Two zone process for biological treatment of waste water

Patent · Tue Aug 18 04:00:00 EDT 1981

OSTI ID:5955328

Hornsey, D; Lee, R G; Savard, G

A biological waste water treatment process carried out in a single tank is disclosed. The conditions in the tank are controlled to provide a biological reaction zone containing waste water and biodegrading organisms and an overlying clarification zone from which an effluent of treated waste water flows. The recycle stream is continuously withdrawn from the biological reaction zone, supplemented with influent waste water, passed through an oxygen-dissolving device, and the supplemented stream returned to the reaction zone. The oxygen is monitored and supplied to satisfy the demands of the organisms and, at the same time, to keep the oxygen in solution. According to the invention, the supplemented recycle stream is continuously injected along the bottom of the biological reaction zone in a horizontal shallow inflow having a width substantially greater than its depth and a flow considerably greater than that of the influent. And, the recycle stream is withdrawn from near the bottom of the reaction zone, at a vicinity remote from the inflow, in an outflow having a substantially greater width than its depth. In this way there is created between the inflow and the outflow a horizontally relatively fast flowing undercurrent having an extensive uninterrupted interface with an overlying relatively quiescent body of mixed liquor flowing upwardly relatively slowly.

• Assignee: Canadian Liquid Air Ltd (Canada)
• Patent Number(s): US 4284510
• OSTI ID: 5955328
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420900* -- Engineering-- Waste Processing Plants & Equipment-- (-1989)
520100 -- Environment
Aquatic-- Basic Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
BIODEGRADATION
CHEMICAL REACTIONS
DECOMPOSITION
ELEMENTS
HYDROGEN COMPOUNDS
INDUSTRIAL PLANTS
LIQUID WASTES
MANAGEMENT
MICROORGANISMS
NONMETALS
OPERATION
OXYGEN
OXYGEN COMPOUNDS
PROCESSING
RECYCLING
SEPARATION PROCESSES
SOLIDS
WASTE MANAGEMENT
WASTE PROCESSING
WASTE PROCESSING PLANTS
WASTE WATER
WASTES
WATER