Home > Wastewater treatment > C&N Oxidation
Oxidation is used to oxidize inorganic compounds in the reduced state (such as nitrites, hydrogen sulfide, etc.) and for the partial oxidation or certain organic materials.
Secondary treatment is designed to substantially degrade the biological content of the sewage such as are derived from human waste, food waste, soaps and detergent, but physicochemical processes may also be used to eliminate chemical pollutants. Many municipal and industrial plants treat the settled sewage liquor using aerobic biological processes. Bacteria and protozoa consume biodegradable soluble organic contaminants (e.g. sugars, fats, organic short-chain carbon molecules, etc.) and bind much of the less soluble fractions into floc. In general, activated sludge plants encompass a variety of mechanisms and processes that use dissolved oxygen to promote the growth of biological floc that substantially removes organic material.
Most biological oxidation processes for treating wastewaters have in common the use of oxygen (or air) and microbial action. Surface-aerated basins achieve 80 to 90% pollutant removal (Biochemical Oxygen Demand) with retention times of 1 to 10 days.
A well-buffered system maintains the pH where biological activity is optimized and allows for a more efficient use of oxygen (leading to reduced energy costs). This is the reason why we treat wastewaters using the following lime-based reagents which increase the wastewaters' buffering capacity and which help the nitrogen removal step.