AquaO2 Maxi-Plant Process Description
In order to achieve optimum clarity of the treated effluent, the system works on a periodic fill and draw principle (Sequential Batch Process). During day and night hours, raw sewage enters the aeration surge tank chamber. This chamber is sized to hold the daily wastewater flow, plus a minimum 50% safety margin; the system only processes one batch every 4 hours, or 1/6 of the daily wastewater flow. This gives the system the ability to handle the occasional shock load without any detrimental effect on the effluent quality.
Every 4 hours the transfer pump (P-1) pumps for 30 minutes from the aeration chamber filling the clarifier chamber with mixed liquor until it reaches the weir and overflows back to the aeration chamber, thus skimming off floatables for further treatment. Then a 3 hour perfectly quiescent period follows. (Note that during this period there is no movement in the clarifier).
After the 3 hour settling period, the effluent pump (P-2) which is suspended half way up in the clarifier chamber, starts and transfers the clear supernatant to the drip irrigation pump chamber leaving 1/2 of the volume in the bottom for the sludge return pump (P-3). When the liquid reaches a predetermined level, a float switch stops the effluent pump (P-2) and starts the sludge return pump (P-3) transferring the remaining settled sludge to the front end of the aeration chamber for additional biological digestion. Immediately, another 4-hour cycle is initiated for six cycles per day.
It is important to point out, that the sequencing batch process of this system is not affected by flow variations. The sewage is retained in the large aeration surge chamber and only a predetermined volume is transferred to the clarifier chamber every 4 hours. There is no need to worry about peak flows or design peak flow.
During periods of low flow, a low level float switch prevents transfer pump (P-1) from starting, allowing the system to skip one or several cycles. In addition, the air compressors can be programmed to operate at intermittent time cycles, saving energy during low flow periods.
Aeration/Surge Chamber (Treatment Compartment)
This compartment has a capacity of 100% of the calculated daily flow, plus a minimum 50% safety margin. The sewage is continuously exposed to the finely diffused air bubbles. Each regenerative ring compressor is treated to provide a minimum of 2100 cubic feet of air per pound of BOD5, at the maximum water depth possible. The air blowers are highly efficient centrifugal design resulting in only a "whisper" sound level and low power consumption. All air piping and porous air diffusers are fabricated from non-corrosive materials. The length to width ratio of the aeration/surge chamber coupled with air diffusers being spaced evenly across the chamber creates a series of air curtains which make it virtually impossible for any short circuit to take place.
The capacity of the clarifier chamber must equal 2 times the designed batch size or 1/6 the daily calculated flow rate. The system uses this compartment to separate the solids from the clear supernatant and uses time to accomplish the separation.