Means for automatically operating sewage treatment units

Claim 1

Means for automatically operating an apparatus for the aerobic treatment of sewage, said apparatus being adapted for sewage purification where low, wide, units are required, said apparatus including: 1. a closed aeration tank so elongated that the length of its longest side exceeds its height, 2. a vertical impermeable baffle panel interposed between opposite tank walls substantially parallel to the longer side, terminating below the closed top and above the tank bottom dividing the aeration tank into a plurality of aeration chambers with communication zones in both the tank top and bottom portions, 3. an air vent in said tank top portion, 4. a closed purification tank, 5. a vent in the top portion of the purification tank, 6. effluent conduit means opening into the aeration tank above the bottom communication zone and connecting the aeration tank to the purification tank, 7. diffuser means positioned within each tank near the tank bottom to provide oxygen for aerobic biological action, and 8. chemical injection means operably connected to the purification tank to dispense a purifying chemical into said tank, said means for automatically operating the apparatus comprising: a. a normally open valve in said aeration tank vent (3), b. a normally closed valve in said effluent conduit (6), c. a normally open air inlet valve, d. a normally closed air inlet valve, e. air conduit means connecting the normally open air inlet valve to the diffuser means, and the normally closed valve to the top communication zone, f. valve means in combination with chemical injection means (8), and g. means responsive to the liquid level in the aeration tank for automatically controlling the operation of said valves through an operating cycle including a sequence of operations: closing said diffuser air inlet valve (c) to prevent flow of air to the diffuser, opening said air inlet valve (d) to admit air to the upper communication zone permitting solids to settle to the bottom of the aeration tank, opening said effluent conduit valve (b) after said settling period, closing said aeration chamber vent valve (a) forcing air into the upper portion of the tank above the liquid in the aeration tank to drive said liquid through the effluent conduit into the purification tank by virtue of the air pressure on the surface thereof without disturbing the zone of communication beneath the baffle panel, and activating said chemical injector valve means (f) to dispense a quantity of purifying chemical into said purification tank to further purify the effluent.