ICWES15 - Hungry for Power - Challenges for the Municipal Wastewater Treatment Industry. Presented by Ms Amanda Lake, Jacobs Engineering, United Kingdom
Phosphorus, Quality & Energy: Challenges for the Wastewater IndustryAmanda LakePrincipal Process Engineer, Jacobs Engineering, Edinburgh, UK
Overview Phosphorus cycle and Water Quality impacts EU and States’ legislative response P reduction in WWT & carbon impacts Mandatory carbon reduction required by WI Challenges for P, WQ and carbon management Role of Water Industry professionals? Conclusions…
The Phosphorus Cycle (e.g. detergents, food additives) fertilizers Chemical P compounds P in animals & waste Food production(via food chains) decomposition Phosphate Organic P in soil Human in plants Animal consumption husbandry (diffuse source P pollution) biosolids (sludge) P in water/ Wastewater sediments (point source P pollution) treatment erosion (millions of years) P derived chemicals Phosphate rock mining Source: Adapted from Green Alliance (2007) ‘the nutrient cycle: closing the loop’
Phosphorus and water quality Food fertilisers production Phosphate in soil biosolids (sludge) (diffuse source P pollution) P in water/ Wastewater sediments Treatment (point source P pollution) Eutrophication Reduced quality of water bodies Loss of aquatic life, environmental degradation Impacts on human use of water/ecosystems Widespread EU WQ problem
Phosphorus in domestic wastewater (UK) Other Laundry 6% Urine detergents 32%Dishwashing 18% detergents 7% Water Treatment Chemicals 5% Faeces 32%
EU Response to address P in Water Quality Point source pollution - sewage treatment plants Urban wastewater treatment directive (1991/1271/EC) Both point & diffuse source pollution Water Framework Directive (2000/60/EC) Holistic approach to achieve ‘good’ ecological WQ status Source reduction Proposed EU ban on laundry detergent phosphates (by 2013) Net impact – marked reduction in point source sewage pollution, increasing basin level management. – but early stages of the WFD → continued focus end-of-pipe
Chemical P removal in WWT = net increase inCarbon Emissions Ferric salt Possible need for PST Secondary FST TertiaryRaw sewage treatment treatment Final effluent Ferric saltAdditional sludge treatment Sludge treatment Additional sludge transport
But the Water Industry is required to reduce it’scarbon emissions… EU 20% reduction in greenhouse gases below 1990 levels by 2020 Emissions Trading Scheme (2005) >20MW, cap & trade States’ own initiatives: UK Climate Change Act (2008) - 80% below 1990 levels by 2050 CRC Energy Efficiency Scheme – compulsory cap and trade for >6,000MWh Water companies report footprint annually, predict future emissions, purchase permits, pay penalties Purchase CO2 permits ~$18/tCO2 Excess consumption ~$113/tCO2
UK Environment Agency Strategies for mitigatingemissions while complying with WFD (2009) 1. Source control Pollutant reduction at source (e.g. in catchment) Detergent phosphates reduction 2. Low carbon process solutions Changed chemical use? 3. Greater operational efficiencies Chemicals dosing, sludges management 4. Redevelopment of existing treatment processes 5. Renewable energy generation/(purchase) …compliance with WFD possible while mitigating emissions but only looking at catchment basis
Recycling phosphates or a do-nothing solution? Recycling P for use as fertiliser: through recovery from WWT as struvite but not suitable for chemical P sludges Sewage effluent reuse Source recovery - urine separation All result in reduction of raw phosphate rock use and removal from point source discharge. Do nothing on cost benefit basis No legal/policy basis in EU – WQ is key - but WFD does offer flexibility and a mechanisms to address water quality improvement at least cost and defer costly improvements.
Opportunities for the Water Industry 1. Look outside treatment plant boundaries Be familiar with catchment based approach under WFD Be familiar with catchment specific issues or engage those who do Understand and challenge regulatory drivers, water quality needs, timing of planned measures 2. Understand and challenge investment mechanisms Could a no-project save $/carbon? Does the WFD offer opportunity to defer/delay investment in WQ solutions? 3. Consider lower carbon solutions On Capex and Opex basis – saves money & offsets additional treatment Look for operational efficiencies elsewhere 4. Challenge design norms Be aware of new technologies, industry policy and strategies Look beyond site boundaries & borders
Conclusions Human impacts on P cycle →WQ issues + depletion of a non renewable resource. Point source → progressed to basin level management under WFD but end of pipe P solutions prevail at net carbon emissions↑ Recent legislation in EU requires WI to meet ↑ water quality targets and carbon emissions↓ Opportunity for quick wins – e.g. detergents WI professionals well placed to consider technical solutions in the basin context to achieve both WQ ↑ and carbon ↓ Key challenges: appreciation of wider issues – both technical and policy, consideration of no-project option, engaging and communicating with stakeholders in catchment planning & at all project stages Female Engineers & Scientists – good communicators – we can do this!