Alu Circles: Pan-European innovation partnership procedure boosting the circular economy

The Innovation Partnership – an EU based instrument for innovative procurement – is applied to tackle a tough issue: developing a cost-effective and sustainable, circular solution for alum sludge, a residual from drinking water treatment. December 2020 an international Public Buyers Group and the Dutch NETICS B.V. have signed an agreement for development and deployment of an innovative process to convert alum sludge into construction materials. Allied Waters and Corvers Procurement Services have guided and supported the process.

A drive for a circular solution of alum sludges

Worldwide, aluminium hydroxide based flocculants are commonly used in drinking water plants treating surface water. The remaining sludge is typically sent to a disposal site as it has few beneficial uses. In many countries, the sum of internal and out-of-pocket costs of disposal may exceed 100 €/ton sludge (as is) and are ever-increasing. The challenge is to convert this one-off use of material into a sustainable solution, such as upcycling or recycling, at a lower cost. This is the principal goal of the Alu Circles initiative: let cost reduction and sustainability go hand in hand.

Innovation procurement: R&D and deployment of solutions

Alu Circles aims for a co-creation by technology providers, water suppliers and researchers in a multi-stage process combining R&D and deployment of solutions, i.e. Innovation Procurement. Examples of other Innovation Procurement projects in the water sector pertain to smart meters ( or dyke reinforcement ( Alu Circles has been initiated by three leading European organizations in the drinking water industry (the Public Buyers Group): AquaMinerals (NL) (also acting on behalf of the Dutch water companies), De Watergroep (BE) and Scottish Water (UK). Following a Market Dialogue during 2019/20, the Innovation Partnership procedure – a Public-Private Partnership model – has been chosen by the Public Buyers Group as the procedure to tackle the challenge; this includes both the R&D of innovative methodologies and working methods as well as the foreseen possible deployment of the developed innovative solutions in three different countries. The underlying rationale is that based upon a solid economic analysis, the Public Buyers Group can act as an international forerunner and initiator to speed up market developments.

Following a request for proposals and an extensive review process, the Public Buyers Group has recently awarded a development contract to NETICS B.V. (The Netherlands).

Construction materials based on compression technology

NETICS owns proprietary technology for producing building blocks out of soft sediments, the GEOWALL® technology. Part of a tailored recipe sediments or sludges are blended with binders and compressed at pressures up to 100 bar, which results in blocks of a certain size and shape. The final products are building blocks that can be used at the treatment plant or in nearby infrastructural projects, such as paving stones, vertical walls or even small buildings. The GEOWALL® technology has already been proven for various soft sediments and sludges; alum sludge is the next target and is now part of the Alu Circles initiative. Two major advantages are:

  1. Sustainability: a circular solution with low energy demand, as the process runs at ambient temperature
  2. Substantial cost reduction as compared to disposal

On top of the technical-economical aspects, other relevant issues are part of the project, including legislation in the countries involved, potential local markets for the final products and an outlook on the deployment phase.

NETICS B.V. ( is Dutch-based and focuses on research and business development in dewatering and strengthening soft sediments/sludges for beneficial use. For certain activities of the Alu Circles initiative NETICS has liaised with Royal HaskoningDHV (

Further information

For any question, you can contact Allied Waters: Hay Koppers ( or Jos Boere (
For any question on innovation procurement, please contact Stephan Corvers at

About us

Allied Waters focuses on implementing game-changing innovations in the urban water cycle. ‘Driving the circular economy’ is our central motto ( We focus on circularity topics and work in public-private partnerships including research centres, commercial enterprises and end-users.

Corvers Procurement Services ( is specialized in European public procurement law, innovation, economics, IPR and contracting. Corvers acts as an advisor and external expert for governmental bodies offering a complete range of services from legal academic research and analysis to legal consultancy & training. Corvers is the contractor for the EAFIP-initiative of the European Commission.

AquaMinerals is a Dutch enterprise fully dedicated to upcycling residuals from the water sector ( Annually, over 250.000 Mt of residuals are given a second life in many applications. Continuous development and innovation are key elements to establish sustainable and economically feasible valorization routes.

De Watergroep is the largest water supplier in Flanders, Belgium (, serving 3 million people and hundreds of companies. Further, as an integrated water cycle company, De Watergroep offers products and services in the industrial water and wastewater area.

Scottish Water ( takes care of both drinking water supply and wastewater services for the 5 million inhabitants of Scotland, UK. Facilities are spread over a large area, ranging from urban to very rural.

Share on
Driving the circular economy
KWR - Allied Waters

© 2024 Allied waters • All Rights Reserved