Wastewater Treatment Upgrade: Embracing Efficiency with Franklin Miller's DIMMINUTOR®

Fredericton, Canada, a city of 50,000 residents, is the capital of the Canadian Province of New Brunswick. The Wastewater treatment plant, operated by the Fredericton Pollution Control Commission, is a secondary activated sludge system designed to treat an average flow of 5mgd. Septage and incoming wastewater flow through screens which direct oversized objects to the channel grinders where they are reduced to a fine particulate. The solids are allowed to settle in the primary clarifier, are dewatered and sent to a compost site. Treated effluent is discharged into the Saint John River.

Until 2009, when the plant began construction for a major upgrade to the existing infrastructure, equipment was purchased as needed. Replacing the existing channel grinders with more cost effective units became a priority. “We had two Muffin Monsters at our wastewater treatment plant, but the cost of overhaul every three years got to be very expensive and our maintenance budget took quite a hit,” explained Doug Sewell, Maintenance Supervisor.

“We began to look for a less costly alternative,” he continued. “We installed the first DIMMINUTOR® DM25 xf in 2003 and liked it so well that we purchased another one in 2006.” According to Sewell, the decision was a very good one. “The units are extremely reliable, the cost to operate them is very low and the company’s service and personnel have been topnotch,” he concluded.

The DIMMINUTOR DM25 Channel Comminutor provides effective, automatic screening and grinding of wastewater solids in straight through channels and wet wells. This powerful unit reduces plastics, wood, rags and other solids to fine bits, enhancing plant operation and improving the reliability of pumps and other downstream equipment.

The unit employs a smooth, continuously rotating design with high torque. As its three bidirectional rotary cutters intermesh at close clearance with stationary cutters, solids are finely reduced to a size small enough to pass through a sizing screen. With no gaps or openings between the screen and cutters, output is controlled and complete reduction assured.

The DIMMINUTOR has an intrinsically open design to handle high flow rates with low head-loss. This unit is extremely easy and economical to maintain and features individually replaceable cutters, oil lubrication and a simple rotary design requiring no auxiliary diverter screens. A unique, cantilevered design eliminates seals or bearings near the gritty channel floor. Every component of the unit is constructed for precision and long life.