As the United States is making a significant move towards rejoining the Paris Agreement on climate change, there is a high demand for sustainable solutions across various industries, including construction and hospitality sectors. The aim of this project was to design and model an on-site greywater treatment system for a hotel building for the effective reuse of sewage water. The study considered Los Angeles, California, as a case study location and referred to respective climate conditions and construction standards. This study considered various options of greywater treatment plants such as Membrane Bioreactor (MBR), Sequencing Batch Reactor (SBR), and Reverse Osmosis with Upflow Anaerobic Sludge Blanket (RO with UASB) which were carefully reviewed and modeled through the GPS-X software. The design and modeling results were verified by hand calculations and were followed by the estimation of capital and operational expenses required for the implementation of the plants. Having relatively low capital and operational expenditure requirements as well as superior technical performance, the MBR plant proved to be the most effective solution for the considered location and standards and was recommended for use in hotel buildings
