Respirometry

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Respirometry
Optimizing aeration by tracking bacterial
activity in Activated Sludge

• The Strathtox and Bioscope from Strathkelvin
  Instruments Ltd

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The process as we all know it
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What the process is doing
Organic load ends up as CO2 or new biomass
Respiration is integral to BOD removal
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Respirometry

• Measures the bacterias rate of oxygen up-take
• Tells us their REAL oxygen needs
• Shows us how there activity is effected by
  different influents
• Real sludge, real time

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Applications of Respirometry

• Biomass viability or sludge health
• Short and long term monitoring
• e.g. look for chronic inhibition
• Toxicity management
• Calculates inhibition rates and identifies EC 50
• Rapid influent screening
• Check tankered waste for toxicity and avoid high
  re-agent costs since they use plant bacteria
• Process Optimisation
• Determine operational problems using bacterial
  OUR analysis. Make informed decisions to resolves
  sludge blanket and odour problems.

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Applications of Respirometry

• Aeration requirement and efficiency
• Critical Oxygen point analysis saves a UK water
  company 40 of their energy costs
• Nutrient management
• Pulp and Paper mill reduces urea dosing costs by
  70
• Nitrification status and capacity
• A WWTP is able check how influents will effect
  their nitrification and so protect their
  compliance and avoid fines
• Short-term BOD
• Check operational changes now rather than in 5
  days so avoiding consent issues

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Applications of Respirometry

• Aeration requirement and efficiency
• Critical Oxygen point analysis saves a UK water
  company 40 of their energy costs

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Aeration Efficiency

• Establishing what the bacteria need and
  optimising accordingly can..
• Reduce aeration costs
• Solve process issues (odour, rising sludge,
  foaming)
• Increase treatment capacity
• Balance flows

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Energy Efficiency

• The wastewater industry is constantly faced with
  increasing costs that stem from aging
  infrastructure, new health regulations and
  population growth.
• Energy efficiency is a viable solution to these
  challenges.

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Energy Efficiency

• Typically aeration accounts for 30 - 70
• of the total energy consumption in an aerobic
  biological treatment plant

Reducing these aeration requirements by 10 - 40
could result in savings of between 282k and 1M
a year on a WWTP of 100 MGD.
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Aeration Efficiency
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Aeration Efficiency
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Rate of Respiration is not a fixed value

• When the bacteria are feeding
• When the BOD is depleted
• (Starving or endogenous rate)
• When inhibitory conditions are present in the
  mixed liquor
• Seasonal (temp)

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Bioscope
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Bioscope

• Profile biodegradation rate (OUR)
• Real time conditions
• Energy and treatment optimization with critical
  oxygen point
• Measure temp, DO, SVI and SSVI

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Biodegradation, DO, Settlement Profiling.
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Profiling a site
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Site profile
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NOUR profile
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NOUR DO profile
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Optimization
Use it to prove and control existing proposals
(e.g. scheduled retro fits) or to identify new
opportunities

• Risk management
• Multi-stage process controlled and monitored
• Auditable