Abstract: The invention relates generally to a process to treat domestic animal manure, such as pigs and swine, so that the treated manure can be environmentally acceptable. More particularly, the present invention relates to a process of de-phosphatation of manure comprising the steps of i) adding by-products of electrolysis and foundry (BPEF) to liquid manure, ii) stirring the manure-containing BPEF iii) letting the manure-containing BPEF that was so stirred stand for a time sufficient for the manure to separate into a solid fraction and a liquid fraction, the solid fraction depositing in the manure pit; and iv) separating the liquid and solid fractions. The liquid fraction contains less than 50% of total phosphorus initially contained in the manure, the phosphorus being found in the solid fraction.