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Multiple Barriers the role of Phosphorus Eutrophication Control in Water Bodies

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Multiple Barriers the role of Phosphorus Eutrophication Control in Water Bodies

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    1. Multiple Barriers – the role of Phosphorus & Eutrophication Control in Water Bodies Dr David Garman Chairman Phoslock Limited Executive Director Environmental Biotechnology CRC Pty Ltd President International Water Association 15/3/2008

    2. 15/3/2008

    3. IWA - The Premier Global Network for Water Professionals 7,000+ members in over 120 countries Professions: Science & research, utilities, consultants, regulators, manufacturers Scope –> All aspects of water management -> water and wastewater “Leading Edge” of science and practice 15/3/2008

    4. Water Availability Per Capita 1950 15/3/2008

    5. Water Availability Per Capita 2010 15/3/2008

    6. Water Availability Per Capita 2025 15/3/2008

    7. 15/3/2008

    8. A “Rearranged” Population 15/3/2008

    9. Development of World Cities 15/3/2008

    10. 15/3/2008

    11. Urban Portion of World’s Population 15/3/2008

    12. Recognition of the Impacts of Climate Change 15/3/2008

    13. Great Natural Disasters 1950–2005 15/3/2008

    14. Convergence of Forces: Population, Urbanization, Climate Change and Regulatory Requirements 15/3/2008

    15. Emergent Themes Do more with less – new conventional sources are not likely Need to manage both sets of extremes Even those that are wet (underwater) are facing seasonal water shortages Expect the unexpected Seek security through diversity 15/3/2008

    16. 15/3/2008

    17. New sources - implications for water Re-analysis of the fundamentals of supply: micronutrients in new water supply sources can lead to increased biofilm growth & treatment costs, pathogen risk increases esp. non-culturable organisms, energy & pumping costs particularly with membranes disinfectant management & control trace contaminants esp EDCs 15/3/2008

    18. 15/3/2008 Quality issues for water Toxic chemical control ?? Organics Heavy metals Eutrophication ? Nitrogen – NH3- NOX Phosphorus Biodiversity – optimum trophic status Sustainability - variability

    19. 15/3/2008 Water source quality control Multiple barriers – from source to tap Critical factors for waterbodies Source protection Water quality control Ecological protection Diversity maintenance/protection

    20. 15/3/2008 Other pressures Speed for compliance Compliance Risk management Operating costs (Opex) Investment (Capex) Non-compliance penalties

    21. 15/3/2008 Catchment controls Implementation Environmentally sound with public support Typically 4+ years to implement Expensive but early control is effective Full impact only after 10 to 40 years Variability in environmental conditions requires expensive monitoring programs Uncertainty in outcomes dictates increased monitoring to provide greater degrees of resolution

    22. 15/3/2008 Phosphorus as limiting nutrient Hypothesis: Any micronutrient may become the limiting nutrient Limitations associated of other micronutrient controls: N – leads to N fixing organisms Metals – disrupts local ecology

    23. 15/3/2008 Implications of making P the limiting nutrient Changes algal populations Reduces total productivity Alters trophic status Reduces microbial regrowth & survival Reduces biofilm growth in distribution systems as epiphytes/seagrass populations in natural systems reduces bacterial regrowth, viruses etc

    24. 15/3/2008 Biofilms as hazards Bacteria grow in biofilms as flocs or slimes Cyanobacteria are a large visible indicator of this The slimes contain mixtures of bacteria including pathogens as well as viruses The growth and re-growth of bacteria are potential hazards in eutrophic (nutrient rich) water Epiphytes reduce diversity & distort the ecology The growth of these is minimised in low phosphorus waters.

    25. 15/3/2008 Barriers for nutrient control Biological treatment eg WTPs EBNPR Only really suitable for point sources Chemical dosing Not suitable for very low levels & natural waterways Remobilised under some conditions Al & Fe - pH & sludge & sediment problems Denitrification – N removal is expensive High energy(chemical costs) & equipment Nitrogen is refixed opportunistically

    26. 15/3/2008 Diffuse source control Dredging Expensive, disruptive may not remove sediment source – poses new disposal problems? Wetlands Short term unless nutrients harvested – remobilised nutrients Buffer zones Similar to wetlands

    27. 15/3/2008

    28. 15/3/2008 Why invent Phoslock? Limitations of alternative chemicals Al & Fe based have significant risks & lower effectiveness Removal of critical nutrient essential Algicides - existing chemical or biological are unsustainable have risky ecological impacts Internal recycling is critical source of nutrients Dredging of sediments is ecologically disruptive & expensive Secondary disposal now closely regulated External removal unsustainable Pumping & treatment costs prohibitive

    29. 15/3/2008 Phoslock properties Forms a very low solubility complex with Phosphorus Ks <10 -23 Typical low equilibrium values ~ 0.005 mg P/L Surplus of Phoslock – other values can be selected Not released by bacteria or wide range of water conditions

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    33. Phoslock – eutrophication reset Rapid reduction in FRP – typically hours or days TP takes longer- but is equally effective Enables assessment of control measures Provides management with time for option assessment Selection of trophic status depending on end use objectives 15/3/2008

    34. 15/3/2008 Application of Phoslock Open Water Bodies - as slurry with applicator mixing - aerial application of pellets Settles as stable deposit on sediments Industrial - for filter uses – in high concentration P 100 g Phoslock removes 1 to 1.5g P

    35. 15/3/2008 How does Phoslock work? P is adsorbed onto the clay as it falls through the water The P binds to the modified (La) clay, forming an almost insoluble complex The clay settles to the sediments as a very thin layer – 1 to 3 mm Release of P from the sediments is adsorbed by any free Phoslock capacity

    36. 15/3/2008 Phoslock performance Operates over a wide pH range ~ 4 to 11 without changing pH Rapid phosphorus uptake (FRP) - > 90% less than 4 hours Binds phosphorus under anoxic conditions Phoslock is stable under natural conditions Low toxicity Low sludge volume – less than 3mm of sediment Continues to perform if absorbent sites free High settlability compared with other products

    37. 15/3/2008

    38. 15/3/2008 Phoslock is environmentally safe Phoslock has been the subject of extensive ecotoxicity and other testing Recent tests in NZ on algae, juvenile fish (rainbow trout) and water fleas (crustacea). Repeated in Australia & Germany with negative impact results. Risk assessment lodged with Australian authorities prepared by lead independent RA Centre.

    39. Human health safety La used for serum phosphorus reduction in patients with chronic kidney disease Doses equivalent >10,000L water day at max Phoslock dosing Clay & La removed in water treatment Phoslock settles & remains in storages 15/3/2008

    40. 15/3/2008 ‘Do Nothing Risk’ Algal blooms Toxins, ecology disruption with BGA Epiphyte impact on macrophytes DO stress with pH changes Ecology disruption Shift from oligotrophic to eutrophic & exotic species Microbial risk Biofilm increases – pathogen risk increases Corrosion & biodeposition risk Taste, odour Coatings Corrosion

    41. Applications data Phoslock applications - examples of outcomes 15/3/2008

    42. Applications Over 120 major applications worldwide Many minor applications Range of applications from 330 ha lake to 1ha Depth from 3m to 60m P concentrations from 50 ugP/L to >850ug/L Period of monitoring about 3 years 15/3/2008

    43. Examples to be presented Highly eutrophic urban river – Torrens River SA L Emu - Urban Lake Western Australia Off line water reservoir Marulan NSW Low trophic status DWR Productive deep recreational lake - L Okaraka NZ Europe – recreational & high value waters 15/3/2008

    44. 15/3/2008

    45. Torrens River Consistent BG algal blooms Odour, unsightly Largely uncontrolled catchment Highly enriched sediments Algicides, aeration failed Impacts Restricted recreation Tourism adversely impacted Result – re-application(1 year) following rapid restoration of WQ 15/3/2008

    46. Marulan water storage – pumped off river storage 15/3/2008

    47. Marulan Application(4000m2) blue green algae in water supply assessed as health risk rapid correction required Result – effective short & longer term BG control 15/3/2008

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    49. Lake Emu High levels of BG algae in urban water feature Trials successful – full scale application proceeding 15/3/2008

    50. Lake Okareka NZ 15/3/2008

    51. 15/3/2008

    52. Lake Okareka The treated area approx 170 hectares of the 330 hectare total area, Deeper basin approximately within the 20 m contour. Phoslock in the form of small pellets applied at a rate of 118 kg/ha (sediment control) 20 tonnes applied with each annual treatment. Monitoring over 2+y – fish report clearance 15/3/2008

    53. Applications Range of conditions have been successfully treated over a wide range of water body sizes The residual capacity of Phoslock to deal with new inflows is well established No adverse health or environmental issues have been observed. 15/3/2008

    54. Application potential in Canada Ecological reset – open water bodies Catchment control re-assessment Sediment capping Inflow treatment – wetlands & stormwater traps Drinking water reservoirs 15/3/2008

    55. 15/3/2008 Conclusions Phoslock offers first rapid, cost effective way of dealing with eutrophication of large natural water bodies It enables other control measures to be more effective and their impact to be assessed more rapidly It is a stable very low impact material which assists with re-establishment of contaminated sensitive environments. Optimum application for respective control measures for large lake systems requires appropriate data collection It is a control, reset and management tool – it is not ‘fix it’ product. Phoslock applications have implications for water body management to achieve maximum impact and point to cost effective solutions.

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