Destratification and aeration of drinking-water reservoirs, service tanks and lakes — oxygenating the water column, suppressing cyanobacteria and controlling iron, manganese and taste-and-odour at source, before they ever reach the treatment works.
Three disciplined stages turn a water body into a defensible aeration design — geometry first, analysis second, sizing last.
Every assessment begins with a bathymetric survey — the depth–area–volume curve, morphometry and per-position bed depths that the stratification, oxygen-budget and bubble-plume models depend on. Without the basin geometry, none of the downstream numbers are defensible.
Bathymetric SurveyWe characterise the water body and model its oxygen, thermal and biological behaviour from first principles — stratification and stability indices, the hypolimnetic oxygen budget, thermal-coupling and mixing tests, and the bed-safety constraint. The aeration type is the conclusion of that analysis, not an assumption at the front of it.
Explore Our ProcessOnce the aeration type is chosen, we size and lay out the system through a full, transparent calculation chain — water physics, bubble and plume dynamics, oxygen transfer, module and array sizing, and a final set of validation checks, every number traceable to a peer-reviewed source.
The Full Design MethodologyThermal stratification turns a healthy water body into an anoxic source-water problem
In warm conditions a reservoir separates into a warm surface layer (epilimnion) and a cold bottom layer (hypolimnion) divided by a thermocline. The density difference stops mixing, so the bottom water is cut off from atmospheric oxygen and steadily goes anoxic.
Once the hypolimnion loses oxygen, reducing conditions release dissolved iron, manganese, ammonia and phosphorus from the sediment. These raise treatment cost and chemical demand and, for manganese in particular, cause discoloured-water complaints downstream.
Stable, nutrient-rich surface water favours cyanobacterial (blue-green algae) blooms, which produce toxins and the taste-and-odour compounds geosmin and 2-MIB. Breaking stratification removes the calm, warm surface layer that blooms depend on.
Photosynthesis fixes carbon and releases oxygen at the surface; as that organic matter sinks and decays it consumes the oxygen back — deep, which is exactly the deficit aeration is engineered to repay
CO2 and O2 cross the air–water interface; carbon dioxide dissolves into the sunlit surface layer.
Phytoplankton fix dissolved CO2 into organic matter and release O2 in the sunlit epilimnion (photic zone).
Carbonate shells and dead organic matter sink out of the lit zone, carrying the fixed carbon — and its oxygen debt — downward.
At depth (aphotic / hypolimnion) microbial decay consumes the oxygen and regenerates CO2 — the oxygen sink.
O2 falls from near-saturation at the surface toward zero (anoxic) as depth and respiration increase.
Carbon is buried in the sediment; the residual oxygen debt is the sediment oxygen demand (SOD) that aeration must offset.
In the photic layer, photosynthesis fixes CO2 and super-saturates the water with oxygen by day — the carbon and oxygen source term.
Dead biomass and carbonate sink out of the lit zone, carrying fixed carbon downward — the flux that moves the oxygen debt away from where it can be replaced.
Microbial decay consumes the oxygen and regenerates CO2 at depth and in the sediment — the sink that aeration is sized to offset.
Two engineered routes to the same goal — an oxidised bed and habitable water. The choice turns on depth, offtake and whether a cold-water layer must be kept.
Bubble-plume diffusers or mechanical mixers overturn the whole water column, eliminating the thermocline so the entire reservoir re-oxygenates — simple and effective where some surface warming is acceptable.
Oxygen is added to the cold bottom layer without breaking stratification, preserving a cold-water resource while still suppressing iron, manganese and ammonia release from the sediment.
Specific applications, water bodies and engineering guides
Protecting raw drinking-water quality at source — controlling manganese, ammonia and taste-and-odour before the treatment works.
View PageAeration and circulation for shallow service reservoirs and storage tanks where stratification and water-age are the concern.
View PageRestoring oxygen and ecological health in lakes, including eutrophic and amenity waters.
View PageSuppressing harmful algal blooms in reservoirs through destratification and oxygenation.
View PageReversing nutrient-driven degradation in eutrophic lakes with aeration and circulation.
View PageBubble-plume and mechanical destratification engineering for deep reservoirs.
View PageThe documented stratification indices, bubble-plume models, oxygen-transfer theory and system designs behind reservoir and lake aeration — categorised by topic
Schmidt stability (1928), the buoyancy frequency, the Wedderburn number (Thompson & Imberger 1980) and the Lake number (Imberger & Patterson 1990) that predict mixing.
View GuideFritz, Meredith & Middleton (1980), McDougall’s double plume (1978), Asaeda & Imberger (1993), Schladow (1993) and Wüest, Brooks & Imboden (1992).
View GuideTwo-film theory (Lewis & Whitman 1924), kLa and SOTR, areal hypolimnetic oxygen demand (AHOD), sediment oxygen demand and Streeter–Phelps.
View GuideThe Speece cone, full- and partial-lift air-lift aerators (Fast & Lorenzen) and pure-oxygen systems that oxygenate without destratifying.
View GuideAirflow criteria (Lorenzen & Fast 1977), the Zic, Stefan & Ellis (1992) model, destratification efficiency and bubble-plume versus mechanical mixing.
View GuideDimictic versus polymictic regimes and how stratification strength selects hypolimnetic oxygenation, destratification or surface aeration.
View GuideReynolds & Bauhm designs destratification and hypolimnetic-oxygenation systems for drinking-water reservoirs, service tanks and lakes — sized by CFD to your bathymetry, offtake and water-quality targets.
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