This case study from a major wastewater plant in Kiel, Germany shows the optimisation that can be achieved with aeration control and biogas quality monitoring.
The need to increase energy efficiency while stabilising process and meeting the new environmental goals of the city of Kiel required a comprehensive modernisation of the existing aeration system.
Implementing new control valves with a very low pressure drop and an intelligent process controller, significant savings were achieved and process stability was sustainably improved.
Customer benefits
- Annual energy savings: approx. 300,000 €
- Demand-based air flow control and distribution of air injection into long, narrow tanks
- Reduction in oxygen carryover improves biological nitrogen removal
- Stable treatment performance even during sudden load fluctuations (e.g. heavy rainfall)
- Flexible, future-proof operation with expandable control functions due to a fully modular design
The challenge
The wastewater treatment plant is the largest municipal energy consumer in the climate-conscious city of Kiel.
The existing aeration control and distribution system was inflexible, and the control valves used had high pressure losses, leading to increased electricity consumption.
During fluctuating load conditions, the treatment performance was insufficiently stable. Only a complete modernization could unlock the full optimisation potential.
The solution
BINDER supplied and implemented a measuring and control system with 8 set of VACOMASS® jet control valves, air flow meter, and the flexcontrol process controller.
The four rectangular tanks were divided into two zones each to dynamically calculate the changing air demand long the flow path using an intelligent, AI-supportedalgorithm and adjust the control valves accordingly. The system was integrated into the existing SCADA infrastructure with minimal effort and in a short time.
“With flexcontrol, we were able to largely automate our biological stage—.this gives us greater process stability, less manual operation, and a noticeable efficiency boost, ” Head of Process Engineering, Bülk Treatment Plant Michael Wuttke said.
Typical system response to a heavy rainfall event
- Automatic adjustment of DO-SET concentration, valve opening, and system pressure to stabilise treatment performance.
- The old compressors with manual regulation limited the required pressure increase over time.
- The control valves opened fully, significantly reducing the ammonium breakthrough compared to the previous situation.
In summary
INDUSTRY: Municipal wastewater treatment
CAPACITY: 54.000 m³/d, 364.000 PE
TIMEFRAME :2018 – 2019
SYSTEMS / PRODUCTS: 8x VACOMASS® jet control valves, flow meters, flexcontrol;
COMBIMASS® gas analysis station
TREATMENT PROCESS: Activated sludge with upstream denitrification in a plug flow tank
TECHNICAL HIGHLIGHTS: AI-based DO-control, dynamic header pressure control via MOV/MIV, DO-SET NH4-N, diffuser maintenance
ANNUAL SAVINGS: Approx. € 300,000
CUSTOMER INVESTMENT: €450,000 (including installation and pipeline adjustments)
