NEWS > Beer By-Products and Construction Debris Used for Sustainable Container Plant Production

The Cleanleach project for treating irrigation water at nurseries aims to reduce the environmental impact of the nursery industry by using by-products from the beer-brewing process and debris from the construction industry.

Beer is made by fermenting the sugars contained in grains, mainly barley. Beer production begins by soaking the grain in water to obtain a mixture of simple sugars that are then fermented. This process produces two by-products: a solid in the form of spent grain, which is often used as animal feed; and a liquid consisting of the dregs from the soaking tubs.

It is these dregs with their high soluble sugar concentration that are being used by IRTA researchers Rafaela Cáceres and Oriol Marfà in an original on-site system for treating leachates from nurseries . This system makes use of constructed wetland biotechnology to treat the run-off from irrigating nursery plants.

The effluent from beer production has proved to be an effective source of carbon to eliminate all the nitrates from the nursery leachates and convert them into nitrogen gas that is released into the air. Irrigation run-off water from nurseries has a high nitrate concentration due to fertilizer use. However, unlike urban wastewater, it contains practically no organic carbon, which is essential to ensure nitrification occurs in the wetlands through bacterial action.

Thus far, only synthetic products such as sodium acetate and methanol have been used in the process, but using a by-product from agri-food activity is preferable because it has less environmental impact. In this way, by-products from the beer industry are reduced and more sustainable production is encouraged in another industry, i.e. plant production at nurseries.

The tests performed at the Sala Graupera nursery in Sant Andreu de Llavaneres were done in cooperation with the craft breweries Cerveses del Montseny, As de Cors, Birra 08 and Art Cervesers.

Gravel from Construction Debris

The quarry gravel used in the constructed wetlands at IRTA's Cleanleach pilot plant in Cabrils has also been replaced with recycled aggregates from construction and demolition debris supplied by the company Tecnocatalana de Runes. The new material successfully enables nitrification of the leachates to take place and reduces the phosphate content.

The Cleanleach Project is jointly financed by the European Union's Eco-Innovation Programme. Its objectives include developing and disseminating an efficient, sustainable leachate-treatment system. Using recycled gravel has been found to be the most suitable option and real-scale applications will be implemented in the future.

Cleanleach is a technology developed by IRTA. Full-scale commercial implementation is handled by the companies Naturalea, Buresinnova and Salix (United Kingdom).




Cleanleach Project