A method of treating waste matter from animals, the method comprising: a)collecting waste matter from the animals； b) inhibiting urease activity insaid collected waste matter； and c) separating said urease-activity inhibitedwaste matter into a urea-rich fraction and a urea-lean fraction； a system fortreating waste matter from animals； a urea-lean bio-gas fuel product； a urea -rich animal waste-matter product； a method of controlling the content ofnitrogen in manure from animals； a method of reducing gaseous ammonia instables for animals； a stable for animals； a biogas reactor system forproducing biogas from waste matter from animals； a method of producing ureafrom waste matter of animals； a method of producing urea formaldehyde； and amethod of producing biogas fuel from waste matter of animals.
