Zifei Liu - Academia.edu (original) (raw)

Papers by Zifei Liu

Sustainability

The swine diet formulation in the United States of America (U.S.A.) is entering a new era of deci... more The swine diet formulation in the United States of America (U.S.A.) is entering a new era of decision making to promote low-carbon pork production systems. As a part of the decision-making process, the precision nutrition approaches to customize diet and alternative feeding options that are economically viable and environmentally sustainable are given priority. Hence, the objective of this study is to identify an alternative diet over a standard corn–soybean meal diet. The byproducts from the supply chain of human food and biofuels, i.e., distiller-dried grain with solubles (DDGS), are chosen as an alternative option to formulate a swine diet. First, two alternative byproduct diets with low and high DDGS inclusion (10.1% and 28.8%, respectively) were formulated using the least-cost technique. Second, a life cycle inventory was created, followed by data collection from the key sources, including DATA SMART-2017, USDA, RIA-GREET 2018, and the relevant literature. Third, in SimaPro 8.5...

2020 ASABE Annual International Virtual Meeting, July 13-15, 2020, 2020

2019 Boston, Massachusetts July 7- July 10, 2019, 2019

Environmental Science Technology, 2005

Journal of the Air & Waste Management Association, 2014

Animal feeding operations (AFOs) produce particulate matter (PM) and gaseous pollutants. Investig... more Animal feeding operations (AFOs) produce particulate matter (PM) and gaseous pollutants. Investigation of the chemical composition of PM2.5 inside and in the local vicinity of AFOs can help to understand the impact of the AFO emissions on ambient secondary PM formation. This study was conducted on a commercial egg production farm in North Carolina. Samples of PM2.5 were collected from five stations, with one located in an egg production house and the otherfour located in the vicinity ofthe farm alongfour wind directions. The major ions of NH4+, Na+, K+, SO4(2-), Cl-, and NO3- were analyzed using ion chromatography (IC). In the house, the mostly abundant ions were SO4(2-), Cl-, and K+. At ambient stations, SO4(2-), and NH4+ were the two most abundant ions. In the house, NH4+, SO4(2-), and NO3- accounted for only 10% of the PM2.5 mass; at ambient locations, NH4+, SO4(2-), and NO3- accounted for 36-41% of the PM2.5 mass. In the house, NH4+ had small seasonal variations indicating that gas- phase NH3. was not the only major force driving its gas-particle partitioning. At the ambient stations, NH4+ had the highest concentrations in summer In the house, K+, Na+, and Cl- were highly correlated with each other In ambient locations, SO4(2-) and NH4+ had a strong correlation, whereas in the house, SO4(2-) and NH4+ had a very weak correlation. Ambient temperature and solar radiation were positively correlated with NH4+ and SO4(2-). This study suggests that secondary PM formation inside the animal house was not an important source of PM2.5. In the vicinity, NH3 emissions had greater impact on PM2.5 formation.

2013 Kansas City, Missouri, July 21 - July 24, 2013, 2013

Abstract. The goal of this project is to collect currently available measured emissions data or p... more Abstract. The goal of this project is to collect currently available measured emissions data or property line concentration data and integrate the results through meta-analysis for air emissions of NH 3 , H 2 S, VOC, PM10 and PM2.5 from live swine production facilities in North America, including manure storage systems; and to interpret implication of these data relative to existing or potential federal regulations. Results from more than 80 studies have been identified and included in the analysis. Data from reports of the eleven swine sites (IA4B, NC3B, NC4B, OK4B, IN3B, IN4A, NC4A, OK4A, IA4A, NC3A, and OK3A) in the National Air Emissions Monitoring Study (NAEMS) were also included. Histograms of emission rates usually show a skew-right distribution so that the medians were more robust than means. The median emission rates from swine houses were 2.78, 0.09, 0.44, 0.09, and 0.015 kg yr -1 hd -1 , for NH 3 , H 2 S, VOC, PM10 and PM2.5, respectively. The median emission rates from swine storage facilities were 2.08, 0.20, and 0.75 kg yr -1 hd -1 , for NH 3 , H 2 S and VOC, respectively. Accordingly, sizes of swine farm that may trigger the need to report under the Emergency Planning and Community Right-to-Know Act (EPCRA) were 3,410 head for NH 3 and 57,700 head for H 2 S (emissions exceeding 100 lb/day). The average concentrations at the edge of swine houses or lagoons were 5.5±5.2ppm and 40±48ppb, 2.6±7.9 mg m -3 , for NH 3 , H 2 S and VOC respectively. The NH 3 and H 2 S concentrations decreased to 66±66ppb and 5.1±4.1ppb at the distances from 30~1185m from emission sources.

Journal of the Air & Waste Management Association, 2009

Journal of Environment Quality, 2012

Journal of Animal Science, 2013

The objective was to provide a systematic review of the literature on greenhouse gas (GHG) emissi... more The objective was to provide a systematic review of the literature on greenhouse gas (GHG) emissions from swine operations, with a meta-analysis that integrates results of independent studies. A total of 53 studies that measured GHG emissions from swine operations were included in the analyses. Results showed that the Intergovernmental Panel on Climate Change (IPCC) approaches were effective in estimating the overall CH4 and N2O emission levels from swine operations, but the variation of the measured emissions is not adequately captured. An overestimation by the IPCC approaches for CH4 emissions was observed for swine buildings with pit systems in European studies and the average percentage relative difference (PRD) between the measured and the IPCC values is -21.1%. The observed CH4 emissions from lagoons were lower than the IPCC estimated values and the average PRD is -33.9%. In North American studies the observed N2O emission factors for swine buildings with pit systems were significantly lower than the IPCC default values whereas in European studies they were significantly greater than the IPCC default values. The measured CH4 and N2O emissions were significantly affected by stage of production (P = 0.05 and <0.01, respectively) and geographic regions (P = 0.04 and 0.02, respectively). The IPCC approaches were effective in simulating the effect of temperature on CH4 emissions from outdoor slurry storage facilities whereas they could overestimate CH4 emissions from lagoons at low temperatures. The CH4 emissions from pits inside swine buildings were not significantly affected by average ambient temperatures. A positive relationship between diet CP content and CH4 emissions was confirmed in the meta-analysis. The obtained knowledge can be helpful in efforts to improve estimation of GHG emissions from swine operations.

Transactions of the ASABE, 2014

Abstract. Gas emissions from various animal species were measured in controlled environmental roo... more Abstract. Gas emissions from various animal species were measured in controlled environmental rooms at Michigan State University under various dietary strategies over the course of 17 studies, including two broiler studies, four laying hen studies, one turkey study, two swine studies, four steer studies, two heifer studies, and two dairy cow studies. The objective of this article is to summarize the greenhouse gas (GHG) emission data (CH 4 , N 2 O, and CO 2 ) from these 17 studies and the potential diet effects on GHG emissions from multi-species animal operations. The CH 4 concentrations measured by an INNOVA 1412 analyzer showed large discrepancies compared with those measured by a Thermo Scientific Model 55C CH 4 analyzer when CH 4 concentrations were lower than 10 ppm, indicating significant influence of air moisture on the INNOVA measurements of CH 4 at low concentration levels. The ratios of mean measured CH 4 emission rates over estimated values using the Intergovernmental Panel on Climate Change (IPCC) approaches ranged from 25% to 116% in the 17 studies. The measured N 2 O emission rates were much higher than the IPCC estimated direct N 2 O emission rates, especially for poultry. The total GHG emissions in CO 2 equivalent units (CO 2 e) were in the range from 6436 to 31839 g CO 2 e d -1 AU -1 . Poultry operations had much lower CH 4 emissions than ruminants but had higher N 2 O emissions. In poultry operations, contributions of N 2 O to total GHG (19.5% to 21.9%) were much larger than contributions of CH 4 (1.2%). In ruminant operations, contributions of CH 4 (18.5% to 44.4%) were more important than contributions of N 2 O (1.7% to 16.2%). Swine operations had relatively low emissions of both N 2 O and CH 4 ; therefore, their total GHG emissions were lowest compared with ruminants and poultry operations. Lower N diets had no significant effect on CH 4 and direct N 2 O emissions, although they resulted in lower N excretion and therefore could reduce NH 3 and indirect N 2 O emissions. Diet modification related with distillers dried grains with solubles (DDGS) and different feed ingredients could significantly affect CH 4 emissions, which merits further investigation for both ruminant and non-ruminant species.