LIFE CYCLE ASSESSMENT OF THERMOCHEMICAL VALORIZATION OPTIONS FOR POULTRY LITTER

Abstract

Thermochemical valorization technologies serve as valuable approach to reduce environmental impacts and recover energy. Poultry litter refers to the organic residue generated from chickens and turkey, including materials such as excrement, feed remnants, feathers and bedding substances. In 1962, commercial poultry production began in Pakistan. Currently, every year about 544,831 tons of waste is produced by 146.5 million domestic and commercial poultry birds in Pakistan. The alarming rate at which the waste is increasing along with improper treatment of poultry litter can result in detrimental impacts on the environment. In Pakistan poultry litter is typically applied directly to the land and it can give rise to various adverse consequences such as eutrophication, build-up of antibiotic residue, greenhouse gas (GHG) emissions and spreading of pathogens. In this study, a comparison was drawn to determine which thermochemical conversion technology is suitable for treating poultry litter keeping direct land application (DLA) as a baseline scenario. In line with ISO 14040 and 14044 standards, in this study life cycle assessment has been employed to calculate the environmental impacts of any process or activity. Life cycle inventory analysis and impact assessment of six processes including, Incineration (IC), Fast Pyrolysis (FP), Slow Pyrolysis (SP), Gasification (G), Hydrothermal Carbonization (HTC), Hydrothermal Liquefaction (HTL) on categories such as human health and ecosystem quality is evaluated in comparison with direct land application. Using input data from a local Islamabad based poultry farm and LCA software Simapro 9.3.0.3, Impact World+ Endpoint method was performed to categorize the level of impacts of each process. As midpoints are converted to damage categories, the results show that Incineration, Fast Pyrolysis, Gasification, Hydrothermal Carbonization and Slow Pyrolysis outperform direct land application for both categories of ecosystem quality and human health. Hydrothermal liquefaction has the highest impact on both damage categories, whereas Incineration is the most favorable option. This is linked to the highest amount of electricity produced at 550 kWh. Furthermore, the effect of uncertainty of the input parameters on results is noted using sensitivity analysis of all the processes, in order to check which parameters have the highest impact and the amount of value-added products produced.

Thermochemical valorization technologies serve as valuable approach to reduce environmental impacts and recover energy. Poultry litter refers to the organic residue generated from chickens and turkey, including materials such as excrement, feed remnants, feathers and bedding substances. In 1962, commercial poultry production began in Pakistan. Currently, every year about 544,831 tons of waste is produced by 146.5 million domestic and commercial poultry birds in Pakistan. The alarming rate at which the waste is increasing along with improper treatment of poultry litter can result in detrimental impacts on the environment. In Pakistan poultry litter is typically applied directly to the land and it can give rise to various adverse consequences such as eutrophication, build-up of antibiotic residue, greenhouse gas (GHG) emissions and spreading of pathogens. In this study, a comparison was drawn to determine which thermochemical conversion technology is suitable for treating poultry litter keeping direct land application (DLA) as a baseline scenario. In line with ISO 14040 and 14044 standards, in this study life cycle assessment has been employed to calculate the environmental impacts of any process or activity. Life cycle inventory analysis and impact assessment of six processes including, Incineration (IC), Fast Pyrolysis (FP), Slow Pyrolysis (SP), Gasification (G), Hydrothermal Carbonization (HTC), Hydrothermal Liquefaction (HTL) on categories such as human health and ecosystem quality is evaluated in comparison with direct land application. Using input data from a local Islamabad based poultry farm and LCA software Simapro 9.3.0.3, Impact World+ Endpoint method was performed to categorize the level of impacts of each process. As midpoints are converted to damage categories, the results show that Incineration, Fast Pyrolysis, Gasification, Hydrothermal Carbonization and Slow Pyrolysis outperform direct land application for both categories of ecosystem quality and human health. Hydrothermal liquefaction has the highest impact on both damage categories, whereas Incineration is the most favorable option. This is linked to the highest amount of electricity produced at 550 kWh. Furthermore, the effect of uncertainty of the input parameters on results is noted using sensitivity analysis of all the processes, in order to check which parameters have the highest impact and the amount of value-added products produced.