Sewer Systems

Technical Reprints

In the Trenches at Antietam

A major concern for all involved was potential disruption of environment or architecture during the laying in of the sewer system.

The Battle of Antietam, on September 17, 1862, climaxed the first of Confederate General Robert E. Lee's two attempts to carry the Civil War into the North. When the fighting ended more men had been killed or wounded than on any other single day of the war with over 23,000 soldiers lost.

Today the site of that bloodiest day is protected by the National Park Service without all the relative commercialization of the more famous of General Lee's Northern battles, (Gettysburg). The National Battlefield of Antietam is straddled by the charming towns of Sharpsburg and Keedysville. Nowadays, the congeniality of the people of this area is well known and in fact the small billboard which welcomes new arrivals proclaims Keedysville as the place..."Where Northern Thrift & Personality Blend with Southern Charm and Hospitality." Situated in the scenic rolling hills of southern Washington County, the Towns of Sharpsburg and Keedysville exemplify the rural, small town environment of western Maryland.

In the late 1970's, planning began for addressing difficulties with wastewater disposal in the towns. Potential health hazards or environmental deterioration are forcing many communities to convert from septic tanks to community or central treatment systems. Keedysville and Sharpsburg were posed with the same problem, the old septic systems and cesspools were just not working anymore. At the same time, concern was whether a central sewer system and the associated excavation work would disrupt or destroy the historic setting for so long shrouded in the legacy cast by the Civil War. An innovative technology known as a Low Pressure Sewer System (LPSS) proved to offer the solution. Design of the new system took place in 1986 and 1987. PSC Engineers and Consultants of Hunt Valley, Maryland performed the planning, design, and engineering services during construction. The Washington County Sanitary District staff provided for all on site construction management. The project went to bid in 1988. On June 15, 1990, all contracts were complete and the system fully operational.

The success of the project depended on the cooperation and participation of many parties. Foremost were the officials and residents of Sharpsburg and Keedysville. The Commission and staff of the Washington County Sanitary District spent many weeks and months managing, directing and coordinating the entire effort. Funding and regulatory oversight were provided by the Maryland Department of the Environment, the U.S. Environmental Protection Agency, and the U.S. Environmental Protection Agency, and the U.S. Department of Housing and Urban Development. Support of the Washington County Commissioners was essential in the final implementation of the project.

Total project costs were about $17,000,000.00. Over $13,600,000.00 was provided by the U.S. Environmental Protection Agency; approximately $1,000,000.00 was provided by the State of Maryland; $500,000.00 came from the U.S. Department of Housing and Urban Development through the Community Block Grant Program administered by Washington County; remaining project funds were generated by a local bond issue supported by the Washington County Commissioners.

Pressure Sewer Collection System

A major concern for all involved was potential disruption of environment or architecture during the laying in of the system. Gravity sewers were ruled out because of the huge expense of blasting through rock strata and the possible seismic vibrations which could shake, rattle and roll the towns' historic structures.

Collection of wastewater from the homes and businesses in the two communities is by means of an innovative pressure concept. Each customer is provided with a "grinder" pump in a small fiberglass tank which collects the sewage from the home. Several times each day, the pump is automatically turned on to move the wastewater through a small diameter pipe in the adjacent street. Sewage is pumped through a network of these small (LPSS) pipes to centrally located pumping stations and finally to the new Antietam Wastewater Treatment Plant.

Construction of the (LPSS) collection system involved three contracts. One contract was for the Town of Keedysville. This portion of the job was built by Springfield Contractors, Inc. of Glen Rock, PA. A second contract was for most of the town of Sharpsburg. C. William Hetzer, Inc. of Hagerstown, MD constructed this part of the project. The third contract encompassed a development on the west side of Sharpsburg. In order to save money on the total project, this contract was done by personnel from the Washington County Sanitary District. Environment One Corporation, Schenectady, NY, one of the pioneers of the grinder pump system, has provided the grinder pump units for the entire system.

Statistics for the collection system are quite impressive:

   Lateral Pipe (on the customers' property)...12 miles
    Pressure Sewer Collection System...9 miles
    Force Main (from the pumping stations)...5 miles
    Water Pipe...1 mile
    Special Valves...Over 1100
    Grinder Pumps...Over 650
    Pumping Station (with odor control)...2

Antietam Wastewater Treatment Plant

All of the wastewater from Sharpsburg to Keedysville is treated at a new facility located south of Sharpsburg off of Harpers Ferry Road. The plant is based around a full aerobic treatment process called the oxidation ditch to provide a discharge which meets the requirements for maintaining the quality of the Antietam Creek.

Selection of the exterior materials, such as brick and the control building roof, was done by carefully examining the character of many of the Civil War era homes in the area. The red brick and metal roof are examples. This makes the facility more attractive. Also, considerable attention was given to selecting complementary shrubs, plantings and landscaping to enhance the appearance of the facility. Plants such as juniper, forsythia, snowberry, firethorn, and cottoneaster were put in along with cherry, dogwood and selected pine trees.

The plant is designed to treat about 163,000 gallons of wastewater each day. While the plant is small compared with others in Maryland, care and attention was paid in choosing the treatment process and the overall layout of the facility.


The Sharpsburg/Keedysville Low Pressure Sewer System has been on-line for over a year now and the Washington County people are "very happy," according to Lynn Palmer, Executive Director for the Washington County Sanitation District. He is quick to comment on aspects of the project which have proven to be an ideal situation for Low Pressure Sewers, like the ability to cut through and lay small diameter pipes in shallow trenches, avoiding the potential explosive costs of blasting for gravity sewers. But Mr. Palmer notes that it's some of the hidden benefits of LPSS that also help make this job shine. Since the Sharpsburg/Keedysville project is a completely new system that is 100% LPSS, some interesting results are clear:

  1. The system was designed to the EPA level of 200 gallons per day - per EDU (equivalent dwelling unit)
  2. Average daily flow is actually 124-150 GPD per EDU
  3. Measured wastewater flow to the Treatment Plant is about 2% less than metered water consumption in winter and about 10% less in summer (due to lawn watering, etc.)
  4. Infiltration/inflow has been eliminated with the LPSS
  5. Plus - the equipment is experiencing lower than expected operating costs, which translates into customer satisfaction.

Visitors to the area will be rewarded with an experience rich in the history and vernacular of another time, yet served by some of the most modern of utilities. The residents of Sharpsburg and Keedysville are to be commended for their forethought and concern for the environment.

Land and Water, Nov/Dec 1991