Assessing

A number of hot wastewater sources have been identified in the Zambian food industry, specifically blowdown water from the boilers used for steam generation and water from Cleaning In Place (CIP) processes, particularly in dairy processing. These processes generate hot wastewater in the range of 40-90°C which is discharged into sewers or drains.

Our solution is focused on recovering and recycling this heat into the cold-water feed to boilers, reducing the requirement for heating by up to around 6.6 MWh/day, reducing fuel use, carbon emissions, and air pollution.

Our initial monitoring has shown that several options for heat recovery pilot installations at Zambeef facilities exist. We have identified five separate locations which could significantly reduce emissions. The most impactful of these is located at the combined wastewater and boiler blowdown discharge at Huntley farm. Here we measured wastewater at temperatures of 40 to 90°C with variable flow rates. A conservative estimate of the energy recovery potential here indicates that up to 33% of the coal required could be offset using our technology, reducing emissions by >500 tonnes CO2e/yr.

The proposed solution will extract heat from two adjacent wastewater sources (blowdown water & open drain water) depending on the temperature of each. Using our novel heat exchanger design and advanced materials we will extract 50-75% of the available heat and use this to preheat the incoming cold-water supply to the boiler