| 摘要 |
<p>TREATMENT OF SEWAGE SLUDGE (D#79,74l-F) A process for treating sanitary sewage sludge to achieve increased solids, decreased viscosity, and a reduction of pathogens. The aqueous slurry of sewage sludge having a solids content in the range of about 3 to 35 wt.% is simultaneously conveyed and preheated, mascerated, heated in an heat exchanger, hydrothermally treated in a closed vessel under a blanket of nitrogen at about 500.degree.F and a pressure of about 750 psig and above the vapor pressure of water at that temperature, dewatered and cooled in a first multi-step flash evaporation zone where the pressure is dropped in three steps from about 750 psig to about 50 psig and then in a second flash evaporation zone the pressure is dropped to about 25 psig, cooling and condensing the vapor from said first and second flash evaporation zones, and removing a dewatered pumpable slurry of sewage sludge product having a solids content in the range of about 5 to 50 wt.% and a reduced amount of pathogens. The sewage sludge product may be used as land-fill, or land applied, or burned in a partial oxidation gasifier, boiler, or incinerator. AB79741.APP</p> |
