Protecting Our Waterways Removal of Nutrients from Wastewater

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Protecting Our WaterwaysRemoval of Nutrients
from Wastewater

• David Rei Miller
• Masters Student
• Sumit Banker
• PG Diploma Student

Dr Steven Pratt Lead Author Dr Andy Shilton CETE
Director
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Nutrient Removal Research
Domestic Centralised PNCC, RDC
Industrial Forest Research
Domestic Other Gould Systems, Steelserv
Industrial Fonterra
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Presentation Outline

• 1 Problem Nutrient Pollution
• 2 Solutions Nitrogen Removal
• Biological Filter
• Phosphorus Removal Active Rock Filter

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Nutrient Pollution

• Groundwater
• Blue Baby Syndrome NO3-
• carcinogen production NO3-
• Surface Waters
• toxic to fish NH3
• algal blooms N and P
• eutrophication N and P

Methemoglobinemia similar to Blue Baby
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Eutrophication

• Nutrient enrichment
• Algal growth
• Decay of algae
• Oxygen consumption

Oberlin, OH (before)
Oberlin, OH (after)
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Eutrophication
Eutrophication in Hawkes Bay region
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Sustainability

• Protecting Our Waterways
• drinking, recreation resource
• cultural values
• kaitiakitanga, legal obligations
• Sustainable Technology
• low energy, cost, maintenance
• low environmental impact

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Nitrogen

• Domestic Wastewater
• urea, proteins, amino acids
• 80 mg-N/L total (from onsite)
• Discharge Limits
• 10 mg-N/L NO2-/NO3- USEPA
• 30 mg-N/L total (from onsite) Hawkes Bay

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Nitrogen Removal

• Foam Media Biofilter
• biological (microorganisms)
• onsite wastewater treatment
• target 10 mg-N/L effluent
• Key Results to Date
• 30 mg-N/L effluent typical
• nitrification, denitrification confirmed
• nitrification identified as limiting
• likely limited by lack of oxygen

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Septic Tank Biofilter
Nitrification Denitrification
Flotation Settling
Influent Wastewater
Treated Effluent
Org-N ? NH3-
NH3- ? NO3- ? N2
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Nitrogen Removal in Biofilter
Aerobic NH3 ? NO3-
Anoxic NO3- ? N2

• Foam media for biomass growth

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Nitrogen Removal

• Sustainability Potential
• no forced aeration
• no addition of carbon
• inert end product
• But
• foam life, regeneration uncertain
• electricity required (pumps, controls)

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Phosphorus

• Domestic Wastewater
• detergents, various foods
• 5-20 mg-P/L as DRP
• Discharge Limits
• 1 mg-P/L as TP (to bay) Brisbane
• 1 mg-P/L as DRP (to stream) Waipukurau
• not set for onsite

Discovery of P (1669)
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Phosphorus Removal

• Active Rock Filter
• physical other mechanisms
• small community treatment
• can add to existing pond (or onsite)
• Key Results to Date
• limestone 64 P removal
• steel slag 72 P removal

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Phosphorus Removal
Active rock filter bed, Waiuku
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Phosphorus Removal
Treated Effluent
P
74 P Removal

• Possible mechanisms
• ion exchange
• adsorption
• precipitation

Influent Wastewater
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Phosphorus Removal

• Sustainability Potential
• no energy input required
• low cost
• simple and low tech like ponds
• But
• design life, loadings need research
• regeneration, extraction of P needs research

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Summary

• Nutrient removal is essential for
• sustainability of water resources.
• N Removal can be achieved onsite
• by foam media biofilter.
• Low cost P Removal possible with
• an active rock filter.

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Acknowledgments

• Warrick Gould
• Gould GT Systems
• Technology NZ
• Palmerston North City Council
• Steelserv
• Rock Filter Researchers