Patent CA-1139679-A (CA)
Inventor: LOVE LEONARD S
IPC: C02F1/52
Filed: 1980-01-15
Granted: 1983-01-18
Abstract: TITLE:  LIQUID TREATMENT APPARATUS              ABSTRACT OF THE DISCLOSURE           The disclosure describes a chemical treatment apparatus for mixing, coagulating, flocculating and clari-fying water or waste liquid (domestic sewage or indus-trial wastewater).  The apparatus is designed to optimize the efficiency of four basic unit processes (mixing, coagulation, flocculation and clarification) through a high degree of sludge recirculation and full use of tube settlers.  The apparatus includes a tank of steel, or concrete, into which the liquid to be treated is introduc-ed vertically through a centrally located inlet at the tank bottom.  Disposed inside the tank, above said in-let, are a tubular venturi-type eductor member and a conical partition member which defines a liquid mixing, coagulating, flocculating and sludge recirculating zone.          As the entering liquid flows through the eductor, it draws in a very large volume of surrounding sludge to establish a high degree of sludge recirculation and mixing.  The degree of sludge recirculated can be man-ually adjusted by means of a valve located at the liquid inlet.  A deflection baffle located above the eductor directs the liquid and recirculated sludge in a turbu-lent manner under the conical partition to promote mixing, coagulation and flocculation.  The eductor member forms a structural part of a sludge scraping assembly and slow-ly revolves as the assembly scrapes settled sludge into a centrally located sump.  This assembly is driven by a small motor and a hollow drive shaft located at the top of the apparatus.  Following a retention time of 10-15 minutes (or more) under the conical partition, the mix-ture of floc particles and liquid flows under the outer periphery of the conical partition and upward into the settling section of the apparatus tank.  The shape of the conical partition is such that the area available for settling increases as the floc particles rise, ef-fectively reducing the upward velocity of the floc par-ticles and promoting settling.  This phenomenon establi-shes a suspended blanket of sludge about the periphery of the conical partition which extends about one third of the vertical distance to the top of the tank.  Clari-fication is effectively accomplished by upward filtra-tion through this suspended blanket of floc particles (sludge).  The liquid leaving the suspended sludge blanket will contain small quantities of minute floc particles commonly called 'pinpoint floc'.  These will be  effec-tively removed in tube settlers which are located above the suspended sludge blanket and about 6-12 inches (or more) below the liquid level at the top of the tank.          Through the settling action of the tube settlers the pin-point floc will agglomerate into sludge particles with sufficient mass to settle into the suspended sludge blanket below.  The slowly revolving sludge scraping assembly removes sludge from the bottom of the suspended sludge blanket and scrapes it towards the centrally located sump.           As this sludge slowly comes under the influence of the eductor, located above the sump a portion is drawn into the eductor and recirculated with the incoming liquid.  The remainder flows into the sump where it is thickened and discharged at a controlled rate.  Due to the action of the - 1a -tube settlers, a sparklingly clear water is produced which flows into a series of collection troughs located above the tube settlers.  The treated and clarified liquid is discharged from the periphery of the treatment tank.                  - 1b -