Project Manager for Stantec Consulting Michigan Inc.

licoricehealthΤεχνίτη Νοημοσύνη και Ρομποτική

14 Νοε 2013 (πριν από 3 χρόνια και 11 μήνες)

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Presenter: Walid Al
-
Ani, P.Eng, P.E., BCEE, LEED® AP
Project Manager for Stantec Consulting Michigan Inc.



Overview of the Cadillac WWTP


Background Information


Filtration Technologies Evaluation &
Selection


Design Highlights


Construction Highlights


Post
-
Construction Performance


Questions and Answers

2


Plant Rated for 3.2 MGD Average Daily Flow and 4.5 MGD Maximum Daily
Flow


Influent Pump Station


Screw Pumps


Equalization Basin


Preliminary Treatment


Primary Treatment


Secondary Treatment


Activated Sludge/Chemical Addition for Phosphorous
Removal


Rotating Biological Contactors


Tertiary Filters


UV Disinfection


Anaerobic Digestion


Biosolids Land Application

3

4


Project plan prepared in 2006 to address overall plant needs


Requirement for seeking State Revolving Funds (SRF)


Tertiary Treatment major needs identified:


Replacement of the sand filters that were nearing the end of their useful life


Replacement of the sampling pumps


Replacement of the samplers


Design completed in the summer of 2007


Construction completed in the early spring of 2008


Overall construction cost approximately $3,800,000


Construction cost for Tertiary Treatment Improvements approximately
$1,000,000


Construction cost for the installed filters approximately $620,000

5


Three sand filters (Hydroclear)
commissioned in 1977


Some rehabilitation work performed over
the years including replacement of filter
media, valves, and control system


Deteriorating performance and extensive
backwashing necessary

6


Traveling Bridge Filters


Traveling Hood Filters


Disc Cloth Media Filters


Synthetic Media Filters


Deep Sand Filters


Membrane Biological Reactors (MBRs)

7


Continuous downflows, automatic backwash, low head,
granular medium depth filter.



Filter bed is divided into independent filter cells.



Treated wastewater flows through the medium by gravity and
exits to the clearwell plenum via a porous
-
plate, polyethylene
underdrain.



Each filter cell is backwashed individually by an overhead
traveling


bridge assembly, while the other cells remain in
service.



During the backwash cycle, wastewater is filtered continuously
through the cells that are not being backwashed.



Example is the US Filter Davco Products


Gravisand.

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9

Source Aqua
-
Aerobics Systems, Inc.


Similar to the Traveling Bridge Sand Filter.



Uses a pneumatically driven self


propelled hood
instead of a conventional rail
-
mounted traveling
bridge.



Simpler, more compact installation, lower equipment
cost compared to the Traveling Bridge Sand Filter.



Example is EIMCO Water Technologies.

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11

Source Water Online


Filter tank contains a series of circular disk elements
covered with a specialized cloth media.


The cloth media traps particulates within its interior as
well as forming a particulate layer upon its outer
surface.


Backwash cycle begins at a predetermined water level.


During the backwash cycle, the center tube rotates while
a centrifugal pump draws filtered water through a
suction header from the clean side of the filter cloth.


Examples are the Aqua
-
Aerobic Aqua Disks and the
Kruger Hydrotech Disc Filter.

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13

Source
Aqua
-
Aerobic Systems,
Inc
.


Filters use highly porous synthetic medium.


Porosity modified by compressing the filter medium.


Wastewater flows through medium; not around filtering
medium as in conventional sand and anthracite filters.


Wastewater introduced in bottom of filter and flows
upward through filter medium, which is retained by two
porous plates.


Upper porous plate raised mechanically in backwash.
Flow to filter continues and air introduced below lower
porous plate causing medium to move in a rolling
motion.


Example is Schreiber’s Fuzzy Filter.



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15

Source Schreiber

Source: Schreiber

16


Wastewater introduced into bottom of filter where it
flows upward through a series of riser tubes.


Wastewater then flows upward through downward
moving sand and exits filter.


Sand particles and trapped solids are drawn downward
into the suction of an airlift pipe. A small volume
of
compressed air draws sand, solids, and water upward.


At the top of the airlift, the dirty slurry spills over into a
central reject compartment. Sand settles and is cleaned
further as it moves down through a washer.


Example is Parkson’s DynaSand
Filter.




17

Source DynaSand

Source: DynaSand

18


MBRs combine secondary & tertiary treatment into one
process.


Integrated bioreactor uses membranes immersed in
bioreactor; re
-
circulated MBR in which mixed liquid circulates
through a membrane module located outside the bioreactor.


In the integrated bioreactor wastewater is drawn through the
membranes using vacuum. Compressed air is used to scour
the membrane surfaces.


In the re
-
circulated MBR wastewater is pumped into the
membranes where solids are retained inside the membranes
and wastewater passes through to the outside. The
membranes are backwashed systematically to remove solids.


Examples are MBRs manufactured by Zenon, US Filter
Memcor, and Envirogroup.



19

Source: Memcor


Required performance based on NPDES effluent
limitations for the summer months listed in the
Cadillac WWTP permit:


30
-
Day Average BOD
5




7 mg/L


30
-
Day Average TSS





20 mg/L


30
-
Day Average Ammonia Nitrogen (N) 0.9 mg/L


30
-
Day Average Phosphorous



0.5 mg/L



Evaluation of all technologies indicated that the
effluent limitation for TSS could be met.



20

Filter Type

Budgetary Price *

Traveling Bridge Sand Filter

$200,000

Traveling Hood Sand Filter

$300,000

Disc Cloth Media

Filter

$500,000

Synthetic Media Filter

$700,000

Deep Bed Sand

Filter

$800,000

Membrane

Biological Reactor

$2,400,000

21

* 2006
Prices


Based on equipment cost from manufacturers

Filter Type

Remarks

Traveling Bridge Sand Filter

Does not fit into the existing building.

Traveling Hood Sand Filter

Does not fit into

the existing filter
footprint but may fit into existing
building with structural modifications.

Disc Cloth Media

Filter

Fits into the existing filter footprint

but requires removal of the mud well.

Synthetic Media Filter

Fits into the existing filter footprint

but requires removal of the mud well.

Deep Bed Sand

Filter

Does not fit

into the existing building.

Membrane

Biological Reactor

Does not fit into the existing filter
footprint but may fit

into existing
building with structural modifications.

22

Filter Type

Remarks

Warrants Further
Consideration

Traveling Bridge Sand
Filter

Does not

fit into existing
building

No

Traveling Hood Sand
Filter

Does fit into existing filter
s
footprint

No

Disc Cloth Media

Filter

Fits into existing filters
footprint

Yes

Synthetic Media Filter

Fits into existing filters
footprint

Yes

Deep Bed Sand

Filter

Does not fit into existing
building

No

Membrane

Biological
Reactor

Does

not fit into existing
building and is too costly

No

23

Filter Type

Installations in MI
and other
Surrounding States
as of early 2007

Remarks

Warrants
Further
Consideration

Disc

Cloth
Filter
Media
(Aqua


Aerobic)

Several nationwide
including MI


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Sanitary District WWTP

Yes

Disc

Cloth
Filter
Media
(Kruger)

One in MI one

in
Ravenna, OH


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24

Item of
Comparison

Cloth Media Disc Filter

(Aqua
-
Aerobic)

Cloth Media Disc Filter
(Kruger)

Equipment Cost

$547,000

$500,000

Structural
Modifications


Demolition of Mud Well


Columns and beams

remain


Partial

demolition of mud well


Columns and beams remain


Significant concrete work required
to accommodate open channel
flows

Access Into Existing
Building


Requires

demolition of building exterior
wall


Requires demolition of building
exterior wall

Experience in
Michigan


Several Installations


Pilot testing not required


One

installation only as of early
2007


Pilot testing likely required

Experience at Similar
Installations

Sutton Bay WWTP


In Operation

since 2006


No Mechanical Problems


Good Workmanship


Urbana
-
Champagne Sanitary District WWTP


In Operation since 2005


Good responsiveness during construction,
start
-
up, and post construction


Decision to install same type of filters at
the larger District’s WWTP


Peak flows of 17 MGD were handled with
no reported problems

Ravenna

WWTP


Difficulty meeting the 2 MGD
peak flow with one filter out of
service


Belt supporting the discs has
failed


Major rigging required for belt
replacement

25


Decision was to adopt the cloth media filter
technology (Aqua
-
Aerobic) based on the
following:



Established experience nationwide including
Michigan


Ease of Maintenance


Demonstrated ability to handle peak flows


Ability to meet the project’s strict milestones
since no pilot testing would be required




26


Limitations on when construction could occur
had to be established, due to the NPDES
Limitations


Higher SS discharge limits allowed December
1 through April 30 (30 lbs/day on a monthly
basis compared to 20 lbs/day for rest of the
year)


Therefore, taking the existing filters off
-
line
and completing installation of the new filters
was allowed for December 1 through April 1

27


Structural integrity had
to be confirmed to
allow partial
demolition of the walls
and slab


Existing piping
arrangement had to be
confirmed to allow
bypass of the filters to
the disinfection
process


Demolition of existing
exterior walls had to
be addressed to verify


access issues

28


Hydraulic
calculations had to
be performed to
ensure new filters
would not be a
bottleneck


Filters, piping,
platforms, and
controls had to be
fitted into the
existing space

29


Entire work (demolition, installation, start
-
up, on
-
line) had to be
completed in three months

30


Access limited through existing building wall

31


Filters demolished and removed

32


All piping in gallery removed

33


“Mud Well” slab demolished

34


New Floor

35


Filter concrete support pads

36


New filter piping

37


Filters installed on concrete pads

38


New piping in gallery

39


Filters in operation

40


Filter Control Panels

41


Backwash and Sludge Valves

42

Back Wash Cycle


Back Wash Initiation:


Water level exceeds specified level


Time interval elapses


Manual back wash cycle


High level float switch activates



Back Wash Set Points:


Back Wash interval, time between
automatic backwash cycles


Back Wash duration, wash time for
each collection manifold


Back Wash level, water level that
triggers a back wash cycle


43

Sludge Cycle


Sludge Removal Initiation:


Time interval elapses


Back wash counts elapse


Manual

sludge cycle



Sludge Cycle Set Points:


Sludge interval, time between
automatic sludge cycles


Backwash count, number of back
washes between automatic sludge
cycles


Sludge

duration, duration of the
sludge cycle



Filters are operating successfully and meeting the NPDES requirements

44

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