Deep inside rock caverns in the city center of Turku, the Kakolanmäki plant processes wastewater from 14 municipalities, serving 300,000 people. Like many wastewater treatment facilities, it handles raw mixed sludge that changes from season to season. It’s especially tricky in summer months when there’s less rainfall, which usually results in dry and rotting biological sludge. These conditions make both the sludge treatment process and secondary clarification more difficult and expensive.
The Kakolanmäki plant turned to Kemira for help. A long-term partner to the plant, Kemira has worked with them since they opened their doors in 2009. Our team was already familiar with the treatment processes at Kakolanmäki including their dewatering technology, a decanter centrifuge. But the plant needed two solutions, one for sludge treatment and one for secondary clarification. Or so they thought.
Kemira has a broad offering of chemistry for wastewater treatment, but our applications experts suspected that our Superfloc® XD polymer could be an ideal solution for both challenges. Superfloc® is a range of flocculants designed to help customers decrease their total cost of ownership through more efficient sludge handling. It significantly improves cake solids and filtrate quality compared to conventional cationic polymers and is effective at low dosage levels.
In laboratory tests, Kemira’s applications experts confirmed that Superfloc® XD-5100 was suitable for both sludge dewatering and secondary clarification. We effectively found a 2-for-1 solution that offered cost efficiencies for the customer, as well as easier storage and more reliable supply. Initial lab tests were followed by a full-scale trial from May through August 2020, which proved that Superfloc® XD could improve the plant’s treatment processes and reduce costs.
The Kakolanmäki plant will officially switch over to Superfloc® XD in 2021. The plant expects an overall cost reduction of five percent.
“Kemira has solid knowledge of the various chemicals used in the process. Their product range is high-quality and comprehensive, and delivery is flexible. Prices are competitive and customer service is excellent,” said Jouko Tuomi, process engineer at the Kakolanmäki plant. “What we value most is the security of supply, even in challenging conditions, in a flexible way and the excellent availability of products,” he added.
Now the plant will enjoy additional environmental benefits because Superfloc® XD reduces sludge volumes and drying times, thus reducing energy demand.
Improved sludge handling also means another leap forward in environmental performance at a plant that is already achieving high marks. Kakolanmäki’s purification process is very efficient. They remove up to 99% of organic matter, phosphorous and solids even though local requirements specify 95% removal. Similarly, authorities mandate removal of 70% of nitrogen from processed water but Kakolanmäki removes 79%. Now the plant will enjoy additional environmental benefits because Superfloc® XD reduces sludge volumes and drying times, thus reducing energy demand.
Kemira representative Juha Kartsalo, who works with the plant on a weekly basis, said, “The team at Kakolanmäki deserves a lot of credit. They are never happy with just okay. They always want to improve, especially on environmental performance, which is great especially considering their proximity to the Baltic Sea.”
Sustainability is one of the reasons that plant managers at municipal wastewater treatment facilities and water-intensive industrial companies across Europe turn to Superfloc® to improve the carbon footprint of their processes.
“Like Turku, many other major cities in Europe rely on Superfloc® XD technology to improve their sustainability. Just two years after its introduction to the market, about 10% of Kemira’s dry polymers customers use Superfloc XD,” explained Jean-Christophe Ades, senior marketing manager.