Bolsover ‘P’ Trial

Caroline Huo1, Lynn Smith2 and Karen Young3

Bluewater Bio1, Yorkshire Water2, Arup3, UK

FilterClear To Meet Low Phosphorus Consent

The BIG Phosphorus Conference and Exhibition – Removal and Recovery. 4-5th July 2017

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The CIP(2) scheme was directed

by the EA to demonstrate best

endeavours to achieve 0.1 mg/l

total phosphorus with a variety of

technologies

➢ FilterClear Technology

➢ Site information

➢ Trial performance

➢ Trial observations

➢ Lessons learned

➢ Recommendations

Introduction

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• Down-flow, depth filtration

• Four media, coarse to fine

– High effluent quality

– High solids holding capacity

– Prevent solids breakthrough

– Long runtime

• Light to heavy

– Stratification after backwash

• Ferric dosing at inline static mixer

for rapid mixing

• Flocculation in the headspace of

FilterClear (no purpose built

flocculation tank needed)

FilterClear: High Effluent Quality @ High Solids Loading

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• Compact, skid-mounted systems

• Wide range of filter diameters

• Standard design & control philosophy

• Offsite manufacturing & testing

• Package plant delivery

• Quick installation, plug & play

FilterClear - Offsite Manufacturing

• High filtration rate 25 m/h to 35 m/h

• Smaller footprint

• Less material, lower embodied carbon

• Average operating pressure: 0.5 bar

• Backwash initiation pressure: 0.9 bar

• Low energy consumption, lower

operational carbon

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FilterClear: TP Removal with single point dosing

➢ Large trickling filter site (Longbridge STW @ Severn Trent)

➢ Single point Ferric dosing upstream of PST

➢ FiterClear influent TSS 18mg/L, effluent TSS 6 mg/L

➢ FilterClear influent TP 0.7mg/L, effluent TP 0.3mg/L

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PSTs

Trickling

Filters

Humus

Tanks

FFT

Ferric

sulphate

FilterClear

Stage 1

Stage 2

Outfall to river

Caustic

80%-100%0-20%

B/W

Bolsover STW - Overview

Parameter Value

FFT 54 l/s

PE 10,000

Ave final effluent SS 27.2

95%ile final effluent SS 58

Consented SS, 95%ile 70

Control Dose

Stage 1 P load

profile

3.5 kg Fe/kg TP

Stage 2 Flow

proportional

12 mg/l as Fe

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Bolsover Site Layout

Stage 1

ferric

Stage 2

ferric

Caustic

FE

p/s

Clean water tank B/W water tank

Ferric Caustic

FilterClear

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FilterClear Results – TP Sample data

Biofilm

Stage 1@ 3.5 2.0 1.5

Stage 2@ 12 6 0

Media

topped

up

0

1

2

3

4

5

6

7

8

TP

mg/l

TP in TP out target TP mg/l

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FilterClear Results for first period of trial

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FilterClear Results – Iron, TSS data

0

10

20

30

40

50

60

70

0

1

2

3

4

5

6

7

8

9

10

TSS

mg

/l

Tota

l iro

n, m

g/l

Total iron in Total iron out TSS in TSS out

Biofilm

Stage 1@ 3.5 2.0 1.5

Stage 2@ 12 6 0

Media

topped

up

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Trial Observations – FilterClear feed flow

0

10

20

30

40

50

60

70

80

L/s

Bolsover FFT and FilterClear feed flow

FFT, l/s FilterClear, l/s

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Trial Observations – Solids generation

➢ FilterClear solids holding capacity

3 to 4 kgTSS/m3 media

➢ Underestimated solids generation

from stage 2 dose

Design basis,

kg/d, filter run

time

Measured

average

conditions

Estimated

maximum

conditions

TSS (mg/L) 37 122 122

Flow (m3/d) 5046 3639 5046

TSS (kg/d) 187 444 616

TSS (kg/h) 7.8 18.5 25.7

Solids holding capacity,

kgTSS/m3 media

3.5 3.5 3.5

Total media volume 7.2 7.2 7.2

Filter runtime, h 3.2 1.4 1.0

➢ Seasonal impact observed

➢ Jar tests at each site

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Trial Observations – Backwash control

➢ Filter designed to backwash on pressure

differential

➢ Pressure controlled backwash was not

sufficient in higher flows and also

morning flow peaks.

➢ A layer of flocs developed during low

flows

➢ The backwash return had to be restricted

during storm events to 6 l//s to meet

consented FFT +10%.

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Operational issues – Instruments

➢ All instruments required additional maintenance

➢ The ortho P instrument was not sufficiently reliable

for control purposes

➢ The iron monitor frequently alarmed for high iron,

inhibiting ferric dosing or shutting the plant down

Inlet biosolids

Ortho P feed

strainerIron monitor

inlet solids

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Operational issues – Biofilm

➢ Stage 2 ferric dose

wasn’t optimised

➢ High iron

environment

➢ Biofilm growthPlenum

Plenum cover

Clean water tank

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TP Achieved at High 2nd Point Ferric Dosing

Conditions:

2nd Point dosing: At high Ferric dose of 30 mg/L

• Flow rate 17l/s (30% FFT)

• Backwash frequency: 2 hours

FilterClear Influent

(pre ferric dosing)

FilterClear Influent

(after ferric dosing)FilterClear effluent

TSS

mg/l

TP

mg/l

Total Iron

mg/l

TSS

mg/l

kg solids/

kg ferric dosed

TSS

mg/l

TP

mg/l

Total Iron

mg/l

55 3.8 4.7 131 2.5 < 3 <0.08 < 0.2

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Trial Observations – Media loss

• Media loss noted after a few months

• The reason for the media loss was a combination of increased

viscosity of water in cold weather and biofilm growth due to

shutdowns.

• Backwash adjusted with temperature factor

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Lessons Learned

➢ Thorough site audit is essential to understand the existing plant performance and site constraints

➢ Fully account for solids loading, including effluent TSS and chemical sludge production.

➢ Jar tests can be very useful for diagnose and trouble-shooting

➢ Chemical dosing control need to be adjusted in response to any changes

➢ Instrument selection, location, cleaning & maintenance

➢ Feed pumping control

➢ Hydraulic checks, including storage and backwash control & return

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Trial Conclusions and Recommendations

➢ FilterClear is capable of achieving TP of 0.1mg/L,

but not without challenges

➢ Online instruments need to be maintained and

calibrated regularly

➢ 2-3 months for optimisation

➢ Plan for up-skilled operators and increased

maintenance

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Big P Conference – Bolsover P Trial

Thank you

Any Questions?

Presented by:

Caroline Huo, Principle Process Engineer, Bluewater Bio, caroline.huo@bluewaterbio.com

Karen Young, Process Engineer, Arup, Karen.young@arup.com

Lynn Smith, Technical Specialist, YWS, lynn.smith@yorkshirewater.co.uk