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Mellifiq’s ozone solution treats drinking water
Introduction.
Our current client is a public utility company owned and operated by one of Sweden’s larger cities. The company supplies the city with electricity, internet fiber infrastructure, and clean water among other things.
One of their latest projects involves building a new drinking water plant with 1500 m3 per hour to supply the city with potable water. Such a water treatment plant can take many years to design and construct.
The problem.
Since 1962, the city has been supplied with drinking water from a suburbian water treatment plant. After almost 60 years in operation, it is pushing past the expected 50 years of service. The machinery is both outdated and unable to keep up with the current treatment standards.
The actual plant draws water from a nearby canal, which poses several risks for the production of clean and safe drinking water. The canal is a high-traffic waterway for both recreational and commercial boats. Furthermore, many local industrial facilities and wastewater treatment plants discharge their effluent into it. Due to these contamination risks, the new treatment plant will use water directly from Sweden’s largest lake, Vänern, which has its own water composition and particular set of challenges. In addition, official demands are getting stricter when it comes to microbial control and removal of micropollutants, such as pharmaceutical residues and pesticides. In recent studies, traces of several micropollutants—such as pharmaceutical residues, PFOS and PFAS—have been identified in Sweden’s largest lakes.
The public utility company initiated a comprehensive pilot project in order to ensure that the treatment solution for the new plant would be both high-quality and reliable. The pilot project included all treatment steps that would be part of the complete treatment process in the new plant. In addition, through the pilot project, they could also research the process layout and the dimensions of the full-scale systems.
A smaller, complementary study was performed at an existing water treatment plant that also uses water from lake Vänern.
The solution.
Several combinations technologies are being tested in order to find the right treatment configuration for the canal water. Looking at the best available technologies, ozone was chosen as an extra microbial barrier. Mellifiq was contacted to supply ozone treatment systems for both the pilot project and the complementary study. We quickly delivered two Ozonetech RENA Vivo systems to our client, with these systems being at the client’s disposal for a total of two years.
Our RENA Vivo systems are high-class, turnkey ozone systems that can be used for various water applications. They produce ozone on-site by using the ambient air as raw material, and are fitted with robust safety mechanisms that activate in case of any malfunction.
The overall scope of the pilot project is to mimic the entire drinking water production process at a small scale and a much lower flow of water. Treating the actual water ensures that the new plant will deliver high-quality drinking water according to today’s standards when scaled up. By running the system during a 6-month period, important data on running cost and maintenance needs were attained.
The overall treatment process is configured as follows:
- Coagulation with subsequent sand filtration
- Ozonation followed by slow-filter
- Ultra-filtration
- Activated carbon filter as a polishing step
- Several chemical dosing points for pH adjustment
Evaluation.
As even the smallest model in the RENA series includes all necessary features for a fully functioning water ozonation process, the design can now be scaled to fit the full-scale installation.
The Mellifiq system delivers automated ozonation at variable outputs between 0.1-4 ppm of dissolved ozone. All products and components were assembled in containerized modules and placed right outside the current facility. This way, there was a limited intrusion on the day-to-day operations of the current plant. The construction of a new plant will be initiated during 2023, with an expected completion in 2026.