About us

Mienis: A family business

Let us introduce you to a small innovative family business! The Mienis family have been drilling sources for more than 150 years and have been specialising in the design, construction and installation of reverse osmosis systems for more than 40 years. We have customers throughout Europe and the Middle East. Our customer base includes nurseries, carwashes and truckwashes, laundries, industry, hotels, campsites and authorities.

On this page, we want to tell you about ourselves through photographs and details of the highlights from our family history:

The Mienis business at an exhibition for small and medium-sized businesses in 1923


The 1970s: Brochure


Our well-known brochure from the end of the 1970s.

Article in De Telegraaf

The following article about our company appeared in De Telegraaf at the beginning of the 1980s. The transcribed version and translated can also be found below

By Eef Bos



A small business based in the village of Nieuwveen in South Holland has developed a treatment system that could be of great significance to the supply of drinking water in the Netherlands in the future.

We are talking about a unique system using unimaginably fine filters which enable even the most contaminated ground, surface and even sea water to be turned into water suitable for drinking, without having to use chemicals as part of the process.

The revolutionary possibilities offered by these filters have been discovered over the past few years, with the help of a government grant of a quarter of a million guilders, by Mr J.C. Mienis, the 38-year-old director of the eponymous water treatment company in Nieuwveen.

The company’s activities have been followed both with astonishment and delight by filter manufacturer and American chemicals giant Du Pont de Nemours.

Jan Mienis: "Our company has been carrying out soil drilling in order to provide water sources for agricultural and industrial companies for more than a century. As a result of the fast increase in salination in North and South Holland in particular, our move towards tackling the problem of water treatment was more or less a natural progression. Several hundred of our systems are already in operation at home and abroad."

The sensational results of treatment that Mienis BV has achieved were rewarded by the Ministry of Economic Affairs with a development grant of a quarter of a million guilders. That contribution has since lead to the development of:

  • a so-called sea water treatment plant which has proved extremely successful at a horticultural company in the supersalty Westland region, for example;
  • a drinking water system at a campsite in Leimuiden that seems to have met all the necessary requirements;
  • the possibility of tackling larger scale projects in agriculture and industry.

krantMr W.A. van der Vet, the adviser on these projects, said: "It is all about the life span of the filters. In our country, you certainly can’t use them without making special provisions on account of the level of contamination in our water. They would constantly keep breaking down and at a price of at least several tens of thousands of guilders each, that proved to be too costly. Our contribution comes down to the fact that we have extended the life span of those filters enormously. The treatment systems are now working perfectly. That is the major gain that has been made. As a result, that cleared the way in terms of cost for different types, as well as large-scale, applications."

The most interesting result from the research has been the production of high quality drinking water. Under the approving eye of the ever-critical Water Supply Products Testing and Research Institute of the Netherlands (the KIWA), a system that turns ground water which can hardly be called pure into high quality drinking water for just under three hundred families has been in operation since April at a large caravan park in Leimuiden.

Campsite owner, farmer Roos, is especially pleased with the equipment that has earned him the nickname of 'Director of the Netherlands’ first private water supply company'. "It looks as though I, or should I say the campers, will now be significantly better off than if it had been necessary to install a connection to the provincial water supply system," says Mr de Roos.

Mr A.J. Kraaijveld, head of the Technology department at the National Institute for Drinking Water, confirms that the drinking water in Leimuiden complies with the relevant stringent requirements. "They have really thought things through at Mienis and developed an interesting system. Usually, drinking water supply systems of this type are not only too expansive but above all also too expensive."

Jan Mienis: "This campsite project should turn out to be a major breakthrough. I am confident that over the next few years, drinking water companies will also have to make the switch and start using treatment systems of this type for purely environmental reasons."

The man from Nieuwveen envisages plenty more opportunities for using his equipment which, in the meantime, is being used not only in greenhouse cultivation but also in breweries, the dairy industry and (Fokker) aircraft construction, for example. He can now focus his attention on large users such as open ground cultivation, laundry services, photographic development companies, etc. As far as the possibilities for drinking water are concerned, for the time being I am primarily thinking about campsites, for example. There are also major opportunities in connection with sea-going vessels. We have already supplied systems for sea-going yachts where the direct utilisation of sea water as drinking water has been turned into reality.

Beginning of the 1990s: Brothers Jan and Kees Mienis at work


Drilling a new water source at a nursery in Aalsmeer.

Horticultural trade fair in Aalsmeer in the mid-1990s


Father Jan Mienis and daughter Brigitte Mienis at the horticultural trade fair in 1994.

2004: Visit to our company by the municipal council of Liemeer


The municipal council of Liemeer during a visit to the Mienis workshop.

In 2008, the business was taken over by the next generation.


Daughter Anita Mienis along with her husband Jochum, daughter Tanne and son Finch.

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