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
British scientists trial 15-minute Ebola test in Guinea
British researchers are to conduct trials in Guinea on a...
medicalxpress.com
Behavioral interventions to prevent progression to diabetes equally effective in men and women
Behavioural and drug interventions aiming to prevent people with prediabetes...
medicalxpress.com
Thai parliament votes to ban commercial surrogacy
Thailand's parliament has voted to ban commercial surrogacy after outrage...
medicalxpress.com
S. African disease lab on frontline of Ebola fight
South African professor Janusz Paweska hesitates for a moment as...
medicalxpress.com
Mindfulness treatment as effective as CBT for depression and anxiety
(Medical Xpress)—Group mindfulness treatment is as effective as individual cognitive...
medicalxpress.com
'Trigger' for stress processes discovered in the brain
At the Center for Brain Research at the MedUni Vienna...
medicalxpress.com
Size matters: Men perceived as more masculine if they are taller and heavier, regardless face shape
Researchers at the University of St Andrews have found that...
medicalxpress.com
Canada sending medics to West Africa to fight Ebola
Canada will send 40 military medics to West Africa to...
medicalxpress.com
Italy bans Novartis flu vaccine after suspicious deaths
Italy suspended the use of a flu vaccine made by...
medicalxpress.com
Survival differences seen for advanced-stage laryngeal cancer
The five-year survival rate for advanced-stage laryngeal cancer was higher...
medicalxpress.com
Long-term complication rate low in nose job using patient's own rib cartilage
Using a patient's own rib cartilage (autologous) for rhinoplasty appears...
medicalxpress.com
Ebola aid dogged by coordination lags in Guinea
Eight months into West Africa's Ebola outbreak, aid efforts in...
medicalxpress.com
Secret of tetanus toxicity offers new way to treat motor neuron disease
The way that tetanus neurotoxin enters nerve cells has been...
medicalxpress.com
Post-PCI bleeding rates vary widely across hospitals
(HealthDay)—Patient case-mix and procedural factors may contribute to wide variation...
medicalxpress.com
Health care organizations see value of telemedicine
(HealthDay)—Health care organizations are developing and implementing telemedicine programs, although...
medicalxpress.com
Breast cancer treatments more effective now than in the past
(HealthDay)—Comparison of recurrence and outcome patterns shows that current treatments...
medicalxpress.com
Turkey fryer mishaps can cause serious burns
(HealthDay)— Celebration can quickly turn to tragedy if popular turkey...
medicalxpress.com
Want kids to eat better? Get them cooking
(HealthDay)—Getting kids involved in the kitchen, through cooking classes or...
medicalxpress.com
Don't let chronic heartburn spoil your Thanksgiving feast
(HealthDay) —Planning on seconds at Thanksgiving Day dinner this year?...
medicalxpress.com
Expert shares gluten-free Thanksgiving tips
(HealthDay)—Thanksgiving meals can pose a challenge for people who have...
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 +