Cities slash sludge, costs and CO₂

Sludge dewatering, treatment and disposal can run up the cost of municipal wastewater treatment and consume a lot of energy. Now cities are saving money with new cost-effective solutions that reduce their sludge volumes, drying time and carbon footprint.
River view on the museum island in Berlin.

Cities around the world are focused on improving public health, sustainability, and their economies. They are often under pressure to do more with less. That can mean more scrutiny on certain municipal services including the cost, quality, and environmental impact of wastewater treatment.

Fortunately, there are a range of solutions to help public utilities better manage some of the most expensive and energy-intensive parts of the wastewater treatment process: sludge dewatering, treatment and disposal.

The purpose of sludge dewatering is essentially separating solids from water. The water is cleaned and goes on to a new life. The sludge, meanwhile, is dried, incinerated, composted or shipped elsewhere as fertilizer.

Optimizing sludge dewatering is simple in theory. The less water that is present in the sludge, the less sludge there is to dry, incinerate or ship. That lowers the cost, energy and environmental footprint of the whole wastewater treatment process. Voila! Well, not so fast…

Today some of Europe’s major capitals rely on Kemira’s sludge dewatering chemistries and technologies.

Cities rely on Superfloc®

Today some of Europe’s major capitals rely on Kemira’s sludge dewatering chemistries and technologies. But it only takes a glance at the skylines to see that no two cities are alike, and neither is their sludge. Wastewater treatment systems and sludge dewatering methods will vary based on the composition of sludge and a host of other factors. So while the concept of sludge dewatering is simple, variations can complicate the process, making it a headache.

That’s why Kemira offers hands-on support and a broad portfolio of polymers including Superfloc®, a range of high-performing sludge dewatering flocculants. The Superfloc® range includes cationic, anionic and non-ionic dry powder and emulsion flocculants. Kemira works closely with each municipality to identify the best Superfloc product and dosing to optimize their sludge dewatering application.

But our collaboration doesn’t stop there. It continues well beyond the tender process. Kemira has developed smart digital technologies for the optimization of different water treatment processes. The Kemira KemConnect™ SD helps wastewater treatment plants optimize their sludge treatment with the help of real-time data. The solution enables a 24/7 stabilized process, bringing energy savings and CO2 footprint reduction.

Continuously improving chemistry

With more than 100 years of experience in water treatment, we continuously improve our chemistry to help our customers meet new challenges. Our decades of experience with municipal and industrial sludge dewatering have shaped our current Superfloc® range and our approach to R&D.

Today, we focus on helping customers reduce the overall volume of the dewatered sludge and improve the quality of the centrate (i.e. reject water). In 2018, we proudly presented our new high-quality dry polymer product line: The Superfloc XD-5000 series. This very high molecule weight product line increases cake dry solids at lower flocculant dosages.

Ronald van Rossum, Application Development Manager at Kemira, explains, “Superfloc® XD-5000 can often increase dry solids in cakes by a couple of percentage points. This significantly reduces sludge disposal costs. Depending on the size of the plant, it could result in savings of hundreds of thousands of Euros each year.”

Superfloc® also helps improve centrate quality. When Gästrike Vatten’s treatment plant in Gävle, Sweden wanted to reduce suspended solids in their centrate, they asked Kemira for support. Our senior research scientist, Susanna Holappa, modified the chemical structure of Superfloc® XD to help Gästrike Vatten reach their target of less than 400 mg/l target of suspended solids.

Getting outside of the city

Cities aren’t the only Kemira customers optimizing their sludge dewatering systems. Water-intensive industries are also under pressure to reduce costs and carbon footprint. For example, Kemira helps the mining industry operate more efficiently and sustainably with dry flocculants. Superfloc nonionic flocculants are the established best-in-class product in the extraction of copper from low-grade copper leach solutions with proven compatibility in solvent-extraction circuits.

The Superfloc polymer portfolio includes a wide range of flocculants and coagulants with a variety of molecular weights, charge types and charge densities. Our treatment programs can be customized to suit the equipment and wastewater treatment challenges of both our municipal and industrial customers.

Glass of water and paper straw.

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