Dense sludge handling system - for transferring sludge from an effluent treatment chamber to a sludge thickener

摘要

A circular thickener with scraper gear for the treatment of effluent comprises a central inner vessel surrounded by a circular section outer vessel of the known type having (a) an annular distribution launder for incoming effluent connected to an annular outlet chamber by discharge shafts; (b) a floc-turbulence chamber with a purified water offtake designed as an annular outer vessel surrounding and connected upwardly to the outlet chamber; (c) a sludge-thickening chamber surrounded by the floc-turbulence chamber; and with a central inner vessel for sludge withdrawal. This system is so arranged that the sludge thickening chamber is connected to the floc-turbulence chamber via a floc-overflow rim or circular weir and in addition the turbulence chamber has a sludge-collecting channel with an associated sludge chamber as well as being connected to the sludge thickening chamber. Finally, the thickener chamber has draw-off openings and is connected to a sludge recirculating unit incorporating a pump the outlet from which opens into the annular distributor launder for the incoming effluent, generally as disclosed in the parent Application, the further improvement whereby:- (f) the sludge collecting channel is connected to the sludge thickening chamber by means of a downcomer connection, pref. constructed as an annular slit. Enables the (air) lift pump required in the original design to pump the sludge from the sludge collecting launder to the sludge thickener chamber to be dispensed with. This pump requires a considerable amt. of maintenance and observation and gave trouble where the effluent contained dense readily sedimented solids as well as colloidal impurities.