Testing biodigester effluent is also important in order to know how effective it is as a fertilizer. Many farmers rely on manure from their animals and biodigesters take this animal manure to produce gas. Making sure the resulting biodigester effluent can also be used as a fertilizer with equal or better results to that of traditional or commonly used fertilizers is extremely important to insuring that the biodigester can become an integrated addition to the farm.
Testing is being done by the Laboratorio de Ajusco de Tecnologia Alternativa, a nonprofit laboratory providing technical assistance in testing different appropriate technologies. Right now they are working with Isla Urbana for rainwater quality testing and the International Renewable Resources Institute-Mexico for biodigester effluence water and fertilizer quality studies.