BUDAPEST UNIVERSITY OF TECHNOLOGY AND ECONOMICS. DEPARTMENT OF CHEMICAL AND ENVIRONMENTAL PROCESS ENGINEERING. FACULTY OF CHEMICAL AND BIOCHEMICAL ENGINEERING. WASTEWATERS CONTAINING PLANT NUTRIENTS. Dr. Bajnóczy Gábor Tonkó Csilla. WASTEWATERS CONTAINING PLANT NUTRIENTS.
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DEPARTMENT OF CHEMICAL AND
ENVIRONMENTAL PROCESS ENGINEERING
FACULTY OF CHEMICAL AND BIOCHEMICAL ENGINEERING
WASTEWATERS CONTAINING PLANT NUTRIENTS
Dr. Bajnóczy Gábor
There is no one special element regulating the growth of plants
Apart from the microelements three elements regulate the plants activity
Three elements : carbon, nitrogen, phosphorus
Photosynthesis of hydrophytes:
utilize dissolved carbon-dioxide content of water
The necessary nitrogen is taken up by the hydrophytes in nitrate form.
blue algae : nitrogen from the air is consumable
phosphorus up take :
from the erosion of soil.
Trophity: capacity of organic matter production of water
trophic phosphorus content clarity nitrogen content chlorophyll content
state [μg/dm3] [cm] [μg/dm3] [μg/dm3]
oligotrophic 4 – 10 > 260 < 400 1,0 – 2,5
mezotrophic 10 – 35 160 – 260 400 – 600 2,5 – 8,0
eutrophic 35 – 100 60 – 160 600 – 1500 8,0 – 25
hipertrophic > 100 < 60 > 1500 > 25
Racial diversity and large number of individuals in oligotrophic waters
can not be formed due to the low nutrient content. The sludge is negligible.
decreased transparency but better conditions foraquatic life
eating fresh water
option of eutrophication change
eutrophic waters: possibility of diverse aquatic life
classified into two categories
a.) benthic: good clarity and presence of higher-order hydrophytes
b.) planktonic: poor transparency and dominant species: algae
Simultaneous presence of the two types is possible
Well supplied by nutrients, very poor transparency ,hydrophyteor algae blooming is possible,
Diverse aquatic life but the system is very unstable.
Large amount of dead organic material may cause lack of oxygen.
excess nutrient intake
growth of aquatic plants
more diverse wildlife,
increased number of
decrease of oxygen claiming
decay of large amount of dead biomass → → reduction of water’s oxygen content
Inhibition of carbon intake
Can not be limited because of the chance of carbon dioxide uptake from air.
Inhibition of nitrogen intake
Due to nitrogen-cycle unlimited amount nitrogen is carried by rainwater in nitrate form
Rational use of fertilizers may help!
Inhibition of phosphorus intake
The only way at present to reduce the phosphorus content of waste waters.
The human activity is mainly responsible of the ≈ 70% of phosphorous content
of natural waters.
adult bug fly out land
phosphorus in alga
phosphorus in fish
Chironomid larvae: liveing in water,
accumulates significant amount of
Fe +++ increase
increase of temperature
Ca ++ increase
increase of acidity
decrease of O2 concentration
Sludge excavation: significant decrease of dissolved oxygen
Main resources: municipal wastewater → phosphorus content from water
softeners in washing powders
Claim of environment: phosphorus-free water softener in detergents!
Phosphorus elimination of municipal wastewaters
Biological wastewater treatment: phosphorus content is reducible about 20 – 30 %.
Removal of residual phosphorus: by chemical processes precipitating in form of
iron, calcium or aluminium salts.
3 Fe 3+ + 2 PO43- + 3 H2O = (FeOH)3(PO4)2 + 2H+