Design and application of new type of oxygen supplier for water and wastewater treatment
A new oxygen supplier was designed to inject both ozone and air into the water under high pressure. The oxygen transfer coefficient (KLa) of the system with air and ozone were 0.0264 and 0.4900, respectively. The oxygen transfer efficiencies of the system with ozone and air were 73.58 and 52.17%, respectively. The system could be applied to increase the dissolved oxygen (DO) in domestic wastewater. DO of the wastewater from septic tank was increased from 0.0 to 4.9 ± 0.5 mg/L within 1.6 h by the system with air injection and up to 8.0 ± 0.5 mg/L within 1.6 h with ozone injection. The system with ozone injection could reduce the COD and BOD5 by 54.6 ± 3.5 and 50.9 ± 3.4%, respectively, by increasing the DO. The system could be also be applied into shrimp ponds to increase DO. The DO of the water was increased from 2.5 to 4.3 ± 0.5 and 6.1 ± 0.7 mg/L within 20 and 80 min, respectively, by the system with ozone injection. Also, the system could reduce the organic matter during operation. The COD and BOD5 were reduced by 81.2 ± 1.2% and 57.1 ± 3.0%, respectively, within 1.6 h by the system with ozone injection.