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 water. One of the fundamental control parameters in aerobic processes is dissolved oxygen (DO).
Many treatment processes lack sufficient DO due to excess loading, under-performing aeration systems or antiquated designs. Low DO levels encourage the growth of filamentous bacteria that can cause process upsets related to sludge bulking and foaming. Furthermore, low DO levels can result in poor treatment efficiency and lead to potential discharge violations. Adding additional aeration capacity can be complex and costly; however, the addition of ClaasECO-Water UFB (Ultra Fine Bubbles) can be used to supplement under-performing aeration systems by applying biologically available DO exactly where it is needed to support the biological process in quick, cost-effective and modular fashion.
Flotation is a century-old water treatment process in which gas is introduced to a pressurized liquid, generating a buoyant force and resulting in flotation of suspended matter such as fats, oils, greases and suspended solids. Little technical advancement has been made to the way in which gas is introduced to the liquid, and many facilities still use technology that is decades old and antiquated. ClaasECO-Water UFB-advanced gas-to-liquid nanobubble injection technology delivers a high volume of Ultra Fine Bubbles that greatly improves the flotation process. An exponential increase in surface area coupled with the strong negative charge of the Ultra Fine Bubbles brings new benefits to the flotation process that traditional aeration methods simply cannot achieve. These unique properties enable flotation technologies to be more efficient, typically consuming only 10%-to-20% of the energy consumption of conventional methods and help ensure compliance with environmental regulations.
The negative surface charge of Ultra Fine Bubbles limits bubble coalescence, ensuring they stay separated in solution. The bubbles charge, in combination with the high concentration of Ultra Fine Bubbles delivered to the wastewater by the ClaasECO-Water UFB equipment generator, increases the probability of collision with suspended matter and improves floatation rates.
Rise rate Flexibility
The gas-injection rate through ClaasECO-Water UFB nanobubble generator is tuneable, enabling operators to manipulate the size of bubbles produced and adjust rise rates accordingly to meet the needs of the water being treated. As bubble size decreases so does its buoyancy and subsequently its rise rate. A lower rise rate is advantageous for froth flotation of coarse particles and hard-to-float suspensions that require relatively long slide times. Meanwhile, a more rapid rise rate may be acceptable for larger, more buoyant particle removal.
Improved Chemical Efficiency
The flotation process is often heavily dependent on coagulants and flocculants to maximize particle collision rates and produce floc. ClaasECO-Water UFB-system improves this process by generating over one billion Ultra Fine Bubbles per milliliter. The sheer concentration of Ultra Fine Bubbles, coupled with their strong surface charge, increases collision rates and enhances the formation of floc. The net effect is a reduction in the quantity of chemicals needed to achieve flotation.
Most offensive odours produced in wastewater are the gaseous by-product of decomposed organic matter, usually in the absence of sufficient oxygen levels. The most common of these is hydrogen sulphide (H2S), which is formed from the anaerobic degradation of organic matter containing sulphur or from mineral sulphates and sulphites. Hydrogen sulphide is known for its rotten egg smell and can adversely impact human health at levels above 10 ppm. Odour in sewer lines, collection points, treatment plants, and ponds can lead to public complaints and reduces aesthetic value. One means of treating odours, including H2S, is to prevent the water from going anaerobic by increasing dissolved oxygen (DO) or oxidation reduction potential (ORP) using air, oxygen or other oxidants. ClaasECO-Water UFB-effective gas-injection technology delivers a high volume of air or oxygen Ultra Fine Bubbles, efficiently maintaining DO and preventing the anaerobic conditions that lead to odorous compound formation.
A ClaasECO-Water Ultra Fine Bubble generators produces over one billion Ultra Fine Bubbles, each smaller than the wavelength of light, per millilitre of water. The sheer volume of bubbles, coupled with neutral buoyancy and high surface tension, results in industry-leading oxygen transfer of greater than 90%, efficiently increasing DO and ORP and oxidizing H2S and other odour-causing compounds.
Ultra Fine Bubbles produced by the ClaasECO-Water UFB equipment system are neutrally buoyant, meaning they do not float to the surface of the water and rupture. They instead disperse following Brownian motion, distributing evenly throughout the body of water, regardless of water column depth. Upon achieving DO saturation, the remaining Ultra Fine Bubbles introduced to the body of water will remain in suspension creating a DO buffer. When DO is consumed in the water and an oxygen gradient is present, the Ultra Fine Bubbles in solution dissolve additional oxygen into the body of water, maintaining a steady-state DO concentration and preventing the formation of more H2S.
Energy Efficiency through Existing Pumping
ClaasECO-Water Ultra Fine Bubble generators operate as inline gas injection systems meaning as water flows through the generator, gas is injected in the form of a nanobubble. ClaasECO-Water UFB-systems are available with or without a pump. When supplied as the latter, customers can attach ClaasECO-Water UFB-nanobubble generators to the discharge end of a pump as long as the existing pump can accommodate certain pressure drops and still maintain necessary flow. When capable of adding the nanobubble generator to distribution pumps such as those found in pump stations and force mains, ClaasECO-Water UFB-nanobubble generators provide the most energy efficiency aeration solution on the market and can start to treat H2S and even BOD upstream of the treatment plant at a fraction of the energy of conventional aeration solutions.
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 water. One of the fundamental control parameters in aerobic processes is dissolved oxygen (DO). Many treatment processes lack sufficient DO due to excess loading, underperforming aeration systems or antiquated designs. Low DO levels encourage the growth of filamentous bacteria that can cause process upsets related to sludge bulking and foaming. Furthermore, low DO levels can result in poor treatment efficiency and lead to potential discharge violations. Adding additional aeration capacity can be complex and costly; however, the addition of ClaasECO-Water UFB-Ultra Fine Bubbles can be used to supplement underperforming aeration systems by applying biologically available DO exactly where it is needed to support the biological process in quick, cost-effective and modular fashion.
Ultra Fine Bubbles differ from the fine bubbles typically used for aeration because they do not rise to the surface and burst. Instead, they exhibit Brownian motion. They also rapidly transfer oxygen (or any interior gas) to water. Their rapid dissolution and Brownian motion provide efficient oxygen transfer throughout the water column independent of water depth. Additionally, studies have shown that a system aerated with Ultra Fine Bubbles can improve treatment efficiencies, providing more biological treatment per unit volume of bioreactor than a system aerated by fine or coarse bubbles alone.
Plug & Play
ClaasECO-Water UFB-nanobubble technology is simple to install adjacent to an aeration tank without tying into or modifying the existing aeration system. Additional aeration capacity can be implemented within hours, without the use of heavy equipment or having to take basins offline. This is, in part, the reason why ClaasECOWater Ultra Fine Bubble generators are rapidly becoming the preferred industry method to rapidly and efficiently supplement aeration.
Membrane bioreactors (MBR) have been widely applied at industrial facilities to provide pre-treatment of wastewater prior to discharge to the collection system. One of the advantages of an MBR system is that it provides a high degree of treatment in a compact footprint, in part because it is operated at high mixed liquor suspended solids (MLSS) concentrations ranging from 8,000 to 18,000 mg/L. A common problem encountered with industrial MBRs is the inability to maintain the target dissolved oxygen (DO) level during peak loading events. This is partially attributed to the nature of industrial wastewater, which is typically inconsistent in water quality and flow, resulting in periods of low influent loading followed by high influent loading. This dramatic change in loading may cause a sudden spike in oxygen uptake rate in the aeration basin immediately followed by a sustained decline in DO. If the oxygen-transfer system is not able to recover by supplying the DO required to support the biological system, BOD removal across the MBR will decline. The capital expenditure required to expand or upgrade an undersized aeration system can be substantial, often with limited to no return on investment across the expected useful life of the equipment. However, the application of Ultra Fine Bubbles in wastewater treatment provides cost-effective supplemental aeration for MBRs.