While evaluating aeration systems, a total performance and cost of operation analysis is 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 an analysis of how well the systems perform the four basic functions required of all aerators should be included:

• 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.

In any biological aeration system, apart from oxygen transfer, mixing criteria is equally important and it is a must. In an aeration system having any type of effluent the outlet results cannot be achieved, if the mixing efficiency is missing, which many manufacturers and consultants fail to consider. Aeration systems, offered by Vadodara-based Environ Engineering Company, are precisely designed to deal with these shortcomings.  

Environ Engineering Company, having R&D since its inception, is continuously working to increase the oxygen transfer rate along with high mixing efficiency of mechanical aerators. It has developed an energy efficient aerator which can
offer the results of up to 6 metres water depth with minimum energy consumption.

Unique features
J.C. Thakore, Managing Director, Environ Engineering Company explained the unique features of Environ Aerators as follows:
• Fabricated and machined base frame for 5 HP to 15 HP and for 20 HP and above ratings heavy ISMB beam base is provided so vibrations are reduced.  The base is machined on the top surface on heavy-duty lathe so the life of the gearbox is increased.

• Cantilevered load reaction is passed through additional bearings and housing to bottom of the beam base and to RCC platform. So, gear is not at all affected by overhung load. Hence, life of the gearbox is increased.

• Additional bearing support is provided to the aerator shaft so the unbalanced cantilevered loads are not passed to the output shaft of the gearbox. Those loads are taken by two extra bearings provided with housing. Thus the life of the gearbox is increased. Also the maintenance of the gearbox is also very easy. One needs to loose the four bolts of gearbox and six bolts of coupling to take out the gearbox.

• Amply designed MS fully machined solid shaft to take care of heavy cantilevered, unbalanced and torsion loads, supported on two heavy-duty antifriction bearings housed in heavy-duty cast iron bearing housing. Since, shaft is fully machined, no possibility of voubling of shaft concentric running of impeller is ensured. Also tubular shaft in aerators with helical gears are provided.

• Impeller is designed as single shrouded pump impeller to achieve maximum oxygen transfer and mixing efficiency. Being a semi-open type impeller, it has got very valuable features of self cleaning. Hence practically zero maintenance is required for the impeller. Secondly, the impeller is machined at centre for its concentric running. Secondly, due to conical impeller and solid MS shaft, CG lies nearer to centre, so less impact loading.
• New generation of Environ energy efficient aerators having the unique feature of additional impeller at the bottom for efficient mixing at the floor level of aeration tank having tank water depth up to 6 metres. Due to which the oxygen transfer efficiency of the impeller is increased and hence with lesser HP more oxygen transfer is achieved. Secondly, less area is required due to water depth of 6 metres. Civil construction cost and the space required will be less hence economical. It avoids settlement of sludge at the floor level up to 6 metres water depth.

• The life of this aerator is about 12 – 15 years. Environ Engineering guarantees life-long no variation of results in all the four corners of the aeration system due to efficient mixing. Also, maintenance is almost nil in this aerator.

How the aerator works
Mr Thakore detailed the working of Environ Energy Efficient Aerator as follows:
• The top impeller has very high oxygen transfer capacity and the bottom impeller is provided for rigorous mixing.

• With the provision of an additional impeller, vortex is created at the bottom which breaks the pressure of the effluent and do
not allow the sludge to settle at the bottom floor level of the aeration tank.

• Due to rigorous and thorough mixing, the solubility of oxygen is more. So, oxygen transfer efficiency is increased with less energy consumption.

Guaranteed performance
“Environ aerators can reduce minimum 20 per cent to maximum 70 per cent of energy in any existing aeration system having the water depth of up to 6 metres,” informed Mr Thakore.

Environ aerators can reduce minimum 20 per cent to maximum 70 per cent of energy in any existing aeration system having the water depth of up to 6 metres.

J.C. Thakore,
Managing Director,
Environ Engineering Company