Alternate: City of Los Angeles, Bureau of Sanitation (LASAN) Utilizing Innovating Technology For Increasing Carbon Life

ABSTRACT
City of Los Angeles Sanitation and Environment (LASAN) owns and maintains 10,800 kilometers (6,700 miles) of sewer and operates three Air Treatment Facilities (ATF) and ten Carbon Odor adsorbers located along the sewer system for removing odor and other related constituents from the collection system. The ATFs utilize Bio-trickling Filters (BTFs) technology followed by carbon adsorbers as polishing units while the Carbon scrubber sites utilize carbon adsorbers as the only treatment for foul air. In order to improve carbon life and reduce the footprint required for carbon vessels, LASAN started conducting a series of pilot tests to evaluate alternate carbon odor adsorbers with suspended media for all-around air flow compared with traditional flow carbon design. The results of this test were published in Water Environment Federation (WEF) Odor Conference in 2018 (Haddad-Zadegan/Gilani, WEF Odor Conference 2018 and UCLA Odor Conference 2017). The purpose of this test was to evaluate the performance of the new carbon vessel design with Suspended Media Chamber (SMC) and all-around air flow which provides larger media surface area, smaller footprint, and capability to separate moisture from the inlet air stream. This testing project conducted a side-by-side comparison between a deep bed traditional vertical upward air flow and the new all-around air flow design. LASAN procured and installed the new vessel design at eight (8) City carbon scrubber sites and this paper will share the result of the new scrubbers in term of their capability on removal of Hydrogen Sulfide (H2S) and other odorous compounds Volatile Organic Compounds (VOCs) from the inlet air stream. The new vessel design has the capability to separate the water voper from the inlet air stream contributing to a longer carbon life expectancy which results in significant cost savings for LASAN.