Founder of the start-up Octometha, Vin­cent Bachet and his team have devel­oped a major inno­va­tion for decar­bon­is­ing agri­cul­ture: a slur­ry­based methani­sa­tion process that recov­ers agri­cul­tur­al residues that are cur­rent­ly lit­tle or not at all exploit­ed, such as manure and straw.

This tech­nol­o­gy, unique in France, would not have been pos­si­ble with­out the sci­en­tif­ic con­tri­bu­tion of André Pauss, a lec­tur­er and research sci­en­tist at UTC, and Thier­ry Ribeiro, then a researcher at Uni­LaSalle and now a pro­fes­sor at UTC. This advance is all the more rel­e­vant giv­en that France gen­er­ates more than 85 mil­lion tonnes of manure each year, most of which is still large­ly unused.

The project arose from an obser­va­tion: “Liq­uid methani­sa­tion, wide­ly used in France, often requires bio­mass to be grown specif­i­cal­ly to feed the digesters. This is a cost­ly, ener­gy-inten­sive solu­tion that is unsuit­able for medi­um-sized farms,” explains Vin­cent Bachet. “We there­fore want­ed to devel­op an alter­na­tive that could make use of the resources already avail­able on farms.” 

It was in this con­text that a CIFRE the­sis, cosu­per­vised by Thier­ry Ribeiro and André Pauss, was launched in 2018. It focussed, in par­tic­u­lar, on study­ing the rhe­o­log­i­cal prop­er­ties of manure and con­duct­ing pilot-scale trials.

In par­al­lel with the research work, Octometha designed a demon­stra­tion digester with a capac­i­ty of 300 m³: an under­ground cor­ri­dor 40 metres long, 3 metres wide and 4 metres high. This pro­to­type val­i­dat­ed the proof of con­cept. “This mod­el is par­tic­u­lar­ly suit­able for medi­um-sized farms. The con­struc­tion and main­te­nance costs are much low­er than those of tra­di­tion­al digesters,’ he explains. It works on a sim­ple prin­ci­ple: every day, the farmer feeds the raw organ­ic waste into the digester with­out grind­ing it. After 50 days of anaer­o­bic diges­tion, the mate­r­i­al is dis­charged at the end in the form of diges­tate and then can be used as a fer­tilis­er. The bio­gas pro­duced is used to gen­er­ate elec­tric­i­ty or bio­methane, which is sold back to the grid. “This is an addi­tion­al source of income for farm­ers,” empha­sis­es Vin­cent Bachet.

The first oper­a­tional instal­la­tion of this tech­nol­o­gy is sched­uled for the end of 2025, near Amiens. It is a show­case project, with requests pour­ing in from all over France. Vin­cent Bachet also aims to imple­ment the project across Europe, to make this inno­va­tion a bench­mark in sus­tain­able agri­cul­tur­al methanisation.

MSD