Design and Techno‐Economic Analysis of a Process for Transforming Pig Manure into a Value‐Added Product

Abstract

This study involves the design and techno-economic analysis of a process that couples biodrying and conventional drying to increase the economic value of liquid pig manure sludge, by transforming it into a stable organic fertilizer. The process has signifi cant environmental benefi ts compared to other disposal methods, especially considering recent legislative changes restricting the spreading of liquid pig manure, and at the same time provides a return on investment. It was found that the rate of return for the process was 14%, but could reach 25% if the price of the fertilizer product increases as expected.On a effectué la conception et l'analyse technico-économique d'un procédé qui couple le bioséchage et le séchage conventionnel pour accroître la valeur économique de la boue de lisier de porc liquide, en le transformant en un fertilisant organique stable. Ce procédé présente des avantages environnementaux signifi catifs comparativement à d'autres méthodes d'élimination, surtout si on considère la nouvelle législation qui restreint l'épandage du lisier de porc, d'autant qu'il s'avère rentable. On a trouvé que le retour sur investissement était de 14%, mais qu'il pourrait atteindre 25% si le prix du fertilisant augmente comme prévu.

Brief Analysis of the Sludge Bio-Drying Process

“…Moisture is vital to the proper functioning of the microorganisms. The cell membranes must remain permeable to a steady flow of soluble nutrients by osmosis [15] .The metabolic reaction can theoretically take place at high moisture levels, but such levels decrease the availability of oxygen needed to sustain aerobic decomposition. This is due to the slow diffusion of oxygen into the thick liquid biofilm that separates it from the microorganisms [16] .…”