Waste disposal and decomposition

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Waste disposal and decomposition
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Options for sewage disposal
Landfills problems with cost, availability,
ground-water pollution, liquid
content, methane production.
Incineration problems with location, NIMBY,
Not In My BackYard
Oceans the Victoria solution,
Seattles Lake Washington and Puget Sound
experience.
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Some developments leading to recycling
In the 1950s demonstration by Professor Tommy
Edmondson that the Lake Washington ecosystem had
been substantially changed due to discharge of
effluent. Nitrogen pollution In 1958 voters in
Seattle and King County created Metro, an agency
charged with creating a regional wastewater
treatment system.   In 1966 construction of a
primary treatment plant completed at West Point
with discharge into Puget Sound. 1972 Federal
Clean Water Act In 1972 first biosolids
applications at Pack Forest In 1991 Metro
begins an expansion of the plant West Point plant
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Recycling
The principle is (1) to use a treatment plant to
remove soluble nitrogen from the effluent and
kill pathogens, and (2) to apply the solid
processed from bacterial matter to agricultural
fields, forests, and land requiring re-medial
treatment
There are problems associated with
Quantities and collection
Biology and engineering of treatment
Recycling through biosolids application
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Quantities and Collection
In King County 95 of the wastewater is from
homes and businesses, with only 5 from
industries
At the West Point plant
Total Suspended Solids loading (average annual)
181,000 lbs/day
Biosolids produced 53,409 wet tons 13,277 dry
tons per year
Reclaimed water used 0.61 mgd
Electricity generated 7,437,972 kilowatt hours
Outfall 3,600 ft. offshore 240 ft. deep 500 ft.
diffuser
Annual budget for King County Operating, 82
million Capital, 96 million
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Two waste water treatment plants in King County
Average daily capacity of the West plant is 133
million gallons per day
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Biology and engineering of treatment
Most organic matter is converted by
microorganisms to inorganic forms. This process
is called mineralization. Large molecules will
first be broken down to smaller ones by bacterial
exo-enzymes, enzymes that bacteria excrete. The
most important organisms involved in these
conversions are heterotrophic bacteria. It is
extremely difficult to identify bacterial genera,
let alone species, from water purification
systems, but it is obvious that the genera
Flavobacterium and Pseudomonas are important.
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Overview of treatment
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West Point Treatment Plant
O2 bacteria dissolved and suspended organic
matter
Nitrogen removal into biomass
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Nitrogen metaboism
Nitrogen is incorporated into microbial biomass.
Two types of bacteria process ammonium to nitrate
http//bark214-3.berkeley.edu/MCB290/illana.htm
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Anaerobic sludge digester
http//bark214-3.berkeley.edu/MCB290/illana.htm
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Anaerobic methane production
30 of power for the plant
Electricity sold to Seattle City Light
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Problems!
We do not know the precise composition of
bacteria in either the aerobic or anaerobic
processes.
Plating out and culturing provides
micro-organisms with a very different environment
than found in the tanks
There is some hope to use new DNA/RNA
identification techniques to identify bacteria
and seek ways of improving processing rates
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Increased treatment capacity will be needed
What will happen in the future? A third plant
will be added.
But there is resistance to expanding the
processing area of existing plants although their
current capacity may be exceeded
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350 feet deep processor
Temp and O2 control systems
A 350 feet deep processor is being investigated!!
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Recycling through biosolids application
What we do not have!
Some regulations
Seattle Biosolids Applications
The Cornell recommendations
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What we do not have!
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What we need to avoid
Giardia lamblia trophozoites, as they appear with
the scanning electron microscope.  Original image
by Arturo Gonzalez, CINVESTAV, Mexico.
http//www.biosci.ohio-state.edu/parasite/giardia
_sem.html
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Some regulations
The EPA breaks down land application of biosolids
into 4 categories Agricultural lands, Forest
lands, Reclamation sites, and Public contact/Home
lawns gardens.  Each land application category
has its own set of requirements according to WAC
173-308-210, 220, 230, 240, and 250.  Washington
state has adapted the federal EPA rule 40 CFR 503
standards to its own rule, Chapter 173-308 WAC. 
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Different rules for different classes of
biosolids.
Class A biosolids contain no detectible levels of
pathogens and and meet strict vector attraction
reduction requirements and have low levels of
metals. Permits are required to ensure that
these standards have been met.
Class B biosolids are treated but still contain
detectible levels of pathogens. There are buffer
requirements, public access, and crop harvesting
restrictions for virtually all forms of Class B
biosolids.
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Class A Biosolids
Class A production processes include irradiation,
composting, heat drying, heat treatment,
pasteurization, thermophilic aerobic digestion,
and alkaline stabilization. Class A biosolids do
not contain pathogens in sufficient quantity to
warrant restricted access or special precautions
and may be applied the same way as commercial
fertilizer.
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Alternative 1 Thermally treated biosolids
Biosolids must be subject to one of the following
four (4) time-temperature regimes 7 percent
solid or greater biosolids must be heated to 50
degrees Celsius of higher for 20 minutes or
longer. 7 percent solid or greater biosolids
in the form of small particles and heated by
contact with either warmed gases or immiscible
liquid must be heated to 50 degrees Celsius or
higher for 15 seconds or longer. Biosolids
less than 7 percent solid must be heated for at
least 15 seconds but less than 30 minutes using
the following equation D131,700,000/100.14 t
Biosolids less than 7 percent solid must be
heated to 50 degrees Celsius of higher with at
least 30 minutes of longer contact time.
There are chemical alternatives for application
of alkaline
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K-S Nara Paddle Dryer/Cooler
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Class B Biosolids
King County biosolids are anaerobically digested
at the treatment plant to meet Class B pathogen
reduction. Further reduction does take place
after application in what King County (and other
processors) refer to as a hostile environment for
microbes
In practice odor is a principal restriction to
the location where Class B biosolids can be
applied. This can be reduced by chemicals
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EPA Class B biosolids site restrictions
Restricted Activity
Site Restriction Harvest of food crop
touching ground 14 months after
application Harvest of root crop (see next
condition) 20 months after
application Harvest of root crop if sludge on
surface 38 months after
application Harvest of other food, feed, and
fiber crops 30 days after application Grazing
of animals
30 days after application Harvest of turf
for high contact site, 1 year
after application e.g., golf course or lawn or
public access to turf Access to sites with high
potential for Restrict for 1
year public exposure Access to sites with low
potential for Restrict for 30
days public exposure
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Biosolids Quality from the West Point Plant 2000
Average
By weight
Organic nitrogen provides a sustained release of N
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Trace metals in West Point biosolids
West Point Plant
National and State
Regulatory
Standards mg/kg
mg/kg Arsenic
7.07
541 Cadmium 3.7
39 Copper 529
1500 Lead
141
300 Mercury 2.71
17 Molybdenum 11.1
under reconsideration Nickel
35.1
420 Selenium 5.97
36 Zinc 804
2800
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Dryland soils program
Improved moisture retention
Increased growth sometimes too much N
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Forest Application
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Reclamation
Bunker Hill Wetland, Idaho
Rapid establishment of vegetation
Issues returning to natural vegetation
may be retarded by high N
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Four arguments against biosolids application
1. Odor and unpleasantness
2. EPA is not doing its job to ensure
compliance with its own regulations
3. Treatment and disposal should be local
4. Class B biosolids can cause illness to people
applying them
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Cornell University site management
recommendations
--Limiting applications to keep soil metals
low--Testing soils before application--Applyin
g only at agronomic rates--Supplying all
landowners with biosolids quality
information--Monitoring downstream water
bodies and wells--Calibrating application
equipment--Maintaining setbacks and
buffers--Avoiding application to areas prone to
runoff--Imposing access restrictions for the
public.
In practice most of these items are specified in
Washington State and EPA regulations
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Conclusion
According to EPA estimates for 1993,
approximately 33 of the 5.4 million dry metric
tons of biosolids generated annually in the US is
land applied
This is increasing due to rising costs and less
available space in landfills, regulations banning
ocean dumping, and a move away from incineration. 
So application to the land will increase and must
be placed on a sustainable basis
There is likely to be continued discussion as new
regions consider biosolids application
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Courses that deal with this topic
ESC518, formerly Microbial Degradation, to
Bioremediation Science
CIVE 484 On-Site Wastewater Disposal CIVE 482
Water and Wastewater Treatment