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Biological ammonium removal from wastewater requires coupling of nitrification and denitrification processes in respective aerobic and anaerobic conditions. This difference in environmental requirements pose a big challenge in the design of systems intended to effect both nitrification and denitrification processes. Alcaligenes faecalis strain No. 4, however, has both heterotrophic nitrification and aerobic denitrification abilities in aerobic conditions, eliminating the need to provide anaerobic conditions for denitrification. Batch and continuous experiments in a mixed culture of A. faecalis No. 4 and activated sludge were performed to examine ammonium removal and microbial stability of No. 4 in aerobic reactors. At an inflow ammonium load of 500 mg L-1 d-1 in continuous experiment, the ammonium removal rate (21 mg L-1 h-1), under No. 4, was approximately 2 times higher than that of the control (i.e., without No. 4), and the denitrification ratio was approximately 66%. The proportion of intracellular nitrogen converted from removed ammonium in the continuous mixed culture was reduced, compared to control batch and continuous cultures. These results demonstrated stable growth as well as the heterotrophic nitrification-aerobic denitrification abilities of No. 4 in activated sludge systems.

The physical and chemical properties as well as the oxidative potential (OP) of water soluble components of coal combustion fine particles were examined. A laboratory-scale pulverized-coal burning ...

The ideal practice for determining gas emission rates from concentrated animal feeding operations (CAFOs) is continuous measurement throughout the year to capture diurnal and seasonal variations. However, data that meet this criterion are scarce because this approach is costly and technically challenging. A practical approach with reduced sampling time and frequency without compromising integrity is thus necessary. In this study, we examined five reduced sampling protocols for determining emission rates from naturally ventilated dairy barns: (1) six sampling events, during even months, each event running continuously for 24 h (144 hourly data points); (2) six sampling events, during odd months, each event running continuously for 24 h (144 hourly data points); (3) six sampling events, during even months, each event running continuously for 7 d (1,008 hourly data points); (4) six sampling events, during odd months, each event running continuously for 7 d (1,008 hourly data points); and (5) 12 sampling events, one event every month, each event running continuously for 24 h (288 hourly data points). These five reduced sampling protocols were evaluated against baseline emission rates obtained from a protocol consisting of 12 sampling events, one event every month, each event running continuously for 7 d (2,016 hourly data points). The average baseline emission rates for carbon dioxide (CO2), ammonia (NH3), and hydrogen sulfide (H2S) ranged from 7.0 to 10.8 g d-1 AU-1, from 16.9 to 24.3 g d-1 AU-1, and from 0.40 to 0.63 g d-1 AU-1, respectively. Emission rates for CO2 and NH3 obtained from all five reduced sampling protocols had relative biases of less than 20% from the respective baseline emission rates. This implied that even the most reduced sampling protocol (six sampling events per year, each event running continuously for 24 h) would be adequate for determining CO2 and NH3 emission rates. However, for H2S, relative biases of the reduced sampling protocols ranged from 2% to 45%, with a 50% chance of emission rates falling outside ±20% of the baseline emission rates. These protocols, however, are only applicable for quantifying emission rates from barns with steady-state live animal mass. Keywords: Air quality, Emission rates, Air sampling protocol, CAFO, Emission inventories.

Concentrated animal feeding operations (CAFOs) are important sources of NH3 emissions. Manure acidification, however, has the potential to significantly mitigate NH3 emissions. This research investigated achievable NH3 emission mitigation in a dairy barn when maintaining a pH

This study is to investigate the effect of biological seawater properties on sea spray aerosols (SSA). Concentrations of chlorophyll-a and bacteria were measured at coastal site in Korea in fall and summer seasons. Also, aerosol mass spectrometer (AMS) was used to determine chemical constituents (organics, sulfate, nitrate, ammonium, and chloride) of non-refractory submicrometer aerosols sprayed from seawaters using a bubble bursting system. The average concentration of chlorophyll-a in seawater in fall was 1.75±0.78μg/l, whereas it significantly increased to 5.11±2.16μg/l in summer. It was found that the fraction of organics in the submicrometer SSA was higher in summer (68%) than fall (49%), and that the organic fraction in the SSA increased as the concentration of chlorophyll-a increased in seawater, suggesting that the high phytoplankton biomass in seawater could lead to the enhancement of organic species in the SSA.

Indirect methods are widely used for determining air exchange rates (AER) in naturally ventilated barns because they are relatively easier and cheaper than direct methods, which measure actual airflow in and out of the barns. The main goal of this study was to evaluate a common indirect method (CO2 mass balance) against a direct method, and identify factors influencing this indirect method. The mean AER based on 24-h averaging, irrespective of method, ranged from 13 to 39 h−1 during the study-periods. The CO2-balance method tended to overestimate barn AER. The cows' CO2 production rate, in the current study, was estimated at 0.178 m3 h−1 hpu−1 based on 24-h averaging. The CO2-balance method with 24-h data averaging yielded more reliable barn AER than with shorter averaging times (i.e., 1, 2, and 12 h). The 1-h averaging, however, was chosen to analyze the effects of other pertinent factors on the CO2-balance method to capture diurnal variations of AER. Both wind speed and wind direction had significant effects on barn AER as well as the difference between the CO2-balance method and direct method. Barn AER, in general, increased with wind speed. The CO2-balance method was unreliable during milking times, and when indoor–outdoor CO2 concentration and temperature differences were less than 70 ppm and 0 °C, respectively.

This research investigated the use of two relatively cost-effective devices for determining NH3 concentrations in naturally ventilated (NV) dairy barns including an Ogawa passive sampler (Ogawa) and a passive flux sampler (PFS). These samplers were deployed adjacent to sampling ports of a photoacoustic infrared multigas spectroscope (INNOVA), in a NV dairy barn. A 3-day deployment period was deemed suitable for both passive samplers. The correlations between concentrations determined with the passive samplers and the INNOVA were statistically significant (r = 0.93 for Ogawa and 0.88 for PFS). Compared with reference measurements, Ogawa overestimated NH3 concentrations in the barn by ∼ 14%, while PFS underestimated NH3 concentrations by ∼ 41%. Barn NH3 emission factors per animal unit (20.6-21.2 g d(-1) AU(-1)) based on the two passive samplers, after calibration, were similar to those obtained with the reference method and were within the range of values reported in literature.

Mass concentrations of chemical constituents (organics, nitrate, sulfate, ammonium, chloride, and black carbon (BC)) and the number size distribution of submicrometer particles in the ambient atmosphere were continuously measured in urban Gwangju, Korea, during the Megacity Air Pollution Studies (MAPS)-Seoul campaign. Organics (9.1 &mu, g/m3) were the most dominant species, followed by sulfate (4.7 &mu, g/m3), nitrate (3.2 &mu, g/m3), ammonium (2.6 &mu, g/m3), and BC (1.3 &mu, g/m3) in submicrometer particles (particulate matter less than 1 &mu, m (PM1)). The potential source regions of the sulfate were located in the South and East regions of China and South and East regions of Korea, while local sources were responsible for the elevated BC concentration. Diurnal variation showed that concentrations of organics, nitrate, ammonium, chloride, and BC decreased with increasing mixing layer and wind speed (dilution effect), while sulfate and oxidized organics increased possibly due to their strong photochemical production in the afternoon. During the campaign, an elevated mass concentration of PM1 (PM1 event) and number concentration (nanoparticle formation (NPF) event) were observed (one PM1 event and nine NPF events out of 28 days). The PM1 event occurred with Western and Southwestern air masses with increasing sulfate and organics. Long-range transported aerosols and stagnant meteorological conditions favored the elevated mass concentration of submicrometer particles. Most of the NPF events took place between 10:00 and 14:00, and the particle growth rates after the initial nanoparticle formation were 7.2&ndash, 11.0 nm/h. The times for increased concentration of nanoparticles and their growth were consistent with those for elevated sulfate and oxidized organics in submicrometer particles under strong photochemical activity.

The oxidative potential (OP) and chemical characteristics of fine particles collected from urban, roadside, rural, and industrial sites in Korea during spring, summer, fall, and winter seasons and an urban site in the Philippines during dry and wet seasons were examined. Significant differences in the OP of fine particles among sites and seasons were found. The industrial site yielded the highest OP activity (both mass and volume-normalized OP) among the sites, suggesting the strongest reactive oxygen species (ROS)-generating capability of industry source-dominant PM2.5. Seasonal data show that OP activities increased during the spring and summer possibly due to increased heavy metals caused by dust events and secondary organic aerosols formed by strong photochemical activity, respectively. The strength of the OP association with the chemical components highlights the influence of organic carbon and transition metals on the OP of ambient fine particles. The two OP assays (dithiothreitol (DTT) and electron spin resonance (ESR)) having different ROS-generating mechanisms were found to have different sensitivities to the chemical components facilitating a complementary analysis of the OP of ambient fine particles. Multiple linear regression model equations (OP as a function of chemical components) which were dependent on the sites were derived. A comparison of the daily OP and hazard index (HI) (the ratio of the measured mass concentration to the reference mass concentration of fine particles) suggests that the HI may not be sufficient to accurately estimate the health effects of fine particles, and a direct or indirect measurement of toxicity such as OP should be required in addition to the concentration level.

Fine particulate matters less than 2.5 µm (PM2.5) in the ambient atmosphere are strongly associated with adverse health effects. However, it is unlikely that all fine particles are equally toxic in view of their different sizes and chemical components. Toxicity of fine particles produced from various combustion sources (diesel engine, gasoline engine, biomass burning (rice straw and pine stem burning), and coal combustion) and non-combustion sources (road dust including sea spray aerosols, ammonium sulfate, ammonium nitrate, and secondary organic aerosols (SOA)), which are known major sources of PM2.5, was determined. Multiple biological and chemical endpoints were integrated for various source-specific aerosols to derive toxicity scores for particles originating from different sources. The highest toxicity score was obtained for diesel engine exhaust particles, followed by gasoline engine exhaust particles, biomass burning particles, coal combustion particles, and road dust, suggesting that traffic plays the most critical role in enhancing the toxic effects of fine particles. The toxicity ranking of fine particles produced from various sources can be used to better understand the adverse health effects caused by different fine particle types in the ambient atmosphere, and to provide practical management of fine particles beyond what can be achieved only using PM mass which is the current regulation standard.

The size distribution and chemical components of a fine fraction (Implications: Size and chemical characteristics of fine road dust at sites having distinct urban characteristics were examined. Residential coal and biomass burning and traffic affected physiochemical properties of the fine road dust. Different road dust profiles at different sites should be needed to determine the ambient PM2.5 sources more accurately.

Concentrations and emissions of ammonia (NH 3 ) and hydrogen sulfide (H 2 S) data for two naturally ventilated freestall dairy barns, within a one-year window of a two-year measurement effort, are presented in this article. Barn 1 (B1) had a capacity of 400 fresh-lactating Holstein cows, while barn 2 (B2) had a capacity of 850 non-fresh-lactating Holstein cows. The 10 min mean concentrations of NH 3 in the barns ranged from 0.16 to 2.85 ppm, while the concentrations of H 2 S ranged from 0.0 to 135.8 ppb. The concentrations of NH 3 and H 2 S in the barns were significantly below the OSHA permissible and NIOSH recommended exposure levels with respect to safety and health concerns of farm workers. Air exchange rates ranged from 7 to 74 h -1 during all measurement periods, which met and exceeded the standard minimum ventilation rate requirements for dairy barns. Ammonia emissions ranged from 15.1 to 36.7 g d -1 AU -1 (20.3 to 49.5 g d -1 cow -1 ) with a mean of 21.6 g d -1 AU -1 (29.0 g d -1 cow -1 ). Emissions of H 2 S, on the other hand, ranged from 0.0 to 1.5 g d -1 AU -1 (0.0 and 2.0 g d -1 cow -1 ) with an overall mean of 0.51 g d -1 AU -1 (0.69 g d -1 cow -1 ). In general, NH 3 emissions correlated fairly well with temperature (R 2 = 0.29 to 0.51). However, the relationships between NH 3 emission and wind speed were mixed, ranging from zero to moderately positive (R 2 = 0.01 to 0.46). Regression analyses did not indicate any significant relationships between H 2 S emissions and these environmental parameters.

Volatile fatty acids (VFA) play an important role in the biodegradation of organic wastes and production of bioenergy under anaerobic digestion, and are related to malodors. However, little is known about the dynamics of VFA during dairy manure storage. This study evaluated the characteristics of VFA in dairy manure before and after anaerobic co-digestion in a laboratory experiment using eight lab-scale reactors. The reactors were loaded with four different types of dairy manure: (1) liquid dairy manure from a freestall barn, (2) mixture of dairy manure and co-digestion food processing wastes at the inlet of an anaerobic digester, (3) effluent from the digester outlet, and (4) the liquid fraction of effluent from a solid separator. Four VFA (acetic, propionic, butyric, and 2-methylbutyric acids) were identified and quantified in weekly manure samples from all reactors. Results showed that the dominant VFA was acetic acid in all four manure sources. The off-farm co-digestion wastes significantly increased the total VFA concentrations and the proportions of individual VFA in the influent. The dairy manure under storage demonstrated high temporal and spatial variations in pH and VFA concentrations. Anaerobic digestion reduced the total VFA by 86%-96%; but solid-liquid separation did not demonstrate a significant reduction in total VFA in this study. Using VFA as an indicator, anaerobic digestion exhibited an effective reduction of dairy manure odor offensiveness.

Greenhouse gas (GHG) emissions from two naturally-ventilated dairy freestall barns measured for a total of 21 d, one week each in May, July, and September 2009, are presented in this article. The holding capacity of Barn 1 (B1) was 400 Holstein cows, while that for Barn 2 (B2) was 850 cows. Air samples were taken from inlets and outlets of the barns via a custom made multiplexer gas sampling system for measurement of gas concentrations using a photoacoustic infrared multigas analyzer. Barn ventilation rates were based on air velocity measured with arrays of 3-D ultrasonic anemometers at inlets and outlets. Gas concentrations (10 min means) in the barns ranged from: 443–789 ppm for CO2, 0.0–39.4 ppm for CH4, and 0.25–0.39 ppm for N2O; with mean concentrations ranging from 6 to 20%, 0 to 4%, and 26 to 180% above the average background concentrations for CO2, N2O, and CH4, respectively. The correlations between CO2 and CH4 enhanced concentrations were relatively stronger (R of 0.67–0.74) than between CO2 and N2O enhanced concentrations (R of 0.10–0.20). Environmental conditions did not significantly (p = 0.46) impact the enhanced concentrations of N2O in the barns. All three parameters (T, RH, and v) had significant (p

The goal of this study was to determine the effects of suspended solids (SS) adsorption properties, as well as the concentration of SS, on the mechanisms governing ammonia volatilization from liquid dairy manure. Pertinent properties that influence total ammoniacal nitrogen (TAN = NH 4 + + NH 3 ) adsorption on SS, including particle size distribution (PSD) and volatile solids (VS), of manures from three dairy operations with different feed rations were evaluated. The main parameters governing ammonia volatilization from liquid manure, i.e., the dissociation constant (K d ), the fraction of un-ionized ammonia (I²), and the overall mass transfer coefficient (K O ) of ammonia, for the three manures were determined in a laboratory convective emission chamber. The adsorption characteristics of the SS of the manures from the three dairies were significantly different. In particular, the PSD and VS for the SS of the manures from all dairies were significantly different. Even though the adsorption properties were significantly different among the SS from all three manures, their net effects on ammonia volatilization, at the same concentration, were not significantly different. Briefly, SS adsorption properties did not significantly affect either K d , I², or K O , but SS concentrations significantly affected them all. Removal of SS via solids-liquid separation would therefore exacerbate ammonia loss from liquid dairy manure. Overall, these findings reveal that increasing SS concentration hinders ammonia volatilization from liquid dairy manure, whereas differences in the SS characteristics do not affect the volatilization process in a significant manner.

Air pollutant emission rates from mechanically ventilated (MV) dairy barns are determined from the product of the differences in concentrations of pollutants in air at the inlet and exhaust points and the corresponding ventilation rates. In contrast to well defined entry and exit points in MV barns, large area air inlets or outlets characterize naturally ventilated (NV) freestall dairy barns. Complicating this scenario even more, pertinent airflow characteristics (velocity and direction) necessary for determining ventilation rates vary continuously, both temporally and spatially. This paper describes implementation of a direct method, generally equivalent to the approach used for MV barns, for determining air emission rates of NV barns. Ultrasonic anemometers (sonics) located at salient points in the barn openings mapped air inflow and outflow velocities necessary to calculate ventilation rates. Pollutant concentrations in the air entering or leaving the barn during a given period were measured at sampling points located next to the anemometers. The air inflow rates were, in general, higher than the air outflow rates from the barns, but diurnal profiles were similar. The observed ventilation characteristics were consistent with prevailing wind directions. Air inflows were observed predominantly at windward openings of the barn, while the outflows were mainly at the barn's leeward openings. Results indicated that either: (i) the average of the air inflow and outflow rates (averaging approach), or (ii) the air inflow rates (inflow-only approach) were credible representations of ventilation rates. Results also revealed use of an on-site weather station and one sonic mounted in the middle of each wall of the barn as a possible approach for determining barn ventilation rates. The suggested use of ventilation rates for interpolating missing concentrations from intermittent gas measurements could potentially increase the integrity of emission rates at significantly lower capital investment and operational costs.

Volatile fatty acids (VFA) are among the most abundant volatile organic compounds in dairy manure and are associated with odour nuisance. This paper presents research results of VFA production during a three-month storage of dairy manure from four different sources: a dairy barn (raw), the inlet of an anaerobic digester (influent), the digester outlet (effluent), and the effluent after solid separation (effluent SS). Manure from each source was studied in two lab-scale reactors that were continuously ventilated with fresh air in the manure headspace to simulate manure storage conditions. Two manure samples were taken weekly in the top and bottom manure layers from each reactor for VFA analysis. Five VFA (formic acid, acetic acid, propionic acid, butyric acid, and 2-methylbutyric acid) were identified in all reactors using high performance liquid chromatography (HPLC). The dominant VFA was formic acid for the influent and acetic acid for the other three manure sources. The overall average concentrations of the five VFA were 1963 ± 685 (mean ± standard deviation), 14,175 ± 4825, 286 ± 98, and 169 ± 80 mg l −1 for the raw, influent, effluent, and effluent SS, respectively. The “pre-consumer” organic wastes mixed with dairy manure in the influent significantly increased the total VFA concentrations and the proportion of individual VFA. Concentrations of VFA demonstrated highly temporal and spatial variations. Anaerobic digestion significantly reduced formation of VFA in the effluent and effluent SS. However, the complexity of VFA characteristics made it difficult to reliably model and predict the concentrations and compositions of VFA in dairy manure.

The goal of this study was to determine the effect of anaerobic digestion (AD) on the mechanism of ammonia volatilization from liquid dairy manure, in storage or treatment lagoon, prior to land application. Physical-chemical properties of liquid dairy manure, which may affect ammonia volatilization process, 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 (KoL) and the NH3 fraction of TAN (I²) 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 liquid manure temperatures of 15, 25, and 35 °C. The PSD indicated non-normal left skewed distribution for both AD and UD manures particles, suggestive of heavier concentrations of particles towards 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 than AD manure. Results also indicated significantly higher pH, TAN, ionic strength (IS) and viscosity in AD manure. The KoL and I² for AD manure determined under identical conditions (air temperature, liquid temperature, and airflow) were significantly higher (p > 0.05) than for UD manure. Overall, these findings suggest that AD of dairy manure significantly increased initial ammonia volatilization potential from liquid dairy manure; with the largest increase (~62%) emanating from increased ammonium dissociation. The initial flux of ammonia, during the experiment period, was ~84% more from AD than in UD dairy manure.

Particulate matter (PM) concentrations and ventilation rates, in two naturally ventilated freestall dairy barns, were continuously monitored for two years. The first barn (B1) housed 400 fresh lactating cows, while the second barn (B2) housed 835 non-fresh lactating cows and 15 bulls. The relationships between PM concentrations and accepted governing parameters (environmental conditions and cattle activity) were examined. In comparison with other seasons, PM concentrations were lowest in winter. Total suspended particulate (TSP) concentrations in spring and autumn were relatively higher than those in summer. Overall: the concentrations in the barns and ambient air, for all the PM categories (PM2.5, PM10, and TSP), exhibited non-normal positively skewed distributions, which tended to overestimate mean or average concentrations. Only concentrations of PM2.5 and PM10 increased with ambient air temperature (R2 = 0.60–0.82), whereas only concentrations of TSP increased with cattle activity. The mean respective emission rates of PM2.5, PM10, and TSP for the two barns ranged between 1.6–4.0, 11.9–15.0, and 48.7–52.5 g d−1 cow−1, indicating similar emissions from the two barns.

A series of laboratory scale studies were conducted, over a period of 23 d, to evaluate NH3 losses from simulated storages of scraped manure and flushed manure on the basis of similar: (i) exposed-surface-area to volume ratio (ESAVR), and (ii) exposed-surface-area (ESA). Based on similar ESA; NH3 flux during the 23-d study period from the storage of scraped manure ranged from 2.7 to 1.4 g m−2 d−1 compared to a range of 2.2 to 1.8 g m−2 d−1 from storage of flushed manure. This resulted in significantly higher total NH3 loss from the storage of scraped manure (2034 ± 107 mg) compared to that from the storage of flushed manure (1739 ± 53 mg). Ammonia flux ranging from 5.9 to 2.4 g m−2 d−1 was observed from the storage of scraped manure with similar ESAVR to that of the flushed manure storage. In the latter case, however, the total NH3 losses from either type of storage were not significantly different. The mean cumulative NH3 lost from the simulated storages of flushed manure was 1739 ± 53 mg, while the mean loss from the simulated storages of scraped manure was 1752 ± 56 mg. The results from this study indicate that for geometric similar post-collection storages (i.e. similar ESA), flushing manure mitigates NH3 emissions more than scraping manure, during post-collection storages: at least within the initial 23-d storage duration simulated in this study. In contrast, however, there was no indication of any advantage of using one system over the other if the post-collection storages were based on similar ESAVRs.

About 80% of dairy cattle N intake is excreted in urine and feces. Urinary—N is about 75% urea, whereas fecal—N is mostly organic. Urinary-N (urea) can only be volatilized when it is hydrolyzed to ammonia (NH 3 ) in a process catalyzed by urease, which is predominantly found in feces. Minimizing contact between urine and feces may be an effective approach to reducing urea hydrolysis and subsequent NH 3 emissions. Previous studies have reported 5 to 99% NH 3 emissions mitigation within barns from separation of feces and urine. The objective of this study was to compare NH 3 emissions mitigation via separation of urine and feces in postcollection storage to a conventional scrape manure handling method where urine and feces are comingled. Laboratory scale studies were conducted to evaluate NH 3 emissions from simulated postcollection storage of three waste streams: (i) idealistically separated feces and urine (no contact between urine and feces), (ii) realistically separated urine and feces (limited contact of urine and feces), and (iii) conventionally scraped manure (control). From the results of these studies, NH 3 losses ranking in descending order was as follows: aggregate of realistically separated waste streams (3375.9 ± 54.8 mg), aggregate of idealisrically separated urine and feces (3047.0 t 738.0 mg), and scrape manure (2034.0 ± 106.5 mg), respectively. Therefore, on the basis of these results, the extra effort of separating the waste streams would not enhance mitigation of NH 3 losses from postcollection storage of the separated waste streams compared to the conventional scrape manure collection system.

Strong acid solutions have been widely used in acid traps to determine concentrations of ammonia in ambient air or exhaust air stream. A literature survey indicates the method has a long history and a wide variation in use. Through a series of studies, this paper examines several factors including volume of the acid, depth of the acid, and airflow rate; that might affect the efficiency of sulfuric acid traps and recommends steps researchers and other users may take to ensure reliable results from this method. The results from these series of studies indicate: (i) an inverse relationship between the efficiency of the acid traps and the amount of ammonia to be trapped even when the capacity of the acid trap is excessively greater than the maximum theoretical stoichiometric capacity needed to dissolve all of the ammonia, (ii) for the same volume of acid, the efficiency of the acid trap increased with the acid depth but overall, the efficiency at any given acid depth decreased as the amount of ammonia through the trap increased, and (iii) at the two airflow rates examined in this study (0.5 and 1.0 L/ min) the efficiency of the acid traps decreased at similar rates as the concentration of ammonia in the sample air increased but the efficiency of the trap was significantly higher at the lower airflow rate. To obtain reliable measurements from this method, therefore, multi-point calibrations within the entire range of target measurements is recommended to provide accurate corrections of the measurements.

Even though petroleum-degrading microorganisms are widely distributed in soil and water, they may not be present in sufficient numbers to achieve contaminant remediation. In such cases, it may be useful to inoculate the polluted area with highly effective petroleum-degrading microbial strains to augment the exiting ones. In order to identify a microbial strain for bioaugmentation of oil-contaminated soil, we isolated a microbial strain with high emulsification and petroleum hydrocarbon degradation efficiency of diesel fuel in culture. The efficacy of the isolated microbial strain, identified as Candida catenulata CM1, was further evaluated during composting of a mixture containing 23% food waste and 77% diesel-contaminated soil including 2% (w/w) diesel. After 13 days of composting, 84% of the initial petroleum hydrocarbon was degraded in composting mixes containing a powdered form of CM1 (CM1-solid), compared with 48% of removal ratio in control reactor without inoculum. This finding suggests that CM1 is a viable microbial strain for bioremediation of oil-contaminated soil with food waste through composting processes.

To improve ammonium removal efficiency in wastewater treatment, a mixed culture of Alcaligenes faecalis no. 4 and its mutant L1, both of which have heterotrophic nitrification and aerobic denitrification abilities, was performed. In a batch culture, no. 4 has a higher denitrification ability than L1, but its ammonium removal rate was lower. In a mixed continuous culture in the ammonium loading range of 750 to 3500 mg-N/l/d, the average ammonium removal rate and the average denitrification ratio were 61 mg-N/l/h and 31%, respectively. In the mixed culture, the ammonium removal rate was twofold higher than that in a single culture of no. 4, the rate was similar to that in a single culture of L1, and the denitrification ratio was very high compared with that in the single culture of L1.

Field and laboratory studies were conducted to evaluate the effects of anaerobic digestion (AD) and solids-liquid separation on emissions during subsequent storage and land application. The lab storage tests were conducted for 21 days with manure samples obtained at the following four points in a full-scale AD system: raw manure (RM) delivery, raw manure supplemented with other substrates (AD influent), AD effluent, and AD effluent after solids-liquid separation (AD liquid effluent). Ammonia fluxes from stored AD effluent declined from 3.95 to 2.02 g m−2 day−1. Lower NH3 fluxes, however, were observed from AD liquid effluent (1.1 g m−2 day−1) and AD influent (0.25 g m−2 day−1). Ammonia emissions from full-scale manure storages were similar to those obtained in the lab. Results also indicated significantly lower volatile fatty acid (VFA) in AD effluent and AD liquid effluent compared with that from the AD influent, indicating significant reduction in odor generation potential due to AD and solids-liquid separation processes. Two manure application methods (surface application and manure injection) for both non-AD and AD manures were simulated in the lab and studied for 9 days. Surface-applied non-AD manure exhibited the highest NH3 flux (0.78 g m−2 day−1), while injected AD manure led to the lowest NH3 flux (0.17 g m−2 day−1). Similar NH3 emissions results were observed from the field studies. Overall, while AD of dairy manure resulted in significant increases in NH3 emissions from stored effluent, the AD process significantly reduced NH3 emissions following application of AD manure on land.

This study investigated particulate matter (PM) loading rates and concentrations in ambient air from naturally ventilated dairy barns and also the influences of pertinent meteorological factors, traffic, and animal activities on mass loading rates and mass concentrations. Generally, relationships between PM2.5 concentration and these parameters were significantly poorer than those between the PM loading rate and the same parameters. Although ambient air PM2.5 loading rates correlated well with PM2.5 emission rates, ambient air PM2.5 concentrations correlated poorly with PM2.5 concentrations in the barns. A comprehensive assessment of PM2.5 pollution in ambient air, therefore, requires both mass concentrations and mass loading rates. Emissions of PM2.5 correlated strongly and positively with wind speed, temperature, and solar radiation (R(2) = 0.84 to 0.99) and strongly but negatively with relative humidity (R(2) = 0.93). Animal activity exhibited only moderate effect on PM2.5 emissions, while traffic activity did not significantly affect PM2.5 emissions.

Alcaligenes faecalis strain No. 4, which has heterotrophic nitrification and aerobic denitrification abilities, was used to treat actual piggery wastewater containing high-strength ammonium under aerobic conditions. In a continuous experiment using a solids-free wastewater (SFW) mixed with feces, almost all of the 2000 NH4+ -N mg/L and 12,000 COD mg/L in the wastewater was removed and the ammonium removal rate was approximately 30 mg-N/L/h, which was 5-10 times higher than the rates achieved by other bacteria with the same abilities. The denitrification ratio was more than 65% of removed NH4+ -N, indicating that strain No. 4 exhibited its heterotrophic nitrification and aerobic denitrification abilities in the piggery wastewater.

Alcaligenes faecalis no. 4 has heterotrophic nitrification and aerobic denitrification abilities. By taking the nitrogen balance under different culture conditions, 40-50% of removed NH4+-N was denitrified and about one-half of removed NH4+-N was converted to intracellular nitrogen. The maximum ammonium removal rate of no. 4 (28.9 mg-N/l/h) and its denitrification rate at high-strength NH4+-N of about 1200 ppm in aerated batch experiments at a C/N ratio of 10 were 5-40 times higher than those of other bacteria with the same ability. Only a few percent of the removed ammonium was converted to nitrite, and the main denitrification process was speculated to be via hydroxylamine which was produced by ammonium oxidation.

Dairy cattle houses are important sources of ammonia (NH 3 ) and other gaseous and particulate emissions. Manure slurry acidification has the potential to significantly mitigate NH 3 emissions. The manure acidification practice can be improved through recirculation of the liquid stream of flushed manure. This research study investigated the potential mitigations of NH 3 in the barn, when a pH 2 SO 4 ). The main treatments for manure effluents from the barn included screening, sedimentation, and acidification steps. Bench-scale studies were performed to evaluate proof-of-concept. Tests were conducted in 0.5 L Polypropylene cylinders with reconstituted manure (50 g) and flush water (0.45 L) mixture to simulate barn flushing and the resulting effluents were screened and allowed to settle to remove solids. The solids were discarded while the liquid stream was adjusted for pH before repeating the procedure. A pilot-scale dairy barn model measuring 183 (l) cm A— 38 (w) cm A— 33 (h) cm was constructed to simulate dairy flush system. Fifty four grams of manure were applied to the model’s manure alleys every 20 min during a 1 h study period. Each alley in the model was flushed with 0.75 L flush water at the end of 1 h, followed by effluent treatments. Two manure-pH management methods were tested at the pilot-scale: (i) pH-adjustment of flush water, and (ii) sprinkler-irrigation of manure alleys with acid water between scheduled flushing. A separate lab-scale study was conducted to evaluate NH 3 emission mitigation potential during post-collection storage of treated manure against untreated manure (control). Ammonia measurements were made using a closed-chamber method coupled with a photoacoustic multi-gas analyzer. Cumulative ammonia emissions during 1 h study period were: 50.28 ± 7.95 mg m -2 for control, 14.96 ± 1.01 mg m -2 for pH-adjusted flush water (70% reduction), and 6.50 ± 0.26 mg m -2 for irrigating manure alleys with acid water (87% reduction). Adjustment of recycle flush water pH reduced the average consumption of acid by 82% within two cycles. Adjustment of pH in the barn reduced ammonia emissions during storage of barn effluents by approximately 60% compared storage of untreated flushed manure. The results from this research indicate significant potential mitigations of NH 3 in the dairy barns as well as in subsequent storage of effluents; while also demonstrating that operating the flushing system in a closed-loop has significant cost benefits accruing from reduced acid dosages.

Greenhouse gases (GHG) emissions from two naturally-ventilated free-stall dairy barns were measured during a three-month study period (May, July and September, 2009). Barn 1 (B1) housed 400 fresh cows, while Barn 2 (B2) housed 850 lactating cows. Air samples at inlet and outlet of the barns for measurement of GHG (CO 2 , N 2 O, and CH 4 ) concentrations were delivered to a photoacoustic gas analyzer (INNOVA model 1412) using a custom-made gas sampling system. Ventilation rates in the barns were determined using three dimensional ultrasonic anemometers mounted on air inlets and outlets. Emissions of CO 2 averaged 23.14 in B1 and 18.53kg-CO 2 /cow/d in B2, respectively. Emissions of CH 4 averaged 326.5 in B1 and 374.5 g-CH 4 /cow/d in B2. The respective emissions of N 2 O in B1 and B2 were 16.00 and 7.86 g-N 2 O/cow/d. Emissions of CO 2 and CH 4 in both barns, in particular, were similar. Emissions of N 2 O from the two barns, however, were significantly different probably because of manure management differences. One half of B1 consisted of an open dirt floor (no stalls) and manure (urine plus feces) deposited on this dirt was thus rarely removed and resulted in significantly higher emissions of N 2 O from this barn (B1). Conversely, the correlation between CO 2 and N 2 O was considerably higher than that between CO 2 and CH 4 emissions (R 2 ranged from 0.82 to 0.98).

Ammonia is one of the major air pollutants from concentrated animal feed operations (CAFOs), which have potential to negatively impact the environment and ecosystem. Anaerobic digestion (AD), on the other hand, is steadily being adopted, more and more, for extracting bioenergy from dairy wastewater in CAFOs prior to storage or land application. The AD process is associated with changes in manure physical-chemical properties, which may affect ammonia emission from AD effluents. Field and laboratory studies were conducted to evaluate the effects of AD and solids-liquid separation on ammonia emissions during subsequent storage of the AD. The lab manure storage tests were conducted for 21 d in plastic containers with open surface areas of 386 cm2 filled with 2.5 L manure samples obtained at the following four points in a full-scale AD system: raw manure (RM) feed substrate, raw manure supplemented with other substrates (AD influent), AD effluent, and AD effluent after solids-liquid separation (AD liquid effluent). Higher ammonia fluxes were observed on day 1 from the AD effluent (5.58 g m-2 d-1) and RM (2.12 g m-2 d-1) storages but both decreased to zero after 21 d. Lower ammonia fluxes were observed from AD liquid effluent (0.53 g m-2 d-1) and AD influent (0.12 g m-2 d-1), which remained constant during the entire 21 d of the study. The cumulative ammonia emissions during the 21 d test were: 1608 ± 34 mg from AD effluent; 660 ± 19 mg from RM; 429 ± 44 mg from AD liquid effluent; and 99 ± 11 mg from AD influent. Field measurements of ammonia emissions from both AD liquid effluent and RM storages were conducted using a floating chamber and a photoacoustic gas analyzer. Ammonia emissions from full-scale manure storages were similar to those obtained in the lab. Ammonia emissions from storages of AD (AD liquid effluent) and non-AD manure (RM) from winter to summer ranged from 0.12 to 1.4 g m-2 d-1 and 0.09 to 0.79 g m-2 d-1, respectively. In general, anaerobic digestion of dairy manure, therefore, resulted in significant increases in ammonia emissions from stored effluents. However, solids-liquid separation further mitigated ammonia emissions from AD liquid effluent.

Manure residence time in the manure-alley and recycled flushing water are the two main factors determining gaseous emissions from naturally ventilated dairy buildings. Mitigation of gaseous emissions from such facilities can thus be accomplished through optimal management of manure removal by flushing, scraping, or both and select pretreatments of flushing water. Greenhouse gases (GHG), ammonia, and hydrogen sulfide emissions from a naturally ventilated dairy barn which housed 850 lactating cows were measured following implementation of alternative manure management strategies. The manure management strategies included: (i) more frequent flushing from every 6 h to every 3 h, (ii) alternating flushing and scraping, and (iii) centrifuging solids from flush water. Concentrations of gases in the air within the barns were compared to concentrations during the normal every 6 h manure flushing with recycled secondary lagoon water. Ammonia emissions (31 g-NH 3 /cow/d) after doubling flushing frequency (from 6 h to every 3 h) was similar as for the normal every 6 h flushing (32 g-NH 3 /cow/d), while CO 2 and N 2 O emissions were reduced by 12% and 9%, respectively. On the contrary, CH 4 and H 2 S emissions for the 3 h flushing regime were 9% and 186% higher than for the 6 h flushing-cycle. Alternating flushing and scraping every 6 h reduced CO 2 and H 2 S emissions by 10% and 17% than the 6 h normal flushing. The concentrations of other gases were similar. Centrifuging to separate solids from the flush water was significantly more effective than the other manure management strategies. Reductions of concentrations in the air in the barns after centrifuging flush water were: 37 % for NH 3 , 37 % for N 2 O, 24% for CO 2 , and 42 % for H 2 S.

Ammonia emission from manure following land application reduces fertilizer value of the manure and could have adverse impacts on the environment. Manure pretreatments and methods of manure application, however, may impact ammonia volatilization. Field- and lab-scale experiments were conducted to study the effects of anaerobic digestion (AD) and manure application methods (surface application and manure injection) on ammonia emission. In general, most of the ammonia emissions occurred within 5 d after manure application. Soils receiving undigested manure (UM) emitted more ammonia than soils receiving digested manure (DM) irrespective of manure application method. Surface-applied DM resulted in 56% less ammonia emission than surface-applied UM, while injected DM emitted 27% less than injected UM. Although injected DM did not significantly affect ammonia emission for both application methods, injected UM resulted in 42% less ammonia emission than surface applied UM. Surface application of UM exhibited the highest ammonia emission flux (0.78 g m -2 d -1 ) immediately after application but the flux dropped to zero within 3 d. The lowest initial ammonia flux of 0.17 g m -2 d -1 , which gradually approached zero within 5 d, was observed from injected DM. Similar results were obtained from field studies as follows. Surface applied DM resulted in 49% less ammonia emission than surface applied UM. Surface application resulted in 63% and 25% more ammonia loss than manure injection for UM and DM, respectively. Manure injection was thus a more effective method for mitigation of ammonia emission than surface application. Together, these studies indicate that land application of DM is both economically (retention of manure fertilizer-value) and environmentally friendlier (reduced ammonia emissions) than application of raw manure or UM.

This paper presents study results of volatile fatty acids (VFA) production during three months of storage of dairy manure collected from four different sources: (1) a dairy barn, (2) the inlet of an anaerobic digester (influent), (3) the outlet of the digester (effluent), and (4) the effluent after separation of biosolids. Manure from each source was tested in two lab-scale bioreactors of 61.0 cm high and 38.1 cm in diameter. Each bioreactor was initially filled with manure to as depth of 25.4 cm. The bioreactors were continuously ventilated with 6.5 L/min of fresh air in the manure headspace during the entire test to simulate manure storage conditions on dairy farms. Two manure samples were taken weekly from each bioreactor for VFA concentration analysis: one in the top manure layer within 2.5 cm below the surface and another in the bottom manure layer within 5.0 cm above the reactor bottom. Five VFA including: formic acid, acetic acid, propionic acid, butyric acid, and 2-methylbutyric acid, were identified in manure samples from all reactors using HPLC (High Performance Liquid Chromatography). Significant differences in VFA concentrations between the digested and undigested manure were observed. Results showed that the dominant VFA in the stored manure from the dairy barn was acetic acid followed by propionic acid. Concentrations began to decline around the fifth week of storage. The stored influent manure had initial formic acid concentrations as high as 27 g/L, but the concentration declined within 4 wks of storage. The acetic and butyric acids were the dominant VFA after the decline of formic acid. For all digested manure, the dominant VFA was acetic acid but its concentrations only reached a maximum of 0.9 g/L compared with a maximum concentration of 5 g/L in influent manure. This study provides a better understanding of the environmental effects of anaerobic digestion on the dairy manure storage.

Anaerobic digestion (AD) of livestock manure is better known for the economic advantage derived from biogas for energy rather than for its environmental benefits. Demonstration of relevant environmental benefits from AD of manure would thus enhance adoption of this technology on animal feeding operations (AFOs). The effect of AD of dairy manure on the emissions of ammonia (NH3) and greenhouse gases (GHG) during manure storage and also in subsequent land applications are presented in this paper. Measurements of GHG emissions from both AD and non-AD manure storages were made using a floating chamber and a photoacoustic gas analyzer (INNOVA model 1412). Emissions of GHG were determined using the standard closed chamber method from field plots applied with AD and non-AD manure. Data obtained indicate significantly higher fluxes of GHG (CO2, N2O, and CH4) from land applied with non-AD manure than from land applied with AD manure. In addition, injection of non-AD manure seemed to further increase CH4 flux from the soil. More than 50% emissions of CO2 and CH4 were observed during the first 3 days after manure was land applied. Emissions of GHG from the anaerobic lagoon holding AD manure, during all four seasons, were significantly lower than from the anaerobic lagoon with non-AD manure. In contrast, the reverse was observed with NH3 emissions. This data demonstrate some environmental benefits for AD of dairy manure prior to its storage and field application but also some potential increased emission of NH3 during storage.

Ammonia (NH3) is one of the major gaseous pollutants emitted from livestock facilities. Estimates indicate that the largest portion (about 80%) of the total nitrogen entering a dairy facility is lost as NH3 from manure storages; such as anaerobic lagoons. Direct measurements of NH3 emissions from these storage structures are not only tedious but also quite complex and expensive exercises. Process-based models offer an alternative cost-effective approach of making emissions estimations. This research coupled theoretical and empirical analyses of NH3 emissions mechanisms to increase the reliability of process-based NH3 emission models. A process-based model was developed to predict NH3 emission from dilute dairy manure via incorporation of two newly developed empirical sub-models of: the overall mass transfer coefficient (KoL) of NH3 from liquid dairy manure; and the dissociation constant (Kd) of ammonium (NH4+) in liquid dairy manure. The KoL was modeled based on lagoon liquid temperature (TL), air velocity, air temperature, and total solids (TS) concentrations. The Kd was modeled based on TL, and TS concentrations. The model predictions were validated with directly measured NH3 emissions using an open-path ultra-violet differential optical absorption spectroscopy (UV-DOAS) technique. Directly measured NH3 emission fluxes from our study lagoon ranged from 16.1 to 41.2 µg/m2/s, which compared well against our model predicted fluxes with a normalized mean error (NME) of 15%. Sensitivity analyses showed NH3 emission is most sensitive to the lagoon-liquid temperature compared to the other factors (air temperature, air velocity, and total solids concentrations) examined in this study.

Manure scraping and flushing are the two common manure handling systems in concentrated animal feeding operations (CAFOs) in the United States. Previous studies have reported on the impacts of these two manure handling systems on ammonia emissions within barns. There are no studies comparing the impacts of the two manure handling systems on ammonia emissions during post-collection storages in lagoons and other similar manure storages although these facilities are known to account for the largest portion of ammonia volatilization in CAFOs. A series of bench scale experiments were conducted for a period of 23 days in controlled laboratory conditions to quantify and compare ammonia losses from typical storages of simulated scraped manure, and simulated flushed manure. Ammonia emission fluxes estimates (with cumulative ammonia emissions in the parentheses) over a 23-day period were 2.25±0.08g/m2/day (2034±106.5 mg) from the simulated scraped manure storage, 2.04±0.04g/m2/day (1739.3±53.3 mg) from the simulated flushed manure storages with 411 cm2 exposed surface area each, and 4.62±0.13g/m2/day (1752±56.3 mg) from the simulated scraped manure with 183 cm2 exposed surface area, respectively. These results indicate that ammonia emission fluxes from scraped manure storage would be more than from flushed manure storage by at least two times if both manure post-storages had approximately the same exposed surface area to the volume ratio. However, results also revealed significantly higher cumulative ammonia emissions from simulated scraped manure storage with 411 cm2 than from both the simulated flushed manure storage with 411 cm2 and the simulated scraped manure storage with 183 cm2 exposed surface areas.

About 80% of dairy cattle N intake is excreted as urine and feces. Urinary-N is about 75% urea and fecal-N is mostly organic. Ammonia can only be volatilized when urinary urea is hydrolyzed by the urease enzyme present in the feces (urease is not present in the urine). Minimizing contact between urine and feces may be an effective approach to reducing urea hydrolysis and thus subsequent ammonia emissions; indeed, previous studies have reported 5 to 99% ammonia emissions mitigation within barns through separation of feces and urine. The objective of this study was to compare the efficacy of ammonia mitigation by separation of urine and feces in the waste stream against a conventional scrape manure handling method where urine and feces are comingled. Laboratory scale simulation studies were conducted to evaluate ammonia emissions from post-collection storages of three waste streams: i) idealistically separated feces and urine (no contact between urine and feces), ii) realistically separated urine and feces, and iii) conventionally scraped manure. From the results of this study, ammonia losses ranking in descending order was: aggregate of idealistically separated waste streams, aggregate of realistically separated urine and feces, and the scrape manure, respectively. Based on the results of our studies, therefore, the extra effort of separating the waste streams would not enhance mitigation of ammonia loss from the post-collection storages of the separated waste streams compared to the conventional scrape manure collection system.

In mechanically-ventilated freestall dairy barns, pollutant emissions can accurately be determined from the differences in concentrations between the influent and exhaust gases and the measured flow of the ventilating air. In contrast, emissions from naturally ventilated (NV) freestall dairy barns do not have well defined specific air entry or exit points. In addition, pertinent airflow characteristics (velocity and direction) vary continuously, both temporally and spatially. This scenario significantly complicates the determinations of emissions. This paper examines a method being developed and tested for determining emissions from NV livestock barns. The method essentially entails placement of sonic anemometers (to measure air movement in and out of the structure) at salient points all around the barn in order to determine the airflow characteristics. Air samples are simultaneously collected at these selected points to determine the respective representative concentrations of the air entering or leaving the barn over a given sampling cycle or time. The airflow data is subsequently coupled with pollutant concentrations data to determine respective emissions from the barn. Results indicate credibility of sonic anemometers in the determination of ventilation characteristics in naturally ventilated barns, which are critical to accurate determination of pollutant emissions calculations from such barns.

We investigated the simultaneous degradation of diesel oil in soil and the organic matter in food waste by composting in 8 l reactors. Using a 0.5 l/min air flow rate, and 0.5-1% diesel oil concentrations together with 20% food waste, high composting temperatures (above 60 degrees C) were attained due to the efficient degradation of the food waste. Petroleum hydrocarbons were degraded by 80% after only 15 days composting in the presence of food waste. In a 28 l reactor scale-up experiment using 1% oil, 20% food waste and 79% soil, removal efficiencies of petroleum hydrocarbons and food waste after 15 days were 79% and 77%, respectively.

Alcaligenes faecalis sp. No. 4, that has the ability of heterotrophic nitrification and aerobic denitrification in high-strength ammonium at about 1200 mg-N/l, converted about one-half of removed NH4+-N to intracellular nitrogen and nitrified only 3% of the removed NH4+. From the nitrogen balance, 40-50% of removed NH4+-N was estimated to be denitrified. Production of N2 was confirmed by GC-MS and 90% of denitrified products was N2. The maximum ammonium removal rate, 29 mg-N/l h and its denitrification rate in aerated batch experiments, were 5-40 times higher than those of other bacteria with the same ability.