Hein Pieper, voorzitter waterschap Rijn en IJssel

‘Afval kan waardevol zijn’

Diverse afvalstoffen van fabrieken, zijn helemaal geen afval. Er zitten vaak waardevolle stoffen in, onder andere voor de kunstmestindustrie. We moeten op weg naar een 100% circulaire economie. In dit interview dat gepubliceerd wordt in onze Engelstalige Aquatech 2017 special, gaat voorzitter Hein Pieper van Waterschap Rijn en IJssel in op de vraag hoe we afvalwater en afvalproducten kunnen hergebruiken. Hij geeft enkele sprekende voorbeelden uit de regio.



‘Don’t treat sludge like junk’

Climate change and climate adaptation incite the Water Authority Rijn en IJssel to implement more sustainable methods for cleaning wastewater. “It is all about a mind shift. We have always approached all the materials we supposedly did not need as waste, but in reality we should recover and (re-)use all raw materials from our wastewater, because they are valuable and in some cases even indispensable”, says Waterschap Rijn en IJssel’s chairperson Hein Pieper.

“As a water authority, we are firm believers in the circular economy. Nothing should be wasted, because we are convinced all waste has value, and should either be re-used or recycled. To achieve that goal, we are looking differently at our tasks. Sure, we are responsible for water treatment, but also for seeing and seizing emerging opportunities in our immediate surroundings. Therefore it is our policy to work together with local and regional partners.”

The Water Authority Rijn en IJssel is responsible for water control in a large part of the provinces Gelderland and Overijssel, and already operates a sustainable energy factory, where renewable energy is generated from waste water. This biogas is then delivered to Aviko, one of the four largest potato processing companies in the world. Three out of their other twelve wastewater treatment plants do also generate biogas, but use this renewable energy source themselves But it does not end there.

Mr Pieper: “We have begun recovering struvite, a phosphate fertiliser, from the relatively clean wastewater stream of a nearby potato factory. A good thing, because this way we don’t have to produce fertiliser, which normally is an energy-consuming process, and do not waste phosphate, an indispensable and finite compound containing phosphorus.”


The Water Authority is also working on a project called The Fruitful Circle. The addition of organic matter to soil does not only improve its fruitfulness and water holding capacities, but also increases the number of micropores and macropores, either by ‘gluing’ soil particles together or by creating favourable living conditions for soil organisms. Less water comes into the water streams, less nutrients reach the water.

“The farmers and the water board are working together to achieve the best results, and don’t forget, their land, their soil, is their capital, and therefore we should look at it from a different perspective. We are also participating in the Arnhem InnoFase project, which is powered by Gelderland province and the municipal government. Their aim is to make this industrial estate energy-neutral and circular. We are assessing how we can make good use of the residual heat generated by the companies that are situated there”, Mr Pieper says.

Alginate factory

After wastewater or effluent has been treated, so-called sewage sludge remains. It has to undergo further treatment, but unlike past practices, it should not be disposed of or made suitable for land application just like that. For example, there are methods to recover finite phosphate and other raw materials from sewage sludge, such as an alginate-like polymer. Together with other partners the water authority is planning to build the world’s first industrial Nereda Extracted Organic (NEO) alginate factory in the city of Zutphen, which will be using residual water from two FrieslandCampina dairy plants. NEO-alginate is a sustainable raw material that can be extracted from the sludge granules obtained by the Nereda wastewater treatment plant.

Mr Pieper says: “The substance we extract from the aerobic granular sludge resembles the alginate made from brown algae (seaweed). However, extracting the natural product is a relatively expensive process, and therefore only used on a limited scale. NEO-alginate is an extremely strong binding and thickening agent, of which you need only one tenth of the amount of seaweed alginate . When you add neo-alginate to paper it becomes more water resistant. You could use it to make paste used in dental moulds. There are many known, and still unknown possibilities.”

Royal HaskoningDHV, Water Authorities Rijn en IJssel en Vallei en Veluwe, Delft Technical University, and the Foundation for Applied Water Research STOWA have carried out years of intensive research into the extraction, production and use of NEO-alginate.

Our aim: 100 percent retrieval

“This incredible project shows that you should not treat sludge like junk. Its components are far too valuable. Some water boards use these raw materials to produce bioplastics, others try to recover cellulose fibres. Out of every 100 kilograms of waste, we are now able to retrieve 25 kilograms of usable materials. I am convinced this could be 100 percent in the not too far away future. This approach is new and there is still much to be discovered. But already there is a bonus, we have to pay less and less for sludge removal.”

‘There is still much to be discovered. But already there is a bonus, we have to pay less and less for sludge removal’

Mr Pieper’s advice: “Be open to your surroundings, keep on making new connections. As a government we are not allowed to make a profit, that is one reason why we hope the corporate world wants to become involved in projects like the production of NEO alginate, even though they might not know this product yet. What we can do is investing, and saving money at the same time, by paying less for sludge removal, and treating wastewater in a more energy-effective way.”

Waterschap Rijn en IJssel would also like to welcome private companies in sustainable hubs on the company grounds. “In case of a heat surplus, and one or more companies could use that for their processes, we are willing to research whether it is feasible to make that happen.”

A total concept

In the waterlogged Netherlands, climate change is considered neither a hypothetical nor a drag on the economy. Instead, it’s an opportunity. New York Times reporter Michael Kimmerman is right. The Netherlands is the first country people think of when someone talks of water management. But according to Mr Pieper, we don’t make the most of it. “Climate change and climate adaption are still seen as two different things, but should actually be treated as one unique selling point. On top of that, most climate adaptation challenges are related to water! We have to promote our skills much stronger than we have done so far, by presenting a total concept, and focusing on sustainability instead of just water treatment plants.”

‘We have to promote our skills much stronger than before, by focusing on sustainability instead of just water treatment plants’

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