Air Purification at a Wastewater Treatment Plant
Ludmila Ziabrikova, Arseny Fokanov and Alexander Shallar
NPO ENT Ltd., St. Petersburg, Russia
Wastewater treatment systems, located near population centers, create problem air pollution and unpleasant odors for the inhabitants of closely spaced buildings. Air pollution – in particular, hydrogen sulfide (H2S) – occurs at the aeration step by evaporation from the exposed surfaces of the wastewater containing sewage.
NPO-ENT has developed a device using an Advanced Oxidation Process (AOP) for air purification. This device is a metal case that contains fans, low-pressure mercury lamps and a photocatalytic filter installed in the air flow across the exposed surfaces (see Figure 1). The air flow of the device is 1700 m3/h. Device tests were carried out on an urban wastewater treatment system with a capacity of 350,000 m3/day.
The device was located outdoors, 3 m above the surface of the wastewater. Tests were conducted with daytime sunlight, 26°C air temperature, wind speed of 2 to 5 m/s and humidity 73%. Air samples before processing were taken 5 m from the entrance to the device. Air samples after processing were taken from the device exit (see Figure 2). Distinctions of gas dynamic samplings conditions on the entrance and exit of the device were taken into account. The test results are in Table 1.
Plans are to carry out indoor tests of all stages in a wastewater treatment plant with application to an exhaust ventilation of devices on the AOP technology for air protection of inhabited places.