Biomedical Engineering Reference
In-Depth Information
3.
Solids contents:
The total solids are made up of both dissolved and sus-
pended material that remains as residue in wastewater (Metcalf and Eddy,
1987) upon evaporation at 103°C to 105°C.
4.
Temperature:
The wastewater temperature will vary season to season and
with the geographical location, from 10°C to 21°C (Muttamara, 1996).
Temperature plays a major role in wastewater treatment, and its variation
may cause changes as a result of the chemical and biological reactions of
planktonic organisms. Wastewater contains bacteria and fungi that may
have a substantial influence on the physical characteristics of the wastewa-
ter, especially when in abundance due to abnormal temperatures. Turbidity
and color are indirectly related to temperature because most of the chemical
reaction products, including equilibrium of wastewater coagulation, can
change with temperature. Temperature is also very important in the deter-
mination of various parameters, such as changes in pH often occurring in
regions with low acid neutralizing capacity, conductivity, different satura-
tion levels of gases, various forms of alkalinity, etc.
12.2.2 C
heMiCal
C
haraCteristiCs
The chemical compounds of wastewater characterization are most important with
respect to effective treatment. Identification of the chemical components and
their concentrations are used as a measure of wastewater quality. Domestic and
industrial wastewaters contain a variety of organic and inorganic chemicals. The
principal chemical components in sewage wastewater are carbohydrates, proteins,
lipids, and urea. The urea in wastewater is largely from an organic compound,
urine, which is the chief constituent forming large quantities of nitrogenous mat-
ter (Rawat
et al
.
, 2011) via rapid decomposition. Organic chemicals, which are
mainly composed of carbon, hydrogen, oxygen, and other components such as
sulfur, phosphorous, iron, ammonia, proteins, fats, lignin, soaps, oils, and other
synthetic organic chemicals that are readily biodegradable and their decomposi-
tion products, are found in the system. The physico-chemical parameters in waste-
water, such as total dissolved solids (TDS), of the organic chemical characteristics
involve interactions of pH, alkaline minerals, and other nutrients. These are related
to the solvent capabilities of wastewater (Drinan and Whiting, 2001). Some of
the common inorganic chemicals compounds present in wastewater are nitrogen,
sulfur, chloride, phosphorus, irons, hydrogen, and trace amounts of heavy metals
(Muttamara, 1996).
12.2.3 b
ioloGiCal
C
haraCteristiCs
Generally in wastewater, millions of microscopic and macroscopic organisms are
widely distributed, originating from discharged domestic wastewater. These include
bacteria, protozoa, viruses, and limited algal species. Many of these micro- and
macroorganisms are considered harmless, and the large diversity of organisms is
highly adapted to their conditions and effective in wastewater treatment and acti-
vated sludge treatment within the treatment facility. Several recent publications have
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