Oxidation equipment refers to the mechanisms and devices that chemically treat water via oxidation. Strong chemical oxidizers are introduced into supplies of wastewater and groundwater to remove organic and inorganic contaminants. Oxidation equipment is an essential part of pollution control and is applicable across a breadth of industries.
Contaminated water is collected in a reservoir, which is almost always a pond- or ditch-like excavation. These oxidation pools are typically the second or third step in modern sewage treatment for facilities remediating one million gallons per day or less. Pooled water is then subjected to several cleansing mechanisms that can remove aromatics, biocides, petroleum constituents, and VOCs.
The hydroxyl radical (·OH) is the strongest water-compatible oxidant and is produced with the aid of primary oxidants such as ozone, hydrogen peroxide, or oxygen, in conjunction with UV light or a catalyst. Precise dosages are administered to the oxidation pool to obtain sufficient ·OH quantity that will eliminate most kinds of macromolecules, eventually mineralizing them. ·OH is recognized to reduce contaminants in a water supply from 100,000-plus ppm to 5 ppb in ten days or less.
Activated sludge is introduced to suspended-growth treatment systems to: oxidize carbonaceous and nitrogenous matter; remove phosphates and trapped gases; create a floc of nonconsumable material that settles on the bottom of the basin; and generate a semi-filtered liquor. Activated sludge consists of saprotrophic bacteria and protozoan species that filter-feed on introduced contaminants. The sludge is created by downstream treatment processes and reintroduced to an aeration tank. Sludge that is not recycled is composted or digested anaerobically.
Several machines are used in oxidation treatment.
Aerators: surface-floating, electric motor aerators or underwater bubble screens infuse water supplies with the oxygen required for oxidation reactions, and also provide some dispersal of suspended particles.
UV light sources activate the creation of ·OH.
Agitators: various stirring and mixing equipment is required to properly disperse contaminants amongst treatment materials.
Trickling filter: a fixed-growth treatment process where sprinklers disperse wastewater over beds of coal coke, limestone chips, or artificial media that supply a surface area for biomass to thrive. Contaminants are captured while cleaned water is drained away. Snails or insect larvae regulate biomass growth.
Rotating biological contractors: a rotating wheel, not unlike a water wheel, has thriving ecosystems of contaminant-consuming bacteria and protozoans. It is another fixed-growth treatment process. Oxygen is introduced by wheel rotation. Once enough contaminants accumulate on the wheel, they fall into the water and settle at the bottom.
Membrane bioreactors: activated sludge and low pressure microfiltration or ultrafiltration membranes improve settling of sludge over conventional aeration tanks.
Biofilters: combine biological carbon reduction and nitrification or denitrification. A filter media supports the biomass and filters solids.
Wastewater pumps: centrifugal pumps are most common for wastewater applications.