Lake Aeration
Sub surface aeration systems
Lake Aeration systems control water quality and ecosystem health by oxygenating and circulating water from the bottom of the lake to the surface.
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This circulation of bottom water to the surface breaks thermoclines and oxygenates the bottom sediments.
Lake aeration is useful to control water quality in lakes and ponds by:
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- oxygenating bottom sediments and breaking down sludge, reducing nutrient, pathogens, and BOD
- mixing and balancing of water temperature/breaks
thermocline
- circulation of highly oxygenated and degassed water back to bottom of the water body
- diffusion of oxygen directly into the water column through high oxygen transfer of colorite aerotube
- Homogenising of water quality throughout the lake/pond/dam
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This constant circulation of the water body, and upwards flow of the air plume is useful for:
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- freeze over protection
- effluent pond aeration and remediation
- livestock water aeration (Bovine, Caprine, Equine, Ovine, Porcine)
- aesthetic water feature aeration (public ponds)
- marina aeration
- water storage and fishing impoundment aeration
- golf course dam aeration
- cold water pollution prevention in water storage dams
- dock aeration
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Lake Aeration - The BTA design approach
Lake aeration systems have been around for a long time, and sub-surface bottom diffused aeration systems especially have seen many different designs and approaches.
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One thing is for certain though, especially in water deeper than 1.5 meters, you simply cannot beat the efficiency and effectiveness of diffused aeration for water quality control and oxygen transfer.
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BTA's diffuser assembly is designed to maximise oxygen transfer as well as maximising circulation of the water at high rates to provide the best water quality and health possible.
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The objective of lake aeration is to circulate oxygenated water from the surface of the water to the bottom, where the oxygen can fuel waste breakdown and improve water quality.
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While the colorite aerotube in these diffuser assemblies does have very high oxygen transfer, especially at water depths over 1.5 meters, the main source of oxygen and simultaneous removal of toxic gases and waste products/nutrients from the water is from circulation of water volume.
The constant movement of low oxygen water to the surface, and circulation of oxygenated water to the bottom provides a more homogeneous dissolved oxygen level throughout the water body while also working to mix water chemistry and quality as a whole.
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As the plumes of bubble dense air rise through the water column towards the waters surface, they bring cold water, low in oxygen and potentially higher in dissolved gases (like CO2 and H2S) from the bottom to the warmer surface layers in the lake/pond.
The constant movement of this cold and oxygen low water to the surface, where it termintes at the surface and the upward velocity of the aeration plume is no longer directly effecting its position in the water column.
This water is more dense than the surface water, and this difference in density cause the water to sink back through the through the differing layers of water densities to a depth of of where it becomes neutrally buoyant again and moves away from the origin of the bubble plume. this constant exchange of different density water causes mixing in the local vicinity of the aeration plume, this constant mixing results in constant disruption of the differing water density structure and thus breaks thermal stratification.
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Lake Aeration- how BTA differs
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As such, BTA's subsurface aeration systems are designed based on the design volume of the lake or pond to provide the correct turnover rates.
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Oftentimes, sizing of lake aeration systems has been based on "average" water depth of the lake/pond and a surface area recommendation given based off of this average volume.
Some approaches even use water depth up to 4.5meters to increase their ratings assuming that depth improves effectiveness, when it is in fact the reverse, as deeper water volumes are slightly more challenging to mix.
As depth increases per m2 of surface area, the size of the system required increases as the volume does. Recommending the same system to suit a larger water volume as the volume increases is assuming that somehow the system moves more water the deeper it is applied when that is not the case.
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TECH NOTE: ------ if water volume is not known, more accurate volumes than a simple average water depth calculation can be achieved by measuring water depth across several points in the water body and taking into account sludge depth.
Mapping of the surface area can then be done, these areas with different depths split up, and a far more accurate volume can then be calculated and used for sizing.
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When a lake aeration system is applied, It should be based off the actual operating volume and applied to achieve a water turnover rate of between 24 hours (for smaller volumes) up to 48 hours for very large and deep water bodies that can regulate water quality better simply based on their excess volume and depth with a lower turnover rate.
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Whilst air pump/compressors/blower's remain relatively standard across the industry, the diffuser assembly used is critical to maintaining circulation and oxygen transfer.
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The DUAL PLUME aeration assembly features Colorite Aerotube as the diffuser tube for much more than its flexibility:
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- Very high oxygen transfer efficiency compared to other diffusers
- Easy to replace if needed
- Resistant to blocking
- Resistant to breakdown
- Inbuilt antimicrobial to prevent growth
- Very low pressure loss
- Evenly distributed pores for most effective aeration
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This makes Colorite a very effective diffuser option for all applications where diffused aeration can be applied.
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DUAL PLUME aeration assemblies have the following features:
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- 10mm 316SS diffuser mount, Completely machine rolled and TIG Welded
- strain relief on both the barb assembly and for the delivery tube
- available with 13mm, 16mm or 19mm hose barbs
- All barbs are clamped with quality Antelco hose clamps
- All barb fittings are quality Antelco irrigation fittings
- All hose joins clamped with Oetiker hose clamps.
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The double level DUAL PLUME design of the diffuser assembly allows for unseen water movement for a lake aeration diffuser assembly.
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- double level diffuser placement allows for passage of debris preventing blocking or snagging
- double level allows for larger passage of water in and around each plume of air
- DUAL PLUME creates localised velocity resulting in high water flows, ideal for degassing and distribution of oxygen
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Critcal Hardware
Custom Solutions
While our off the shelf systems suit a wide variety of applications sometimes we need to custom design a system due to the environment, water quality or odd sized water bodies such as large surface area vs shallow depth.
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Applications we can custom make solutions to are:
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Higher oxygen demand systems (such a waste settlement/effluent ponds)
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High levels of dissolved minerals that may require oxidation (eg: iron)
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Higher water quality requirements (such as supply dams for hatcheries)
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Shallow water vs high surface area water bodies
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Larger water volumes requiring custom compressor solutions
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Additional weather/soundproofing systems for larger installations, especially those in public areas.
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