Now the year 2019 is drawing to a close and we too can only tune in to the general whisper: "That went fast now.". Of course this is a classic opportunity for a little review.

One year Merus-Blog

Our small corporate blog has been around for one year now. These are twelve texts in which we explain, describe, list, present, expose and summarize what has no place elsewhere on the website.
This is how we have presented charitable projects that are close to our hearts. Always in the hope that perhaps a reader feels inspired to make a small contribution as well. After all, we can only preserve our world together. We have also taken up topics that we encounter again and again at work. Questions about Merus, the technology and the scientific background. We hope you have found some answers here. But ultimately, we still prefer to prove on site that our product delivers what it promises.
Finally, I had the opportunity to bring up some comparisons and examples and relate them to our way of thinking. Those who missed this can read in the previous articles what Merus has to do with ice skating, an apple or photosynthesis.

Merus around the world

Here at headquarters it was an eventful year with guests from all over the world and visits all over the world. We were invited to taste chocolates from Argentina, coffee from Thailand and tea from China. Apart from that we supported many new and interesting projects around fluid treatment. This is an enriching experience for both sides, especially when dealing with customers on site. On the subject of business travel: It is possible to compensate for CO2 emissions from flights. This means that the same amount of CO2 is reabsorbed elsewhere - by plants, for example. We are also currently taking a few big steps towards CO2-neutral production. I'll tell you about this in the blog when we get there.

New paths and proven methods

Last year we added two videos to our range of information. We would like to continue to prepare and explain more technical topics in the form of videos in the future. This is important to understand Merus technology in its overall context. We explain cooling circuits, heat exchangers, key figures and, of course, the Merus Ring. So far two videos are available, everything else will be produced step by step. We are particularly pleased that Merus' holistic approach is made clear in this way: We always look at the entire system and thus combat its weaknesses in terms of deposits, corrosion or biofouling.

To conclude the old year and begin the new one, we would like to thank everyone who has contributed to Merus as a partner, customer, supporter, colleague or friend. Thank you for sharing our idea of clean water and making our work so colourful.

We are actually in the middle of a blog series. However, I would like to use the current news about fish dying in a lake in our region to discuss the biological oxygen demand (BOD). The processes in the lake and in the water are directly related to our work, however, in a different context than we usually use the BOD. The article is intended to supplement the glossary entry and also to deal with the problems and solutions for the domestic pond.

Biological oxygen demand (BOD) in Lake Max-EythWaterBubbles

Max-Eyth-See in Stuttgart is an artificial lake that was created by gravel mining at the beginning of the 20th century. In the 1930s, the area around the lake was transformed into a recreational area. It is under landscape protection. In summer the lake can be used for boating, but swimming is not allowed.

The lake does not have its own fresh water supply and is therefore an ecosystem in itself, which gets out of balance summer after summer. Ongoing warm temperatures favour in particular the growth of blue-green algae, which spread rapidly. As the lake is shallow, it warms up particularly quickly and is also highly endangered. Plants that have been able to grow in the lake are cut off from the sunlight by the blue-green algae and die. They gradually sink to the ground, where they are decomposed by bacteria. Similar to us, these bacteria need oxygen for their metabolism. They receive this oxygen from the water. The more dead biomass there is, the better for the bacteria. This increases the BOD, i.e. the need for oxygen to break down the biomass.

Innocent victims - fish deaths

At a certain point in the lake, more oxygen is consumed than can get into the water through the surface of the water. If this development is not detected and stopped in time, no oxygen remains for the fish in the lake. To a certain extent, they suffocate in the water.

This year the death of fish was particularly devastating. Within a few days, about 50,000 fish died. The lake is "tilted", as the vernacular says.

Measures against the lack of oxygen in the water

Firstly, aquatic plants can be specifically used to filter nutrients out of the lake and release oxygen again. This works in a similar way to the indoor plant that provides good air in the living room at home.

Secondly, it is important to circulate the water in the lake or pond. That means nothing else than to increase the water surface so that more oxygen gets into the water. For example, fountains or small waterfalls serve this purpose. In this area we are also present with our Merus rings. If you have already read on our homepage, you may be familiar with the following sentence: "The Merus rings increase the solubility of substances soluble in water". This also includes oxygen. If the water is treated with our technology, it is theoretically able to absorb more oxygen. Of course, this is only useful in practice if there are sufficient possibilities for oxygen to enter the water.

The third possibility is actually the most obvious, but it is difficult to implement, especially in large lakes: If fresh water is constantly supplied, the low-oxygen water is diluted. In this way an increased BSD can be compensated.


Julika Wolf (2019a): Anglerverein zum Fischsterben im Max-Eyth-See. „Größte Naturkatastrophe, die es in Stuttgart je gegeben hat“ In: Stuttgarter Nachrichten, 04.09.2019. Available online at, last checked on 11.09.2019.

Julika Wolf (2019b): Fischsterben in Stuttgart. Was passiert mit dem Max-Eyth-See? In: Stuttgarter Nachrichten, 06.09.2019. Available online at, last checked on 11.09.2019.

Stuttgart-Marketing GmbH (ed.): Naherholungsgebiet Max-Eyth-See Stuttgart. Available online at, last checked on 11.09.2019.

We are convinced that respect is the key to sustainable success. This respect applies to business partners, customers and nature.

When I read it that way, it sounds a little bit like phrasemongering to me. In fact, however, long-term relationships with business partners can only develop if you meet at eye level. More than 20 years of Merus prove this philosophy right. Sustainable success = success that sustains.

For our everyday life this also means that we do not carry out any nonsensical installations. If we believe that the interested party does not need water treatment, we will say so openly. This can be the case, for example, in areas with very soft water. We don't talk anybody into this.

Guiding principles for our business relationships

Three basic ideas are important to us:

  1. Every customer should decide for himself for our solution and our product. Only in this way can it live up to its expectations. We support with information and generous test phases. But never force us on.
  2. We treat our business partners fairly. Transparency and openness are important to us. After all, everyone benefits from long-term, positive partnerships - we, the partner and the customer. Experience results in expertise and ultimately in good advice.
  3. Respect for nature - quite hackneyed and difficult to implement. We are operating worldwide and often also personally on site. In general, we carefully consider the necessity of a trip. For a single appointment we do not fly around the globe and accept the CO2 emissions. Our products are all manufactured around our headquarters in Sindelfingen. This means that long transports between the production sites are not necessary.

We reuse (also) old packaging material for the journey to the customer so that as little waste as possible is produced. Filling material for padding or cardboard boxes are thus used more than once.
Most importantly, however, in many places we are helping to reduce the amount of chemicals that get into the water. Where Merus rings are installed in industry, less or no chemical additive is required in the water to dissolve lime or other deposits or to remove algae.

In this way we contribute at least a little to environmental protection.

In the next few articles I would like to present three projects that we at Merus support financially. They all have the idea of seeing us as part of the environment. Without unspoiled nature, survival is not possible for us as a company and as people.

Merus is associated not only with a journey through time (90s until now), but also with journeys around the globe. This year alone, my colleagues and I have flown a total of about 80,000 km. This corresponds to a journey that extends twice around the equator.

- How we try to balance our CO2 balance, I will take up in one of the next articles. -

Our journey takes us to places that could hardly be more diverse. From the hull of a ship to an oil rig, from a pineapple plantation to a wastewater treatment plant.


By the way, did you know how pineapple grows? I was surprised that it does not hang at all from the tree (keyword: "Pine-Apple"), but rather grows on a shrub rather near the ground.


Sometimes it is the small conversations that bring the most joy. When the municipal employee thanks us for making the fountains wonderfully easy to clean thanks to Merus, we have done a good job and are happy about the success with him.

Occasionally, however, there are also large projects that provide a special motivation at work.

When it comes to chemicals in cooling and waste water, for example. Then at the beginning of a project there are often long and difficult discussions. The "5 phases of scepticism-management", which I have lovingly described, must always be overcome: Skepticism/ Dislike - Disbelief - Interest - Acceptance - Surprised Enthusiasm
The fifth phase is only achieved after a test installation at the customer's site. Particularly skeptical interested parties can only win when a test is carried out. Suppose the Merus Ring doesn't work. Then they've "known it from the beginning" and look good. However, since the Merus Ring usually works well and large sums of money are saved, they were pioneers of the new technology and also benefit.

Thus, the biggest skeptics ultimately become satisfied customers and occasionally even multipliers of our technology.

What about us? We go home with the good feeling that thanks to our work a little less chemistry gets into the sea again or energy is wasted. So we like to fight many small battles and install environmentally neutral water treatment step by step. After all, the war to protect the environment is far from won.
What began 20 years ago in Germany is now being continued worldwide.

The Merus story is a story that has always been about finding new ways to contact customers. For us it is and was important to recognise trends, try out different media and talk and listen a lot.

We learned a lot and tried a lot. Of course, not every plan you think about will work.

We also had to get to know our customers bit by bit. Where direct contact via trade fairs or telephone conversations used to be important, today all information has to be prepared for the Internet.

The most important lesson?

Do not assume from the own taste to that of others! At the beginning of the 2000s it was time to say goodbye to the style of the 90s. By this we mean not only flared trousers and platform shoes, but first and foremost the corporate design of Merus. That had become a bit out of date with a lot of colour and colourful pictures.

So a new, "adult", classic design in elegant blue was developed. But the world was apparently not yet ready for it.
That means then on multiple desire of the dealers and customers: Roll backwards, the old packagings and flyers are out again and the revolution in design is shifted backwards.

So now a blog...

... Right. We would like to tell you a little about what is important to us and who is behind Merus. With the blog we create a platform for all our ideas, encounters, experiences, without spoiling the clarity of the homepage. So the whole project should be carried out apart from explanations and case studies, apart from business, even if both are interlinked.

The writing is mainly done by me, Annika. I have been working for Merus since the end of 2014 and have completed my master's degree in a cooperative study program with Merus. I'll make that an issue at an appropriate time. My colleagues and our managing director will also contribute some texts so that different stories will be told.

We are looking forward to telling you more about us and look forward to your feedback.
In this sense: Have fun reading.

Reviews Merus Ring Water Treatment

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