Sewage is a water-carried waste, in
solution or suspension, that is intended to be removed from a specific
place. It consists mostly of grey or
black water. It is characterized by rate of flow, physical condition, chemical
and toxic constituents and its bacteriologic status.
Types
of sewage
·
Domestic/sanitary sewage: The
wastewater from residences and institutions, carrying bodily wastes, washing
water, food preparation wastes, laundry wastes, and other waste products of
normal living.
·
Commercial wastes: Liquid-carried
wastes from stores and service establishments serving the immediate community.
·
Surface run-off: is that
portion of precipitation that runs rapidly over the ground surface to a defined
channel.
Types
of pollutants
Organic
pollutants and nutrients: sewage is a complex
mixture of chemicals, with distinctive chemical characteristics. These include
high concentrations of ammonium, nitrate etc. Sewage also contains the
nutrients nitrogen and phosphorus.
Pathogens
and micro-pollutants: Sewage can be monitored for
both disease-causing and benign organisms with a variety of techniques.
Traditional techniques involve filtering, staining, and examining samples under
a microscope.It is highly essential to eliminate sewage from our surrounding to
prevent all kinds of air and water borne diseases. To eliminate sewage, we need
to undertake sewage treatment.
Sewage treatment is the process of removing
contaminants from wastewater, primarily from household sewage. It includes
physical, chemical, and biological processes to remove these contaminants and
produce environmentally safe treated wastewater.
Treatment
includes three stages;
Primary
treatment: consists of temporarily holding the
sewage in a quiescent basin where heavy solids can settle to the bottom while
oil, grease and lighter solids float to the surface.
Secondary
treatment: removes dissolved and suspended
biological matter. Secondary treatment is typically performed by indigenous,
water-borne micro-organisms in a managed habitat. Secondary treatment may
require a separation process to remove the micro-organisms from the treated
water prior to discharge or tertiary treatment.
Tertiary
treatment: Treated water is sometimes disinfected
chemically or physically prior to discharge into a stream, river, bay, lagoon
or wetland, or it can be used for the irrigation of a golf course, green way or
park. If it is sufficiently clean, it can also be used for groundwater recharge
or agricultural purposes.
With suitable technology, it is possible to
reuse sewage effluent for drinking water, although this is usually only done in
places with limited water supplies.
Lashari group is highly proficient in
providing sewage cleaning along with some additional services. To know more
about our services, visit our website at www.lasharigroup.com
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