Alkaline Hydrolysis of Swine Mortalities and Using Hydrolysates to Grow Lettuce Hydroponically

Abstract

HighlightsAlkaline hydrolysis is an effective way of managing livestock carcasses.The hydrolysates can be aerobically treated to prepare a nutrient solution.Mixing the nutrient solution with a traditional fertilizer increases lettuce quality.The fertilizer expenses of hydroponic lettuce growth can be reduced by 50%.Abstract. Animal mortality management is an essential part of livestock production. Choosing a proper method to handle mortalities is essential for preventing the spread of animal diseases and maintaining the sustainability of livestock facilities. The objectives of this study were (1) to test the efficacy of alkaline hydrolysis at ambient conditions to dispose of piglet mortalities, and (2) to demonstrate if the hydrolysates of the alkaline hydrolysis process could be used to grow lettuce hydroponically. Three alkaline concentrations (1M, 2M, and 4M) were tested to hydrolyze piglet mortalities. The pH of all alkaline solutions stayed above 12.8 for 31 days, which could eliminate all the pathogens that might concern swine producers based on previous studies. The hydrolysates were neutralized using corn silage with a pH of 3.9 ±0.2 and aerobically treated for 15 days. After aerobic treatment, mixing 20× diluted hydrolysates with 2× diluted control (commercially available fertilizer) provided the highest yields (on average, 18.2% more fresh weight compared to control). This mixture also yielded the highest chlorophyll and total soluble sugar content. We concluded that alkaline treatment of piglet mortalities at ambient temperature and pressure was feasible, and the neutralized and aerobically treated hydrolysates could be used to grow lettuce, reducing the risk of environmental releases. Keywords: Alkaline hydrolysis, Hydroponic, Hydrolysate, Livestock, Mortality, Real-time sensors.