GB210785A - System for treating activated sludge - Google Patents

Abstract

210,785. Sando, W. J. Feb. 5, 1923, [Convention date]. Plant. - Activatetl sludge is heated to a temperature at which the solid matter coagulates so that its separation by filtration is facilitated, the waste heat of the filtrate and waste heat from thepower system being used to heat the sludge. The sludge passes from a suction well 8 through a primary heater 1, a secondary heater 2 and a pipe 15 to tanks 16 in which rotate vacuum filter drums 17. The submerged and upper portions of the drums are connected respectively through condensers 4 to high and low vacuum pumps 5, 6, driven by a steam prime mover 20. The filtrate is passed by a pump 24 through the heater 1 to serve as heating agent therein. The solid matter is removed from the drums by scrapers and passed to drying apparatus for conversion into fertilizer. Gases withdrawn from the drums are cooled and condensed in the chambers 4 into which a portion of the filtrate passing from the heater 1 is sprayed. The condensate from the chambers 4 is supplied as additional heating agent to the heater 1. The exhaust from the pumps 5, 6, the engine 20 and other steam prime movers is passed to the heater 2, its pressure and the temperature in the heater being governed by the operation of a condensate pump 34 and an air pump 35. As shown in Fig. 3, the heater 2 may also receive steam from a turbine 37 which drives an electric generator 89. To automatically secure a constant temperature of the steam in the heater 2 its pressure is communicated to a spring-controlled piston 42 which operates a valve through which steam is supplied to the turbine 37. Under normal conditions the current produced by the generator 39 meets the auxiliary power demands of the system, but it is connected in shunt with a main power line 48 to or from which power may be passed. Flue gases from the boiler plant and waste gases from the drying apparatus may be utilized for heating.