Harmful blue-green algae blooms have become all too common in freshwater lakes, including reservoirs that are sources of municipal drinking water. A new white paper from Medora Corporation explores how horizontal long-distance circulation can be an effective and chemical-free solution to the problem. Horizontal lake circulation is like throwing a life jacket to good green algae and diatoms. It keeps them suspended in the water column, prevents blue-green algae from forming a harmful algae bloom and restores nutrient-rich waters for a healthy aquatic ecosystem.
Water quality problems in potable water storage tanks include temperature stratification, stagnation, dead zones and short-circuiting. These problems stem from the simple fact that water in reservoirs forms thin horizontal layers due to differences in temperature and pressure. One solution with proven results is to mix the tank thoroughly, from tank floor to water surface. Well-mixed water delivers consistent sampling, consistent water age and consistent water quality.
The implementation of continuous, active mixing technologies combined with periodic disinfectant boosts can maintain water quality by eliminating sampling inconsistencies and the thermal stratification that leads to the breakdown of disinfection chemicals.
Quiescent waters in potable water storage tanks are associated with water quality problems such as thermal stratification, biofilms, excessive disinfection byproducts and disinfectant residual loss. Ice formation in distribution-system reservoirs is another challenge faced by water utilities in northern climates during winters. Thick layers of ice often form at the surface in storage tanks during prolonged periods of subfreezing weather. Steel tanks can expand during ice formation, causing structural damage and water leakage.
Long-distance circulators are different from any other reservoir equipment in that the adjustable intake takes advantage of the manner in which water forms
thin horizontal layers in ponds and allows a precise horizontal cross-section of water to be circulated throughout the entire pond footprint.