Multistep biological and chemical treatment

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A new technology to process swine manure

• Multi-step biological and chemical treatment
• Anni Kokkonen, Erkki Aura and
• Risto Seppälä
• MTT Agrifood Research Finland
• University of Helsinki
• Tampere University of technology

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Tightening legislation

• Current proposal for agri environmental program
  2007-2013
• The most intensive farms considering to
• stay outside the proposed environmental
• program
• Demand for new technologies

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This new technology

• Effectively decreases the odours of liquid swine
  manure gt completely odorless product
• Enables fractionation of the processed manure to
  humus, water, and concentrated phosphorus and
  nitrogen fertilizers

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Importance of biological treatment

• Manure contains many water-soluble small
  molecules (e.g. water-soluble carbohydrates) gt
  very difficult to handle with existing waste
  water treatment systems

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Microbial processing

• Is based on an amendment of a selected and
  enriched soil microbe population
• During processing, liquid manure is changed to
  an odorless form
• and
• The organic molecules are changed to a form
• where they are easy to precipitate and separate

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Outlet air
Raw manure
Sub container
Compressor air fed to the treatment reactors
Feedback pump
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Theory of function Feedback 11 in relation
to the raw slurry influent gt applicable
proportion intensify process Viable microbe
population Removal of toxic substances with
enzymes gt The enzymes function first The
microbial growth will start not until in the 2nd
chamber Slurry is toxic, the reason why
commercial amendments does not work
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• Operating conditions
• temperature
• aereationgt mixing
• hydraulic retention time (HRT)
• hydraulic flow regimes
• gtmay have an impact on microflora

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Optimal conditions Existing optimal
microbialpopulation/community (culture
addition) Artificially created optimal conditions
as regards to water content, oxygen content
(aeration) appropriate aeration rates because
solution reactions maximal amount of solution
for solution reactions to take place, optimum
temperature, different decomposition stages/steps
can be broaden/distribut to several treatment
reactors, also with appropriate feed-back
(recirculation) a system can be created (self
organization) that it itself intensify its
function
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• The different reactions occur in different
  spaces/locations different decay stages are
  distributed to different reaction chambers

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MgO
Ca(OH)2
Ammonia separation
H2O / H2SO4
After microbial processing, first MgO and then
Ca(OH)2 are added to the liquid manure until pH
9.5-10 is reached to remove NH3 from the
processed liquid in stripping towers
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Ammonia separation in stripping towers
Alkaline liquid manure

• Design criteria
• Hydraulic waste water loading (0.1 to 0.2
  l/min/m3)
• Stripping air flow rate (32 to 54 l/min/m3)
• Packing depth (6.1 to 7.6 meters)
• pH of waste water (9.5-11.5)
• Packing material (plastic or wood)
• Ammonia stripping performance is
• highly dependent on air temperature
• and air/water ratios

Countercurrent tower
Air
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Fe2(SO4)3
Al2(SO4)3
CaCO3

• After stripping
• ferric sulphate
• aluminium sulphate
• calcium carbonate
• is mixed with processed and stripped
• liquid manure. After this manure is
• slowly run through the basins where
• organic matter is precipitated

pH 7-8
pH 4-5
pH 6
humus
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• The residual phosphorus is precipitated with the
  humus and is practically not plant available

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Preliminary results
soluble P precipitated as NH4Mg-phosphate N
collected with outlet air and washed with H2O or
H2SO4 Part of the soluble P precipitated as
NH4Mg-phosphate Rest of the N removed by
stripping towers Rest of the phosphorus
precipitated with the humus, not plant available
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Operated systems

• The laboratory scale multi-step biological and
  chemical treatment system

• The biological tratment pilot system has been
  succesfully tested for two years at a 600-pig
  farm

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Preliminary results

• Quality of separated water

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Preliminary results

• Microbiological analysis
• Each step of the treatment system was evaluated
  for its effectiviness in reducing pathogens
• Fecal coliforms
• Streptococci
• Salmonella

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Preliminary results

No faecal coliforms found in the separated
water Separated humus contains considerably less
faecal microbes than fresh manure
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Preliminary resultsSeparated water

Quality of the separated water is good and
fulfils the standards of Finnish waste water
obligatory standards
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The price

• Total costs of the materials
• (Biological treatment pilot system at 600-pigs
  farm)
• 17500 e

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Future challengies

• Continue to build farm size pilot reactors to two
  other pig farms
• Size of the reaction chambers
• Solve the problems concerning feeding of the raw
  slurry to the system
• Ammonia separation with stripping towers

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Future challengies

• Biochemical analyses
• Forms of org. P, N and C compounds
• Humification
• Enzyme activities
• Identification of microbial populations

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Future challengies
Thank you for your attention

• Biochemical analyses
• Forms of org. P, N and C compounds
• Humification
• Enzyme activities
• Identification of microbial populations