Wastewater Engineering - 03 (Related Processes)

Sludge Stabilization

A treatment process used to convert sludge to a stable product for ultimate disposal or use and to reduce pathogens to produce less odorous product.

Physical-Chemical Treatment

Treatment processes that are non-biplogical in nature.

Contact Process

A wastewater treatment process whereby diffused air is bubbled over a fixed media surface.

Fill-and-Draw

Treatment process whereby a vessel is filled, the reaction occurs, and the contents are withdrawn. Typical of sequencing batch reactors.

Chlorination

The addition of chlorine to a water or wastewater, usually for the purpose of disinfection.

Combined Available Chlorine

The concentration of chlorine combined with ammonia as chloramines and still available to oxidize organic matter.

Free Chlorine

The amount of chlorine available as dissolved gas, hypochlorous acid, or hypochlorite ion.

Advanced Wastewater Treatment

Treatment processes designed to remove pollutants that are not adequately removed by conventional secondary treatment processes.

Chlorine Demand

The difference in the amount of chlorine added to water or wastewater and the amount of residual chlorine remaining after a specific contact duration, typically 15 minutes.

Available Chlorine

A measure of the total oxidizing power of chlorinated lime, hypochlorites, and other materials, used as a source of chlorine as compared with that of elemental chlorine.

Activated Sludge Process

A biological wastewater treatment process in which a mixture of wastewater and biologically enriched sludge is mixed and aerated to facilitate aerobic decomposition by microbes.

Fixed-film Process

Biological wastewater treatment process whereby the microbes responsible for conversion of the organic matter in wastewater are attached to an inert medium such as rock or plastic materials.

Flotation

A treatment process whereby gas bubbles are introduced to water and attach to solid particles, creating bubble-solid agglomerates that float to the surface where they are removed.

Dechlorination

The partial or complete reduction of residual chlorine by any chemical or physical process.

Oxidation Ditch

An extended aeration waste treatment process that occurs in an oval-shaped channel or ditch, with aeration provided by a mechanical brush aerator.

Screening

A treatment process using a device with uniform openings to retain coarse solids.

Stapling

The enlargement of stringy or fibrous debris on a mesh or bar rack.

Recarbonation

The process of introducing CO2 as a final stage in the lime-soda ash softening process.