Download Nutrients ! nitrogen and phosphorous are essential for the growth of

Nutrients
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nitrogen and phosphorous are essential for the growth of plants and animals
consequently they are referred to as nutrients
Nitrogen
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important constituent of protein and nucleic, that is required in greatest quantity next to
carbon and oxygen
special importance are
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ammonia (NH3 ) pH>7
nitrite (NO2 -)
nitrate (NO3 -)
nitrogen gas (N2 )
urea [CO(NH2 )2 ]
organic nitrogen
TKN: Total Kjeldahl Nitrogen: ammonia not driven off before digestion; thus the total
of organic and ammonia nitrogen
Phosphorous
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as nitrogen, phosphorous is cycled between organic and inorganic phosphorous
compounds
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PO4 -3 , HPO4 -2 , H2 PO4 -, H3 PO4
orthophosphates, consisting in some form of PO4 -3 is the only form of phosphorous
readily used by plants and animals
other important phosphorous compounds is polyphosphates, which provides luxury
uptake in secondary treatment for wastewater (BNR)
phosphorous cycle involves two major steps
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conversion of organic (dead plant and animal tissue and animal waste) to
inorganic phosphorous via bacteria
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conversion of inorganic to organic phosphorous (plant and animal tissue)
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natural water has low phosphorous content, resulting in low algal growth
discharges containing excessive amounts of phosphorous result in algal blooms
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results in eutrophication
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phosphorous needs to be removed from source, e.g. soap formulation or at wastewater
through chemical or biological means
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phosphorous loadings increased from 3-4 mg/L to 10-20 mg/L
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in some places like Lake Tahoe they ship wastewater out of the region
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Italy was too effective and now there is insufficient P for the "bugs" at the
treatment plants
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Nutrient Concentrations from Non-Point Sources
(Novotny and B endoricchio, 1989 in WS&T )
SOURCE
NITROGEN (mg/L)
PHOSPHOROUS (mg/L)
Atmospheric Deposition
Surface
Animal Feed Lot
Urban Stormwater Runoff
Irrigation Excess Flow
Septic Tank Surface Leak
Construction Site Runoff
Combined Sewer Overflow
Subsurface
Farm Drainage
Intensive Farm Drainage
Septic Tank Leakage
1-10
>30
0.02-2
>10
1-10
10-30
>30
1-30
>30
10-30
0.2-2
2-10
>10
0.2-10
>10
0.2-2
>30
>10
0.2-2
0.2-2
Note: 1 cow equal to 10 people in terms of waste produced
Nutrient Problems and Solutions (Water 21, July 99:12-13)
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Netherlands and Germany Removed P from Soaps as Netherlands had a major
eutrophication problem in the Rhine
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Netherlands/Germany/Sweden world leaders in BNR
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Czech Republic has plankton problems in their water reservoirs
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sludge applied to land is a long term source of P & N
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major reason N&P levels remain high in smaller watersheds
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per capita use of P exceeds needs by 30%
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phosphate in ham to make it juicy
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phosphoric acid in Coke for zip
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estimates have shown that only 15% of farm applied nutrients end up on the plate
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Eutrophication
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natural waters are classified according to their ability to support life; oligotrophic,
mesotrophic and eutrophic
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oligotrophic: young with low nutrient content, little biological activity and clean
bottom sediment
mesotrophic: middle aged with modest amounts of the three parameters
eutrophic:
aged, with large concentrations of nutrients, excessive biological
activity and large volumes of organic sediments on bottom
extinction:
lake no longer capable of supporting life
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natural process taking thousands of years to complete
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mans activities have speeded up the process
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nutrient discharge must be halted or removed or water body
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no longer suitable for drinking
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no longer suitable for sports
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no longer suitable for fishing
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finally becomes extinct and can no longer be used as a water resource (swamps
were once deep water bodies now filled with organic matter)
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