pH Enhancement of Iron Salts with Magnesium Hydroxide to Control Malodorous Compounds in the Wastewater Collection and Treatment Systems

Orange County Sanitation District (OCSD) has experienced significant cost increases and short-term supply limits due to chemical price increases and sustainability concerns. OCSD continues to diversify and improve odor control performance within its collection system. Due to volatile iron prices, OCSD's objective is to reduce future iron usage. OCSD has previously reported on methods used to continually optimize the odor control program in the collection system using both administrative measures and results of full-scale field tests; however, little data was available at the time on cost-performance benefits of ferrous chloride in combination with magnesium hydroxide.OCSD conducted a field trial that resulted in a full-scale proof of concept. OCSD used a novel treatment approach that integrated a combination treatment of ferrous chloride with magnesium hydroxide in a synergistic manner that allowed iron to be added efficiently to improve cost-performance.