Calculating Rainfall Flow into an Oil-Water Separator

This paper describes a methodology for estimating rainfall discharge to an oil-water separator.The methodology is part of a comprehensive program for substation maintenance analysis developed by Hydro-Quebec.One purpose of hydraulic systems in substations is to collect rainwater with residual oil through a series of different types of oil collection pits connected to a system of conduits in turn connected to an oil-water separator.The oil collection pits and the separator are designed to protect the environment from oil spills or leaks.The methodology developed determines discharge from the pits through outlets of various design using a method of explicit time integration of analytical and empirical equations.One-dimensional Saint-Venant equations were solved by successive approximation using the under-relaxation method to model flow in the conduit network.A fictitious substation is used as an example and the accuracy of the results is analyzed and confirmed.