Digital Optimization Wastewater Treatment Case Studies | Veolia

THE CHALLENGES

The facility discharges its effluent into the sea, making compliance with Denmark's stringent effluent standards critical (total-N <8 mg/L or total-P <1.5 mg/L).

The primary objective was to transform the facility into a state-of-the-art operation through the implementation of advanced technologies with Hubgrade. A key challenge was securing municipal approval for design capacity improvements and obtaining additional funding to operate the enhanced facility.

This case study demonstrates the critical role of continuous improvement and innovation in achieving excellence in wastewater treatment.

THE RESULTS

50% increase in hydraulic capacity over 4 years
45% reduction in total-N in effluent
25% increase in biological treatment capacity
Up to €115,000 annual savings on energy taxes
Up to €75,000 annual savings on coagulants
Plant capacity extended from 150,000 to 175,000 PE
24/7 process adaptation to varying loads and flows

Total Annual Savings:

In 2024, the plant achieved up to €275,000 in annual savings through reduced energy and chemical consumption, plus tax benefits from improved compliance.

THE CHALLENGES

The facility faced non-compliance with EU effluent standards for total nitrogen discharge (10 mg/L limit), resulting from steadily increasing loads over several years.

Energy consumption remained persistently high, impacting operational costs and sustainability targets.

The aeration system presented operational complexity, with five blowers (3 turbo blowers and 2 hybrid blowers) requiring intermittent aeration control. While capable of effective operation, these blowers demanded specialised knowledge and careful management to achieve optimal performance.

THE SOLUTION

A Digital Twin was developed using dynamic modeling to simulate various operational scenarios, enabling the team to identify the most suitable solution and accurately estimate expected benefits before implementation.

The optimisation strategy included:

A process controller for optimised aeration management, operating on a single manifold with valve modulation for precise control
Pulsed aeration technology to provide effective tank mixing without requiring the installation of mechanical mixers
A process controller to optimise mixed liquor recirculation rates
A process controller to optimise chemical dosing for phosphorus removal, reducing chemical consumption while maintaining compliance

Sobacken plant, Borås Energi

Aeration is typically the single largest energy consumer in wastewater treatment plants. But optimizing energy costs while ensuring discharge compliance can be challenging.

Sweden's Sobacken plant solved this challenge with Hubgrade. By integrating real-time operational data into a digital twin, Hubgrade continuously calculates and adjusts oxygen setpoints dynamically.

The outcome: substantial energy savings combined with improved nitrogen removal stability.

Watch Process Engineer Jessika Magnusson Rune explain how they transformed their most energy-intensive process. The video is in Swedish with English subtitles.

Industrial case studies

Learn how industrial operators are optimizing their wastewater treatment processes with Hubgrade. Across food & beverage, pulp and paper, power generation, pharmaceutical, chemical, and manufacturing sectors, these implementations show how companies are reducing operational costs, increasing treatment capacity, and ensuring consistent compliance. Discover real-world results from production facilities where wastewater treatment directly impacts operational efficiency and bottom-line performance.

THE CHALLENGES

The plant was facing significant challenges related to the growing demand for wastewater treatment, to cope with increasing volumes from industrial customers.

At the same time, it was essential to reduce the plant's energy consumption. In particular, the aerators operated continuously 24 hours a day, regardless of the actual needs of the biological process, representing one of the most significant expense items in the operating budget.

The incoming wastewater had highly variable characteristics, both in terms of flow rate and composition, making it difficult to maintain stable process conditions. This variability was further complicated by the fact that oxygen was supplied simultaneously from two different sources: mechanical aerators and liquid oxygen injection.

The plant experienced difficulty in maintaining stable nitrite (NO₂) levels at discharge, with concentrations that could not consistently remain below the regulatory limit. This problem was particularly evident during transition phases and periods of variable load.

Furthermore, the composition of the wastewater was very complicated as the customers connected to the treatment platform included steel mills and coal producers, and therefore the presence of thiocyanates and cyanides in the wastewater could not be excluded. These substances are biodegraded in water by heterotrophic bacteria under aerobic conditions, generating an additional ammonia load that could accumulate in the oxidation compartment, resulting in ammonia concentrations higher than those found in the pre-aeration phase before the biological treatment.

THE SOLUTION

A controller for intermittent aeration was installed at the plant. The system was designed to provide regulation based on direct measurement of oxygen in the oxidation tank, allowing precise and reactive process control. The choice to regulate oxygen was evaluated (after a preliminary test) as the most suitable for the specific characteristics of this plant, given that other more direct measurements of nitrogen forms were made difficult by the characteristics of the wastewater, which would have required excessively high maintenance costs with an unfavourable cost/benefit ratio.

The solution involved independent regulation of the two aerators based on their respective oxygen probes, with intermittent aeration cycles managed directly by the controller based on oxygen concentrations in the tank. This approach allows the system to alternate aeration and anoxic phases optimally, reducing energy consumption while maintaining discharge quality.

The controller was started on line 1 and subsequently, given the satisfactory performance of the controller in terms of discharge quality and energy savings, it was decided to activate the controller on line 2 as well.

The solution also included an assistance service to optimize regulation and remote monitoring of the treatment plant. This specialized technical support allowed progressive operational modifications to further refine system performance.

The implementation of the controller at the plant has demonstrated how intelligent intermittent aeration, based on direct measurement of oxygen in the tank, represents an effective solution for reconciling increased treatment capacity with significant reduction in energy consumption, in contexts where the wastewater is not suitable for more delicate measuring instruments.

"We were experiencing difficulties in maintaining full control of the treatment plant effluent, particularly regarding nitrogen compounds.

We are satisfied with this solution because it has allowed us to operate the two oxidation basins in parallel, doubling the treated flow and ensuring strict compliance with discharge limits and treatment efficiency, despite the high variability of incoming wastewater.

Furthermore, the team supports us with kindness, expertise and promptness."

Process Manager and R&D Manager, Plant Operator

THE CLIENT

Ceccano is wastewater treatment facility located in Central Italy that treats the wastewater of 260 industries - mainly pharmaceutical and agri-food - and 7 small towns in the area of Frosinone. It is managed by Aea S.P.A. unipersonale and serves 270,000 PE (people equivalent) with a treatment capacity of 50,000 m³/d.

The plant operates 28 parallel treatment lines using an activated sludge process with biological nutrient removal.

Project start: July 2024
24,000 m³ wastewater treated per day

THE RESULTS

Intermittent aeration control for optimized oxygen delivery
Energy reduction of 65%
Dosing of dephosphatation reagent for phosphorus removal
Excess sludge extraction management
Reduced Total Nitrogen (TN) in effluent by 42%
Reduced Total Phosphorus (TP) in effluent by 57%
Achieved 93% sample-by-sample compliance with the TN discharge limit of 10 mg/L

The plant is now working with Veolia on an ongoing study to further reduce organic phosphorus and achieve full punctual compliance with the stringent TP discharge limit of 1 mg/L.

About Hubgrade

Hubgrade is Veolia's digital monitoring, control, and optimisation platform for water and wastewater operations. Built on more than 30 years of wastewater process control expertise, it combines advanced digital technologies with the operational knowledge of Veolia's specialised wastewater service experts to help industrial and municipal operators reduce energy consumption, improve asset reliability, optimise biological treatment performance, and build long-term operational resilience.

With over 350 wastewater treatment plants optimised globally, Hubgrade delivers proven results: infrastructure augmented by digital innovation.

Hubgrade is more than a digital platform. It's a partnership that combines technology, process expertise, and continuous service support to unlock the full potential of existing wastewater infrastructure and operations.