The Problem: A Costly Dependency
Tunisia faces a growing imbalance between fertilizer demand and domestic production, leaving the agricultural sector heavily dependent on imports. At the same time, the olive oil industry generates margine (olive mill wastewater) — a toxic by-product that poses major environmental challenges when discharged untreated.
- ● 2.5 million tons of margine are produced every year in Tunisia (source: ANGED, the National Waste Management Agency)
- ● 70% of fertilizers used in Tunisia are imported, exposing the agricultural sector to international price fluctuations
- ● 20% loss of soil fertility results from excessive use of chemical fertilizers in Tunisia (source: INRAT, National Institute of Agronomic Research of Tunisia)
The Solution: Biological Fertilizer from Olive Mill Waste
MargiGreen transforms margine — an environmentally hazardous waste stream — into a high-quality, 100% Tunisian biological fertilizer through a biomethanization process. The approach combines physico-chemical characterization of the raw margine, targeted pretreatment (pH adjustment, co-substrates such as manure or plant residues, and co-digestion with other organic waste) to optimize fermentation, and lab-scale biomethanization testing to measure methane potential and nutrient content (nitrogen, phosphorus, potassium). The resulting fertilizer is then segmented into formulations tailored to different crop types, growth stages, and soil conditions. The process is validated in partnership with the Technical Center for Organic Agriculture (CTAB) before moving through an MVP and pilot production phase — tested directly on partner farms — ahead of full-scale industrial rollout.
Impact
- ● Economic — increases agricultural revenue through better soil productivity, creates jobs in fertilizer production and distribution, and reduces chemical fertilizer imports, helping stabilize prices
- ● Environmental — promotes sustainable, low-contamination farming practices; valorizes olive-oil waste; and contributes to reduced CO₂ emissions through biomethanization
- ● Social — strengthens the food self-sufficiency of local farms and creates employment opportunities for rural communities
- ● Soil health — restores soil fertility that has been degraded by decades of intensive chemical fertilizer use This work contributes to four UN Sustainable Development Goals:
SDG 2 (Zero Hunger), SDG 6 (Clean Water and Sanitation), SDG 12 (Responsible Consumption and Production), and SDG 13 (Climate Action).