An Experimental Study of Reducing Back Pressure of Fine Air Diffuser Used in Wastewater Plants

Aeration is the process at which air is added to water, an essential stage in wastewater treatment plants, since most of organic compounds are being treated through such an aeration process. This process also helps aerobic bacteria to survive from oxygenation to proliferate and digest organic materials. However, aeration consumes around 60% of the total cost of remediation. Therefore, any improvement in aeration efficiency (AE) will save a considerable amount of energy consumption. One way of reducing the power required is to decrease the back pressure of the air diffuser itself. In this study, a new material for manufacturing of fine air diffuser is presented. Polypropylene (PP) membrane, which is the new material chosen, shows lower back pressure values in comparison with Silver Series 2 (SS2) membrane at relatively low flow rates. The main reason behind choosing Polypropylene (PP) is that it has lower material resistance than SS2 with maintaining the capability of operation at the same pressure ranges in the aeration process. Despite the fact that SS2 has better oxygen transfer efficiency (OTE), PP membranes have significantly lower back pressure at relatively low flow rates which resulted in higher AE. In addition, contact angle measurements were done for PP and compared with previous measurements for the contact angle of SS2.