Process and apparatus for the continuous anaerobic decomposition of organic compounds

Claim 1

A process for the continuous anaerobical decomposition of organic compounds in an aqueous feed solution having a neutralized pH of between about 2 and 4, said solution being subjected, in a reactor, to the action of microorganisms which selectively decompose the compounds in a flow-through process which the production of biogas, said process comprising the steps of: (1) introducing said aqueous feed solution into a fixed-bed reactor having microorganisms grown on a fixed-bed material at a first end thereof; (2) discharging aqueous flown-through solution from said fixed-bed reactor at a second end thereof; (3) recycling a portion of the discharged aqueous solution to the first end of the fixed-bed reactor; (4) admixing said recycled portion of discharged aqueous solution with said aqueous feed solution to be introduced into said fixed-bed reactor at the first end thereof; (5) measuring the pH at both the first and second ends of said fixed-bed reactor in order to monitor the pH of said reactor bed; and (6) selecting said portion of the discharged aqueous flown-through solution to be recycled and admixed with said aqueous feed solution such that the admixture introduced into the fixed-bed reactor maintains the pH of said reactor within a predetermined range of between about 6 and 7.2, such that the pH gradient between the first and second ends of said fixed-bed reactor is within a range of 0.3 pH units maintaining the aqueous solution within the fixed-bed reactor at a temperature of between about 30 and 40° C., and selectively reducing the residence time of the aqueous solution within the fixed-bed reactor until the volume of feed solution introduced into the reactor per unit time is maximized.