Full-Scale Interceptor Drop Structure Ventilation Analysis in Los Angeles Reveals Keys to Odor Release

摘要

Several years ago City of Los Angeles (City) engineers identified the buildup of positiverndifferential air pressure in their interceptor system as the primary cause of odor complaints inrnCentral Los Angeles. When the Northeast Interceptor Sewer (NEIS) and East Central InterceptorrnSewer (ECIS) both came online by 2005, interim odor scrubbers had been installed at five droprnstructures along the NEIS and ECIS alignments. The City subsequently recorded more odorrncomplaints when the interim scrubbers were running than when they were turned off, especiallyrnalong the shallow North Outfall Sewer (NOS) segments that carry flows to the NEIS and ECISrnvia the drop structures. This raised a question among City officials as to the ultimate need ofrnpermanent Air Treatment Facilities (ATFs) at these locations. A study, which is the subject ofrnthis paper, was then commissioned by the City to answer this question.