The Nutrient Challenge: Phosphorus Removal Reed Beds

Creating better results together

Samantha O’Hara & Naiara Fonseca

2

What is the Nutrient Challenge?

Increased Nutrient Use

Into Water Bodies

Eutrophication Dead Fish

European Union

This is not acceptable

EU Directives

Decreased Nutrient Use

Into Water Bodies

Less Nutrient in Water Bodies

Happy Fish!

Where are we now?

Watercourse

Agriculture

Detergents

Sewage Effluent

“Inland and coastal waters to reach ‘good water status’ by 2015” Water Framework Directive

3

What does this mean?

4

P leads to “low status”

Reduce P to the

environment

Catchment Challenge

P Removal Treatment

Tightened phosphorus

consents

Large Works

Small Works

The Challenge: Unmanned Rural

Sites

Shock Loading

Large Diurnal

Variation

Difficult Access

Low Operator Presence

No Potable Water Supply

Small Scale

Power Supply

Sensitive Receptors

5

The Solution: Chemical Dosing?

• Dosing metal salts to precipitate

phosphorus from effluent

6

Assets

SludgeChemicals

But….

7

Shock Loading

Large Diurnal

Variation

Difficult Access

Low Operator Presence

No Potable Water Supply

Small Scale Power Supply

Sensitive Receptors

Unwanted chemical reactions

Need Tight Control

Tankering&

DeliveriesControl &

Mechanical parts

Safety showers & eye washes

May need power

upgrade

Pollution Potential

The Solution: P Removal Reed

Beds

8

Reed bed = Constructed Wetlands

What are P removal reed beds?

Supporting media

Reeds

HF

VFGravel

traditionally SS removal

Reactive material

with high P affinity

Basic Oxygen Furnace (BOF) steel slag

Compound Typical composition (%)(*)

CaO 40-45

Fe2O3 25-30

SiO2 10-13

MgO 5-6

(*) Dunster, A. (2001) Building Research Establishment (BRE) Information Paper 18/01 – Blastfurnace slag and steel slag: their use as aggregates, London: CRC Ltd.

9

Hhhh

Hhhhhh

Hhh

ggggg

What are P removal reed beds?

Gravel traditionally SS removal

Reactive material

with high P affinity

10

Large Diurnal

Variation

Shock Loading

Difficult Access

Low Operator Presence

No Potable Water Supply

Small Scale Power Supply

Sensitive Receptors

So… Benefits?

11

Unwanted chemical reactions

Need Tight Control

Tankering&

DeliveriesControl &

Mechanical parts

Safety showers & eye washes

May need power

upgrade

Pollution Potential

No Chemicals

Passive Technology

No Tankering

or Deliveries Few

mechanical parts

No Need for Potable

WaterLow Energy

Creates a new

habitat

12

How do we prove they work?

Demonstration scale trials

Effect of particle size

Potential way of

increasing P removal

Potential roll-out to full scale

Successful full scale

trials - 74% TP removal

Commercially available BOF

slag size employed

Lab scale trials

0.75 mm 1.75 mm 5.09 mm 7.60 mm 10.04 mm

How do we prove they work?

5 fully saturated columns

Synthetic P solution

[TP] 5 mg/L

5 fractions

HF reed bed

13

How do we prove they work?

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Inlet and effluent [TP]

Fraction (mm) [TP]eff (mg/L) % removal

0.75<0.08 >97

1.75

5.09

<1 80-857.60

10.04

Increased surface

area More CaOreleased, more P

removed

Hydraulically not viable

Applicable to full scale

0

1

2

3

4

5

0 5 10 15 20 25 30 35 40 45 50 55 60

[TP

] (m

g/L)

Time (days)

Inlet

Col0.75

Col1.75

Col5.09

Col7.60

Col10.04

CaPO4

Likely P consent

15

pH<9 consent

How do we prove they work?

Acidification solutions

0

1

2

3

4

5

6

7

8

9

10

11

12

0 5 10 15 20 25 30 35 40 45 50 55 60

pH

(-)

Time (days)

Inlet

Col0.75

Col1.75

Col5.09

Col7.60

Col10.04

pH ~ 11

8.5<pH<9.5

Not acid addition

To be monitored for 2 years, starting November 2014

Demonstration scale trials

Humus tank effluent

Dilution

86 m3 86 m3 86 m3

16

How will it fit with AMP6 strategy?

83Sites with

tightened P

consents

49Site for P

Removal

Reed Beds

Outcomes

• Lowest TOTEX solution• Low carbon footprint• Attenuate loadings from flooding & drought• Re-use of the steel slag waste • Potential P recovery

1Site for 3 Pilot

P Removal

Beds

Approximate Figures : To Be Confirmed with Final Issue from EA

17

Lowest TOTEX Solution

Step change in Innovation

No Chemical

No Tankering

Lower Energy

Lower Manpower

Lower Maintenance

Lower CAPEX

Media Regeneration

CAPEX

OPEX

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AMP7 & Beyond

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(1) Cordell et al. (2009) The story of phosphorus: Global food security and food for thought, Global Environmental Change, 19, 292-305(2) Press release, European Commission (2014) http://europa.eu/rapid/press-release_IP-14-599_en.htm(3) The Environmentalist, July 2014, p.4, Institute of Environmental Management and Assessment (IEMA )

Proposal for P as waste

stream in theEC wasterecycling

scheme (3)

P RECOVERY AND REUSE

Fertilizer price

Phosphaterock in EC

Critical RawMaterials

List(2)

(1)

Once saturated

what do we do?

P Recovery

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Dispose to Landfill

Cost of Transport

Landfill Tax

Lowest on Waste

Hierarchy

Reuse as fertiliser

Waste Regulations

?

Market?

Potential Value?

Summary

21

Increased Nutrient Use

Into Water Bodies

Eutrophication Dead Fish

European Union

This is not acceptable

EU Directives

Less Nutrient in Water Bodies

Happy Fish!

Acknowledgements

22

Special Thanks to:

Questions?