Kinetic Evaluation of H₂S and NH₃Biofiltration for Two Media Used for Wastewater Lift Station Emissions

Abstract

In this study, biofiltration using a natural wood chip medium and a commercial biofiltration medium was evaluated for the removal of moderate concentrations of hydrogen sulfide (H 2 S) (up to 100 parts per million by volume [ppmv]) in the presence of significant concentrations of ammonia (NH 3 ). These levels were chosen as representative of wastewater lift station emissions in the Brownsville, TX, area. NH 3 -removing portions of the biofilms may compete with H 2 S-removing portions and inhibit H 2 S removal. H 2 S process removal efficiencies for the commercial and natural media ranged from 90 to 96% depending on inlet loading and media type and bed height. Kinetic analysis of the H 2 S removal process followed apparent first-order reaction behavior. The average first-order reaction rates were 0.03 sec Ϫ1 for the commercial medium and 0.09 sec Ϫ1 for the natural medium.Pressure drops across the columns ranged from 0.41 in. H 2 O/ft for the commercial medium to 1.41 in. H 2 O /ft for the natural medium. NH 3 gas levels of up to 80 ppmv did not affect the H 2 S removal process efficiency, and calculated kinetic rate constants for H 2 S removal remained almost the same. The NH 3 gas also was removed simultaneously with the H 2 S up to 98% removal efficiency by the commercial medium.

Hydrogen sulfide removal by a novel fixed-film bioscrubber system

“…5). Some researchers have found that removal efficiencies increased when the heights of packing were increased [7,20]. When the heights were reduced to one half in experiment 3, the removal efficiency declined (Fig.…”

Two-Stage Biofilter for Effective NH3 Removal from Waste Gases Containing High Concentrations of H2S

“…In fact, the relatively low pressure drop compared favorably with the 48 -120 mm H 2 O m Ϫ1 of other studies under similar operating conditions. 7,11,14,34,35 The low pressure drop results may be attributed to the small size of the sulfur particles. Thus, the system did not require extra maintenance like chemical rinsing, backwashing, nutrient limitation, or directionally switching operation to avoid clogging for a long time, 36 -40 and the two-stage biofilter packed with cell-laden GAC was very economic.…”

“…[1][2][3][4] Mixed gases containing concentrated H 2 S (Ͼ200 ppmv) and diluted NH 3 (Ͻ80 ppmv) exist in some specific emission sources like wastewater lift stations, sewage treatment plants, and night soil treatment plants. [5][6][7] These emissions, in addition to their own toxicity, constitute a source of olfactory nuisance.…”

Sulfur Toxicity and Media Capacity for H2S Removal in Biofilters Packed with a Natural or a Commercial Granular Medium

“…7,8 Buisman et al 9 proposed a degradation mechanism, with sulfate as the final product of aerobic sulfide removal by Thiobacillus sp. They also concluded that elemental sulfur was only one intermediate by-product of the total process.…”