Statistical Exposé of a Multiple‐Compartment Anaerobic Reactor Treating Domestic Wastewater

Abstract

Mainstream anaerobic treatment of domestic wastewater is a promising energy-generating treatment strategy; however, such reactors operated in colder regions are not well characterized. Performance data from a pilot-scale, multiple-compartment anaerobic reactor taken over 786 days were subjected to comprehensive statistical analyses. Results suggest that chemical oxygen demand (COD) was a poor proxy for organics in anaerobic systems as oxygen demand from dissolved inorganic material, dissolved methane, and colloidal material influence dissolved and particulate COD measurements. Additionally, univariate and functional boxplots were useful in visualizing variability in contaminant concentrations and identifying statistical outliers. Further, significantly different dissolved organic removal and methane production was observed between operational years, suggesting that anaerobic reactor systems may not achieve steady-state performance within one year. Last, modeling multiple-compartment reactor systems will require data collected over at least two years to capture seasonal variations of the major anaerobic microbial functions occurring within each reactor compartment.

Succession of founding microbiota in an anaerobic baffled bioreactor treating low-temperature raw domestic wastewater

“…Complete description of ABR-1 is found in Hahn & Figueroa (2015) and Pfluger et al (2018). 10,11 ABR-1 provided anaerobic sludge seed to inoculate a second pilot-scale ABR (ABR-2) consisting of three equal-sized cylindrical compartments (12 : 1 height-to-diameter) with a total system hydraulic volume of 720 liters. Complete description of ABR-2 is found in Pfluger et al (2018) and Pfluger et al (2020).…”

“…Several configurations exist, to include variations of anaerobic membrane bioreactors and anaerobic sludge blanket bioreactors. 5,7–11…”

“…Several configurations exist, to include variations of anaerobic membrane bioreactors and anaerobic sludge blanket bioreactors. 5,[7][8][9][10][11] The anaerobic baffled reactor (ABR) is a multicompartment sludge blanket bioreactor first introduced by Bachmann et al (1985), 12 which is often described as a collection of upflow anaerobic sludge blanket (UASB) reactors coupled together in series. 13 The degradation of organic substrate longitudinally through successive ABR compartments, coupled with spatial separation of sludge blankets in an ABR, can create functional differentiation of the mixed anaerobic consortia in each successive bioreactor compartment.…”

“…14,15 The ABR has been used for several applications, to include the degradation of food production wastewaters, industrial wastewaters, and domestic wastewater streams; 13,16,17 however, few studies of pilot-scale ABRs treating low temperature (6 to 24 °C) raw domestic wastewater over long timescales exist. 10,11,18,19 Of studies examining ABRs treating large volumes of raw domestic wastewater at low temperatures, most analysis centers on ABR operational performance with less attention paid to the development of the anaerobic microbial communities over time and space within the ABR sludge blanket communities, especially immediately after seeding. Transferring seed sludge from functional aerobic activated sludge bioreactors to unseeded bioreactors for start-up purposes is common practice in the wastewater sector today.…”

Looking for lipases and lipolytic organisms in low-temperature anaerobic reactors treating domestic wastewater

“…Baffled or multi compartment reactors benefit the rate-limiting hydrolysis step by providing longer retention time. These reactors have shown good COD removal performance at low temperatures by using mesophilic biomass (Hahn and Figueroa, 2015;Pfluger et al, 2018a;Pfluger et al, 2018b). However, there is no evidence to show to what extent these reactors can remove lipids.…”