||Study of activated sludge separation by dynamic straining /
Dumanowski, James. ;
||FMC Corp., Itasca, Ill. Environmental Equipment Div.;Municipal Environmental Research Lab., Cincinnati, Ohio.
|| Environmental Protection Agency, Office of Research and Development, Municipal Environmental Research Laboratory ; For sale by the National Technical Information Service,
Activated sludge process ;
Sewage treatment ;
Pilot plants ;
Sand filtration ;
Performance evaluation ;
Particle sizes ;
Biochemical oxygen demand ;
Design criteria ;
Process charting ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
||viii, 55 pages : illustrations ; 28 cm.
Pilot plant studies were conducted on domestic wastewater to determine the feasibility of replacing or augmenting conventional activated sludge gravitational clarifiers by dynamic straining. This work was a continuation of the successful program accomplished under EPA report numbered PB-242 848. In the prior program, two dynamic strainers in series were employed. In this program, less expensive techniques for polishing the primary strainer effluent were investigated. Phase I covered pilot operations with the strainer in the aeration tank of an activated sludge plant producing a nitrified effluent. Phase II involved a non-nitrified effluent. In both phases, upflow and downflow sand filtration, settling, and flocculation-settling of the strainer effluent were investigated. Phase I flows were low but correlated well with the previous studies of strainer operating variables. Strainer effluent averaged 35 mg/l suspended solids with mixed liquor suspended solids (MLSS) of 6800 mg/l. The upflow and downflow sand filters, operating on strainer effluent, produced effluents of 8 and 3 mg/l suspended solids, respectively. Phase II, which called for high flows and high BOD loadings, was plagued with an intense growth of filamentous microorganisms, foaming, and development of a 'syrupy' mixed liquor. Proper strainer throughputs could not be maintained. Flow rates were not reproducible and did not correlate with prior work.
Contract no. 68-03-0427. Issued June 1978. Includes bibliographical references. Microfiche.