Lower energy cost for wastewater treatment plants
Using an advanced process and energy simulator, Delprosa demonstrates how to cut electricity costs while maintaining effluent quality.
Maximising the benefit from the tariff
Annual electricity costs depend on tariff structures, influent loads, effluent quality, and plant configuration. Historical data alone cannot quantify the savings achievable by shifting plant operations and control to a real-time energy pricing strategy.
The simulation model reveals what can be achieved. Processes that can wait are moved to times when energy is cheaper without losing the savings to higher peak demand. Constraints such as effluent quality or equipment limits are never compromised.
The simulation
The simulation model provides a visualisation of how the plant behaves. This example shows a 55 ML/day plant with full biological treatment up to 3xADWF. The liquids stream comprises primary settling, bioreactor with anaerobic and pre and post anoxic zones, secondary clarifiers, and disinfection before effluent pump out. RAS and dewatering return streams are included as well as internal nitrates recycle in the bioreactor. Sludge goes to an anaerobic digester with a gas holder and cogen engine, as well as a boiler for maintaining digester temperature. A 200 kWp solar PV system and 2 MWh BESS is included in the analysis and control scheme.
The type of problems we can solve
Will an alternate tariff be cheaper?
The energy transition is disrupting time-of-use retail tariffs. While new tariff structures can initially look appealing, they can unexpectedly drive up long-term operational costs if the plant cannot adapt dynamically. The simulation model goes beyond comparing tariffs against a standard plant load profile. It demonstrates exactly what can be achieved using price-responsive control, uncovering hidden opportunities to maximise cost savings that historical load analysis cannot identify.
Does solar or a battery pay for itself?
Whether adding solar PV, biogas cogeneration, or battery storage to a WWTP is a good investment depends on how well they align with plant operations, timed energy costs, and grid interaction rules and economics. To find the optimal fit, the simulation model uses advanced predictive control algorithms to forecast how best to dispatch these assets against the plant’s real-time loads and tariff demand windows. The final result determines the capital cost, annual saving, and financial returns, for an informed decision.
How to reduce energy costs and meet targets?
There is often room to shift parts of energy intensive operations such as aeration, pumping, and sludge processing to cheaper periods while controlling peak power demand charges. The simulation model analyses the impact on effluent quality and operational stability as well as calculating the net reduction in energy costs. Without this in-depth analysis, the impact of these operational changes are extremely difficult to forecast.
What is the best way to debottleneck the plant?
The simulation model reveals hidden process constraints by evaluating how unit operations interact under dynamic plant loads. Because hydraulic and biological bottlenecks shift with influent fluctuations, they often go unnoticed until the visual simulator and results analysis highlights the undersized components. For a preliminary check, the built-in static sizing guide flags likely equipment constraints before running the dynamic simulation.
How the savings are found
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01
Set up the plant and tariff
Your plant is built from your own data, and your current and alternative electricity tariffs are loaded with it.
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02
Run the simulation
A full year at five-minute resolution, with local weather driving the flows and temperatures.
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03
Compare the cases
Standard against price-responsive control: cost line by line, quality against your limits, and net present value.
How we are engaged
What our fee covers
Delprosa provides a consulting service using the simulation model. We can take full responsibility for configuring the model, analysing the results, preparing the business case, managing the implementation of price-responsive control and monitoring it afterwards. Alternatively, you can self-manage any part of that under a licence, with an agreement that sets what functionality each person has, so the tool always fits the selected service.
Contract changes
A retail electricity contract is between your organisation and your retailer. Delprosa is not party to it, does not negotiate on your behalf and takes no commission from any retailer. We are paid a fee for the work, agreed before it starts, and that fee is our only income: the whole of the energy saving stays with you. With this approach, we stay independent of the offers on the table and have no vested interest in inflating any results.