Stimulating Nitrogen Biokinetics with the Addition of Hydrogen Peroxide to Secondary Effluent Biofiltration

Abstract

Tertiary wastewater treatment could provide a reliable source of water for reuse. Amongst these types of wastewater treatment, deep-bed filtration of secondary effluents can effectively remove particles and organic matter; however, NH4+ and NO2− are not easily removed. This study examined the feasibility of stimulating microbial activity using hydrogen peroxide (H2O2) as a bio-specific and clean oxygen source that leaves no residuals in the water and is advantageous upon aeration due to the solubility limitations of the oxygen. The performance of a pilot bio-filtration system at a filtration velocity of 5–6 m/h, was enhanced by the addition of H2O2 for particle, organic matter, NH4+, and NO2− removal. Hydrogen peroxide provided the oxygen demand for full nitrification. As a result, influent concentrations of 4.2 ± 2.5 mg/L N-NH4+ and 0.65 ± 0.4 mg/L N-NO2 were removed during the short hydraulic residence time (HRT). In comparison, filtration without H2O2 addition only removed up to 0.6 mg/L N-NH4+ and almost no N-NO2−. A DNA metagenome analysis of the functional genes of the media biomass reflected a significant potential for simultaneous nitrification and denitrification activity. It is hypothesized that the low biodegradability of the organic carbon and H2O2 addition stimulated oxygen utilization in favor of nitrification, followed by the enhancement of anoxic activity.

Accelerating Microbial Activity of Soil Aquifer Treatment by Hydrogen Peroxide

“…It is suggested that the higher availability of oxygen also allows for the activity of nitrifiers and the introduction of NO x species in parallel to COD oxidation. It was already demonstrated that, when H 2 O 2 was added to WWTP secondary effluents, genes related to nitrification and, simultaneously, denitrification were significant and dominant in the microbial community structure [35]. Here, we suggest that the addition of H 2 O 2 increased oxygen availability and accelerated the introduction of NO x via nitrification, which subsequently enhanced higher denitrification rates in the top 10 cm, followed by higher nitrogen removal in total.…”

“…Previous studies have shown that SND could occur in soil systems and is related to oxygen availability [49], and that the addition of H 2 O 2 results in significant expression of genes related to denitrification activity [35]. We suggest that the mechanism of accelerating oxidation via microbial activity when H 2 O 2 is added is rooted in the rapid degradation of the H 2 O 2 , which releases oxygen close to the cell membrane, thereby generating conditions of higher oxygen availability than present in standard diffusion from air.…”

“…The generated oxygen is an oxygen source that can substitute aeration [34], accelerate performance in a biofilter system [35], and act as a SAT pretreatment to reduce oxygen demand [36]. However, to the best of our knowledge, none of the studies assessed the possible acceleration of SAT performance using H 2 O 2 directly without releasing any byproducts into the environment, as with AOP treatments.…”

Water and Wastewater Treatment: Selected Topics

“…Friedman et al [7] used a tertiary wastewater treatment to remove NH 4 + , NO 2 − and organic matter from secondary effluents in a pilot bio-filtration system assisted by adding hydrogen peroxide (H 2 O 2 ). The authors examined the impact of adding H 2 O 2 as a supplemental oxygen source on the operational efficiency of a secondary effluent filtration system with biologically active media (biofiltration).…”