Optimization of a Wet Scrubber with Electrolyzed Water Spray-Part Ⅰ: Ammonia Removal.

Electrolyzed water (EW) is an effective disinfectant with a wide range of pH. EW in acid range was proved to be ammonia absorbent which make it valuable for wet scrubbers used in animal feeding operations (AFOs). This study aimed to optimize the design and operating parameters of a wet scrubber with EW spray for ammonia removal, based on the size distribution of droplets, the property of EW and the reduction efficiency of ammonia. The optimized parameters included droplet size, nozzle flow rates, pH and available chlorine concentration (ACC) of EW, nozzle number at single stage, stage number, initial ammonia concentration and air speed in the duct. The ammonia removal efficiency increased with the decrease of droplet size and the increase of flow rate. The pH values of EW showed significant influence on ammonia removal efficiency (P ? 0.05), while ACC of the EW showed no significant influence (P ? 0.05). For inlet ammonia concentration of 70 ppm with one and three spray stages, the wet scrubber with EW (pH = 1.35) spray was able to reduce 55.8 ± 4.3 % and 97.2 ± 3.0 % of ammonia, respectively, when the nozzles with 0.9 mm orifice diameter operated at a flow rate of 1.20 L min^-1. Response surface analysis showed that orifice diameter, nozzle flow rate, and their combination were all significant factors impacting ammonia removal efficiency for both pH =1.35 and 5.50 at a 95 % confidence level. Optimal ammonia removal efficiency was obtained at orifice diameter 0.9 mm and flow rate 1.20 L min^-1 within the selected range. The results of this study demonstrated that wet scrubber with EW spray could be a very effective and feasible ammonia mitigation technology for AFOs.