Automation at industrial wastewater treatment plants

In our latest blog, Niels Tiemessen, product expert and business developer at Royal HaskoningDHV, explores some of the benefits associated with the introduction of automation.

Three benefits of automation

In its simplest form, automation can mitigate operational risks for industrial wastewater treatment plants (WWTPs):

• Save costs
• Make processes more sustainable and meet more stringent compliance
• Reduce the operator’s workload.

With the exploding energy prices and increased cost of chemicals and sludge disposal, operators have seen the cost of wastewater treatment rise sharply. However, advanced process automation can reduce energy costs by up to 20% and chemical costs by up to 15%, which in turn, also leads to a more sustainable process. With the upcoming revision of the European Framework Directive on Urban Wastewater, more stringent discharge limits are to be expected. In particular, the removal of substances of very high concerns (SVHC) like per- and polyfluoroalkyl substances (PFAS). This potentially means adding extra complexity to the wastewater treatment plant, which in turn, requires more attention from operators to keep the systems up and running. These new discharge limits could lead to non-compliance, threatening primary production, with the WWTP needing a license to operate.

On the brighter side, there is also sustainability gain to be made through the optimisation of biogas production, with an increase up to 50%. The gas can be desulphurised and used on site for cogeneration, in some cases providing more than a quarter of the heat demand required for the total plant.

Automation for Industrial wastewater treatment

When you are looking at water treatment in the paper industry, for chemical companies or the food industry, you need to be more aware of the variations in type and degree of pollution. This means that the software must be more flexible and will require customisation. Only a fully holistic solution, that takes all process steps and their relations into consideration, will lead to the best result and not just optimisation of one process or asset.

Our virtual operator, Twinn Aqua Suite builds on over 140 years of deep domain knowledge and uses logic, soft sensors and artificial intelligence to optimise the WWTP 24/7. This includes setpoints for parameters like throughput, pressure, airflow, dosing or temperature. While industrial wastewater treatment is substantially different from treating municipal wastewater – as there are greater variations to contend with and less predictability – with the continuous innovations and new insights into process control, automation can still make a huge difference to a plant’s performance.

Avoiding CAPEX

Wastewater infrastructure often has a write off period of over 20 years. During this time, a lot can change in primary production, with increasing or decreasing volumes to the WWTP or a different composition of the wastewater, not to even mention spills or production stops. This means that the, often biological, systems need to be able to cope with these circumstances, leading to under performance of the plant, safe setpoints for chemical dosing and aeration, and overall bottlenecks when treating wastewater.

With Twinn Aqua Suite it is like this is an extra pair of eyes, ears and hands, continuously taking in new information from the measurements and making immediate setpoint changes to the WWTP to reach the best outcome. This way of optimised (advanced) process control realises the best and safest performance of the WWTP for any given moment in time, potentially mitigating buying new hardware and the need for expensive CAPEX projects. Having a virtual operator can make the difference between maximising performance and going too far, killing or washing out valuable sludge in the process – particularly where reactors are operating near their design limitations.

Wastewater treatment is never a profit model, but when you have to shut down your factory because your effluent does not meet the standards, then you incur significant costs. 

How it works

Twinn Aqua Suite brings together all the process knowledge into one place. The algorithms describe fundamental relationships between the degree of pollution of the incoming water, the process parameters and the quality of the effluent. For example, if there has been a peak in the pollution levels, the virtual operator not only recognises, but also optimises, the inflow into the treatment plant, decreasing it to give the sludge sufficient opportunity to break down the pollution.