Carbon footprint of dairy manure management chains in response to nutrient recovery by aerobic pre-treatment. (15th February 2023)

• Record Type: Journal Article
• Authors: Sobhi, Mostafa; Zheng, Jiabao; Li, Bowen; Gaballah, Mohamed S.; Aboagye, Dominic; Guo, Jianbin; Dong, Renjie
• Is Part Of: Journal of environmental management. Volume 328(2023)
• Publication Date: 2023-02-15
• Subjects: Carbon footprint -- Intermittent treatment -- Manure treatment -- Emissions mitigation -- Greenhouse gas -- Aerobic treatment; A Total cross section -- Ad Downcomer cross section -- Ar Riser cross section -- Bo Maximum methane emission capacity -- CH4 Methane -- CO2 Carbon dioxide -- COD Chemical oxygen demand -- E Required energy -- ECH4 Methane emission -- GIS Geography information system -- GHG Greenhouse gas -- GWP100 100-year global warming potential -- IPCC The intergovernmental panel on climate change -- L height of the untreated liquid -- MCF Methane conversion factor -- MDP Management design practice factor -- N2O Nitrous oxide -- Na Recovered nitrogen by acid -- NH3 Ammonia -- NH4 Ammonium -- NOx Nitrogen oxide -- Nv Volatilized nitrogen -- Ph headspace pressure -- P/V Specific pneumatic power -- Qm Molar flowrate -- R Constant of air -- S Scenario -- SE Specific Energy -- TN Total nitrogen -- TNi Total input nitrogen -- TNo Total output nitrogen -- TP Total phosphorus -- TS Total solids -- U Superficial gas velocity -- VFA Volatile fatty acid -- VS Volatile solids -- vvm Volume of air per volume of liquid per minute -- εp Pump efficiency -- εm Motor efficiency -- ρL liquid manure density; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.116975
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Aerobic pre-treatment of liquid dairy manure has previously been reported as an effective nutrient export and emissions mitigation approach. The first objective of this study was to experimentally determine the optimal intermittent aeration ratio for nutrient recovery from liquid dairy manure through an on-site pilot-scale reactor to partially reduce the required energy for the aerobic process. The second objective was to theoretically investigate the total carbon footprints of direct manure spreading on croplands and permanent manure storage in open anaerobic lagoons in response to nutrient removal by the optimal determined intermittent aerobic treatment ratio. Four scenarios (S) were included; S1 was the traditional scenario of manure spread on croplands without the aerobic pre-treatment, S2 was the modified scenario of manure spread on croplands that included the aerobic pre-treatment, S3 was the traditional scenario of manure storage in lagoons, and S4 was the modified scenario of manure storage in lagoons that included the aerobic pre-treatment. The results showed that comparable nutrient removal efficiencies could be obtained with a 5:1 intermittent aeration ratio. Total nitrogen (TN) and total phosphorus (TP) were recovered were 41.5 ± 1.3% and 37.0 ± 4.0%, respectively, in ammonium sulfate and phosphorus-rich sludge, while 55.3 ± 1.4% of the chemical oxygen demand (COD) was removed. The estimated total carbon footprint for S1, S2, S3, and S4 were 24.4, 37.9, 45.3, and 45.9 kg CO2-eq ton −1, respectively. However, the total carbon footprint of S2′ and S4′, which used renewable-based energy to run the reactor instead of fossil-based energy used in S2 and S4, were estimated to 29.5 and 37.5 kg CO2-eq ton −1, respectively. Clearly, applying the aerobic pre-treatment increased the total carbon footprint of all cases except S4′, in which the total carbon footprint was mitigated by −17.2%. Accordingly, the aerobic pre-treatment is only recommended in the case of S4' from a carbon footprint point of view although it is an effective nutrient recovery technology. Highlights: Some intermittent aeration ratios were experimented through a pilot-scale on-site reactor. Comparable results could be obtained with the 5:1 intermittent aerobic pre-treatment ratio. TN, TP, and COD were recovered and removed by 41.5 ± 1.3%, 37.0 ± 4.0%, and 55.3 ± 1.4%, respectively. Aerobic liquid manure pre-treatment is not always suitable for mitigating the carbon footprint. Aerobic pre-treatment is recommended with storage chains if renewable-based electricity is used.