River Remediation
Why Dissolved Oxygen (DO) is important in rivers
Oxygen dissolves in rivers by diffusion from the surrounding air; aeration of water that has tumbled over falls and rapids; and as a product of photosynthesis. Adequate dissolved oxygen is required for good water quality and is a necessary element to all forms of life. Fish and aquatic animals cannot split oxygen from water (H2O) or other oxygen-containing compounds therefore rely upon an adequate supply of DO to survive.
One of the main factors increasing the risk of poor ecological status in rivers is nutrient enrichment (eutrophication) from organic waste around areas of high population density, combined with high industrial development. High levels of organic pollution tend to reduce the concentration of oxygen in water and thus affect all riverine species and habitats. A recent study was carried out on the water quality of the Port of Stockton Deep Water Ship Channel (DWSC) in the San Joaquin River, California USA. In 2004, the last twelve miles of the DWSC, before re-entering the port, were showing insufficient concentrations of Dissolved Oxygen (DO), risking degradation of water quality, aquatic habitat and aesthetics. Large scale artificial aeration was deemed essential for its restoration but prohibitive from a capital cost perspective - the deployment of HydroVenturi technology could overcome both these challenges.
