Each year Spanish oil mills generate some 40 million cubic meters of effluent that cannot be discharged into public waterways. These wastes need to be disposed of and if possible sold for profit. New solutions are required, the Alameda del Obispo Center of the Institute of Agricultural and Fisheries Research and Training of the Regional Government of Andalusia (IFAPA in Spanish), in collaboration with the the Spanish Olive Oil Interprofessional, are working together to find a solution to the problem. The team led by Rafaela Ordoñez is assessing the effect of the application of olive mill washing water on the groves. In particular, the medium and long term effects on cultivation and soil condition. The team is working with a dose of 250 cubic meters per hectare per year. The research could provide data to support proposed changes to the legislation on the management and use of such effluent.