Abstract A process for the aerobic treatment of sewage. Raw sewage or the liquid portion of primary settled sewage and the sludge portion of secondary settled sewage are simultaneously aerated in the presence of a plurality of bio-surfaces - a bio-surface being a body capable of attracting and offering surface area for the growth of sewage treating microorganisms and also attracting the nutrients necessary for the growth of these microorganisms and the sewage organic materials to be degraded by the treatment process. The bio-surfaces, therefore, form favorable microenvironments where the microorganisms, their life-sustaining nutrients and organic matter in the sewage are brought together in concentrated fashion which promotes the capacity and rate of sewage treatment. The bio-surfaces comprise synthetic plastic surfaces preferably having a surface charge thereon.
The process as defined in claim 1, wherein said added surfaces comprise plastic particles having surface charges thereon.
Claim 2
Dependent Claim
24 words
The process as defined in claim 1, wherein said particles have an average particle size of from about 0.05 to 1.0 mm. in diameter.
Claim 3
Dependent Claim
18 words
The process as defined in claim 2, wherein said particles comprise inorganic particles coated with a synthetic polymer.
Claim 4
Dependent Claim
23 words
The process as defined in claim 1, wherein said surfaces are particles having a specific gravity of from about 0.9 to about 1.3.
Claim 5
Dependent Claim
36 words
The process of claim 2 wherein said sludge before recycling is passed to a phosphate-stripping zone wherein it is treated to cause the microorganisms in the sludge to release phosphate and provide a phosphate-enriched supernatant liquor.
Claim 6
Dependent Claim
16 words
The process as defined in claim 1, wherein said surfaces are recirculated with said returned sludge.
Claim 7
Dependent Claim
20 words
The process as defined in claim 1, wherein said surfaces are recirculated after being separated from said clarified liquid portion.
Claim 8
Dependent Claim
28 words
The process of claim 1, further comprising the step of adding to the system a make-up quantity of surfaces to maintain the concentration of same within predetermined limits.
Claim 9
Dependent Claim
35 words
The process of claim 1 wherein a portion of said sludge is passed to waste and wherein particles of synthetic plastic added surfaces present in said waste sludge are reclaimed for reuse in said process.
Claim 10
Dependent Claim
22 words
The process as defined in claim 2 wherein said particles of synthetic plastic added surfaces are present during the entire aerating step.