Lifecycle Comparison of Mainstream Anaerobic Baffled Reactor and Conventional Activated Sludge Systems for Domestic Wastewater Treatment

Abstract

The objective of this study was to evaluate the lifecycle impacts of anaerobic primary treatment of domestic wastewater using anaerobic baffled reactors (ABRs) coupled with aerobic secondary treatment relative to conventional wastewater and sludge/biosolids treatment systems through the application of wastewater treatment modeling and three lifecycle-based analyses: environmental lifecycle assessment, net energy balance, and lifecycle costing. Data from two pilot-scale ABRs operated under ambient wastewater temperatures were used to model the anaerobic primary treatment process. To address uncertain parameters in the scale-up of pilot-scale anaerobic reactor data, uncertainty analysis and Monte Carlo simulation were employed. This study demonstrates that anaerobic primary treatment of domestic wastewater using ABRs can be incorporated with existing aerobic treatment strategies to reduce aeration demand, reduce sludge production, and increase energy generation. The net result of coupling anaerobic primary treatment with aerobic secondary treatment is a more favorable net energy balance, reduced environmental impacts in most examined categories, and lower lifecycle costs relative to conventional treatment configurations; however, the removal and/or capture of dissolved methane is required to reduce global warming impacts and increase on-site energy generation. With further study, anaerobic primary treatment can be a path forward for energy-positive wastewater treatment.

Retrofitting Municipal Wastewater Treatment Facilities toward a Greener and Circular Economy by Virtue of Resource Recovery: Techno-Economic Analysis and Life Cycle Assessment

“…The CapdetWorks estimate results also include material and energy consumption, biogas generation, and effluent quality predictions. This work follows recent articles that include economic analyses based on CapdetWorks estimation and thus does not consider sulfur recovery. , The water quality is characterized mainly in terms of solid content, biological oxygen demand (BOD), chemical oxygen demand (COD), nitrogen, and phosphorous, while the sulfur element is not explicitly considered in the CapdetWorks model.…”

“…The blocks in blue refer to the wastewater treatment subsystem, the blocks in cyan represent the sludge treatment subsystem, the blocks in purple indicate the nutrient removal/recovery unit, and the blocks in red stand for the utility generation subsystem. The functional unit of this LCA study is defined in terms of the volume of treated WW, specifically treatment of 1 million gallons of domestic WW …”

“…The functional unit of this LCA study is defined in terms of the volume of treated WW, specifically treatment of 1 million gallons of domestic WW. 64 In the inventory analysis phase, the rigorous life cycle inventory (LCI) is established based on the life cycle system boundary and the functional unit to quantify the mass and energy balance relationships for the relevant technology/process alternatives. The major data/assumption sources of this LCI are the Ecoinvent database version 3.6 and CapdetWorks version 4.0.…”

Coupling a rotating biological contactor with an anaerobic baffled reactor for sustainable energy recovery from domestic wastewater

“…[6][7][8][9][10][11][12][13][14][15][16] In addition to not meeting discharge requirements for BOD 5 , anaerobic effluents can contain between 40-50% of the methane produced in dissolved form. 4,[17][18][19][20][21] Dissolved methane in anaerobic effluents can reach degrees of supersaturation between 1.3 to 6.9. 20,[22][23][24][25][26][27] Supersaturation of methane can be explained by mass transfer limitations that dominate for dissolved methane in anaerobic systems.…”

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

“…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.…”