Potential €2m annual opex saving for effluent treatment

The challenge

Anaerobic processes are sensitive to fluctuations in the quantity of organic compounds in the influent stream. When significant variation occurs, the biological treatment process can fail to work optimally. This leads to reduced biogas production (a valuable bi-product of the treatment process). Furthermore, fewer organic compounds are removed, which then need to be addressed downstream requiring additional energy. Washout can also occur, leading to a loss of valuable biomass.

This was the situation facing our client which had recently extended its production plant with two new anaerobic reactors to treat effluent from pulp and paper operations. Royal HaskoningDHV was approached to provide operational support to help manage issues with the new reactors. “We calculated these issues were leading to an excess operational cost of more than €2 million annually – including from lost biogas production, extra energy costs and the cost of reseeding the process with anaerobic sludge after washout,” explained Robert Jan Smeets, Global Coordinator, Water for Industry at Royal HaskoningDHV.

The solution

Organic compound input assessed and smoothed

Our team identified that Aqua Suite Anaerobic Controller offered a long-term and more sustainable solution for our client because it autonomously optimises operations around the clock. This advanced process control software is based on our extensive domain and software knowledge and uses soft sensors, predictions and process monitoring to regulate the organic load.

The modular software can be quickly tailored to the client’s specific needs and then draws on output from existing instruments and data points. It requires no capital expenditure and no significant modifications to the plant, so its introduction does not interrupt ongoing operations. Equally, as soon as the software is in use, system optimisation starts, and performance improves.

The result

Huge savings offered from low-threshold solution

“In practice, industry influent always has spikes and dips,” Robert added. “Where Aqua Suite makes a difference is that it takes signals from the control system and, using algorithms and predictions, regulates the pump speed based not on flow but on the required quantity of organic compound."

This is a low threshold solution which can create a very big impact, offering potentially huge savings for businesses that operate on small profit margins. In this case, we anticipate annual opex savings of around €2 million. Similar impact has been replicated elsewhere - for example at a smaller food plant Aqua Suite Anaerobic Controller led to annual savings of around €1 million.