According to this website: http://droit-finances.commentcamarche.net/contents/immobilier-emprunter/un-eco-pret-a-taux-zero-pour-les-travaux the Biorock would also qualify for the 0% interest Eco Loan Scheme for up to a 10,000 Euros interest free loan for replacing an old sewage system. The Klargester and many of the others would not as they use electricity?