Presentation on theme: "Protecting Our Waterways Removal of Nutrients from Wastewater"— Presentation transcript:
1 Protecting Our Waterways Removal of Nutrients from Wastewater David Rei MillerMasters StudentSumit BankerPG Diploma StudentDr Steven PrattLead AuthorDr Andy ShiltonCETE Director
2 Nutrient Removal Research Domestic CentralisedPNCC, RDCIndustrialForest ResearchNutrient pollution is seen as the challenge of the next decade.Domestic OtherGould Systems,SteelservIndustrialFonterra
3 Presentation Outline 1 Problem Nutrient Pollution 2 Solutions Nitrogen RemovalBiological FilterPhosphorus Removal Active Rock FilterFirst… PROBLEM of Nutrient Pollution. Then… SOLUTIONS for N and P removal. My Masters project is on N removal.
4 Nutrient Pollution Groundwater Blue Baby Syndrome NO3- carcinogen production NO3-Surface Waterstoxic to fish NH3algal blooms N and Peutrophication N and PMethemoglobinemiasimilar to “Blue Baby”Many of you will have seen evidence of nutrient pollution in the news. NP = Nitrogen and Phosphorus.
6 Eutrophication in Hawkes Bay region HB pic is eutrophication from agricultural runoff (not OWTS).Eutrophication in Hawkes Bay region
7 Sustainability Protecting Our Waterways drinking, recreation resource cultural valueskaitiakitanga, legal obligationsSustainable Technologylow energy, cost, maintenancelow environmental impactEffective wastewater treatment is needed to protect our waterways. Essential part of sustainable society. RMA reflects importance.
8 Nitrogen Domestic Wastewater urea, proteins, amino acids 80 mg-N/L total (from onsite)Discharge Limits10 mg-N/L NO2-/NO USEPA30 mg-N/L total (from onsite) Hawkes BayFor OWTS resource consent in Hawkes Bay. Pressure to remove N in OWTS before disposal to land due to variability of soils, etc.
9 Nitrogen Removal Foam Media Biofilter biological (microorganisms) onsite wastewater treatmenttarget 10 mg-N/L effluentKey Results to Date30 mg-N/L effluent typicalnitrification, denitrification confirmednitrification identified as limitinglikely limited by lack of oxygenResearch project to improve current Gould system. Removal varies between sites. Effluent concs are TN.
10 Septic Tank + Biofilter Flotation & SettlingNitrification & DenitrificationInfluent WastewaterTreated EffluentHydrolysis and ammonification in septic tank.Org-N NH3-NH3- NO3- N2
11 Nitrogen Removal in Biofilter Aerobic NH3 NO3-Anoxic NO3- N2Cutaway of one foam block showing anoxic zoneGood air flow properties; superior to sand filters. NH3/NH4+ to NO2/NO3- to N2. Define aerobic and anoxic.Foam media for biomass growth
12 Nitrogen Removal Sustainability Potential no forced aeration no addition of carboninert end productBut…foam life, regeneration uncertainelectricity required (pumps, controls)Overall N management includes reduction, planting (Gunn 04). FIRST get it out of the river, then look at power, etc. Further research.
13 Phosphorus Domestic Wastewater detergents, various foods 5-20 mg-P/L as DRPDischarge Limits1 mg-P/L as TP (to bay) Brisbane1 mg-P/L as DRP (to stream) Waipukuraunot set for onsiteDiscovery of P (1669)Amateur alchemist Brand discovered P in 1669 by heating urine in the absence of air.
14 Phosphorus Removal Active Rock Filter physical + other mechanisms small community treatmentcan add to existing pond (or onsite)Key Results to Datelimestone 64% P removalsteel slag 72% P removalRetrofit to pond or wetland systems (Ashhurst 2000 ppl). * explain results set-up: two media for active rock filters have been tested (shown in literature to be promising). Both show significant P removal can be achieved….
15 Active rock filter bed, Waiuku Phosphorus RemovalPlace after pond/lagoon (after solids have been removed).Active rock filter bed, Waiuku
16 Phosphorus Removal P Possible mechanisms: ion exchange adsorption Treated EffluentP74% P RemovalPossible mechanisms:ion exchangeadsorptionprecipitationNow let’s look at what’s happening in there! Different media support various mechanisms (paper).Influent Wastewater
17 Phosphorus Removal Sustainability Potential no energy input required low costsimple and “low tech” like pondsBut…design life, loadings need researchregeneration, extraction of P needs researchNo problems with heavy metal leaching have been reported in literature. Alternative is to use chemical dosing or EBPR.
18 Summary Nutrient removal is essential for sustainability of water resources.N Removal can be achieved onsiteby foam media biofilter.Low cost P Removal possible withan active rock filter.CETE will research oxygen limitation in N removal, also P Removal studies with Dr Ibrahim Elmetri, formerly of UQ, 2 yrs PostDoc.
19 Acknowledgments Warrick Gould Gould GT Systems Technology NZ Palmerston North City CouncilSteelservRock Filter ResearchersThanks to PNCC for access to pond effluent for rock filter study; other rock filter researchers included Lynaire, Sumit, Babar, Rachel.