Intensive farming, which is widely implemented in agricultural sector and food production to achieve global food security, generates substantial amount of wet biomass waste including annual production of 3 billion tons of wet manure, 10 million metric tons of acid whey, and 1.6 billion tons of wasted food in the U.S. Mismanagement of these wastes through a linear economic model (e.g., composting, direct use as liquid fertilizer, and incorporation of anaerobic digestate into soil) poses several potential environmental threats, e.g., greenhouse gas emissions, eutrophication and acidification of water basin, aerosol pollution, acid rain, and cross-contamination risk between the farm and food production facilities. In this dissertation, the implementation of circular bioeconomy was used to develop a model framework. This framework includes hydrothermal liquefaction or HTL (i.e., with biocrude oil as the main product) and struvite crystallization (i.e., with solid slow-release fertilizer as the main product) as key processes for maximizing the performance of valorization of wet biomass waste, particularly acid whey and anaerobic digestate of cattle manure, into high value-added products in a sustainable manner. An evaluation of the performance of HTL and struvite crystallization was conducted by investigating the chemistry, thermodynamics, and kinetics of respective process in order to specify a range of optimal process conditions for controlling target products’ composition and properties relevant to energy and nutrient recovery goal. A method to comprehensively characterize the elemental speciation of the solid HTL byproduct namely hydrochar and the underlying chemistry of its formation was developed to modify products characteristics by adjusting the HTL process conditions. Mechanistic, optimization, and characterization results obtained through well-designed HTL and crystallization experiments were used to inform future development of agricultural and food waste management systems that may include the integration of several processes into the HTL-Crystallization systems for more sustainable outcomes.