Surface Covers Affect Liquid Manure Temperature, Albedo, and Evaporation

Greenhouse gas emissions from stored liquid swine manure in a cold climate

Methane emissions from liquid manure storage are currently estimated with a methane conversion factor (MCF) based on manure temperature inputs or air temperatures as a substitute in the 2019 IPCC Tier 2 method. However, differences between peak manure temperature and peak air temperature (Tdiff ) in warm seasons are likely to occur and result in poor estimates of MCF and methane emissions. To address this concern, this study aims to investigate the relationship between the Tdiff and ratio of manure surface area to manure volume (Rs:v ) using a mechanistic model and by analyzing farm-scale measurement studies across Canada. Positive correlations between Tdiff and Rs:v were found using a modeling approach and from farm-scale results (r=0.55, p=0.06). Tdiff ranged from -2.2 to 2.6°C in farm-scale results mainly collected from eastern Canada. We suggest that manure volume and surface area, in addition to removal frequency, could be used to estimate Tdiff and be part of the criteria for improving manure temperature estimates, which could lead to improved estimates of MCF.

Manure temperature prediction for slurry storage in Sweden: Model validation including effects of shading, snow cover and mixing

A physics-informed long short-term memory (LSTM) model for estimating ammonia emissions from dairy manure during storage

The composting process results in immobilization of inorganic N. When high-Ndemanding crops are grown in compost- amended soils, additional N fertilizer is often applied. The combination of elevated nitrate levels from N fertilizer and high C inputs from the compost may result in enhanced greenhouse gas emissions. Hence, the objective of this laboratory incubation study was to characterize CO2 and N2O emissions from a Brookston clay loam soil that has received organic amendments in the presence or absence of added nitrate. The organic amendments included urban yard waste compost (YWC), liquid pig manure + wheat straw compost (PMC), and liquid pig manure (LPM). The nitrate treatments included added nitrate (100 mg KNO3-N kg soil-1) or no added nitrate. Total CO2 emissions during aerobic incubation followed the pattern: YWC > LPM > PMC > control (no organic amendments) for both nitrate treatments. Nitrate addition increased CO2 emissions from the YWC- and LPM-amended soils by 9 and 43%, respectively, but had no significant effect (P < 0.05) on CO2 emissions from the control or the PMC-amended soil. All organic amendments increased N2O emissions compared to the control. When nitrate was added to aerobically incubated LPM-amended soils, N2O emissions were increased over seven times; however, N2O emissions were decreased by 93% for PMC-amended soils and by 50% for YWC-amended soils. These decreases in N2O production occurred when nitrate was added to the YWC and PMC treatments under aerobic conditions but not under anaerobic conditions. Composted liquid pig manure was found to be more environmentally friendly than raw liquid pig manure as it stabilized the manure C and reduced CO2 and N2O emissions compared to the liquid pig manure. Key words: Compost, liquid pig manure, carbon dioxide, nitrous oxide, denitrification

Abstract. The goal of this study was to determine the effects of suspended solids (SS) adsorption properties and concentration on the mechanisms governing ammonia volatilization from liquid dairy manure. Pertinent properties that influence ammonia adsorption on SS, including particle size distribution (PSD) and volatile solids (VS) of manure from three dairy operations with different feed rations were evaluated. The main parameters governing ammonia volatilization from liquid manure, namely the dissociation constant (Kd), the fraction of un-ionized ammonia (I²), and overall mass transfer coefficient (KoL) of ammonia for the three manures were determined experimentally in a laboratory convective emission chamber. The Kd and I² values for the three manures were not significantly different (p-values >0.05); suggesting that SS ammonia adsorption did not significantly affect the Kd of ammonium in liquid dairy manure. Both I² and Kd, however, decreased linearly (R2 = 0.89 and 0.88, respectively) with increasing SS concentrations in the manure, which implies that SS impedes ammonia volatilization, and conversely that SS removal via solids-liquid separation would exacerbate ammonia loss from liquid dairy manure. Data also indicated no significant effect (p > 0.05) of the SS adsorption properties on the KoL for liquid dairy manure. The KoL, however, also decreased linearly (R2 = 0.96) with increasing SS concentration in the manure. Overall these findings reveal that increasing SS concentration hinders ammonia volatilization process from liquid dairy manure, while the observed differences in the SS ammonia adsorption properties did not significantly affect this process.

National inventories of methane (CH4 ) emission from manure management are based on guidelines from the Intergovernmental Panel on Climate Change using country-specific emission factors. These calculations must be simple and, consequently, the effects of management practices and environmental conditions are only crudely represented in the calculations. The intention of this review is to develop a detailed understanding necessary for developing accurate models for calculating CH4 emission from liquid manure, with particular focus on the microbiological conversion of organic matter to CH4 . Themes discussed are (a) the liquid manure environment; (b) methane production processes from a modeling perspective; (c) development and adaptation of methanogenic communities; (d) mass and electron conservation; (e) steps limiting CH4 production; (f) inhibition of methanogens; (g) temperature effects on CH4 production; and (h) limits of existing estimation approaches. We conclude that a model must include calculation of microbial response to variations in manure temperature, substrate availability and age, and management system, because these variables substantially affect CH4 production. Methane production can be reduced by manipulating key variables through management procedures, and the effects may be taken into account by including a microbial component in the model. When developing new calculation procedures, it is important to include reasonably accurate algorithms of microbial adaptation. This review presents concepts for these calculations and ideas for how these may be carried out. A need for better quantification of hydrolysis kinetics is identified, and the importance of short- and long-term microbial adaptation is highlighted.

Mass transfer coefficients of ammonia for liquid dairy manure

The South African electroplating industry generates large volumes of hazardous waste water that has to be treated prior to disposal. The main source of this waste water has been the rinse system. Conventional end-ofpipe waste water treatment technologies do not meet municipality standards. The use of technologies such as membranes, reverse osmosis and ion exchange are impractical, mainly due to their cost and technical requirements. This study identified source point reduction technologies, close circuiting of the electroplating process, specific to the rinse system as a key development. Specifically the application of a low flow counter current rinse system for the recovery of the rinse water in the plating bath was selected. However, the recovery of the rinse tank water was impeded by the low rates of evaporation from the plating bath, which was especially prevalent in the low temperature operating plating baths. This master’s study proposes the use of an induced draft evaporative cooling tower for facilitation of evaporation in the plating bath. For total recovery of the rinse tank water, the rate of evaporation from the plating bath has to be equivalent to the rinse tanks make up water requirements. A closed circuit plating system mathematical model was developed for the determination of the mass evaporated from the plating bath and the cooling tower for a specified time and the equilibrium temperature of the plating bath and the cooling tower. The key criteria in the development of the closed circuit plating system model was the requirement of minimum solution specific data as this information is not readily available. The closed circuit plating system model was categorised into the unsteady state and steady state temperature regions and was developed for the condition of water evaporation only. The closed circuit plating system model was programmed into Matlab and verified. The key factors affecting the performance of the closed circuit plating system were identified as the plating solution composition and operational temperature, ambient air temperature, air flow rate and cooling tower iv packing surface area. Each of these factors was individually and simultaneously varied to determine their sensitivity on the rate of water evaporation and the equilibrium temperature of the plating bath and cooling tower. The results indicated that the upper limit plating solution operational temperature, high air flow rates, low ambient air temperature and large packing surface area provided the greatest water evaporation rates and the largest temperature drop across the height of the cooling tower in the unsteady state temperature region. The final equilibrium temperature of the plating bath and the cooling tower is dependent on the ambient air temperature. The only exception is that at low ambient air temperatures the rate of water evaporation from the steady state temperature region is lower than that at higher ambient air temperatures. Thus the model will enable the electroplater to identify the optimum operating conditions for close circuiting of the electroplating process. It is recommended that the model be validated against practical data either by the construction of a laboratory scale induced draft evaporative cooling tower or by the application of the induced draft evaporative cooling tower in an electroplating facility.

Animal manure is an important source of anthropogenic GHG (greenhouse gas): methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2). The livestock contributes with 37% of global CH4 emission. The sources of GHG (CO2 and CH4) are the liquid manure or slurry storage and the compact solid manure. Measurement systems of GHG emission are important for the selection of the appropriate technology. By using the closed chamber method for soil, landfills, volcanoes etc., the present study evaluates the estimation of total emissions of methane and carbon dioxide from an experimental farm in Cluj County, Romania. The investigated area covered with sheep solid manure was about 579 m2 and ~5 cm thick, for cattle was about 12 m2 and 5 m thick and for swine was about 1.5 m5 and 0.5 m thick. The total methane emission measured for sheep manure was 0.83 t CH4/year and for cattle manure was 0.185 t CH4/year. The total carbon dioxide emission measured for sheep manure was 61.3 t CO2/year and for cattle manure was 4.7 t CO2/year. The measurement for pigs manure was high and this could be due to the freshness of the manure. The estimated emissions showed that a considerable amount of CH4 and CO2 is produced also by an experimental farm and an appropriate management of manure is important for reducing greenhouse gas. In this respect, we believe that the future solution for a green economy is to use manure in biogas plants.

Diet manipulation is a promising way for reducing phosphorus (P) content in manure and subsequently in surface water. The objective of this study is to clarify the effects of dietary fiber content on P distribution in fresh and stored liquid hog manure. Ten, 25 L liquid manure storage tanks were constructed and operated to simulate farm-based manure storage lagoons. Fifteen pigs were randomly grouped into three pens and the pigs in each pen were fed with a diet of different fiber contents (12%, 16%, and 21%). For 20 weeks, one litre of liquid manure from each pen was fed to each storage tank once a week with 3 replicate storage tanks per diet treatment. The samples of fresh and stored manure, each representing a diet treatment, were analyzed for P distribution along the fractions of dissolved organic, dissolved inorganic, particulate organic, and particulate inorganic. The results showed that fresh manure derived from the high fiber diet contained lower total P concentrations. Of the four fractions of total P, particulate organic P and particulate inorganic P composed 95.3% to 97.5% of total P in the fresh manure. After storage, the dissolved P concentration increased from around 25 ppm to 30–60 ppm. Inorganic P was the main fraction in dissolved P and composed 80% of the dissolved P in stored manure. The dissolved inorganic P, and therefore the total dissolved P were speculated to increase with manure storage time, indicating microbial activity through digestion. It was concluded that a higher fiber diet yielding manure with higher fiber content resulted in enhanced anaerobic degradation during manure storage. This, in return might promote the destruction of organic materials, resulting in the release of P and subsequent formation of inorganic dissolved P.

Previous studies on solids/liquid (S‐L) separation for odor control from swine manure indicated that the practice might not technically be feasible because of the complexity of removing the fine particles, which are usually the major source of the odor problems. This study coupled S‐L separation by sedimentation with an aeration treatment to quickly break down the fine as well as dissolved solids. Results showed that S‐L separation of manure prior to aeration, at the same level of aeration, took only 1.5 days compared to 3 days needed for the control, to bring down volatile fatty acids (VFAs) to the “threshold of unacceptable level”. In addition, it took 2.3 and 5 aeration‐days for VFAs to reach the “acceptable level” for the separated liquid manure and the control, respectively. Results also showed that within the three weeks of post‐aeration storage, the VFAs in the separated liquid manure consistently stayed 13.5 folds below the acceptable level. In the unseparated manure, the VFAs gradually increased upwards from 2.2 folds below acceptable level achieved at the end of aeration treatment, to 1.38 folds below the acceptable level at the end of the third week of storage and looked poised to definitely rise above the acceptable level in a matter of days. A strong relationship (R = 0.99) between pH and the VFAs in the manure suggested that; degradation of VFAs rendered manure more basic as shown by the increase in pH. After only three days of aeration, the oxidation reduction potential (ORP) in the separated liquid manure stabilized at a much higher level of − 15 mV, while the ORP in unseparated manure stabilized at a much lower level of − 200 mV. The S‐L separation treatment thus significantly improves the oxygen transfer efficiency, which in turn significantly reduces the aeration power needed to maintain adequate ORP if prolonged aeration is desired.

Land application of dairy (Bos taurus) manure has generated concern regarding the downward movement of nutrients and pathogens from the manure through the soil profile into subsurface drainage water and ultimately to surface waters. The objective of this study was to determine the effect of dairy manure and urea applied at equivalent rates of “available” N on (i) NO3−N, total phosphorus (TP), ortho‐P, NH3−N, and Escherichia coli losses to subsurface tile drainage; (ii) corn (Zea mays L.) production; and (iii) changes in soil test phosphorus (STP) and soil test potassium (STK). Liquid dairy manure and urea fertilizer were broadcast applied at equivalent total “available” N rates ranging from 154 to 224 kg ha−1 yr−1 each fall during 1993–1996. The soil was a poorly drained Webster clay loam (fine loamy, mixed, superactive, Typic Endoaquoll). Nitrate N, TP, and ortho‐P concentrations and NO3−N losses in the subsurface drainage water were not different between the two N sources. Total P exceeded the minimum detection limit in 40 and 52% of the drainage samples from the urea and manured plots, respectively, while only 22 and 35% of the samples had detectable levels of ortho‐P. Losses of TP and ortho‐P were very small and averaged 31 and 10 g ha−1 yr−1, respectively, from the manured plots or <0.02% of the manure‐P applied. Four‐year average corn yields were 0.7 Mg ha−1 greater for the urea treatment compared with dairy manure. Soil test P and STK in the top 20 cm were increased 1 mg kg−1 for every 12 kg P ha−1 and 10 kg K ha−1 applied as manure. We conclude that dairy manure, when applied at optimal rates and incorporated immediately, does not lead to greater losses of N and P in subsurface drainage water on this fine‐textured soil compared with urea.

<abstract> <bold><sc>Abstract.</sc></bold> The goal of this study was to determine the effect of anaerobic digestion (AD) on ammonia volatilization from liquid dairy manure, in storage or treatment lagoon, prior to land application. Physical and chemical properties of liquid dairy manure, which may affect ammonia volatilization, were determined before and after AD. The properties of interest included particle size distribution (PSD), total solids (TS), volatile solids (VS), viscosity, pH, total ammoniacal nitrogen (TAN), and ionic strength (IS). The overall mass transfer coefficient of ammonia (K_oL) and the NH₃ fraction of TAN (β) for the undigested (UD) and AD manures were then experimentally determined in a laboratory convective emission chamber (CEC) at a constant wind speed of 1.5 m s^-1 and fixed air temperature of 25°C at manure temperatures of 15°C, 25°C, and 35°C. The PSD indicated non-normal left-skewed distributions for both AD and UD manures particles, suggestive of heavier concentrations of particles toward the lower particle size range. The volume median diameters (VMD) for solids from UD and AD were not significantly different (p= 0.65), but the geometric standard deviations (GSD) were significantly different (p = 0.001), indicating slightly larger particles but more widely distributed solids in UD manure than in AD manure. Results also indicated significantly higher pH, TAN, ionic strength (IS), and viscosity in AD manure. The β for AD manure, determined under identical conditions (air temperature, liquid temperature, and airflow), was significantly higher (p < 0.001) than for UD manure. However, mass transfer of ammonia (K_oL) was significantly lower for AD manure than for UD manure (p < 0.001). Overall, these findings suggest that AD of dairy manure significantly increased initial ammonia volatilization potential from liquid dairy manure, with the largest increase (~61%) emanating from increased ammonium dissociation. The initial flux of ammonia, at 15°C, was ~16% more from AD manure than from UD manure.

Confined swine production generates large volumes of wastewater typically stored and treated in anaerobic lagoons. These lagoons may require cleanup and closure measures in the future. In practice, liquid and sludge need to be removed by pumping, usually at great expense of energy, and land applied at agronomic rates on adjacent fields without damage to ground or surface water. Alternative lagoon cleanup methods were investigated in a pilot lagoon study by pre-treating the liquid swine manure prior to entering the lagoon. The study consisted of comparing side by side the effect of solid-liquid separated effluent and a new advanced system (solid-liquid separation followed by biological N treatment) on water quality improvement and sludge mass reduction. As a control, an anaerobic lagoon regularly loaded with raw manure was included in the study. Lagoon liquid was monitored for water quality improvements on a monthly basis. After 15 months, water quality improvements with respect to the anaerobic lagoon control (such as reduction of suspended solids, chemical oxygen demand and N concentration) were moderate with separated liquid but highly significant with the biological N pre-treatment. Anaerobic sludge mass reduction with respect to the control was significant for both pre-treatments; sludge mass reduction was 34% with separated liquid alone and 45% with biological N pre-treatment. Implementation of this technology could resolve the problems of excess sludge distribution during lagoon cleanup or extend lagoon life.