algae event june 1, 2012 - credit valley conservation · 2014-11-13 · long-stringy algae 30 ntu...

Algae Event

June 1, 2012

Lorne Park Water

Treatment Plant

Overview

The Storm and the Algae

The Equipment Damage

The Recovery

The Repairs

The Impact on the Membranes

Water Treatment Capacity

Lakeview WTP

1150 ML/d (800 ML/d membranes)

Lorne Park WTP

500 ML/d (380 ML/d membranes)

Lorne Park Treatment Processes

GAC Filters

Intake Coagulation Flocculation Sedimentation

Coagulant Low Lift

Pumping Station

GAC contactors

(retrofitted filters)

New Low Lift Pumps

and Fine Screens

Membrane

Equalization Tanks

(ex. flocculation

Tanks)

New Membrane Filtration

(retrofitted Sedimentation

tanks)

Conventional / UV Plant (120 ML/d)

Membrane/ UVAOP/ GAC Plant (380 ML/d)

Reservoir

High Lift PS UV

Sodium

Hypochlorite

UV

Zone 1

Zone 2

Membranes

380 ML/d capacity

16 trains

7800 individual modules

Warranty based on:

influent 1mm screening,

coagulant type (among other conditions)

The Storm

June 1st, 2012

Rain: 37.4 mm

Wind: 59 km/h (East)

Turbidity

1 to 60 NTU is common

during storms

Long-stringy Algae

30 ntu

Raw Water Turbidity Trend

Standard Methods:

Filter-clogging

algae

Algae Coating

Travelling Screen Damage

1 mm travelling screens

Large differential caused damage of baskets

Screens couldn’t rotate

algae passed around bent screens

Low Lift Pump Basket Damage

Basket coated in

algae

Pump taken out of

service

11 p.m. to fully

understand extent of

damage

The Solution

Several attempts to

get 1 mm screened

water to membranes

Conventional and

membrane plants are

hydraulically

separated by 1.5 m

Lorne Park Treatment Processes

GAC Filters

Intake Coagulation Flocculation Sedimentation

Coagulant Low Lift

Pumping Station

GAC contactors

(retrofitted filters)

New Low Lift Pumps

and Fine Screens

Membrane

Equalization Tanks

(ex. flocculation

Tanks)

New Membrane Filtration

(retrofitted Sedimentation

tanks)

Conventional / UV Plant (120 ML/d)

Membrane/ UVAOP/ GAC Plant (380 ML/d)

Reservoir

High Lift PS UV

Sodium

Hypochlorite

UV

Zone 1

Zone 2

X

Fixing the Flow Rate Interconnect

valve approx. 30% open

Reprogram SCADA

60 ML/d using 4 Membrane Trains

Switch from 1 mm to 10 mm screens

June 1

The Repairs

Repair crew consolidated undamaged baskets into one screen

7 days for one screen

8 weeks to repair second screen

27 damaged baskets in total

The Membranes

3240 modules

exposed to the

unscreened algae for

several hours

2160 modules

exposed to 10 mm

screened water with

coagulant for 7 days

Impact on the Membranes

Algae

Event Chlorine

Clean

Citric

Clean

Acknowledgements

Ontario Clean Water Agency

Consultants

AECOM, GENIVAR

Contractors

Kenaidan, Maple Reinders

Equipment Suppliers

GE Water & Process Technologies

(membranes)

Siemens (travelling screens)