Sand and manganese-enriched media have been substituted by Filtralite, thus extending filter run lengths.

The water company Keski-Uudenmaan Vesi (KUVESI) manufactures and supplies domestic water to in the inhabitants of Järvenpää, Kerava, Tuusula and Sipoo. The average daily consumption of drinking water in the area is 25-30,000 m³. There are also large industrial customers in the area, such as the Sinebrychoff soft drink factory in Kerava, for which high water quality is mandatory.

Of all the water produced by KUVESI, groundwater accounts for 70% and, on average, half of the water comes from the company's largest water intake, Jäniksenlinna. "We pump 750-850 m³ of water per hour," says head of operations Ossi Laaksonen.

The Jäniksenlinna groundwater plant began operation in 1979. The construction of the water plant, which cost a total of six million euros, was completed in 2016. The plant can produce up to 19,000 cubic meters of water per day.

Chemical-free water production

No chemicals are needed for the treatment process in KUVESI. Limestone alkalization and UV disinfection are used in the process of the Jäniksenlinna water treatment plant

The iron and manganese filters of the Jäniksenlinna water plant originally used sand. However, the sand filters had to be cleaned every two days. Washing is a time consuming and laborious process that consumes a great deal of water, as well as energy.

“We set out to explore an alternative material to sand and, in 2018, we ended up trying Filtralite,” Laaksonen says.

Saves time, water and energy

Filtralite Pure filter media, manufactured at the Leca plant in Raelingen, Norway, was installed in May 2018 in the iron-removing filters to replace a total of 37 m³ of sand.

Changing filter media is not an easy task. The sand has to be removed with a suction vehicle, after which the filter unit is cleaned, and new filter media is blown into place. When blowing new filter media into place, it is a good idea to use a clean vehicle. "A vehicle used in wastewater processes cannot be used in a clean water environment without thorough washing and disinfection," Laaksonen explains.

Laaksonen says that, at first, working with a new kind of media required learning. “Once we got everything to work, the difference from the past is obvious. A sand filter had to be washed every two days, while a Filtralite filter can last a week.”

Laaksonen says that the washing time has also been shortened, because since air washing is no longer needed at all, just washing the filter bed with water is enough.

Also for manganese removal

Jäniksenlinna water plant has now more than two years of experience in using Filtralite filter media, instead of sand filters.

In May 2020, 9 m³ of Filtralite filter material was also used to replace sand in one manganese filter.

"For manganese removal, three more filters work with sand, but they will also be changed to Filtralite media in time," says Laaksonen.

Although sand also works in the filters, the KUSVESI groundwater treatment process at Jäniksenlinna plant is not prepared to switch back to it. "We have 30 m³ of Filtralite already awaiting in the warehouse, which we will also start to use at another water plant in Rusutjärvi."

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Jäniksenlinna groundwater plant

Client: Keski-Uudenmaan Vesi Oy

Replacement of iron and manganese sand filters by Filtralite Pure in 2018 and 2020