Turning road side grass into growing media

Turning roadside grass into growing media is a sustainable and innovative idea that aligns with circular economy principles.

Roadside Grass is mostly abundant and underutilized. It is regularly mowed and often discarded it is also a local resource reducing transportation costs. Being rich in organic matter it can improve soil structure and water retention.

In 2023 a European LIFE grant of 2.3 million Euro was rewarded to the GR4SS project. GR4SS aims to turn grass from roadsides and natural areas via anaerobic digestion into carbon-neutral biomethane and a renewable and circular raw material for growing media. The project is running  from 9/2022 to 04/2026.

This project brings together D4, HoSt Biogas, and Kekkilä-BVB. D4 and HoSt Biogas are developing, engineering,  financing and exploiting the anaerobic digestion plant, while Kekkilä-BVB is in  responsible for the development and application of the digestate fibres into renewable raw material for growing media.

As there was only a little information available about the quality and suitability of digested grass fibres for growing media an extensive 6-month pilot test with a 250-liter anaerobic digester was executed by Opure an environment technology consultancy  under supervision of Kekkilä-BVB. This way larger volumes of digestate fibres were produced for  extensive testing in Kekkilä-BVB Quality Control lab in De Lier and R&D lab in Venlo on chemical and physical characteristics and in plant pot trials. The digestate fibres showed excellent properties for application in consumer products and even prospects for the Professional growing market.

D4 and HoSt biogas plan to build their first anaerobic digestion plant in Leeuwarden which is very close to Kekkilä-BVB location in Drachten and is planned to start operation in 2026.

Adrie Veeken