Participatory budgeting is a democratic approach to decision-making in which citizens or residents of municipalities and communities directly vote on the allocation of public resources to projects and proposals. The combinatorial model of participatory budgeting, in which projects must either be fully or not at all funded, is widely solved using an arbitrarily bad greedy approach which fails to utilise the resources maximally. This project aims to improve participatory democracy by investigating, designing and evaluating optimisation algorithms to identify more accurate, feasible alternatives to this greedy approach, and implementing these in a budget allocation library for e.g., budget decision-makers, researchers and students to solve their own problems.