GHG Emission Reduction and Renewable Energy Production Through Anaerobic Digestion of Organic Wastes and Biogas Production

本研究计划涵盖与沼气生产和厌氧消化相关的三个主要研究方向，包括养分回收、原料配方优化和厌氧消化(AD)过程建模。主要目标是：i)开发从厌氧消化液中回收氮、磷和钾(NPK)作为生物肥料的综合营养回收工艺，ii)优化原料配方，最大限度地提高沼气产量，并使用不同类型的有机材料的不同组合将工艺抑制降至最低，iii)对AD工艺进行建模，包括预处理、消化和下游加工，考虑到该工艺中所有可能的抑制效应、氨去除和养分恢复。根据这一详细的研究计划，每个方向都有几个细分目标，最终导致解决目前沼气领域的这些重要挑战。在第一个研究方向中，将重点放在将NPK从沼泽中分离出来，以实现两个目标。首先，生产一种营养丰富的产品作为生物肥料，取代商业无机肥料，减少温室气体排放，关闭营养循环。第二，减少数字地产的体积，避免目前的运输成本和环境问题。待测试的分离方法包括电磁除磷和生物聚合物处理技术。将研究不同的分离技术，如膜过滤、蒸发、斜率屏蔽以及这些技术的组合，以开发一种从沼气中生产生物肥料和水的工艺。在第二个研究方向，主要的重点将是制定指导方针，以制定优化的原料配方，最大限度地提高生产率，最大限度地减少工艺抑制，同时为沼气厂的健康运行提供所有必要的底物。这将允许根据每种材料类别(蛋白质、脂肪、CHO、木质素和纤维含量)制定原料配方，以预测可获得特定原料的工厂的沼气产量。主要的好处将是最大限度地提高生产率，而不需要运行耗时且昂贵的实验室测试。最后，第三个研究方向的重点将是开发一个模型来模拟从前端到后端的AD过程，包括前处理、消化和下游处理。该项目的主要重点之一将是研究氨的抑制作用，并通过纳入氨汽提过程来增强该模型。该项目的主要好处包括：评估未知行为的新基质，降低基质评估成本，验证工艺稳定性，预测关键成分，模拟厌氧消化与氨汽提相结合的过程，以及消化池中复杂相互作用的基质行为。

This research plan is designed to cover three main research directions related to biogas production and anaerobic digestion including, nutrient recovery, feedstock recipe optimization and Anaerobic Digestion (AD) process modelling. The main goals are: I) to develop an integrated nutrient recovery process for Nitrogen, Phosphate and Potassium (NPK) recovery from anaerobic digestate to use as biofertilizer, II) to optimize the feedstock recipe to maximize biogas production and minimize the process inhibition using different combinations of varied types of organic materials, and III) to model the AD process including pre-treatment, digestion and downstream processing considering all possible inhibitory effects, ammonia removal and nutrient recovery in the process. Based on this detailed research plan, there are several breakdown objectives for each of these directions ultimately leading to address these current important challenges in the biogas field. In the first research direction, the focus will be on separating NPK from digestate for two objectives. First, to produce a nutrient-rich product as biofertilizer replacing commercial inorganic fertilizers reducing GHG emission and closing the loop for nutrients. Second, to decrease the volume of the digestate to avoid the current transportation costs and environmental issues. The separation methods to be tested include electromagnetic phosphorous removal and biopolymer treatment techniques. Different separation techniques such as membrane filtration, evaporation, slope screen and the combination of these techniques will be investigated to develop a process to produce biofertilizer and water from digestate. In the second research direction, the main focus will be on developing a guideline to formulate the optimized feedstock recipes maximizing the productivity and minimizing the process inhibition while providing all necessary substrates for healthy biogas plant operation. This will allow to formulate the feedstock recipe based on each material category (protein, fat, CHO, lignin and fiber content) to predict the biogas production in the plants where specific feedstock materials are available. The main benefit would be maximizing the productivity without the need to run time-consuming and expensive lab-tests. Finally, the focus of the third research direction will be on developing a model to simulate AD processes from front-end to back-end including pretreatment, digestion and downstream processing. One of the main focuses of this project will be investigating the inhibitory effect of ammonia and also to enhance the model by incorporating the ammonia stripping process. The main benefits of the proposed project include evaluation of new substrates with unknown behavior, reduced cost for substrate evaluation, process stability verification, prediction of critical components, simulating the anaerobic digestion combined with ammonia striping and substrates behavior of complex interactions in a digester.