| 摘要 |
<p>A process for enhancing the dewaterability of concentrated waste sludges which have a substantial content of a water retaining cellular structure arising from microbiological action by heat treating them at temperatures in excess of about 260 DEG F is disclosed. A preferred embodiment involves the use of treatment temperatures of less than about 390 DEG F and consequently a treatment pressure of less than about 200 psig. The heat treatment is advantageously conducted by direct contact between the concentrated waste sludge and pressurized steam. The effect of the heat treatment may be accelerated by adjusting the pH of the sludge to an extreme value, particularly an acid value of about 3 or less. It is beneficial to neutralize the concentrated waste sludge before dewatering it and it is advantageous to neutralize before completing the heat treatment.</p> |
