1. Phosphorus, Quality & Energy:
Challenges for the Wastewater Industry
Amanda Lake
Principal Process Engineer, Jacobs Engineering, Edinburgh, UK

2. 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…

3. 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’

4. 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

5. Phosphorus in domestic wastewater (UK)
Other
Laundry 6% Urine
detergents 32%
Dishwashing 18%
detergents
7%
Water
Treatment
Chemicals
5%
Faeces
32%

6. 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

7. Chemical P removal in WWT = net increase in
Carbon Emissions
Ferric salt
Possible need for
PST Secondary FST
Tertiary
Raw sewage treatment
treatment Final effluent
Ferric salt
Additional sludge
treatment
Sludge
treatment
Additional sludge
transport

8. But the Water Industry is required to reduce it’s
carbon 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

9. UK Environment Agency Strategies for mitigating
emissions 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

10. 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.

11. 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

12. 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!

13. Thanks for listening, questions please?