Liquid treatment plant and process, particularly for waste water

Claim 2

A liquid purification treatment plant comprising a unit including, constructed and arranged for serially flowing a liquid containing impurities therethrough at predetermined individual velocities, a first enclosure forming a flocculation chamber, a second enclosure forming a mixing chamber adapted to mix a chemical coagulant and influent to form a liquid mixture therewith and arranged to discharge and to cause raising of the latter into said flocculation chamber through a field of suspended particles formed into the latter, recirculating means arranged to recirculate and reseed deposited sludge particles into the flocculation chamber whereby to enhance flocculation into the latter, sedimentation trays nested adjacent said flocculation chamber, a passage means for the liquid mixture extending from said flocculation chamber to the bottom of said sedimentation trays to cause the liquid mixture from the flocculation chamber to flow through curtains of falling floc under said sedimentation trays and upwardly between the latter for the deposition of sludge and the formation of a clarified liquid mixture, and a third enclosure forming a contact chamber arranged adjacent said sedimentation trays for treating said clarified liquid mixture, said contact chamber being provided with an overflow for the effluent, said second enclosure being provided with a sidewall having an upper end portion extending higher than said overflow, said sedimentation trays having upper ends which are lower then said upper end portion of said sidewall whereby said liquid mixture is allowed to flow under gravity action from said mixing chamber and over said upper ends, to said overflow, said first and second enclosures and said sedimentation trays being nested inside said contact chamber, and said first, second and third enclosures having sidewalls constructed and arranged to Produce an up-and-down tortuous flow path, said first enclosure having a sidewall having an openended downwardly tapering bottom conical portion and an open-ended upwardly tapering top conical portion, the side-wall of said second enclosure having a funnel shape defining a conical hopper portion and a depending discharge tube portion extending into said bottom conical portion and opening adjacent the bottom thereof, a fourth enclosure surrounding said first enclosure and being conically shaped to form a sludge collector around said bottom conical portion, said sedimentation trays being formed of downwardly tapering truncated conical surfaces nested in radially spaced apart relationship one within another and relative to said conical hopper portion and above said upwardly tapering top conical portion, an upright baffle plate being fixed inside said third enclosure and arranged to form an upward flow passage for said effluent leading from said contact chamber to said overflow, and a partition extending upwardly from the upper end of said top conical portion intermediate said conical hopper portion and said sedimentation trays.

Claim 3

A treatment plant for waste water as defined in claim 3, further including a stirring impeller rotatably mounted into said conical hopper portion and arranged upon rotation to counter downward flow therethrough; said recirculating means includes a recirculating and tumbling zone into said flocculation chamber, an airlift pump having a suction inlet positioned into the bottom of said fourth enclosure and arranged to suck deposited sludge particles into a sludge container above said flocculation chamber and a supernatant discharge pipe connected to said sludge container and having an outlet extending into said circulating and tumbling zone and arranged to feed supernatant into said zone to cause recirculation of deposited sludge particles.