Anerobic Treatment in Novel Contact Digester

by Jan A. Oleszkiewicz, Duncan, Lagnese, and Assocs., Inc., 3185 Babcock Blvd., Pittsburgh, Pa. 15237.,
Szymon Koziarski, Section Head; Research Inst. for Environmental Development, Rosenbergow 28, 51-616 Wroclaw, Poland,

Serial Information: Journal of the Environmental Engineering Division, 1982, Vol. 108, Issue 2, Pg. 367-378

Document Type: Journal Paper


Laboratory studies are presented on a combined jet gas mixed and sludge blanket anaerobic contact digester with continuous sludge recycle. Raw piggery waste substrate is used as feed with a CODnf contents of 13-14 g/L. The aims of the study are to establish lower limits of hydraulic retention and upper limits of COD loading, in conditions of continuous sludge recycle without intentional sludge wasting, in order to formulate design criteria for the process operated either as a roughing treatment or a combined primary-secondary treatment of strong industrial wastewaters. The studies show the feasibility of obtaining methanogenic conditions at hydraulic retention (HRT) as low as 0.5 d and corresponding organic load of 28 kg COD/m³d. Satisfactory secondary treatment is attained at HRT = 3.5d and a load of 4 kg CODnf/m³d, yielding steady state CODnf removals in excess of 85% and filtered effluent CODf and BOD5f of 1,200 and 500 mg O2/L³, respectively. The biogas production at that loading is 3.15 m³/m³d (75% CH4) which corresponds to 0.17 m³/kg CODnf removed.

Subject Headings: Oxygen demand | Sludge | Hydraulic loads | Laboratory tests | Recycling | Industrial wastes | Hydraulic design | Feasibility studies

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