Quantcast Biological Characteristics. - Wastewater Treatment

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
Wastewater is called strong or weak depending upon the amount of oxygen that is
required to oxidize and stabilize it.
(1)  Dissolved oxygen. Fresh water normally contains dissolved oxygen
(DO) in amounts ranging from about six to about 12 parts per million (ppm) parts of
water. Fresh wastewater normally will have a DO content within or just below this
range. As wastewater becomes stale, the DO is consumed. Thus, the DO of
wastewater is a measure of its freshness. Oxygen in wastewater is necessary to
support aerobic bacterial action.
(2)  Biochemical oxygen demand. The organic matter in wastewater,
primarily of human or food origin, is unstable and readily decomposed and oxidized by
biological or chemical agents to form more stable substances. This process requires
oxygen. The stronger the wastewater, the greater the amount of oxygen that is
required. The biochemical oxygen demand (BOD) is defined as the quantity of oxygen
required for the biochemical oxidation of the decomposable (organic) matter at a given
temperature within a given time, usually 5 days at 20C (68F). It is normally expressed
as the 5-day BOD in milligrams per liter (mg/l) or ppm. Average domestic wastewater
varies from approximately 150 to 250 mg/l (ppm) 5-day BOD.
c. Biological Characteristics. Bacteria, viruses, and parasites make up the
biological characteristics of wastewater. Wastewater contains vast quantities of
bacteria and other organisms that originate in discharged wastes. The feeding activities
of these organisms assist in decomposing wastewater. Aerobic bacteria decompose
organic matter in the presence of free oxygen. Anaerobic bacteria decompose organic
matter that is shut off from free oxygen, such as in the interior of a mass of feces or a
dead body. The products of anaerobic decomposition have an extremely unpleasant
odor. Matter in which this condition exists is said to be septic. A large number of the
bacteria in wastewater are coliform bacteria -- those found in the digestive tract of
normal humans. While most of these bacteria are harmless, pathogens will usually be
present in wastewater containing the discharges of many persons. It is these relatively
few pathogenic organisms that pose the greatest public health hazard. Wastewater that
is not properly treated may eventually find its way into a community water source and
spread waterborne diseases.
d. Composition of Wastewater. The composition of wastewater varies from
hour to hour, day to day, and season to season; but its average composition can be
determined for a given period. Normally, wastewater is 99.9 percent water by weight.
The remaining 0.1 percent (1,000 ppm) is organic and mineral matter (dissolved,
suspended, organic, and inorganic solids). Most of the mineral matter consists of salts
from the water supply, urine, meat and vegetable extracts, and permissible acids and
alkalies from industries. The organic matter, primarily from human or food origin, is
unstable and readily decomposed and oxidized by biological or chemical agents to form
more stable substances. The total organic and mineral matter in wastewater comprise
about 0.1 percent by weight. This matter is further classified as filterable and
nonfiltrable residue.
MD0161
1-6



Medical News
FDA strengthens warning on device linked to cancer
U.S. regulators have strengthened their warning against use of a...
medicalxpress.com
Has a possible new lead been found in the fight against neurodegenerative diseases?
Good communication between brain cells is vital for optimal (mental)...
medicalxpress.com
Sleep apnea linked to poor aerobic fitness
People with moderate to severe obstructive sleep apnea may have...
medicalxpress.com
Experience with family verbal conflict as a child can help in stressful situations as an adult
The holiday season gives people the opportunity to reconnect with...
medicalxpress.com
New treatments for cancer, diabetes, and heart disease—you may have a pig to thank
Genetically engineered pigs, minipigs, and microminipigs are valuable tools for...
medicalxpress.com
Drugs to block angiogenesis could provide new treatment for TB
The body responds to tuberculosis infection by locking the bacterial...
medicalxpress.com
Pain in a dish: Researchers turn skin cells into pain sensing neurons
After more than six years of intensive effort, and repeated...
medicalxpress.com
Excessive contact between cellular organelles disrupts metabolism in obesity
Researchers at Harvard School of Public Health (HSPH) have found...
medicalxpress.com
Scientists identify bone cells that could help children who need corrective facial surgery
Our bones are smart. Bones know that by adolescence it's...
medicalxpress.com
New research discovers gene that reduces risk of stroke
Scientists have discovered a gene that protects people against one...
medicalxpress.com
Masking HIV target cells prevents viral transmission in animal model
Cloaking immune cells with antibodies that block T cell trafficking...
medicalxpress.com
Liberia free of Ebola by Christmas, says president
Liberia's president on Monday urged her countrymen to double their...
medicalxpress.com
Football players found to have brain damage from mild 'unreported' concussions
A new, enhanced MRI diagnostic approach was, for the first...
medicalxpress.com
Breaking with tradition: The 'personal touch' is key to cultural preservation
"Memetics," or the study of memes, is a very popular...
medicalxpress.com
Sorting through recycling bins to learn about alcohol use
When researchers wanted to verify alcohol-use survey results at a...
medicalxpress.com
Madagascar working to contain plague outbreak
Madagascar said Monday it is trying to contain an outbreak...
medicalxpress.com
Cell therapy trial offers new hope to liver disease patients
Liver disease patients could be helped by a new cell...
medicalxpress.com
Threats of terrorism perceived differently depending on identification within a group
People who see their group as more homogenous - for...
medicalxpress.com
Teens prescribed anxiety, sleep medications likelier to illegally abuse them later
The medical community may be inadvertently creating a new generation...
medicalxpress.com
Protein that rouses the brain from sleep may be target for Alzheimer's prevention
A protein that stimulates the brain to awaken from sleep...
medicalxpress.com
 


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +