2nd lecture Wastewater

500,000-5,000,000 per mL

Bacterial counts in raw sewage may be expected to range from ________

lag phase

Acclimatization is the adjustment phase of microorganism

Log growth phase

Microorganism multiply since there is an ample supply of food

Declining growth phase

The point atwhich the food is largely depleted and food becomes the limiting factor in further growth

stationary phase

Food =microorg

Endogeneous phase

Uaing stored energy

Diauxie growth

2 log in bacterial growth pattern

Anaerobic bacteria

Oxidize organic matter utilizing electron ecceptors other that oxygen

Aerobic bacteria

Utilize free oxygen as an electron ecceptor

Facultative bacteria

Function both aerobic and anaerobic

Algea

Are photosynthetic microorg which can produce oxygen

Protozoa

Single celled protists which reproduced a binary fission. Major food source is the bacteria

Fungi

Multicellular non photosynthetic plants

Rotifers

Simplest milticellular animal

Rotifers

Their presence is a good indicatiin of the relative stability of a treated waste

Presumptive test

Based on the ability of the coliform group to ferment lactose broth, producing gas

Confirmed test

Consist of groing of cultures of coliform bacteria on media that supress the growth of other organisms

Fecal coliform

Human being, great than 4.0

Fecal streptococci

Domestic animal, less than 1.0

Grab sampling

Sample is taken at random with no particular time

Composite sampling

Mixture of grab samples taken over a period of time

Continuous sampling

Total flow over some period of time

Unit operation

Removal of contaminants is brough about by the physical or mechanical sources

Unit Process

Treatment occurs due to chemical and biological reactions

Physical unit operations

Treatment methods in whichthe application of physicl forces predominates

Chemical unit process

Treatment method in which the removal of contaminants is brought about by the addition of chemicals

Screening

1st step in WTP. They are used to remove large objects

grit removal

Remove heavy metals such as sand, gravel, eggshells etc.

Primary sedimentation

Use to remove settleable solids

Filtration

Use to polish the effluent. Tss and turbidity are removed

Reversed osmosis

Demineralization applicable to produce high quality water from effluent

Chemical precipitation

Producing a chemical precipitate that will settle

Adsorption

Removal of specific compounds from wastewater on solid surfaces

Disinfection

Use to reduce number of water borne pathogens in the effluent

Breakpoint chlorination

Amonia nitrogen is oxidized to nitrogen gas in a mixing basin

Biological process

Treatment methods which the removal of contaminants is brought about biological activity

Flowsheet

Graphical representation of unit operation and process

Process loading criteria

Basis for sizing the unit operation ang processes

Solid balance

Identifying the qauntities of solid entering ang leaving

Hydraulic profiles

Identify the elevation of the free surface of the WW

Plant layout

Physical facilities of the treatment pant

Screening

Treatment used for the removal of of coarse and settleable solids by enception

bar screen

Parallel bars can be hand of mechanically cleaned

Fine screen

Wire/cloth mesh

Pseudomonas

Reduce NO3 to N2

Zooglea

Help through its slime production in formation of floc

Sphaerotilus natans

Cause sludge bulking

Acinetobacter

Storge large amount of phosphate aerobic conditiin release under aerobic. Usefull in phosphate removal

Nitrosomonas

NH4 to NO2

Nitrobacter

NO2 to NO3

Flow measurement

flowrate needed for efficient operation

Average daily flowrate

Average flowrate over a period of time

Peak hourly flowrate

Highest flowrate measured in 24 hr period

Maximum daily flowrate

Maximum daily flowrate over a period of time

Comminution

Grinding of coarse

Comminutor

Device used to cut up solids in WW

Barminutor

Combination of bar screen and comminutor

Grit chamber

Enlarge channel where the velocity of water is controlled to allow only heavier solids to settle out

Grit chamber mustmaintain a min velocity of 2 ft per second

1 ft per second

Velocity in the grit is reduced to about

Equalization bazin

Maintain a constant volumetric flow of wastewater from pretreated to other downstream operation. It dampens hydraulic or flowrate variations