This document summarizes a study on treating dairy wastewater using an upflow anaerobic sludge blanket (UASB) reactor. The study tested treating dairy wastewater from a dairy plant in India using a UASB reactor over varying hydraulic retention times. Key findings include: - The UASB reactor effectively removed biochemical oxygen demand, chemical oxygen demand and other parameters, achieving a maximum 78% COD removal rate. - Both COD removal efficiency and biogas production increased as hydraulic retention time increased, up to 43 days when gas collection was highest. - Parameters like temperature, pH, microbial populations and ammonia levels affected reactor performance. - The UASB reactor is