Rivanna Water & Sewer Authority has upgraded its Moores Creek Wastewater Treatment Plant (WWTP), which serves the City of Charlottesville, the urban areas of Albemarle County, and Crozet. This upgrade is the most comprehensive revision to the WWTP since the early 1980s. Rivanna Water & Sewer has upgraded this facility for several different, yet equally important, reasons:
Reduction of Nutrients
RWSA was required by the Virginia Department of Environmental Quality (DEQ) to meet new wasteload allocations for total nitrogen and phosphorus by the end of 2011. Under the law RWSA had the choice to meet these allocations either by upgrading the Moores Creek WWTP, or by purchasing nutrient credits from wastewater facilities that treat beyond their allocation. RWSA chose to be a regional leader in environmentally responsible nutrient removal technology through a capital upgrade that met the allocation in 2011, and will go beyond our regulated allocation when the project is completed in 2012. Treated wastewater contains several nutrients, among them phosphorous and nitrogen, which, in large amounts, can disrupt the natural balance of the bodies of water into which they are released. When combined with other nutrient sources, it can disrupt the natural balance locally (Moores Creek), in downstream areas (the Rivanna and James Rivers), and in its final destination, the Chesapeake Bay. Upgrading the nutrient removal process at the Moores Creek facility decreases the amount of nutrients being released into Virginia’s waterways from this facility.
In upgrading the existing facilities at Moores Creek WWTP, not only does RWSA become a better steward of its environment, but it will be able to benefit other treatment plants throughout the Commonwealth through the nutrient exchange program. Now that the upgrade has been completed, RWSA will go beyond its nutrient allocation quota, for which nutrient credits can be received. RWSA is an active member of the Virginia Nutrient Credit Exchange Association, which allows it to “sell” its surplus of nutrient credits to other facilities in Virginia that may not have the funds to upgrade their facilities.
State of the Art Odor Control
One of the naturally occurring characteristics of the treatment of human organic wastes is the odor emanating from it. A large quantity of the odor occurs at the septage receiving facility where septic tank cleaning contractors deliver their tank contents to the Moores Creek facility. A new fully-enclosed septage receiving facility has been constructed, thereby eliminating a majority of the offensive odors at the entrance of the facility, and both the Pump Station and gravity thickeners have been enclosed. The new septage receiving facility is equipped with an “odor scrubber,” a device that creates a vacuum which cleans the odor from the air. Lastly, RWSA installed water cannons on the large overflow basins that were already in use, which will facilitate rapid wash-down after wet weather events, further reducing the potential for offensive odors.
Renovating and Refurbishing Equipment
Most of the equipment that was in use at the Moores Creek Wastewater Plant was over or nearing thirty years in age. By renovating and refurbishing the existing equipment, and in some areas purchasing new equipment to replace that which had reached its life-span, the Moores Creek facility has become more efficient and reliable in its service to the City and County.
Creation of Renewable Energy
Just as exciting as the reduction of nutrients being released into area waterways is the ability to produce renewable energy, which enables the Moores Creek facility to partially power itself from the use of methane gas to create electricity. This feature saves the Authority in operating costs, and most importantly, reduces our carbon footprint.
The digestion of biosolids naturally produces methane gas which was formerly used to power compressed air for the aerobic treatment process. In reconfiguring the old methane piping system, the methane now directly powers the anaerobic processes, which boosts its efficiency and reliability enormously. As an added bonus, any unused methane-created electricity is placed on the plant’s power grid, enabling the plant to use less energy from outside sources, reducing costs and impacts on our environment even further.
This upgrade is projected to receive an estimated $21.5 million in grants from Virginia’s Water Quality Improvement Fund, which will help defray the total construction cost of approximately $40.3 million.