5. Wastewater treatment I

Domestic wastewater

Wastewater that contains human and animal waste, as well as gray water from various activities such as washing, cooking, and bathing.

Wastewater treatment

The process of reducing organic and inorganic materials in wastewater to a level that no longer supports microbial growth and eliminating potentially toxic materials.

Reduction of organic content

The process of decreasing the amount of organic matter in wastewater.

Removal of trace organics

The elimination or reduction of organic compounds that are resistant to biodegradation and may be toxic.

Removal of toxic metals

The process of eliminating or reducing the presence of harmful metals in wastewater, often originating from industrial activities or mining.

Removal of nutrients

The reduction of nutrient levels, such as nitrogen and phosphorus, to prevent pollution of receiving waters.

Removal of pathogens

The elimination or inactivation of disease-causing microorganisms present in wastewater.

Characterization of wastewater

The process of analyzing and understanding the composition of wastewater, involves assessing physical, chemical, and biological characteristics.

Monitoring of wastewater treatment process

The continuous observation and assessment of the wastewater treatment process.

Safe disposal of treated wastewater and sludge

The proper and secure disposal of the treated wastewater and the semi-solid material left after the treatment process.

Organic carbon

The carbon present in organic compounds in wastewater.

BOD (Biochemical Oxygen Demand)

The amount of dissolved oxygen consumed by microorganisms during the biochemical oxidation of organic and inorganic matter in wastewater.

NOD (Nitrogenous Oxygen Demand)

The amount of dissolved oxygen required for the biological oxidation of organic nitrogen in wastewater.

COD (Chemical Oxygen Demand)

The amount of oxygen needed to completely oxidize organic carbon to carbon dioxide, water, and ammonium ions in wastewater.

Total Organic Carbon

The measurement of the total amount of organic carbon in a given sample, regardless of its oxygen state.

Suspended Solids (SS)

The solid particles present in wastewater that can be removed by filtration.

Primary and preliminary treatment

The initial stage of wastewater treatment that focuses on removing solids, debris, and coarse materials.

Secondary treatment

The stage of wastewater treatment that involves biological and physical processes to accelerate the degradation of organic matter.

Tertiary treatment

The additional treatment of secondary effluent to achieve a higher quality of treated wastewater.

Trickling filters

A type of secondary treatment that uses watertight basins filled with rocks or permeable plastic medium for the biological degradation of organic matter.

Rotating Biological Contactors (RBC)

A type of secondary treatment that utilizes circular disks submerged in wastewater and rotated slowly to facilitate biological growth and degradation of organic matter.

Activated sludge treatment

A common form of secondary treatment that involves the degradation of organic matter in wastewater using suspended microbial biomass.

Anaerobic digestion

A process used for sludge stabilization or secondary treatment, where organic compounds are converted to methane and carbon dioxide by bacteria and archaea in the absence of oxygen.

Sludge processing

The treatment and disposal of the semi-solid material left after the wastewater treatment process.

Disinfection

The process of eliminating or reducing the number of microorganisms in wastewater to prevent the spread of diseases.

Pathogenic microorganisms

Disease-causing microorganisms present in wastewater, including bacteria, viruses, protozoa, and helminths.

Chlorination

A method of disinfection that involves the introduction of chlorine gas or chlorine dioxide to water to form hypochlorous acid, which kills microorganisms.

UV disinfection

A disinfection method that uses ultraviolet light to damage the DNA of microorganisms, rendering them unable to reproduce.

Suspended solids removal

The process of removing residual biological flocs from secondary effluent by filtering the wastewater through a porous medium.

Precipitation of inorganics

The use of chemical precipitates to remove various inorganic compounds, such as phosphate, from wastewater during the treatment process.