Aeration is used in water and wastewater treatment processes to deliver oxygen to microorganisms responsible for the biological oxidation of carbonaceous material and ammonia. Aerobic processes are used to degrade biological oxygen demand (BOD), chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), and ammonia from the water. Dissolved oxygen (DO) is a fundamental control parameter in aerobic processes.
Many treatment processes lack sufficient dissolved oxygen due to excess loading, under-performing aeration systems or antiquated designs. Low dissolved oxygen levels encourage the growth of filamentous bacteria that can cause process upsets related to sludge bulking and foaming. Furthermore, low dissolved oxygen levels can result in poor treatment efficiency and lead to potential discharge violations. Adding additional aeration capacity can be complex and costly; however, adding Ultra-OXYGEN Micro and Ultrafine Bubble generators can replace and supplement under-performing aeration systems by applying biologically available dissolved oxygen exactly where it is needed to support the biological process in quick, cost-effective and modular fashion.
Business Case
Ultra-Oxygen Micro and Ultrafine bubble technology include an award-winning patented nozzle type. The technology has a unique character as it can produce more significant amounts of Micro and Ultra-Fine bubbles in the water with higher viscosity and exhibit a higher capacity for dissolving gas in the water. Therefore, Ultra-Oxygen UO2-SS/PVC 1N and the UO2-Viper can dissolve gasses such as oxygen in the water up to 90% more efficiently than currently known aeration equipment. Being able to manage the size of the bubble and flow of air, we can increase the DO levels up to 30 times faster than old technology aerators.
So what does this all mean?
So what does this all mean? Taking into consideration that aeration accounts for 25-60% of the total energy consumption of a wastewater treatment plant, it is a no-brainer that this is where you need to focus if you want to save money. Ultra-Oxygen do way more than that.
We can cut old aeration equipment’s electricity bills up to 90%, recover lost DO levels within hrs, reduce the use of chemicals drastically, drastically reduce the cost of sludge management, and produce discharge water at healthy levels suitable for re-use.
- Over 100,000,000 old-type “fine” bubble diffuser units are installed in thousands of treatment plants worldwide. ISO now classified these units as producing SMALL COURSE BUBBLES, not fine bubbles.
- Over 10,000,000 coarse bubble diffuser units are installed in thousands of treatment plants worldwide. They can now all be replaced by Micro/Ultrafine bubble generators outperforming these old dinosaurs on every level thinkable level.
- Bottom-Up aeration is now possible with Top-Down maintenance capabilities.
- MB/UFB equipment is easy to install and has a turnaround time of seeing results within 2-14 days.
- Over 900 Billion litres of Wastewater are Treated per Day with outdated aeration equipment piling up energy consumption costs.
Old vs New
Comparison
| System | Oxygen Transfer Efficiency % ( @ 4.572 m depth ) | Oxygen Transfer Rate ( kg/kW-hr ) |
|---|---|---|
| Ultra-Oxygen MB/UFB Generators | 40-65 | 25 – 45 |
| Fine-Micro Bubble Generators [old incorrect terminology – Micro Bubble Generators] | 6.1 – 16.47 | |
| Fine Course Bubble Diffuser [(old incorrect terminology – Fine Bubble Diffusers] (total floor coverage) | 22-32 | 3.66 – 3.965 |
| Fine Course Bubble Diffuser [(old incorrect terminology – Fine Bubble Diffusers] (side wall installation) | 18-20 | 2.135 – 2.745 |
| Jet Aerators [Medium Course Bubble – old incorrect terminology – fine bubble] | 18-25 | 1.83 – 2.135 |
| Static Aerators [Medium Course Bubble – old incorrect terminology – medium bubble] | 10-12 | 1.403 – 1.708 |
| Mechanical Surface Aerators [Large Course Bubble] | 1.525 – 2.135 | |
| Large Coarse Bubble Diffusers (wide band pattern) [old incorrect terminology – Course Bubble Diffusers] | 8-12 | 1.22 – 1.83 |
| Large Coarse Bubble Diffusers (narrow band pattern) [old incorrect terminology – Course Bubble Diffusers] | 6-8 | 0.915 – 1.22 |
Where is aeration implemented to treat wastewater?
In Wastewater treatment plants, dams, reservoirs and in all artificial water features. Below are the areas in a typical WWTP.
What are the benefits?
- Production of a large amount of Micro and Ultrafine bubbles with extremely high oxygen dissolubility.
- Increased saturation of dissolved oxygen in the water.
- Compact, portable, and easy installation.
- Low energy consumption (only 250W, 400W, 1.5kW).
- Low and easy maintenance.
- Mixing and reducing the biofilm media.
- To maintain the DO level for the survival of aerobic bacteria.
- For BOD removal at a fast rate and for the Nitrification process.
- Maintain the aesthetic condition of the water.
- To avoid foul smell.
WWTP’S MAIN COSTS FACTORS
The aeration system consumes approximately 50 to 70% of the net power demand for a typical activated sludge wastewater treatment plant. Therefore, the designer is responsible for selecting a system that will meet the mixing and oxygen requirements for the process at the lowest cost possible. Once the criteria for aeration are determined, comparative costs for different types of aeration systems can be estimated, and the final equipment configuration can be selected to best match the job’s requirements.
Construction cost items mainly consist of aeration basins, air piping and headers as appropriate, aeration devices and their supports, air cleaning equipment, blowers, and buildings to house these items.
New vs Old Aeration Calculations
Assumed:
Oxygen required per aerator = 77.9 kg/h
Correction factor for site solubility = 1.071 Correction factor for minimum DO in aeration tank = 1.217
Old way of calculating:
Assume transfer efficiency of 2.0 kg oxygen/kWh for slow speed aerators into clean water under standard conditions and an alpha factor of 0.85 for transfer into mixed liquor Aerator power required = 77.9/(2.0 x 0.85) x 1.071 x 1.217 = 59.7 (say) 60 kW per aerator and 60 x 6 = 360 kW for say six aerators. (402kW).
In specifying aerators, it should be borne in mind that allowance should be made for motor and gearbox efficiency. It is common practice to select a service factor of 2.0 for the gearboxes and to allow 10 to 15% additional motor capacity (say 67 kW motors in the present case).
When using the Ultra-Oxygen MB/UFB technology, the calculations look different.
The new way of calculating:
Assume transfer efficiency of 65.88 kg oxygen/kWh for slow speed aerators into clean water under standard conditions and an alpha factor of 0.85 for transfer into mixed liquor Aerator power required = 77.9/(65.88 x 0.85) x 1.071 x 1.217 = 1.813 (say) 2 kW per aerator and 2 x 6 = 12 kW for all six aerators.
No allowance is necessary for motor and gearbox efficiency because the unit is driven by a pump.
- Massive saving OF 3 350 % on electricity alone.
OTHER SAVINGS:
- The Ultra-Oxygen eliminates the construction costs related to blower rooms and associated equipment.
- 430 % more efficient than disc diffusers in dissolving oxygen in the water.