What is Helea®?

Helea® is now available to the UK water industry, supporting water companies to meet their Net Zero targets by offering a more affordable and sustainable route to advanced sludge digestion. Helea® significantly increases the biogas yield over conventional digestion. At the same time, it transforms the remaining biosolids into enhanced quality biosolids resources that can be safely recycled for agriculture as a nutrient and a soil conditioner. The process reduces both operating costs and the carbon footprint associated with sludge treatment.

First, the temperature of the raw sludge is raised to approximately 40-45°C, using hot water recovered from Combined Heat and Power (CHP) engines. No additional support fuel is needed, making the process energy self-sufficient and optimising carbon benefits. Sludge is pumped forward to the pasteurisation tank where it is heated to 55°C by recirculating it through a steam injector. Once the pasteurisation tank is full, the sludge feed is changed over to the second pasteurisation tank, and the sludge in the first pasteurisation tank is held for five hours to achieve pasteurisation.

This sludge is then transferred to the hydrolysis tank, where it is cooled to a temperature of 38-42°C, with a retention period of typically 1.5 days, to achieve maximise biological hydrolysis, before being pumped forward to the digesters.

Helea® is installed upstream of digesters, allowing them to operate at a significantly increased organic loading rate, solids destruction and biogas yield. Helea® provides optimum conditions for pasteurisation and biological hydrolysis, with the resulting sludge more amenable to anaerobic digestion.

Future applications for Advanced Digestion