Responsible Stewards of the Environment: Town of Bristol Replacing Wastewater Treatment Equipment

May 4, 2015

Bristol, RI – The Town of Bristol is replacing the Rotating Biological Contactor (RBC) units used to treat wastewater at their Water Pollution Control Facility (WPCF). The Town is working with BETA Group, Inc., a Lincoln-based engineering consultant, and contractor Hart Engineering Corporation, based in Cumberland, to make the improvements.

The facility’s secondary treatment system consists of 24 RBCs that biologically treat wastewater without the need for costly chemicals or power hungry aeration systems. The existing units were installed approximately 30 years ago. Due to the diligent maintenance efforts of the Bristol WPCF personnel, the units have surpassed their estimated service life. However, maintenance has become particularly challenging over the years as storm characteristics continue to change. The extreme wet weather events in recent years have caused flood conditions at the plant, resulting in flooded RBC tanks and submerged RBC drive motors.

The Town began to aggressively replace the RBCs in 2012, starting with the first stage units which handle the majority of the treatment loading. At a cost of approximately $250,000 per unit, 6 RBCs were replaced in 2012, 6 will be replaced in 2015, and an additional 4 are scheduled for 2016.

To protect against future damage from flooding, the new RBCs are being installed with their drive motors approximately 2.5-feet higher than the existing motors.