Using sewage to make Europe’s economy truly circular

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Sewage sludge is a valuable source of recyclable nutrients. [SKY2015/Shutterstock]

Sewage sludge is a potentially vast source of nutrients for fertilisers. The Commission is missing a golden opportunity by excluding it from the Fertiliser Regulation, writes Arne Haarr.

Arne Haarr is chair of the EurEau Working Group on Waste Water Resources.

Sewage sludge is not mentioned as a source of recyclable nutrients in the European Commission’s draft revision of the Fertiliser Regulation.

This is a gross emission on the Commission’s behalf. The explicit exclusion of sewage sludge as an input material for fertilisers means that we are missing a potent source of useful nutrients.

The Commission needs to describe the quality criteria of the final product, without limiting the input material.

How does the executive intend to meet the target of recycling 30% of phosphorus without considering sewage sludge as an input material?

Adding sewage sludge as a component of compost and digestate will help to increase not only the phosphorus supply in Europe but also the other ‘positive elements’ such as organic carbon, nitrogen, micronutrients and structure to the soil, the lack of which is responsible for the low fertility of European soils today.

There is no valid reason why sewage sludge should be excluded. As a result of the Sewage Sludge Directive and REACH, the quality of sewage sludge has improved significantly over recent years. Long term measurements show that concentrations of hazardous metals in sewage sludge have drastically decreased.

In many cases, the quality of the sewage sludge already meets the technical parameters listed in the proposed Fertiliser Regulation’s annex. Excluding all sewage sludge is not only severely limiting the possibility of recycling an important source of nutrients and organic matter for EU traded fertilisers, it might naturally and dangerously drive sludge management towards solutions like incineration that are very expensive. In addition, there is no proof that these solutions are sustainable.

Sewage sludge management and control at source measures are available and efficient. They allow for high rates of nutrient recycling through the production of quality sewage sludge-based products. A good example is the Swedish certification system called REVAQ. It is operated by the Swedish Water & Waste Water Association, the Federation of Swedish Farmers, The Swedish Food Federation and the Swedish Food Retailers Federation, in close cooperation with the Swedish Environmental Protection Agency. This extended support across national authorities in different sectors brings confidence and trust to the final product. This is made possible through the implementation of different source-control measures, preventing heavy metals and other contaminants from entering the sewers, ensuring the safe recycling of nutrients to agricultural land.

One of the main drivers behind REVAQ is to increase the recirculation of nutrients. Special attention is given to phosphorous and nitrogen, micronutrients and organic matter which are important components of fertilisers and which contribute to soil quality improvement.

In 2015, the REVAQ-certified digestate contained almost 3,000 tonnes of phosphorous, out of which 1,300 tonnes were used in the agricultural sector.

The REVAQ certification system has shown that it is possible to implement systematic, transparent and goal-oriented cooperation between stakeholders such as farmers, the food industry and food retailers.

We believe that the Commission is missing a golden opportunity by excluding sludge as an input material for fertilisers. Including it would provide an important source of nutrients and contribute to the Circular Economy while reducing costs and dependencies on imports. We urge the EU institutions to reconsider.

The Commission has to work to assuage fears from the food chain actors and consumers of any potential cross-contamination. Water operators have the capacity to provide traceability and guarantee the safety of the sludge that could be used in agriculture, like we do today. The Commission must legislate to assure quality standards of the final fertilising products, not limiting the potential for nutrient recycling.

MEPs are currently examining this report. The first draft opinion report of the ENVI Committee (Gardini, EPP) is going in the wrong direction as it follows the proposal of the European Commission. If this proposal passes, politicians are disregarding the efforts of water operators to produce good quality sludge and will indirectly promote incineration. In the end, European citizens will bear the cost. Why would we raise barriers to the recycling of a major source of nutrients in Europe?

Including sewage sludge in the current proposed Fertiliser Regulation would be only through adding struvite or ash-based products as a new Component Material Category, which the JRC is currently evaluating. These products will mainly help to recover phosphorus. However, the current price of phosphorus per kilo of phosphate rock is €1-2, when the same kilo of recovered phosphorus is at least five times more expensive. The commission must also ensure that the market for the recovered phosphorus in Europe is viable in the short and long term. A regulation on blending – similar to what was successful for biofuels or steel – might be the winning tool to make Europe into a real circular economy.