Mariners Landing Wastewater Collection System

Mariners Landing is a multi-use resort and golf community located in Bedford County, Virginia and is a prominent development at Smith Mountain Lake. Consisting of single-family, multi-family, condominiums, and commercial area, the 1000-acre community will eventually have two 18-hole golf courses to compliment its lake front access and conference center facilities.

In 2001, the developers of Mariners Landing commissioned ACS DESIGN to perform a detailed analysis of the existing and potential need for advanced wastewater collection, treatment, and disposal with the understanding that public sewer was not and would not be available and that demand for land development was strong. In the end, ACS DESIGN developed a series of engineering recommendations that resulted in the current construction of one of the largest private central sewer systems in Central and Southwest Virginia.

The Mariners Landing central sewer system consists of conventional gravity sewers, master sewage pump stations, common low pressure sewer forcemains, centralized advanced secondary wastewater treatment facilities, and unique state of the art mass drainfield treated effluent disposal systems. The design of the sewer system is such that it can be expanded as future demand and growth require.

In 2002, the Phase I sewer project included the design and construction of three major sewage pump stations rated at 100, 217, and 255 Gallons Per Minute (GPM) respectively along with approximately 5,000 linear feet of sewer forcemain and 4,500 linear feet of conventional 8-inch gravity sewer. A 45,000 Gallons Per Day (GPD) modular wastewater treatment plant facility was installed along with a 20,000 gallon effluent pump station, and 94,000 gallons of subsurface mass drainfield.

In 2005, the Phase II sewer project included the design and installation of a second 45,000 GPD treatment plant module, a second 20,000 gallon effluent pump station, and 105,000 GPD of subsurface mass drainfield. Additional collection and conveyance systems are currently planned or under construction to facilitate the delivery of raw wastewater to the treatment plant facility.

The design and installation of the Mariners Landing Central Sewer System represents a combination of technologies and design guidelines. The sewer utility is a hybrid system in that it reflects a more robust design reflecting the Virginia Department of Environmental Quality regulations and is similar to many larger municipalities, yet relies upon a common mass drainfield disposal system administered by the Virginia Department of Health.

At present, the Mariners Landing Central Sewer System has treatment capacity equivalent to 90,000 GPD and mass drainfield disposal capacity equal to approximately 215,000 GPD.

Mariners Landing WWTP Facility (90,000 GPD Advanced Secondary Treatment Facility)

The Wastewater Treatment Plant produces an Effluent Quality with BOD (Biological Oxygen Demand) and TSS (Total Suspended Solids) less than 10 milligrams per liter (mg/l). More importantly, total Nitrogen is less than 5 mg/l, which eliminates the need for nitrogen dilution areas within the community and further protects local groundwater resources.

The treatment plant implements an Integrated Fixed Film Activated Sludge process that recognizes the advanced nitrification benefits of a fixed film system with the simplicity of a conventional activated sludge process. The primary aeration system is referred to as the BioWheel process as manufactured by Wastewater Technology, Inc in Monterey, Virginia and was selected because of its denitrification and low energy consumption characteristics.

The soda ash tank is the only chemical system used in the WWTP facility and is required to compliment the robust denitrification process.

The electrical controls and data gathering systems are located in the existing laboratory building situated within the treatment plant compound. The wastewater systems are designed with several different forms of wastewater influent flow measuring so that accurate historical data can be acquired, analyzed by the wastewater operator and engineer, and then used to make effective treatment plant operational adjustments and to determine the need for treatment plant or disposal system expansions.

A fully functional laboratory space is provided for the wastewater operator who attends to daily operations of the wastewater treatment plant facility. It is here that the operator conducts wastewater testing and records daily quantitative and qualitative measurements. A monthly Discharge Monitoring Report (DMR) is prepared, signed by the operator and owner, and submitted to the Virginia Department of Health for review and filing purposes.

Given the fact that the sewer facility is located in close proximity to Smith Mountain Lake, the entire treatment facility is Reliability Class I rated, meaning that an emergency generator and multiple forms of equipment redundancy are provided to ensure continuous 24-hour per day operations. (center photo)

The laboratory space, electrical controls, and soda ash feed systems are contained in a small multi-purpose building (bottom photo). The entire facility is secured within a chain line fenced compound that is locked and monitored. Additional safeguards include autodialer capability that will automatically call a manned station to report any electrical or mechanical failures that may occur.

After treatment, the high quality effluent is pumped from an effluent pump station through several effluent forcemains to a series of mass drainfield systems located approximately one mile away and strategically within the Mariners Landing community.

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