Individual Sewage Disposal Systems Research Articles

Nonpoint Source Phosphorus Trading in the Cherry Creek Reservoir Watershed in Colorado

The Cherry Creek Reservoir in the Denver Metropolitan area is subject to the Cherry Creek Reservoir Control Regulation (control regulation), which establishes a total maximum annual load for the reservoir of 6,473kg(14,270lb) of phosphorus. The load is distributed among phosphorus sources including background, nonpoint, and regulated storm water, municipal and industrial wastewater facilities, individual sewage disposal systems, and industrial sources. As a part of the control regulation, the Cherry Creek Basin Water Quality Authority (CCBWQA) is authorized to implement and maintain a trading program that allows phosphorus trading and the sale of phosphorus (kg/lb) in the Cherry Creek watershed. The trading program allows dischargers seeking new or increased phosphorus waste load allocations to obtain additional kilograms/pounds of phosphorus by constructing nonpoint source projects meeting certain criteria to immobilize phosphorus. This paper provides an overview of the CCBWQA trading program guidelines and describes two Arapahoe County Water and Wastewater Authority (ACWWA) trade credit projects: Lone Tree Creek Pond L-3 and Windmill Creek Pond W-6/W-7. The Pond L-3 and Pond W-6/W-7 projects are unique because they are the first two (and only two to date) projects that have successfully obtained trade ratios and estimated trade credits under the CCBWQA trading program. This paper describes the administrative and technical process for determining trade ratios and estimating trade credits for nonpoint-source-to-point-source phosphorus trades in the Cherry Creek watershed. The process for going from an established trade ratio and estimated trade credits to actual trade credits applied to a point source discharge presents its own set of challenges. Actual trade credits must be demonstrated by monitoring, which can be very expensive. The monitoring results must be reviewed and approved by CCBWQA before trade credits are awarded, and the Colorado Department of Public Health and Environment Water Quality Control Division must amend the facility’s discharge permit before additional phosphorus can be discharged. Therefore, establishing a trade ratio and estimating trade credits for CCBWQA approval of a phosphorus trading project is only the first step in a potentially expensive and time-consuming process for actually discharging additional phosphorus through a nonpoint-source-to-point-source trade in the Cherry Creek watershed.

Fate of individual sewage disposal system wastewater within regolith in mountainous terrain

In order to improve understanding of the fate of septic tank or individual sewage disposal system (ISDS) effluent in regolith overlying fractured-rock aquifers, effluent from an ISDS in such a setting was tracked via geophysical, hydrological, and geochemical methods. Under typical precipitation conditions, the effluent entered the fractured bedrock within 5 m of the boundary of the constructed infiltration area. During a period of unusually high spring recharge, the plume migrated between 50 and 100 m within the regolith before infiltrating the fractured bedrock. The chemical signature of the effluent is similar to that required to account for the decline in water quality, suggesting a causative relationship (as estimated from mass-balance models of the surface-water chemistry near the mouth of the basin). The elevated salt content of the effluent during periods of high natural recharge to the infiltration area correlates with elevated salt concentrations in surface and groundwater at the basin scale, suggesting that some of the effluent salt load may be stored in the unsaturated zone during dry periods and flushed during periods of elevated natural recharge.

The Role of Sediment Denitrification in Reducing Groundwater-Derived Nitrate Inputs to Nauset Marsh Estuary, Cape Cod, Massachusetts

The Nauset Marsh estuary is the most extensive (9.45 km2) and least disturbed salt marsh/estuarine system within the Cape Cod National Seashore, even though much of the 19 km2 watershed area of the estuary is developed for residential or commercial purposes. Because all of the Nauset watershed is serviced by on-site individual sewage disposal systems, there is concern over the potential impact of groundwater-derived nutrients passing from these systems to the shallow receiving waters of the estuary. The purpose of this study was to determine whether denitrification (the bacterial conversion of nitrate to gaseous nitrogen) in estuarine sediments could effectively remove the nitrate from contaminated groundwater before it passed from the watershed to the estuary. Rates of denitrification were measured both in situ and in sediment cores, in areas of active groundwater discharge, in relatively pristine locations, and in areas situated down-gradient of moderate to heavily developed regions of the watershed. Denitrification rates for 47 sediment cores taken over an annual cycle at 5 stations ranged from non-detectable to 47 μmol N2 m−2 h−. Mean denitrification rates were positively correlated with sediment organic content, and varied seasonally due to changes in sediment organic content and to the effect of water temperatures on sediment oxygen penetration depths. There was no correlation between observed denitrification rates and corresponding nitrate concentrations in groundwater. A comparison of in situ denitrification rates (supported by groundwater nitrate) with denitrification rates observed in sediment cores (supported by remineralized nitrate) showed that groundwater-driven denitrification rates were small, and not in excess of denitrification rates supported by remineralized nitrate. Most of the denitrification in Nauset sediments was apparently fueled by remineralized nitrate through coupled nitrification/denitrification. Denitrification did not contribute significantly to the direct loss of nitrate from incoming groundwater at Nauset Marsh estuary. Groundwater flow was rapid, and much of it occurred in freshwater springs and seeps through very coarse, sandy, well-oxygenated sediments of limited organic content. There was little opportunity for denitrification to occur during groundwater passage through these sediments. These results have important management implications because they suggest that the majority of nitrogen from contaminated groundwater crosses the sediment/water interface and arrives at Nauset Estuary, where it is available to primary producers. Preliminary budget calculations suggest that while denitrification was not an effective mechanism for the direct removal of nitrate in contaminated groundwater flowing to Nauset Marsh estuary, it may contribute to significant nitrogen losses from the estuary itself.

Integrating state government for improved coastal water quality: Analysis of the Rhode island salt pond region

The salt pond region in southern Rhode Island includes eight shallow estuaries that span across four municipalities and come under the jurisdiction of two state environmental agencies. The salt pond region is largely dependent on individual sewage disposal systems (ISDSs) for sewage treatment, which are loading nitrogen and fecal coliform bacteria into the salt ponds. Ambient water quality, aquatic vegetation, and shellfish closures are an indication that current water quality management by state and local managers is not effective. These inadequacies are a result of a management system that relies on site‐specific decisions to manage for watershed‐based issues. This article addresses the problem of watershed‐scale water quality management in the salt pond region by identifying three major institutional issues: the two principle authorities for water quality management in the salt pond watersheds do not have the same standards or measurements; the Rhode Island Coastal Resources Management Council (CRMC) d...

Hybrid Disposal Systems and Nitrogen Removal in Individual Sewage Disposal Systems

The use of individual disposal systems in ground-water basins that have adverse salt balance conditions and/or geologically unsuitable locations, has become a major problem in many areas of the world. There has been much research in design of systems for disposal of domestic sewage. This research includes both hybrid systems for disposal of domestic sewage. This research includes both hybrid systems for disposal of the treated waste in areas with adverse geologic conditions and systems for the removal of nitrogen and phosphorus prior to percolation to the ground water. This paper outlines the history of development and rationale for design and construction of individual sewage disposal systems and describes the designs and limitations of the hybrid and denitrification units. The disposal systems described include Mounds, Evapotranspiration and Evapotranspiration/Infiltration systems. The denitrification units include those using methanol, sulfur and limestone, gray water and secondary treated wastewater for energy sources.

Modeling Sodium and Chloride in Surface Streams During Base Flows

Sodium and chloride contamination of shallow groundwater can be frequently attributed to three major sources: (1) Individual sewage disposal systems (ISDS); (2) road salt application during winter deicing activities; and/or (3) road salt storage. Effluent streams in a large reservoir watershed were sampled during baseflow conditions. Sodium and chloride concentrations were regressed against different land use types including roadway, residential, commercial, industrial, agricultural, and forest areas. Results indicate that roadway areas are the largest single influence of sodium and chloride concentrations. Data from other watersheds are compared to the developed relationships and agreement is favorable. Additionally, a mass balance is performed and indicates that, typically, roadway deicing activity in the test watershed can potentially introduce far greater amounts of sodium and chloride in the local groundwater than the next greatest influence, residential septic systems.

Methods of Geologic Evaluation of Pollution Potential at Mountain Homesitesa

ABSTRACTDevelopment of mountain homesites is accelerating in the Rocky Mountains of central Colorado. These homesites often require individual water wells and sewage disposal systems. Unfortunately, the widely used septic tankleach field system generally is not suited for use in the mountainous terrain where soils are thin or missing. Although current federal regulations call for six feet or more of soil at the leach field site, many of the individual sewage disposal systems now in operation in the Rocky Mountain Region of Colorado fail to meet this requirement. Sewage effluent at these sites may directly enter bedrock fractures and travel large distances without being purified. As a consequence, contamination of streams, lakes, and ground water from these malfunctioning leach fields has become a problem of increasing magnitude.Investigations of geologic, topographic, and hydrologic conditions at over 100 homesites in the Rocky Mountains of north‐central Colorado have resulted in the development of objective criteria for evaluating pollution potential at mountain homesites. In addition, the results of these investigations indicate that contamination of water wells may be decreased significantly where geologic conditions are considered in the selection of sites for leach fields and wells. Although the results of these studies should be considered preliminary, they do tend to confirm that the orientation of jointing surfaces in the bedrock significantly affects the travel path of contaminants.

Urban Planning for Environmental Health

U RBAN PLANNING for a healthful environment involves water, sewage, refuse, air, roads, churches, schools, open spaces, houses, money, and, last but not least, it involves people. People demand healthful facilities only to the extent that they are educated. Too few, for example, are sufficiently educated to demand sewers in a housing development rather than septic tanks. And who is to educate them? County commissioners, mayors, councilmen, sanitary district commissioners, and similar public officials have not been trained as environmental hygienists, as planning experts, or as educators, even though they are saddled with such responsibilities. The talents of educator and community leader are needed urgently to help in promulgating water, sewage, and refuse disposal facilities, and well-planned housing. To provide for these facilities in a master plan of development is to use today's decisions to protect the interests of a city's children and grandchildren, as well as the living generation. An organized plan of public improvement clearly and logically presented, so as to be understood by civic leaders and the public, has an infinitely greater chance of achievement than an unorganized approach. A classic result of inadequate planning is the widespread use of septic tanks and private wvells in housing areas. More are being installed every day with the knowledge of engineers, yes; but with their consent, no. Why does this happen? Consider a hypothetical situation: Suppose a large development is being constructed on the fringe of a city. The usual services will be needed. The community's water and sewer mains at the corporate limits may be inadequate to serve the fringe area. How are financial arrangements made to provide service equitably? Sometimes the community will refuse to talk about extension of services unless the fringe area agrees to annexation. Or the community agrees to provide water-supply service but cannot or will not provide sewer service, with the result that septic systems make enemies of neighbors, even though the drinking water is safe. In this situation, the engineer-planner, who doubles as a salesman with a major in public relations, will strive, if extensions of services are feasible, to satisfy the city that it is not giving something for nothing and to convince the fringe-area people that they are not being fleeced. Many fringe areas which a few years ago were rather sparsely settled are now booming communities, with large, modern shopping centers. Where water and sewerage facilities are inadequate for present structures, it is reasonable to require that the facilities be expanded before authorizing new construction. Such a decision may be predicated on (a) individual well-water supplies being threatened by pollution, (b) individual sewage disposal systems either overflowing and causing visible hazards or contaminating ground water supplies, or (c) areas having sewers but no sewage treatment. An editorial, entitled Day by Day, in The Salisbury Times, Salisbury, Md., May 30, 1963, had this to say: The health department is conducting an antipollution campaign that will be effeictive Mr. Brown is chief, bureau of environmental hygiene, Maryland State Department of Health. This article is based on his speech at a workshop session of the Conference of State Sanitary Engineers in Washington, D.C., June 26, 1963.

Closure to “Design Detail for Individual Sewage Disposal Systems”

Closure to “Design Detail for Individual Sewage Disposal Systems”

Closure to “Design Detail for Individual Sewage Disposal Systems”

Closure to “Design Detail for Individual Sewage Disposal Systems”

Discussion of “Design Details for Individual Sewage Disposal Systems”

Discussion of “Design Details for Individual Sewage Disposal Systems”

Design Details for Individual Sewage Disposal Systems

Design procedures and simplification of design methods and comment on design of septic tank systems. Some standardization is provided and methods and reasons therefor described.

Research studies on individual sewage disposal systems.

Research studies on individual sewage disposal systems.