SEMP srl, a company specializing in the disposal of special, hazardous, and non-hazardous waste through advanced chemical-physical and biological treatment processes, has significantly optimized its wastewater treatment operations at its Milan facility. By switching from liquid oxygen (LOX) to Novair’s on-site oxygen generation technology, the plant, which treats approximately 60,000 m³ of industrial and civil wastewater annually, has realized improved operational efficiency and cost savings.
The Challenge: SEMP's wastewater treatment process initially utilized air injection and then transitioned to liquid oxygen to enhance the biological degradation of pollutants. However, the high costs associated with liquid oxygen supply and transportation, coupled with the environmental impact, led the company to seek a more sustainable and cost-effective solution. Moreover, the company faced challenges in balancing oxygen consumption and optimizing process efficiency while ensuring full compliance with environmental regulations, particularly for the Integrated Environmental Authorization (AIA).
The Solution: SEMP decided to implement on-site oxygen production using Novair’s OP-80 + EOP-80 Ecoline LPSA Oxygen Generator, which produces 80 m³/h of oxygen at 93% purity with a pressure of 3 bars. This system was designed to meet the plant's specific oxygen needs while offering several advantages:
- Reliable Oxygen Supply: Continuous and uninterrupted oxygen supply that ensures smooth operations.
- Cost Savings: Reduced operating costs through highly efficient energy consumption of only 0.9 kW/m³.
- Eco-Friendly: Lower energy consumption leads to a reduced carbon footprint, aligning with the company’s sustainability goals.
- Operational Flexibility: The Master & Slave generator setup allows seamless operation, even during peak demands.
- Quiet Performance: Noise levels as low as 75 dBA ensure a quieter work environment.
SEMP’s facility also employs microbioflotation technology, which combines high-pressure pure oxygen to enhance the efficiency of biological degradation. This technology, when paired with the on-site oxygen generation, enables the plant to treat high COD wastewater more effectively.
Water Parameters Before Treatment: The water parameters before treatment show variability depending on the influent characteristics:
- COD (Chemical Oxygen Demand): Can reach peaks of up to 100,000 mg/kg.
- pH: Remains between 6.5 and 7.5.
- TKN (Total Kjeldahl Nitrogen): The value is around 1,500 mg/kg.
Results: After one year of using Novair’s on-site oxygen generation technology, SEMP has observed the following key improvements:
- Cost Reduction: Significant savings on oxygen supply and transportation costs, as well as reduced energy consumption.
- Treatment efficiency: Current treatment enables a COD reduction of over 90%, with TKN levels decreasing by around 50%.
- Improved Wastewater Quality: The biological treatment process is more efficient, leading to better odor control, foam management, and effluent stability.
- Compliance with Regulations: Oxygenation plays a critical role in meeting environmental regulations, ensuring compliance with the Integrated Environmental Authorization (AIA) requirements.
Why Novair: SEMP chose Novair after conducting extensive research in both the European and international markets. Novair’s solution provided the necessary guarantees for supply, installation, and maintenance, offering a complete solution that met all operational needs. The Novair team’s expertise and support from the design phase through to commissioning were highly valued by SEMP.
Maintenance and Support: The oxygen generator requires minimal maintenance, with a service contract that includes four annual visits. No extraordinary interventions have been necessary, and the plant has been satisfied with the generator’s simple design and ease of control.
Conclusion: The switch to Novair’s on-site oxygen generation system has proven to be a highly effective solution for SEMP’s wastewater treatment plant in Milan. With significant cost reductions, improved treatment efficiency, and enhanced compliance with environmental regulations, the plant continues to benefit from a reliable, sustainable, and cost-effective oxygen supply.
