Overview of the Issue

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1 4 Hydrogeology: Wastewater Reclamation and Groundwater Recharge for a Sole-Source Aquifer: The Successes and Failures of Cedar Creek Treatment Facility, Nassau County, Long Island CHELSEA WOOD ʻ06 Overview of the Issue The Cedar Creek Wastewater Reclamation and Groundwater Recharge program was conceived as a response to the serious water quality and quantity issues that confronted Long Island at the end of World War II. Skyrocketing water consumption accompanying the post-war population boom produced a decline in water table elevation, while pollution of public supply aquifers steadily increased with the number of septic tanks installed to serve Long Island homes. This trend was most acutely felt in Nassau County, one of four counties on Long Island. Of the two counties that rely on groundwater as the sole source of potable public water supply, Nassau County has traditionally been the most densely populated, feeling the pinch of expanding population more deeply than Suffolk, its sparser neighbor to the east. To address the dilemma of more polluted, less abundant water for public supply, in the early 1970 s the Nassau County Department of Public Works (with grants from the United States Environmental Protection Agency (EPA) and other government organizations) designed and built a facility to reclaim wastewaters that would normally be treated and released into the Atlantic Ocean. Under the program, tertiary treated wastewaters water that has been completely filtered and disinfected - would be processed at an existing facility, Cedar Creek Sewage Treatment Plant, and piped to a recharge site on County property. The site is located in East Meadow, a city near the geographic center of Nassau County. The program was designed to investigate the feasibility of a system for recharging a significant amount of reclaimed water to stressed Long Island aquifers via basins and injection wells at the East Meadow site. Trial runs for the facility conducted in 1982 were less than promising. Though the effluent produced during the tertiary treatment process met EPA standards Figure 1. Cross section of Long Islandʼs groundwater system. for drinking water contaminant concentration, water sampled from observation wells around the recharge site contained concentrations of trihalomethanes (THMs) in violation of EPA standards. Suspected carcinogens which form as a consequence of the chlorination process, THMs increase in concentration due to the reaction of residual disinfectants with ambient organic carbon when reclaimed water is recharged. Previous studies have focused exclusively on the political, hydrologic and economic aspects of this important issue. This paper seeks to give a more integrated analysis of this highly controversial topic. An analysis of Long Island s water situation as a whole will establish the necessity of the project s goal to create a sustainable water supply for Nassau County s growing population. Some important details of the project itself will be reviewed, as well as highlights of the project summary completed by the EPA in Finally, an analysis of the implications of the project will be presented, including the scientific and social ramifications of the study s findings. Hydrogeology Long Island s water supply issues are intimately bound to its unique hydrogeologic features. Part of a series of southward-dipping unconsolidated deposits, the two aquifers of most concern to our examination are the Upper Glacial (water table) and Magothy aquifers, which have been given sole-source designation by the EPA (1). These two formations are, for the most part, hydraulically connected and have medium to high conductivity (2). Long Island receives approximately 44 inches of precipitation per year. Under natural conditions, approximately half of this amount percolates into the water table and is drawn down into deeper formations like the Magothy (1). Groundwater is essentially the only source of fresh water for Long Island s 2.78 million residents; however, Images courtesy of Chelsea Wood

2 only the Magothy aquifer is a viable supply of potable water (3). The clays in the Raritan lend to the aquifer an extremely low permeability which makes pumping from it nearly impossible. The Lloyd is too deep to be a cost-efficient source of water, and the Upper Glacial has become too polluted to provide water of sufficient quality for public supply (4). Water Quality and Quantity Issues The degradation of the Upper Glacial can be traced to the effects of several conditions brought to bear on Nassau County in the wake of World War II. With the war over, suburbanization of many Eastern regions began with full force; an influx of families to newly-built Long Island suburbs required increased pumpage to support the rapidly expanding population. Green lawns, golf courses, swimming pools, and other amenities of suburban living all demanded continuously increasing amounts of water to be pumped from the island s underlying aquifers each year. To compound the problem, this development decreased the infiltration of rainwater (the aquifer s only input of fresh water), crippling the recharge of Nassau county groundwater even as it was being depleted at an unprecedented rate (1) (Figures 2 and 3). Declining water table elevation had several major repercussions in the hydrogeologic mechanisms of Long Island s aquifers: freshwater streamflow decreased, bay salinity increased, and landward movement of salty groundwater began to threaten freshwater supply (5). Coinciding with these effects in irreparably polluting the Upper Glacial, the waste released by the cesspools and septic tanks of Nassau county homes wreaked havoc on aquifer water quality (4). Even as late as 1978, some 60% of the population (then, approximately 1.5 million people) resided in unsewered areas and discharged 60 million gallons per day of domestic wastes directly into the shallow zone of the groundwater reservoir (1). Research and Development In the 1930s, recognizing the degree to which population expansion and its effects were beginning to influence the quality of Long Island s groundwater, Figure 2. U.S. Geological Survey data for annual streamflow in Pines Brook, Malverne, New York, is used here as a proxy for water table elevation. From 1937 to the present, Pines Brook has been a relatively uninterrupted, representative Nassau County stream, and thus, its flow can be considered a reliable approximation of overall water table levels and may indicate the degree to which pumping and prevention of infiltration affect the water table. Before indicating a correlation between suburbanization and water table decline, it must be proven that climatic change is not responsible for the significant drop in stream flow that is observed after Here, National Oceanic and Atmospheric Administration data for annual precipitation on Long Island is plotted against streamflow to show that although precipitation can account for year-to-year variability in streamflow for Pines Brook, it is not responsible for overall decline in streamflow (10). Figure 3. U.S. Geological Survey data for annual streamflow in Pines Brook, Malverne, New York, is again used as a proxy for water table elevation in this figure. Here, population data for Nassau County is plotted against streamflow to show the correlation between population (a proxy for suburbanization) and streamflow. (U.S. Census Bureau) From this data, it is clear that there is relationship between increasing suburbanization and decreasing water table elevation. Potential mechanisms for this relationship may include increasing water pumpage in response to increasing consumption of a growing population, decreased infiltration due to the development that accompanies increasing population, etc (10). SPRING

3 the government of Nassau County began researching technologies with the potential to mitigate these effects. In 1963, a report by the firm of Greeley and Hansen recommended that Nassau County initiate research into water reclamation and recharge (5). An experimental recharge program was undertaken in 1968 by the U.S. Geological Survey in cooperation with the Nassau County Department of Public Works (1). The effort, which involved the injection of tertiary-treated sewage into the Magothy aquifer through a screened well was unsuccessful as a recharge project because buildup of injected water required frequent redevelopment of the well (1). A water supply study conducted in 1971 emphasized the urgency of the pollution situation in the central part of Nassau County and elsewhere. It recommended that clean water be recharged into Nassau s aquifers; the recommended source for this water was importation or wastewater reclamation (4). Responding to the immediacy of the situation, the U.S. Environmental Protection Agency drafted an Environmental Impact Statement in 1972 to summarize the feasibility and operations of a 5 mega- gallons per day (mgd) wastewater reclamation-recharge demonstration facility on the site of the Cedar Creek Water Pollution Control Plant (4). In 1974, a feasibility study by the engineering firm of Consoer, Townsend and Associates was approved by the EPA to serve as the basis for the design of the Cedar Creek project. The total construction cost amounted to $22 million, which was paid for in grants from the EPA, New York State Department of Environmental Conservation, and the Nassau County Department of Public Works (1). Figure 5. Schematic diagram of the waterreclamation process (5). Figure 4. Map of western Long Island. Note location of Cedar Creek Pollution Control Plant, on the South shore, and East Meadow (Meadowbrook) Artificial Recharge Site (2). Operations at Cedar Creek and the East Meadow Recharge Site The Cedar Creek Wastewater Reclamation and Groundwater Recharge project had three main components: the reclamation plant, the transmission-main system, and the recharge facilities (1). Located on the Great South Bay in Wantagh, Long Island, the Cedar Creek sewage treatment plant was in operation before the development of the recharge project. Prior to 1973, the plant operated exclusively as a treatment facility and released all discharges into the Atlantic Ocean as secondarily treated wastewaters. The approach taken for design of the reclamation plant attempted to coordinate the best available technology with the maximum use of the existing facilities (6). The plant is designed to treat million gallons of sludge per day; five million gallons is reclaimed daily and piped to another location for recharge (1) (Figure 5). For reclamation, sludge must pass through a fourstep process: 1. chemically aided primary treatment to improve the removal of phosphorus, biochemical oxygen demand (BOD), suspended solids and heavy metals; 2. a two-stage biological treatment system consisting of a nitrification-denitrification process to promote biological nitrogen removal in combination with oxidation of remaining carbonaceous material; 3. filtration and carbon adsorption to reduce organic compounds in the effluent to a few parts per billion; and 4. chlorination and storage to disinfect and store this effluent to allow for continuous delivery of 4 mgal/day to the injection wells and basins at the recharge site (1). Once this process is completed, a pipeline carries tertiary-treated wastewater (also referred to as reclaimed water) from the Cedar Creek facility northwest 6.25 miles to the recharge site (6). New York State and federal drinking-water standards must be satisfied before effluent may be transmitted through the pipeline (1). The recharge facilities consist of a system of ten shallow basins and five injection wells situated on County-owned land in East Meadow (2) (Figures 6 and 7.). Approximately 2.0 million gallons of reclaimed water were recharged through the basins daily in the early 1980 s; a similar amount was recharged via the wells (5). The site is surrounded by a network of monitoring observation wells and other sampling tools (5). 6

4 Figure 6. Position of injection wells and recharge basins at the East Meadow recharge site (2). Evaluating the Successes and Failures of the Project Monitoring of ambient groundwater quality prior to recharge took place from November 1979 to June 1980; recharge operations began in July 1980 and continued to 1982 (5). Samples taken from monitoring wells at the recharge site were analyzed for 128 priority pollutants, 31 volatile organics, 47 base/neutral-extractable and 11 acidextractable organics, 25 pesticides/pcb s, 13 metals, total cyanide, and various non-priority organic pollutants (6). In the raw wastewater, 72 priority and 35 nonpriority pollutants were identified (6); analysis of the efficacy of removal of these pollutants in the reclamation process yielded the following results, based on total mass of identified contaminants: Analysis of the effects of recharge on the water quality in Long Island s sole-source aquifers, however, yielded mixed results. Initially, recharge decreased the concentrations of certain priority pollutants present in the groundwater prior to injection through dilution. However, despite the fact that trihalomethanes were not detected in any of the monitoring wells before recharge, they were detected at disconcertingly high levels for the post-recharge samples. Figure 7. Typical shallow recharge basin at the East Meadow recharge site (2). For two wells evaluated after recharge, THM data spiked from below detectable levels to 256 and 258 µg/l, well above the 1982 maximum contaminant level of 100 µg/l (6) and the current maximum contaminant level of 80 µg/l, as specified by the EPA (7). An analysis of data at various points along the recharge path suggests that a possible explanation for this mechanism is the reaction of residual chlorine and ambient organic carbon (6). The Failures of the Recharge Project Trihalomethanes are formed when chlorine or other disinfectants used to control microbial contaminants in drinking water react with naturally occurring organic and inorganic matter in water (7). According to the EPA, prolonged consumption of drinking water containing concentrations of trihalomethanes in excess of EPA standards may cause liver, kidney, or central nervous system problems and may increase the risk of cancer (8). The trihalomethane group includes chloroform, bromodichloromethane, dibromochloromethane, and bromoform, compounds which have been linked to bladder, colon, rectal, and pancreatic cancers in humans. (9) Reclaimed water must be disinfected before recharge in order to meet minimum drinking water standards. However, THM s are inevitable by-products of the chlorination process when disinfected water is stored for long periods of time in the presence of organic carbon (i.e. underground). This presents a serious obstacle to the recharge process. Recommendations in many reviews of the Cedar Creek project suggest balancing the amount of disinfecting chemical added with the potential amount of THMs that might be resultantly produced in order to reduce THM concentration to below EPA standard levels while still assuring that disinfection is complete. However, since THM levels increase with increasing detention time of disinfected water, it is likely that the minimum amount of disinfectant that could be expected to properly sterilize wastewater would produce enough byproduct to create unacceptable levels of THM in the stored water. Searching for Solutions Recharge of reclaimed wastewater can not proceed as a viable solution to the water quantity and quality dilemmas facing Long Island and other water-limited regions. In the Cedar Creek Reclamation and Recharge project, we have an exemplar of the kind of interplay between science and policy that has come to characterize the mediation of water issues in the past thirty years. Here, policymakers, concerned for the future of their constituents water supply, turned to the scientists and engineers of the EPA, Department of Public Works, and the United States Geological Survey to derive a viable solution to a complex problem. Though the solution SPRING

5 proposed was ultimately not feasible, the effort represents of the kind of cooperation that will be required in the search for sustainable water supply options on Long Island. Because the search has been abandoned in the wake of the $22 million recharge project failure is cause for alarm. A number of alternate avenues that must be pursued by a coalition of government and scientific agencies if water crises such as this one are to be defused. Aeration of treated wastewater prior to recharge, for example, may eliminate enough of the residual disinfectant byproducts to minimize THM development in groundwater storage. Sites for recharge may be chosen with more thought to the natural sedimentation of the area: instead of an impacted, urbanized substrate, a site chosen for looser, more permeable sediments may improve recharge infiltration and reduce the mounding that slows the recharge process. Clearly, the work of the Nassau County Department of Public Works was not finished when the East Meadow project failed: the experience, data, and technological infrastructure borne of that failure should support further research into sustainable water policy on Long Island. If the failure of this project signifies the end of proactive research, then it also forebodes an inevitable water crisis. REFERENCES 1. B. G. Katz, G. E. Mallard, Chemistry in Water Reuse 1, 165 (1981). 2. B. J. Schneider, H. F. H. Ku, E. T. Oaksford, Hydrologic Effects of Artificial-Recharge Experiments with Reclaimed Water at East Meadow, Long Island, New York (U.S. Geological Survey Water Resources Investigations and Nassau County Department of Public Works, New York, 1987). 3. Long Island Power Authority, LIPA Releases Its 2002 Long Island Population Survey: Nassau-Suffolk Region Totals 2.78 Million People (2002; 4. J. A. Olivia in Artificial Recharge of Ground Water, T. Asano, Ed. (Butterworth Publishers, California, 1985), pp F. J. Flood, R. J. Avendt, Groundwater Recharge Case Studies Cedar Creek Wastewater Reclamation and Groundwater Recharge Facility, Nassau County, New York: Proceedings of the Symposium held at California State Polytechnic University at Pomona, 6-7 September, 1979 (California State Water Resources Control Board, Office of Water Recycling, Sacramento, 1980). 6. T. D. Brisbin, S. H. Ahn, R. I. Foster, S. A. Labunski, J.A. Olivia, Project Summary: Priority Pollutants in the Cedar Creek Reclamation-Recharge Facilities (United States Environmental Protection Agency, Ohio, 1984). 7. U.S. Environmental Protection Agency, Disinfection Byproducts: A Reference Resource (EPA, 2003; gloss_dbp.html). 8. U.S. Environmental Protection Agency, List of Drinking Water Contaminants and MCLs (EPA, 2003; mcl.html). 9. U.S. Environmental Protection Agency, Integrated Risk Information System: Chloroform (EPA, 2003; html. 10. U.S. Geological Survey, Calendar Year Streamflow Statistics for the Nation: USGS Pines Brook at Malverne, NY. (USGS, 2003; no= ). submit to the DUJS Genome Sciences: From Double Helix to Human Sequence: Just the Beginning BRANDON L. MORRIS ʻ05 April 2003 marked the completion of the Human Genome Project. Remarkably, this celebratory event occurred 50 years to the month after the landmark publication of Watson and Crick s discovery and description of DNA (1). With this recent milestone achieved, scientists project a new beginning in biological sciences. Visionaries anticipate that advances medicine and in agriculture will accelerate, human health diagnostics will be revolutionized, and individualized therapeutic options designed for patients will become commonplace (2). Biology has indeed moved into a new era. Dr. Eric S. Lander, professor of biology at MIT, member of the Whitehead Institute and Director of the Whitehead Center for Genome Research located in Cambridge, MA, has described this scientific progression as a movement from the era of biology of organisms to the era of biology of molecules to the new era of biology of information (3). How will we read the information provided by the mapping of the human genome? With approximately three billion letters, or bases, of the human genetic code and currently some ten million common single nucleotide polymorphisms (SNPs) (points in the genome at which 8