Replacement of water treatment plant completely without downtime

MEC is situated just outside Holstebro in Denmark. MEC is a combined waste and biomass-fired heating and power plant, which supplies district heating and electricity to households in two Danish municipalities. Since the commissioning in 1993, a water treatment plant consisting of a reverse osmosis system with subsequent service-regenerated mixed bed plant has produced deionate for the power plant's high-pressure boiler. The boiler produces steam for the plant's steam turbine.

Unfortunately, the water treatment plant had very high operating costs during its useful life, so when engineer Jørgen Pors-Nielsen in 2018 became operations manager for turbine operation and water treatment, it was decided to take care of this.

Nourished with SILHORKO water

Jørgen Pors-Nielsen, the 32-year-old operations manager, almost grew up with a pipe wrench in his hand. As a child, he lived in a disused school with its own water supply – nothing less than a nice red NSB sand filter from Silhorko-Eurowater, which he and his father serviced.

Operations Manager at MEC, Jørgen Pors-Nielsen.

Here he also built a small mobile forge from an old Nilfisk vacuum cleaner with a playing card as a regulator (to replace the prototype with double bellows), where he forged small knives, arrowheads, and nails. It was obviously a completely natural thing for Jørgen to train as a locksmith and then an engineer.

After graduating, he worked for a period for DONG (now Ørsted Energy, formerly DONG), but after a few years was hired as operations manager at MEC. He even sits on the board of the district heating plant that supplies his own home.

New plant with RO and EDI

When Jørgen had agreed with the management on the improvement of the water treatment situation, he inquired within his network. Here he was advised to contact SILHORKO; a name that for Jørgen evoked positive memories from his childhood home. After a good conversation at the Ajour trade fair 2019, the dialogue started on a solution proposal: A double-pass reverse osmosis system (DPRO) with subsequent EDI system, an electrically regenerated mixed bed plant used for total demineralization of water.

The upgrade from single-pass to a double-pass system provides a much better operation of the EDI system resulting in significantly longer operating time between regenerations for the subsequent mixed bed plant.

Jørgen Pors-Nielsen from MEC confers with Thomas Dalsgaard and Lennart Poulsen from Silhorko during the installation of the new water treatment plant. To the left is the EDI system and to the right the DPRO.

The actual dimensioning and design of the plant was carried out in close cooperation between MEC and SILHORKO. In addition to the technological solution, there were practical things to consider. The location of the plant should match existing foundations and connections. The plant was required to communicate with the existing control. Thanks to almost 85 years of experience and some of the most skilled employees in the industry, it was no problem for SILHORKO to construct the perfect solution.

But to replace a water treatment plant producing treated water for turbine operation is not something that you just do. Shutdown of boilers resulting in downtime is a serious operation that can take a very long time – operational disruptions that a CHP plant would very much like to avoid. Therefore, it was necessary to find a temporary solution to provide the right water quality during the replacement work.

Read more: Rental of mobile water treatment units for a temporary need 

SILHORKO's product range offers many construction options for rental units to solve specific problems. In this case, MEC's water requirements fitted well with a container solution combining reverse osmosis and an external mixed bed plant.

In informal settings, both parties discuss the next phase of the project: Membrane degassing of the district heating water instead of dosing to remove oxygen. (Image: Christian Steffensen © Silhorko-Eurowater)

As Jørgen Pors-Nielsen experienced it: “The support from Silhorko was impeccable – it has just been running along – a real textbook example. I will even say that this thoroughness I have not experienced before. It has given peace of mind in relation to further developments and operation.”

With the short payback period and large cost reduction on operations, no wonder that MEC and Jørgen are enthusiastic about the new solution.