Membrane Pre-treatment Using Plate Settlers - Ohiowater.org

Membrane Pre-treatment Using Plate Settlers
Joe Brauch
Meurer Research
6270 Joyce Drive
Golden, CO 80403

MEURER RESEARCH, INC.
• Established in 1977 – Has over 35 years experience in
designing clarifiers
• Has been issued over 50 patents related to the
sedimentation process
• MRI has over 500 plate settler installations, more plates
than anyone in the world.
• MRI has manufactured over 4,000 sludge collectors,
more than anyone in the world.

Plate Settlers in the Pre-Treatment Process
•Effective pre-treatment will maximize the downstream
processes, i.e. membranes and granular media filters
•Sedimentation is the most popular method of pretreatment
•The sedimentation process is designed to remove the
majority of settleable solids by gravitational settling

CONVENTIONAL SETTLING BASIN
• Design parameters are that particles moving at velocity V H , starting at the
water surface and falling at a velocity V S must reach the bottom, depth D,
within the basin length L.
• Influent elevation “d” must be used for calculations
• Through calculations, Overflow Velocity (V O ) or Surface Overflow rate (SOR)
can be determined
L
D
d
v S
v H

MANY THINGS AFFECT THE PERFORMANCE OF A
CONVENTIONAL BASIN
• Flow rate changes
• Local climate conditions
o Air and water temperature changes – Water density
o Wind velocity and direction
• Events such as heavy rains
• Inadequate sludge removal

CONVENTIONAL BASIN WITH SLUDGE
ACCUMULATION
•Reduces the size of the basin
•Causes short circuiting

CONVENTIONAL BASIN AS SLUDGE BUILDS UP
EVEN DISTRIBUTION
INTO THE BASIN
HIGHER VELOCITY DOWN
THE BASIN
FLOC CARRYOVER OCCURS
SLUDGE BUILDS UP
RESIDENCE TIME IS
SHORTENED

EVOLUTION OF PLATE SETTLERS
• Allen Hazen’s 1904 paper marked the beginning of
modern sedimentation theory with the notion that a
basin should be shallow therefore reducing the effects
of hydraulic factors.
• This was later advocated by Camp and the theory of the
“tray settler” was born.

The problem was sludge removal from a horizontal tray.
The answer was found by tilting the plates
(trays) which resulted in the velocity vectors
within the plate settler as we know it today
3.5"
Vg
55 0

SETTLED SOLIDS EVACUATION
Camp determined that settled solids accumulate into a mass.
When the weight of the mass exceeds the shear resistance of the
plate surface the mass slides down the 55 0 angle and off of the
plate as a clump.
The settled solids
accumulate as a mass
The weight of the mass
exceeds the shear
resistance and breaks
away

Plate
Cartridges
Feed Channels
Flow Control
Decks
Stainless Steel Support Beam
Sludge Collection

ADVANTAGES OF PLATE SETTLERS
1. The settling distance is reduced by 98%, 3.5” compared to
15’ in a conventional basin
2. Plate settlers provide a “perfect environment” low
velocities and minimized hydraulic effects
3. Effects from wind, turbidity spikes and temperatures are
minimized
4. Plate settlers “overlap” therefore basin footprints are 20%
as large as a conventional basin
5. Effluent turbidities are

Plate settlers are set on 55 0 angle
Falling particles see the
“Projected Area” of each
plate settler
The loading rate is the rate of
flow over the projected areas
i.e. .3 gpm/ft 2
The Projected Areas
overlap
The settling surface is
much larger without plate
settlers

Determine the horizontal projected area needed
1. Choose the specific loading rate. For example a standard
loading rate is 0.3 gpm/ft 2 of effective plate area at 90%
efficiency.
Calculations for 10 MGD (6950 GPM) example:
Divide the flow in gpm by the loading rate:
Flow = 6,950 = 23,166 ft 2 = projected area
the Loading rate .3 GPM/ft 2
Apply the efficiency
SIZING CALCULATION EXAMPLE
2. Divide the projected area by the efficiency – 90%
Projected area = 23,166 ft 2
efficiency .9
= 25,740 ft 2 effective area

Convert the horizontal projected area to
55 0 plate angle
3. Divide the effective area by .574 (COS of 55 0 )
to convert the surface area to 55 0
25,740 ft 2 = 44,843 ft 2 of actual plate surface
.574
Convert the plate area to number of plate
settlers
4. Divide the actual plates surface area by the
area of each plate (i.e. 45 ft 2 )
44,843 ft 2 = 997 plates for 10 mgd
45 ft 2

SITE INSTALLATION PROCESS
Beams installed & Plates are set into
positioned
Plate Packs are secured to the
Beams
Weirs are leveled and Installation
completed
Troughs are lowered in
position

MIRAMAR WTP SAN DIEGO, CA – 220 MGD

BUNDAMBA AUSTRALIA – 40 MGD

LUGGAGE POINT, AUSTRALIA – 31 MGD

AUGUSTA, GA 20 MGD

ATLANTIC CITY, NJ - 20 MGD

WYOMING, MI – 90 MGD

JERSEY CITY, NJ – 90 MGD

GALLATIN, TN SUBMERGED PLATES – 20 MGD

SLUDGE REMOVAL

Design Criteria for Sludge Removal
• Must remove settled solids over the entire floor
• Provide low head sludge discharge such as:
Low head directional orifice blocks
• No flexible hoses or articulating pipes.
• Must have the capability of higher removal rates in the
front areas of the basin

GUIDE CURB
TELESCOPING
PIPE
SUCTION
HEADERS
SLUDGE SCRAPERS

AUGUSTA, GA
AUGUSTA, GA 4 UNITS

Cleaning cycle initiated: Valve opens - Drive starts

Cleaning cycle: Solids Removal

Cleaning cycle completed:
Drive stops – 3 minute pipe flush – Valve closes

Return cycle:
Drive starts - Orifices are back flushed

Return cycle completed:
Drive stops

Membrane Pre-treatment Using Plate Settlers
THANK YOU FOR ATTENDING
51 st Annual
Water Workshop
& Exhibition
Joe Brauch
Meurer Research
6270 Joyce Drive
Golden, CO 80403