Sludge treating apparatus

Claim 1

An apparatus for treating a sludge produced by waste water treatment, comprising: mechanical condensing means (17) for forcedly condensing a produced raw sludge, an anaerobic digestion tank (23) of a deep well type buried to extend under the ground in the depth direction, fluid conduit means operatively connecting said digestion tank to said condensing means for receiving and anaerobically digesting the raw sludge condensed by said mechanical condensing means, said anaerobic digestion tank comprising a downward flow chamber extending in the depth direction for flowing a sludge being treated downwardly therethrough, an upward flow chamber disposed in association with said downward flow chamber and also extending in the depth direction, fluid communication means between said upward flow chamber and said downward flow chamber for flowing a sludge being treated therethrough in the upward direction, circulating means operatively connected to said downward flow chamber and said upward flow chamber for forcedly circulating the sludge being treated between said downward flow chamber and said upward flow chamber and for expediting the reaction in said anaerobic digestion tank, and enclosure means for maintaining said digestion tank in an anaerobic condition, whereby conversion from fatty acid into methane gas and carbon dioxide takes place during the anaerobic digestion in said tank with simultaneous conversion from said carbon dioxide into methane gas as a result of the static pressure head afforded by the deep well location of said anaerobic digestion tank, said apparatus further comprising dewatering means operatively connected to said anaerobic digestion tank for receiving and dewatering the sludge digested by said anaerobic digestion tank, methane gas collecting means operatively connected to said anaerobic digestion tank for collecting methane gas produced in said anaerobic digestion tank, and post-treatment means operatively connected to said dewatering means for further treating the digested sludge after the sludge has been dewatered by said dewatering means, said post-treatment means comprising heat generating means, means operatively connected to said methane gas collecting means for supplying said methane gas collected by said methane gas collecting means to said post-treatment means as a source of energy for said heat generating means.

Claim 2

An apparatus for treating a sludge produced by waste water treatment, comprising: mechanical condensing means (17) for forcedly condensing a produced raw sludge, an anaerobic digestion tank (23) of a deep well type buried to extend under the ground in the depth direction, fluid conduit means operatively connecting said digestion tank to said condensing means for receiving and anaerobically digesting the raw sludge condensed by said mechanical condensing means, said anaerobic digestion tank comprising a downward flow chamber extending in the depth direction for flowing a sludge being treated downwardly therethrough, an upward flow chamber disposed in association with said downward flow chamber and also extending in the depth direction, fluid communication means between said upward flow chamber and said downward flow chamber for flowing a sludge being treated therethrough in the upward direction, circulating means operatively connected to said downward flow chamber and said upward flow chamber for forcedly circulating the sludge being treated between said downward flow chamber and said upward flow chamber and for expediting the reaction in said anaerobic digestion tank, and enclosure means for maintaining said digestion tank in an anaerobic condition, whereby conversion from fatty acid into methane gas and carbon dioxide takes place during the anaerobic digestion in said tank with simultaneous conversion from said carbon dioxide into methane gas as a result of the static pressure head afforded by the deep well location of said anaerobic digestion tank, said apparatus further comprising dewatering means operatively connected to said anaerobic digestion tank for receiving and dewatering the sludge digested by said anaerobic digestion tank, methane gas collecting means operatively connected to said anaerobic digestion tank for collecting methane gas produced in said anaerobic digestion tank, and post-treatment means operatively connected to said dewatering means for further treating the digested sludge after the sludge has been dewatered by said dewatering means, said post-treatment means comprising heat generating means, means operatively connected to said methane gas collecting means for supplying said methane gas collected by said methane gas collecting means to said post-treatment means as a source of energy for said heat generating means.