Environ aerators for efficient aeration and operational flexibility

November 15, 2014 1:21 pm

When evaluating aeration system, a total performance and cost of operation analysis are critical. The components of this analysis should include an evaluation of the initial capital cost of system installation, all operating and energy costs, and projected maintenance costs. Also included should be an analysis of how well the systems perform the four basic functions required of all aerators:• Provide sufficient oxygen transfer to promote biological treatment• Provide sufficient mixing to ensure homogeneity of mixed liquor suspended solids and to prevent solids settling• Respond to varying process conditions to maximise energy efficiency• Provide reliable service, without costly maintenance and downtime, and without reduction in oxygen transfer capability. A detailed evaluation will quickly reveal that diffused aeration systems in India are able to perform only one basic function reasonably well. On the other hand, the new generation of Environ energy efficient aerators accomplishes all four goals –, excellent mixing, operational flexibility and a life expectancy of 12 – 15 years with minimal maintenance. Diffused aeration system has gained popularity based on only one aspect of their performance: they provide high oxygen transfer efficiencies in clean water. However, the waste water is not clean. A fine bubble diffused system which performs efficiently in clean water instantly becomes less efficient in waste water. Secondly, mixing efficiency is missing in diffused aeration system.
Over a few months or so, the degrading of oxygen transfer efficiency becomes more pronounced until, eventually, the diffusers porous membranes will need to be cleaned manually. This is an undesirable and time consuming maintenance operation. Many industries like ETP, municipal corporation, STP, CETP and plant operators, environmental engineers, and turnkey executors have faced such issues.
Surface aerators, unlike diffusers, never foul, and will provide the same high oxygen transfer rate along with efficient mixing with minimum and economical running and also saving in energy over the life of the equipment.
Secondly, in diffused aeration system, as the blower blows hot air, the temperature of the effluent rises by 5 C to 8 C due to which the oxygen transfer efficiency reduces. While in Environ aerators, due to efficient mixing the temperature of the effluent reduces by 10 C to 20 C (depending on ambient temperature) and hence oxygen transfer efficiency increases.The distribution of air is also not equal in diffused aeration system. While, the air is equally distributed in all the 4 corners of the aeration tank without settlement of sludge by environ energy efficient aerators.
Spares, like diffusers, maintenance of blowers is costly and time consuming and specialised mechanic is required. In Environ aerators the additional features are provided, due to which maintenance is very low and less time consuming. Only gearbox is to be maintained which can be maintained by maintenance department. Noise level is also low in Environ aerators.
If the diffusers are placed at a short distance (220 mm) as placed in foreign countries, the power required will be more than 3 – 3.5 times than the power required in mechanical aeration system. Secondly, if the system is installed as per the recommendation of the manufacturers of foreign countries then the installation, operational and maintenance cost will also increase.