Transcript No Slide Title

Wastewater Treatment
Engineering
Environ. Engineering Course Sequence
Thermo
CE3501
Fluids
CE4506
Regs,P2,3
CE4504
Air Quality
CE4620 Open
Channel Flow
GE3850
Geohydrol.
P-Chem
CE3502
CE3620
Water Resources
CE4501
Env.Chem
ce4505
Surf.Water
CE4508, 4507,4509
Drinking & WasteWater
CE4630
Hydraulic structures
BL4451
Limnology
CE5508: Biogeochem., CE5504: Surf.Water Qual. Modeling
FW4220
Wetlands
Historical Background
Public Health
Investigation of an outbreak of cholera
in London in 1854 provided one of the
first links between sewage disposal,
drinking water supply and waterborne
disease.
Environmental Protection
A 1920s, study of the East and Fox
Rivers in Green Bay was commissioned
because workers in downtown could not
open windows in summer due to the
stench. Environmental problems plague
this system to this day.
Nature of Wastewater
What’s in wastewater?
 human feces and urine
 food from sinks
 soaps and other cleaning agents
 runoff from streets and lawns
 industrial discharges
Nature of Wastewater
… and water … lots of it!
 Urinal - 1 gallon per flush – 0.4 gal/flush
 Toilet - 4 gallons per flush – 2 gal/flush
 Shower - 20 gallons per use
 Overall - 55 gal/person/day
Nature of Wastewater
So what’s
the problem?
P o llu ta n t
P ro b lem
S o lid s
A esth etics
P a th o g en s
D isease
O rg a n ic m a tter
O x y g en
N u trien ts
P lan t g ro w th
O rg a n ics/M eta ls
T o x icity
Levels of Treatment
L evel
P rim a ry (1 )
A pp ro ach
P h y sica l
R em oved
S o lid s, o rg an ic
m atte r
S e co n d a ry (2 ) B io lo g ica l
O rg an ic m atte r,
T e rtia ry (3 )
V a rio us
N u trie n ts,
D isin f e ctio n
V a rio us
P ath o g e n s
n u trie n ts
to x ic s
Regulatory Basis
Clean Water Act of 1972 (since amended)
• Technology-based standards (2°)
• Water quality-based standards
• Fishable-swimmable
• NPDES (permitting system)
• TMDLs (maximum daily loads)
Scope of Application
On-Site
Rural - Municipal
Urban - Municipal
Industrial
Portage Lake Wastewater Treatment Plant
RAS
2°
Clarifier
1°
Clarifier
Flow
Equalization
Fe
added
Fe
added
Aeration
Tank
1°
Clarifier
2°
Clarifier
RAS
Grit
Chamber
UV
Disinfection
WAS
Recycle
Bar
Screens
2nd Stage
Anaerobic
Digester
Supernatant
Lift
Station
Land
Application
Sludge
Storage
Filter
Press
Polymer Added
1st Stage
Anaerobic
Digester
1°S
Wastewater Treatment
(Preliminary)
Bar Racks
and Screens
Bar racks and screens remove large
solids which could clog pumps and
pipes in the wastewater treatment
plant. Solids are collected and sent
to a landfill.
Wastewater Treatment (Primary)
Settling Tank
Settling tanks remove the large solids
which remain suspended in the
wastewater and about 50% of the
oxygen-demanding substances. The
solids are sent on for further
treatment (sludge digestion) and
ultimate disposal.
Wastewater Treatment (Secondary)
Activated Sludge
In the activated sludge process, bacteria and other microorganisms are used
to remove small solids and oxygen-demanding substances present in the
wastewater. Outflow from this tank undergoes settling and the excess sludge
is sent on for further treatment (sludge digestion) and ultimate disposal.
Wastewater Treatment (Tertiary)
Tertiary treatment refers to any of a variety of biological, chemical, and/or
physical methods used to reduce levels of specific pollutants in a wastewater
stream. Among these are levels of solids and oxygen-demanding materials,
toxic metals and organic chemicals, and algal nutrients such as nitrogen and
phosphorus. All wastewater treatment plants (>2 MGD) discharging to the
Great Lake are required to remove phosphorus. This is often accomplished
through chemical precipitation as described below.
Phosphorus removal by precipitation …
Ferric chloride, Fe(Cl)3
producing FePO4 and Fe(OH)3
Alum, Al2(SO4)3·18H2O
producing AlPO4 and Al(OH)3
Wastewater Treatment (Tertiary)
Carbon adsorption
Carbon adsorption is an incredibly effective means
of removing organic chemicals from wastewater …
chemicals which would otherwise pass through the
plant and enter the environment. This technology is
also applied in drinking water treatment, both
municipally and with consumer-installed devices.
Wastewater Treatment (Disinfection)
Ultraviolet Light
Disinfection is the most important
step in wastewater treatment
because it removes pathogens
and thus protects receiving
waters used for contact
recreation and as a drinking
water supply. Chlorine is the
most commonly used
disinfectant. Because of adverse
effects on the environment,
chlorine is being replaced by
other methods such as ozonation
and ultraviolet light (the method
used a our plant in Houghton.
Wastewater Treatment (Sludge)
Incineration
A variety of means are available for ultimate disposal of sewage sludge.
Landfilling and incineration are the most common. Here, the sludge is introduced
to the top of a multiple-hearth furnace. The sludge dries and ultimately ignites as
it moves down the surface toward the fire. The product is ash (landfilled) and
stack gases which are collected for further treatment.
Wastewater Treatment
(Effluent)
P o llu ta n t
R em ova l
S o lid s
> 90 %
P a th og en s
> 99 .9 %
O rga n ic m atter
> 90 %
N u trien ts
> 90 %
O rga n ics/M eta ls
trace
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Coursework
CE4507 - Wastewater Collection & Water Distribution
CE4508 – Water & Wastewater Treatment and Design
CE4509 – Environmental Process Simulation
CE5501 - Environmental Process Engineering
CE5502 - Biological Waste Treatment Processes
CE5503 – Physical-Chemical Treatment Processes
CE5507 - Sorption and Biological Processes
Students have the option of
building a ‘concentration’ in
water and wastewater
treatment as part of the B.S. in
Environmental Engineering at
Michigan Tech.
Employment
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Government (MDEQ, City of Detroit)
Industry (GM, Kodak)
Consulting (CH2M-Hill, Montgomery-Watson)
Graduate Study & Research (U.S. EPA, MTU)
Check out the web pages of these organizations for professional opportunities.
Study Question
Where does the wastewater from your home
go? What kind of treatment system is utilized?
Reading Assignment
Take a wastewater treatment plant tour (“Go With
the Flow”) courtesy of the Water Environment
Federation.
http://www.wef.org/publicinfo/#