Removal of effluent organic matter with biofiltration for potable reuse: A review and meta-analysis

Control of Pre-formed Halogenated Disinfection Byproducts with Reuse Biofiltration

“…The BDOC and DBP removals achieved at less than 5 min EBCT in the site-chlorinated experiments required at least a 30 min EBCT in the source-chlorinated experiments. The faster removal corresponded with higher water temperature (Table ) and also reflects the wide range in treatability across different WWefs for biodegradable EfOM removal during biofiltration that is only partially explained by engineered treatment parameters . While the majority of the biofilter and BAC filter performance observed in this study achieved DOC removal that was typical for similar potable reuse treatment conditions, the site-chlorinated biofilter was a higher-performing outlier and the source-chlorinated biofilter was a lower-performing outlier (Figure S4).…”

“…On the other hand, for the source-chlorinated condition (with preozonation), doubling the EBCT from 15 to 30 min had a notable benefit on BDOC and DBP removal, especially at the highest ozone dose (Figure ). That outcome reflects the improved organic matter removal associated with higher ozone doses and longer EBCTs in reuse biofilters . However, short EBCTs can also be effective.…”

“…Across the three experimental conditions, the initial BDOC concentrations (1.9 to 3.3 mg/L) and BDOC removal during biofiltration (18% to 74%; Table S6) were generally representative of literature values based on EBCT (1.6−30 min), ozone dose (0−2.0 mg O 3 /mg DOC), and media (sand, anthracite, or BAC) (Figure S4). 29 In addition to BDOC removal, the nitrifying biofilters (EBCT = 15 min) converted 67 ± 14% of the initial ammonia concentration, 2.0 mg N/L (Table S6), into about equal parts nitrite and nitrate. The initial dissolved oxygen (5.7−7.5 mg/L) was sufficient to support growth of heterotrophs and autotrophs but may have been insufficient for complete nitrification in these experiments.…”

“…The biofilms that colonize biofilter media under drinking water and water reuse conditions are comprised of diverse taxa that reflect the presence of diverse substrates (i.e., both bulk DOM and specific organic and inorganic compounds) . Trace organic contaminants can be aerobically biodegraded as secondary substrates through coutilization of primary substrates that satisfy the biofilm’s long-term energy requirements. , The primary substrates in wastewater effluent and reuse treatment include the biodegradable fraction of effluent organic matter (EfOM) and ammonia (i.e., mg/L levels) and can support degradation of organic micropollutants such as pharmaceuticals, but the biodegradation potential of DBPs at similar concentrations (ng/L to μg/L) is unknown. The presence and subsequent removal of primary substrates is impacted by engineering decisions; for example, ozonation increases the amount of biodegradable organic matter (BOM) and BOM removal is impacted by the biofilter empty bed contact time (EBCT) and type of filter media (i.e., sand or anthracite vs BAC) .…”

“…The presence and subsequent removal of primary substrates is impacted by engineering decisions; for example, ozonation increases the amount of biodegradable organic matter (BOM) and BOM removal is impacted by the biofilter empty bed contact time (EBCT) and type of filter media (i.e., sand or anthracite vs BAC). 29 However, the potential impacts of primary substrate utilization on removal of pre-formed DBPs have yet to be evaluated.…”