CITY OF LOS ANGELES PILOT TEST ON BIO-TRICKLING FILTERS WITH DIFFERENT pH LEVELS AND USING TREATED WATER TO IMPROVE PERFORMANCE

摘要

The LA Sanitation and Environment owns and operates three Air Treatment Facilities (ATFs) logistically located along with the sewer system for removing odor and other related constituents from the collection system. These ATFs utilize Bio-Trickling Filters (BTFs) followed by carbon scrubbers as polishing units. City's Biological Air Treatment Facilities have one of the highest freshwater usages in the whole Bureau and approximately consume 15 million gallons of fresh water per year. The purpose of this test was to identify an alternative source to replace the current water consumption for the BTFs while evaluating the performances of the BTFs under different pH operating conditions. Several pilot tests were conducted to evaluate and improve the biological process performance in terms of odor and specific compound removal efficiencies under different pH irrigation conditions, and using treated wastewater to substitute for fresh water as the source of make-up water. The removal efficiencies of BTFs for Hydrogen Sulfide (H2S), speciated Volatile Organic Compounds (VOC) and Total Non-Methane Hydrocarbon (TNMHC) were measured and recorded for different pH levels during these tests. The purpose of this testing project is to evaluate performance in BTFs in terms of its odor and specific compound removal efficiencies under new water used for irrigation. Also, a side by side comparison was conducted to compare the BTF's performances for the BTFs using treated water, fresh water, and Plant Effluent water (HPE) as the source of the make-up water. The knowledge and information gained from the results of these tests are used to save water in BTF operation procedure followed at the City's collection system Air Treatment Facilities (ATFs).