CIRCULATING WATER SUPPLY UNIT Russian patent published in 1998 - IPC

FIELD: sewage treatment for subsequent re-use. SUBSTANCE: sewage is supplied through pipeline tangentially into sewage pre-treatment apparatus where oil and oil derivatives cone to surface and are periodically discharged via pipe to connector, while sand and dense slurry settle to form sediment. Sewage flows in tangential direction along annular gap defined by casing and cylinder. Partially clarified water arrives into interior of cylinder, flows upward and is discharged via pipeline to thin-layer settling tank. As water flows between tank trays, suspended matter is settled in thin layer of water, and water passed through tank is subjected to final purification by ascending filtering technique in coalescent-clarifying filter. Remaining, essentially soluble, oil derivatives are sorbed and coalesced on bundles of synthetic fibers which with oil are torn away and retained together with fine suspended particles by expanded polystyrene layer. Purified water is collected in reservoir or tank and pumped into water recirculating system for re-use. As sand and suspended matter get accumulated in unit, sediment collected in it is discharged by overflow into settling compartment of thin-layer settling tank. Filtering bed is washed by water heated by electric heaters and supplied from compartment placed above filter. To admit washing water flowing from top downward, it is necessary to open water admission valve on pipeline and to interrupt sewage supply via pipeline 15. Simultaneously, sediment is removed from receiving conically-shaped compartment of unit. After closing of water admission on pipeline and switching on sewage supply pump, purification process id repeated. EFFECT: higher efficiency of sewage purification. 1 dwg