DDI Heat Exchangers Inc.

DDI Heat Exchangers Inc., founded in 1980 and headquartered in Dollard-Des Ormeaux, Quebec, Canada, designs and manufactures patented rectangular-channel heat exchangers for thermal energy recovery from high-solids liquid waste streams, particularly municipal wastewater sludge. DDI's core innovation is the Rectangular, Square, Cube channel design, which features minimum 3-inch gaps on both sides with no internal obstacles and rounded curves, enabling clog-free operation with stringy and sticky materials containing up to 26 percent solids content. Unlike spiral and shell-and-tube designs, DDI's rectangular channels accommodate equal flow on both sides and permit true double-wall construction for compliance with potable and grey water codes, all in a more compact footprint than conventional alternatives. DDI serves four primary markets: wastewater treatment plants, where direct sludge-to-sludge heat recovery from hot digested to cold raw sludge achieves payback in under one year; grey and black water energy recovery in large buildings and hotels yielding 10 to 30 percent heating cost savings; city sewage energy recovery for district heating and cooling without holding tanks, screens, or macerators; and sludge pasteurization via the Yes Pasteurization process. Installed references include the North Shore WWTP and Lions Gate plant in Vancouver, the Niagara Region, and Owen Sound WWTP. DDI systems eliminate the need for grinders, macerators, or pre-screening equipment, saving approximately 200,000 dollars over ten years compared to spiral designs, and incorporate ECPS cleaning port systems and pig cleaning capability for in-situ maintenance without system shutdown.