Wastewater Aeration |
Free Cost Estimate For Your Wastewater Aeration |
What is the Difference between CLEAN-FLO International Wastewater Continuous Laminar Flow Inversion and Wastewater Aeration?
Before 1970 the Water Pollution Control Federation had determined that fine bubble bottom air diffusers were by far the most efficient and energy saving of all types of wastewater aeration systems. The problem was that fine bubble diffusers quickly clogged. So the majority of the wastewater treatment industry went to the less efficient surface aerators. Surface wastewater aerators not only sit on the surface, they also oxygenate only the surface water of wastewater lagoons, leaving the rest of the lagoon water anoxic (without oxygen). Most important, in temperate and colder climates, surface aerators often freeze in the winter, rendering them useless. Our wastewater aerators have a unique design that allows us to achieve high capacity water movement with aeration.
In designing its first wastewater aeration system, CLEAN-FLO tackled all the toughest problems. Because of the energy crisis, the wastewater aerator had to be a fine bubble bottom diffuser. But it had to be non-clogging. It had to be more efficient than wastewater surface aerators. It had to remove odor. And it had to remove bottom organic sediment (muck). To achieve these goals, the CLEAN-FLO wastewater aeration system had to be especially engineered to be non-clogging and to have the following characteristics:
CLEAN-FLO Wastewater Aeration System Characteristics
CONTINUOUS: To accomplish these great improvements over existing wastewater aeration systems, it had to operate continuously without failure.
LAMINAR FLOW: To be the most efficient of all fine bubble bottom diffusers and not stir up bottom muck and not mix phosphorus, nitrogen and other pollutants in the muck into the water column, wastewater aeration must not create turbulence. It must create a laminar flow of the water from the bottom to the surface without mixing bottom water in with the wastewater lagoon water.
INVERSION: To duplicate nature, which kept lakes clean for thousands of years, the CLEAN-FLO wastewater aeration system had to be properly engineered to duplicate spring and fall turnover, or inversion, of lakes several times a day. The reason for this is because our wastewater aerator brings water to the surface where it spreads out in a thin sheet 0.1 inches thick. Oxygen transfer from the atmosphere to the wastewater is then much higher than it is in standard clean water tanks, which have very low surface area.
OXYGENATION: To bind phosphorus and nitrogen to the bottom sediment instead of re-suspending it into the water column, the wastewater aeration system had to be engineered to fully oxygenate the water from surface to bottom. It also had to oxygenate the bottom so bacteria and insects could feed on and biodegrade organic sediments and so anaerobic bacteria would not produce odors and toxic gases.
The CLEAN-FLO Continuous Laminar Flow Inversion and Oxygenation System was successfully engineered and designed in 1970, and accomplished every one of these goals. The system is still today the only wastewater aeration system to our knowledge capable of doing all these things. To our knowledge, other than inefficient coarse bubble diffusers, competitive fine bubble bottom diffuser aerators are known to quickly clog.
CLEAN-FLO International has two types of wastewater diffusers.
Fine Bubble Diffuser: The most efficient diffuser is fine bubble, usually non-clogging microporous ceramic. This is not used in oil-laden water, as the oil will quickly clog the ceramic. In worst-case conditions in non-oily water, they may have to be cleaned twice a year, or replaced once a year.
One severe problem with bottom diffusers is that when they fail, the entire lagoon has to be drained and people have to wade on the bottom of the pond to replace defective diffusers.
To avoid this nuisance mess, CLEAN-FLO International developed self-sinking wastewater diffusers that can be raised and lowered from the surface.
Medium Bubble Diffuser: Some companies have developed expensive and energy guzzling coarse bubble diffusers to avoid the clogging and replacement problem. CLEAN-FLO International developed an economical medium bubble diffuser that is non-clogging. This diffuser can also be lowered to the bottom and raised back up for inspection.
Improving the efficiency of existing surface aerators, the CLEAN-FLO waste water diffusers completely mix the entire lagoon, surface to bottom. This means that a few diffusers can be placed on the bottom of an already surface-aerated lagoon. The waste water surface aerators can now oxygenate all the water in the lagoon, which up to doubles the present efficiency of the surface aerators. Some of the surface aerators can then be turned off.
• If your existing wastewater surface aeration systems are not meeting discharge standards, adding a few CLEAN-FLO bottom diffusers to your lagoon will economically and effectively increase oxygen transfer and save energy costs.. • If you are set on purchasing wastewater aerators, by all means add a few CLEAN-FLO wastewater bottom diffusers to the package to get much more oxygen transfer efficiency at much less capital and energy cost.
Bottom diffuser comparison: Carr and Martin1 reported the following oxygen transfer efficiencies for bottom air diffusers in lake water:
Venturi type: 1.8 lb O2 / hp-hrPerforated Pipe: 2.2 lb O2 / hp-hrCLEAN-FLO 4.4 lb O2 / hp-hr
Clean Water and Waste Water Comparisons:
CLEAN-FLO International tested oxygen transfer efficiency in standard clean water for rubber membrane wastewater diffusers, and the efficiency was the same as our fine bubble ceramic diffuser. However, rubber membrane diffusers quickly clog in wastewater, so that the remaining unclogged holes become much larger. Then the oxygen transfer quickly drops considerably. Rubber membrane diffusers are also known to tear.
CLEAN-FLO International measured oxygen transfer of the microporous ceramic diffusers in standard clean water and found it to be 1.8 kg / kW-hr.
In waste water, contrary to other wastewater aerators in which oxygen transfer goes down, the efficiency of the CLEAN-FLO diffuser greatly increases. This is because the CLEAN-FLO wastewater aeration system moves the bottom water continuously across the surface of the lagoons.
Oxygen transfer from the atmosphere is added to the oxygen transfer from the rising bubbles free of energy expense, increasing the Oxygen Transfer Efficiency in field tests up 9.8 kg / kW-hr for CLEAN-FLO medium bubble diffusers and up to 19.6 kg / kW-hr for CLEAN-FLO ceramic diffusers, depending on the surface area of the wastewater lagoons and the retention time.
Please compare the CLEAN-FLO International diffusers to the Table 5.1 taken from the Water Pollution Control Federation.2 Comparing the average field results of The aerators shown in Table 5.1, CLEAN-FLO reduces energy consumption by up to 88 – 95 percent! Because these efficiencies are so unexpectedly large, CLEAN-FLO always includes a Safety Factor of 2 in our design, saving the client up to 80 – 88 percent in energy consumption while including a residual discharge Dissolved Oxygen level of 2 mg/l.
| Aeration Efficiency, kg O2 / kW-hr | ||
| Aerator type | Standard | Field |
| Microporous Ceramic | 1.77 | 19.6 |
| Medium Bubble | 0.9 | 9.8 |
References1. Carr, Joseph E. and Dean F. Martin, 1978. Aeration Efficiency as Means of Comparing Devices for Lake Restoration. Department of Chemistry, University of South Florida, Tampa, Florida. Journal of Environmental Science $ Health, A13(1), 73 – 85.2. Water Pollution Control federation, 1988. Aeration a Wastewater Process.
