclamation projects not included in the consumers' alternative. This $1.3 billion program does not include secondary treatment upgrades, eliminates two of the seven planned water reclamation facilities, delays construction of two, and assumes that two others will be built by other authorities. It contains some capital improvements not included in the original consent decree. The judge suggested San Diego use
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Managing Wastewater in Coastal Urban Areas the additional time to seek administrative and/or legislative relief from the secondary treatment requirement for the Point Loma plant. San Diego is seeking to reopen its waiver application process although it has not yet applied to the EPA for a reopening. In addition, the city is seeking legislative relief from the secondary treatment requirement in its particular circumstance in the upcoming reauthorization of the Clean Water Act. REFERENCES Albert, R.C. 1987. The historical context of water quality management in the Delaware River Estuary. Estuaries 10(3):255-266. Cerco, C., and T. Cole. 1991. Thirty year simulation of Chesapeake Bay dissolved oxygen. Rotterdam: Balkerna. Dortch, M.S. 1991. Long-term water quality transport simulations for Chesapeake Bay. Rotterdam: Balkerna. DRBC (Delaware River Basin Commission). 1989. Attaining Fishable and Swimmable Water Quality in the Delaware Estuary. DEL USA Project, Final Report. West Trenton, New Jersey: Delaware River Basin Commission. DRBC (Delaware River Basin Commission). 1992. Delaware River and Bay Water Quality Assessment, 1990-1991. 305(b) Report. West Trenton, New Jersey: Delaware River Basin Commission. EPA (U.S. Environmental Protection Agency). 1992a. Response to Information Request for the National Research Council, Water Science and Technology Board. Washington, D.C.: U.S. Environmental Protection Agency, Office of Water, Office of Wetlands, Oceans and Watersheds. EPA (U.S. Environmental Protection Agency). 1992b. National Water Quality Inventory, 1990 Report to Congress. EPA 503/9-92/006. Washington, D.C.: U.S. Environmental Protection Agency, Office of Water. Harleman, D.R.F., L.M.G. Wolman, and D.B. Curll. 1993. Boston Harbor Cleanup Can Be Improved. Boston, Massachusetts: Pioneer Institute for Public Policy Research. Marino, G.R., J.L. DiLorenzo, H.S. Litwack, T.O. Najarian, and M.L. Thatcher. 1991. General Water Quality Assessment and Trends Analysis of the Delaware Estuary, Part One: Status and Trend Analysis. Eatontown, New Jersey: Najarian Associates. Mearns, A.J., M. Matta, G. Shigenaka, D. MacDonald, M. Buchman, H. Harris, J. Golas, and G. Laurenstein. 1991. Contaminant Trends in the Southern California Bight: Inventory and Assessment. NOAA Technical Memorandum NOS/ORCA 62. Seattle, Washington: National Oceanic and Atmospheric Administration. NOAA (National Oceanic and Atmospheric Administration). 1990a. 50 Years of Population Change Along the Nation's Coasts, 1960-2010. Rockville, Maryland: National Oceanic and Atmospheric Administration. NOAA (National Oceanic and Atmospheric Administration). 1990b. Coastal Environmental Quality in the United States, 1990: Chemical Contamination in Sediment and Tissues. Rockville, Maryland: National Oceanic and Atmospheric Administration. NOAA (National Oceanic and Atmospheric Administration). 1991. The 1990 National Shellfish Register of Classified Estuarine Waters. Rockville, Maryland: National Oceanic and Atmospheric Administration. NYCDEP (New York City Department of Environmental Protection). 1991. Harbor Water Quality Survey: 1988-1990. NTIS #PB91-2288i. Wards Island, New York: New York City Department of Environmental Protection.
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Managing Wastewater in Coastal Urban Areas Parker, C.A., and J.E. O'Reilly. 1991. Oxygen depletion in Long Island Sound: A historical perspective. Estuaries 14(3):248-264. Swanson, R.L.. A. West-Valle, M.L. Bortman, A. Valle-Levinson, and T. Echelman. 1991. The impact of sewage treatment in the East River on western Long Island Sound. In The Second Phase of an Improved Assessment of Alternatives to Biological Nutrient Removal at Sewage Treatment Plants for Alleviating Hypoxia in Western Long Island Sound, J.R. Schubel, ed. Working Paper 56. Stony Brook, New York: Coast Institute, Marine Sciences Research Center.
Representative terms from entire chapter: