Alexandria Renew Enterprises

A new Centrate Pretreatment Facility (CPF) with three Sequencing Batch Reactors (SBRs) and a new building to house the process equipment will be constructed. This facility will treat the ammonia-rich dewatering centrate, thereby reducing the ammonia load to the BRBs. The system was designed to accommodate conventional nitrification/ denitrification process (similar to the BRBs) but also innovative processes like nitritation/denitritation and deammonification (DEMON). Using cutting edge technology allows AlexRenew to use less carbon, oxygen, and energy than conventional treatment processes. Package B also includes Final Effluent Flow Measurement, which will allow for more accurate calculations of effluent levels.

Project Schedule: The design of SANUP Package B was completed by CH2MHill in December of 2010. The construction is scheduled to begin in June 2011.

Procurement Information: The design of the project was awarded to CH2MHill through the 2005 agreement. The construction of the project was awarded through low bid to CPP Construction in April 2011.

Under SANUP Package C, AlexRenew will construct the Nutrient Management Facility (NMF).  The purpose of the NMF is to reduce the peak mass nutrient loadings to the BRBs. Prior to constructing the NMF, the west plant requires site work.  This includes:  Site demolition and preparation, on-site roadways and related drainage facilities, Hooff’s Run vehicular stream crossing, Hooffs Run pipeline crossing, site underground pipelines, electrical duct banks, coordination with the relocation of Dominion Power lines, and site stabilization (vegetation).

Project Schedule: Construction of this project is estimated to last from FY2012-FY 2013.

The NMF will consist of approximately 12 million gallons of storage space. The purpose of the NMF is to reduce the peak mass nutrient loadings to the BRBs. A portion of the primary treated wastewater will be pumped into the NMF (through an existing pump station) during peak loading periods, and pumped out of the NMF (through a new pump station) and into the BRBs during lower loading periods. This will allow a more consistent load of nutrients to undergo biological treatment. The facility will also include an odor control system.

Project Schedule: Design for this project is estimated to be complete in FY2012, with construction of this project lasting from FY 2013-FY 2015.

The new BRB 6 will be an anoxic tank, located between the existing BRBs and the SSTs, to provide denitrification polishing with the addition of supplemental carbon. The additional volume will increase the treatment capacity by reducing solids loading rates to the SSTs. Mixers will be installed to prevent settling of the mixed liquor. Work also includes constructing a new interconnecting channel to connect BRB 6 to the existing BRBs.

Project Schedule: Construction of this project is estimated to last from FY 2012-FY 2013.

UV System Upgrade

The current UV system at AlexRenew will need to be replaced by a new system when it reaches the end of its useful life. The existing system was installed in 2001 so the need for replacement is predicted to occur sometime between 2014 and 2016. Advances in UV disinfection technology have already reduced the power consumption and footprint impact of UV systems and may reduce it further in the future. Also, new systems are being designed to be easily retrofitted in existing channels replacing one channel at a time should be an acceptable method of performing the work while still maintaining adequate treatment and redundancy.  Since newer UV technology can reach the same level of disinfection with fewer lamps, there is also the potential for significant energy savings.

Project Schedule: Design for this project is estimated to occur in FY2012, with construction estimated to begin in FY 2013.

The Holmes Run sewershed serves the entire western portion of the City of Alexandria and portions of Fairfax County. Flows are conveyed into the AlexRenew maintained Holmes Run Trunk Sewer (HRTS). The Holmes Run Trunk Sewer is owned and operated by AlexRenew and was originally constructed in 1954. The sewer is approximately 6.4 miles.  Recently, the HRTS has been rehabilitated from Van Dorn Street to Eisenhower Avenue. This was done with Cured- In- Place- Pipe Lining and manhole rehabilitation. The remaining two miles still need to be lined.  Lining the interceptor increases the capacity of the sewer and provides additional structural benefits as well. 

Project Schedule: Construction of this project is estimated to occur in FY 2012.

AlexRenew’s advanced treatment process produces high quality effluent that can be beneficially reused in a variety of applications.

Project Schedule: Construction of this project is estimated to last from FY 2012-FY 2015.

The current practice of land application of biosolids for agricultural use is facing public opposition which may result in increased regulatory scrutiny and potentially severe site limitations. Future conditions such as the rapid increase in energy prices and oil supplies could make other biosolids-to-energy alternatives more widely available and cost effective in the future. As an alternative to land application, dewatered biosolids could be incinerated in a waste-to-energy facility to produce electricity.

AlexRenew alone does not generate enough biosolids to support the funding and construction of a waste-to-energy facility.  By combining resources with other local municipalities, this facility becomes technically and financially feasible and provides a renewable source of energy.

Project Schedule: Design for this project is estimated to last from FY 2013-FY 2014 and construction estimated to occur in FY2015.