Record Display for the EPA National Library Catalog

RECORD NUMBER: 46 OF 188

Main Title Downflow granular filtration of activated sludge effluents /
Author Bowker, Robert P. G.
CORP Author District of Columbia Dept. of Environmental Services, Washington. EPA-DC Pilot Plant.;Municipal Environmental Research Lab., Cincinnati, Ohio. Wastewater Research Div.
Publisher Environmental Protection Agency, Office of Research and Development, Municipal Environmental Research Laboratory ; For sale by the National Technical Information Service,
Year Published 1977
Report Number EPA/600/2-77/144; EPA-68-03-0349
Stock Number PB-272 317
Subjects Sewage--Purification--Filtration ; Sewage--Purification--Activated sludge process ; Water--Purification--Filtration
Additional Subjects Filters ; Water pollution control ; Activated sludge process ; Filtration ; Performance evaluation ; Design criteria ; Flow rate ; Backwashing ; Phosphorus ; Pilot plants ; Effluents
Holdings
Library Call Number Additional Info Location Last
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Status
NTIS  PB-272 317 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation viii, 48 pages : illustrations ; 28 cm.
Abstract
The performance of downflow granular filters subjected to effluents from activated sludge processes was investigated at the EPA-DC Pilot Plant in Washington, D.C. Several media combinations were investigated, including both single anthracite and dual anthracite-sand configurations. Effluents from step aeration, plug flow, and completely mixed activated sludge systems were used as feeds. Breakthrough of the suspended solids into the effluent occurred with both the 1.65 mm and 2.0 mm effective size (E.S.) single anthracite configurations, becoming more evident at the higher flow rates. A dual media filter, consisting of 2.0 mm E.S. coal over 0.9 mm E.S. sand, exhibited the most desirable characteristics for filtration of the secondary effluents investigated. The advantages were longer run times and higher suspended solids loadings with virtually no deterioration of effluent quality. A backwash study conducted at a variety of backwash flowrates showed that a 13 percent bed fluidization was achieved with the coarse media (2.0 mm E.S. coal/0.9 mm E.S. sand) at a flow rate of 1.43 cu m/min/sq m (35 gpm/sq ft). This was sufficient to effectively cleanse the media.
Notes
Includes bibliographical references (page 44). Microfiche.