Oldest Nereda plant still performing well ten years on

Between the green pastures and grazing cows, a church tower rises on the horizon. It is the church of Oosterwolde, a tiny village on the border of Friesland and Drenthe. A modest industrial site is located at the edge of the village. Here, you will find the Smilde Foods BV food plant, part of Royal Smilde, a Frisian family concern. Anyone visiting the plant, where salads, sauces and quiches are made, cannot fail to notice the Nereda wastewater treatment plant behind the production hall. It is the oldest Nereda plant still in use. “The relatively compact Nereda plant came into service ten years ago. That was still at the Oldenzaal site. Now, a decade later and following relocation further north, we’re still very satisfied with how the plant works,” explains Jan Koopal, Technical Project Manager at Royal Smilde.

Cost savings

There are a number of reasons why the food company is so positive about the Nereda plant. Firstly, there is the cost factor. Koopal: “Smilde Foods is and remains a commercial company, so the financial aspect is very important. The choice at the time to invest in a wastewater treatment plant like Nereda was largely based on the belief that this would save the company a lot of costs.”

This expectation has been fulfilled. Koopal makes a calculation: “Our Oosterwolde plant produces 260 cubic metres of wastewater every day. This water is contaminated with starch residue, fat, oil and acids from our production process and ends up in the Nereda, which can hold up to 300 cubic metres of water. If we were to discharge this water into the sewer without treatment, it would cost us about 300,000 euros in treatment charges every year. After treatment in the Nereda, this amount has been reduced to 60,000 euros per year. So you can easily see the level of savings.”

Easy to operate

Another benefit and cause for satisfaction is that the Nereda plant, which has been running in Oosterwolde for about eight years and in Oldenzaal for two, continues to deliver an outstanding performance. “The number of serious disruptions or calamities over the years can be counted on one hand. Of course, little things can occasionally go wrong, such as keeping the water temperature below 35 degrees in the summer, above which the Nereda finds it more difficult. But in the majority of cases, Alle Bergsma, our environmental coordinator in Oosterwolde who manages the plant, can find a solution for the minor issues.”

This is partly due to the user-friendliness of the treatment plant. “Operating the Nereda isn’t rocket science. So not only is it great that it requires little work on a daily basis – I estimate an hour a day – it’s also nice to know that the management role can be handed over if needs be. Ale Bergsma currently carries this out with another colleague and we use Royal HaskoningDHV as a backup.”


It is also possible for the person who monitors and manages the plant to do so from a different location by means of the built-in controller. This can be done via a mobile phone with a simple login. “This is especially handy in the evening and during weekends. And it’s also nice to know that we can quickly intervene should something go wrong outside regular working hours,” says Koopal. In addition, checks are carried out bi-monthly. “Then we measure the values in the wastewater before discharging it into the sewer. The costs we pay next year for the discharge are based on the average of the measurements taken this year.”

One of the most striking features of the Nereda plant, of course, is that it involves biological water treatment. The way in which micro-organisms are used to clean the contaminated wastewater means that no chemicals are needed. It also uses 20 to 40 per cent less energy. “It’s good for the environment and, moreover, it’s good for Smilde Foods’ pocket. Our company is located in a beautiful region of the Netherlands: a rural area, rich in nature, that both we and the water board would like to maintain. So every measure that contributes to reducing the environmental impact is welcome. And on the question of whether the area is affected by bad odours, it’s not so bad at all. Perhaps in very warm weather, but in general any bad odours are negligible.”

Ten years

Looking back on the last decade, Koopal can only conclude that the plant functions just fine. “We’re a very satisfied client. And that is not only due to cost reduction, because the gains we make by treating the water before discharging it have already been taken into account. No, it also lies in the fact that the Nereda is so compact, without separate sedimentation tanks or other compartments. This makes the Nereda ideal for us, because our space is limited. Another important point is that the plant is flexible enough to accommodate the fluctuations in our production process, such as during the barbecue season in the summer when we produce much more and employ twice as many people as the normal 150.

“So, yes, I think we can say without hesitation that we would make the same decision again to invest in this biological water-treatment plant. Due to lack of space, we’re unable to extend the plant, but we’re always interested in the latest technology. This is also an important topic in our discussions with Royal HaskoningDHV: how can we perfect the treatment process and what should we do if this plant gives up the ghost? We would then need to make the right choice again, based on the most innovative possibilities Nereda can offer at the time.”

02 - 06 - 2017 Author: maha