The effect of biogas ebullition on ammonia emissions from animal manure–processing lagoons

Abstract

Various models have been developed to determine ammonia (NH3) emissions from animal manure–processing lagoons to enable relatively simple estimations of emissions. These models allow estimation of actual emissions without intensive field measurements or “one‐size‐fits‐all” emission factors. Two mechanisms for lagoon NH3 emissions exist: (a) diffusive gas exchange from the water surface and (b) mass‐flow (bubble transport) from NH3 contained within the ebullition gas bubble (as it rises to the surface) produced from anaerobic decomposition of organic matter. The purpose of this research is to determine whether gas ebullition appreciably affects NH3 emissions and therefore should be considered in emissions models. Specifically, NH3 mass‐flow emissions were calculated and compared with calculated diffusive NH3 emissions. Mass‐flow NH3 emissions were evaluated based on a two‐film model, in connection with the acid dissociation constant of ammonium, to predict the degree of NH3 gas saturation within the bubbles. Average daily ammoniacal nitrogen concentration, pH, and measured biological gas production (ebullition) in conjunction with literature values for Henry's law constant were used to calculate emissions from NH3 saturation of ebullition gases. Ebullition enhancement of NH3 surface emissions due to increased turbulence was estimated from average lagoon ebullition rates and literature values of turbulence enhancement. Ebullition enhancement of NH3 surface emissions and ebullition mass‐flow NH3 emissions was determined to be <10% and <0.052%, respectively, of total NH3 emissions. Therefore, because ebullition effects are small, they may be neglected when developing process models to estimate NH3 emissions from water surfaces of swine manure processing lagoons.

Changes in swine ammonia emissions associated with improved production management

“…However, Weaver et al. (2022) showed that the ebullition rate corresponding to the 75% enhancement was at least 59 times larger than that which occurs naturally under farm waste management treatment conditions (Harper et al., 2000, 2004, 2014; Weaver et al., 2012). Weaver et al.…”

“…Weaver et al. (2022) further demonstrated that the corresponding maximum possible enhancement (which occurs in the summer and not in the winter) is no more than 10%, based on experiments conducted at much lower ebullition rates. The enhancement occurred at an ebullition rate 2–10 times that observed in lagoons of Georgia, North Carolina, and Utah (Harper & Sharpe, 1998; Harper et al., 2014; Weaver et al., 2012).…”

“…This effect would render a model not incorporating ebullition rates less accurate in estimating emission trends. However, Weaver et al (2022) showed that the ebullition rate corresponding to the 75% enhancement was at least 59 times larger than that which occurs naturally under farm waste management treatment conditions (Harper et al, 2000(Harper et al, , 2004(Harper et al, , 2014Weaver et al, 2012). Weaver et al (2022) further demonstrated that the corresponding maximum possible enhancement (which occurs in the summer and not in the winter) is no more than 10%, based on experiments conducted at much lower ebullition rates.…”

“…However, Weaver et al (2022) showed that the ebullition rate corresponding to the 75% enhancement was at least 59 times larger than that which occurs naturally under farm waste management treatment conditions (Harper et al, 2000(Harper et al, , 2004(Harper et al, , 2014Weaver et al, 2012). Weaver et al (2022) further demonstrated that the corresponding maximum possible enhancement (which occurs in the summer and not in the winter) is no more than 10%, based on experiments conducted at much lower ebullition rates. The enhancement occurred at an ebullition rate 2-10 times that observed in lagoons of Georgia, North Carolina, and Utah (Harper & Sharpe, 1998;Harper et al, 2014;Weaver et al, 2012).…”

Biodigestion System Made of Polyethylene and Polystyrene Insulator for Dog Farm (on the Example of the Republic of Chile)

“…The process of obtaining biogas is based on the biological degradation of animal feces through anerobic digestion [73][74][75][76]. Waste from animal husbandry can be used in various ways [77][78][79][80][81][82][83][84]. In general, the direction of application considered here, in the system of organic waste management, has great prospects.…”