Transcript Joseph Jenkins, PE, CH2M HILL

Brushy Creek Municipal Utility
District
Water Facility Project Status Update
Presented at
April 9, 2009 Board Meeting
Joseph Jenkins, P.E., CH2M HILL
Engineering Projects
• Intake Repairs – goal to make sure the operation of the intake
remains reliable and safe until more permanent upgrades can be
completed.
• Coordination with Chisholm SUD and City of Georgetown on use
of some of Brushy Creek MUD’s intake structure and electrical
building site for their new intake and water plant facilities – goal to
be cooperative without compromising desired current and future
levels of operability and make sure upgrades are compatible with
these future plans, i.e., location of surge tank and electrical
building.
• Membrane Testing – goals – to meet TCEQ requirements, increase
capacity, protect membrane investment to water quality changes.
Intake Repairs
• Testing of medium voltage cables and transformer at intake
complete – acceptable for continued use.
• Pumps No.1 and No.3 are now in good reliable operating condition.
• Working with Plant staff to modify automated pump valve
controllers. Signal and electrical shorts from flood have damaged
relays and electronic controller.
• New splice to repair damaged cable on Pump No. 2 has been made
but is not sealed yet.
• Power to compressor building – new breaker to be installed to
determine if we can get power to intake structure – if not,
temporary power from compressor building can be “run-down” to
intake.
• CH2M HILL will provide report on testing and any final
recommendations for repairs before more permanent upgrades will
be made.
Pump No 2. Cable Repair
• step
Proposed Shared Intake
Intake Next Steps
• Brushy Creek MUD should make any remaining
recommended repairs to intake for safe reliable
service until upgrades constructed.
• CH2M HILL to provide proposal to begin design
of permanent upgrades.
• Finalize agreements with Chisholm and
Georgetown – design and construction to have
some shared cost
Membrane Testing
History of the Brushy Creek Water Facility
• July 2001 – Naismith Engineering/CH2M HILL
completed PER –established treatment and capacity
• April 2002 to July 2003 - Membrane Pilot Testing –
established flow per membrane area on Lake
Georgetown Water
• July 2004 – Design complete – TCEQ approves
provided we check membrane operations with Stillhouse
and Georgetown waters
• 2006 Plant starts operations and Stillhouse water
beginning to be pumped to Lake Georgetown
• 2009 – Higher capacity needs, different water quality
and need to test for TCEQ
Plant Capacity
• Plant must have capacity for a peak day water demand.
• During design 6.25 mgd capacity selected – uncertainty of
growth projections and relative ease of expansion.
• Demands are now at plant capacity – need additional
capacity accepted by TCEQ
• Key is to balance capacity against membrane cleaning.
The fewer membrane cleaning cycles the longer the
membranes last.
• Things that effect membrane fouling – flow and water
quality
Changes in Water Quality
• Record Flood – short term suspended solids,
manganese, low pH, low alkalinity – increase in
fouling
• Record Drought – warmer water, higher organic
foulants – algae – increase in fouling
Raw Water Turbidity
Turbidity
100
10
ntu
16" RW
24" BW
1
24" MF
36" FW
0.1
0.01
Apr-07
Jul-07
Sep-07
Dec-07
Mar-08
Jun-08
Sep-08
Dec-08
Mar-09
Average up to 2001 – 3.5 NTU/2007-2009 4.4 NTU
Raw Water Manganese
Manganese
0.7
0.6
mg/L
0.5
16” RW
0.4
24” BW
Groundwater
0.3
36” FW
0.2
0.1
0
Apr-07
Jul-07
Sep-07
Dec-07
Mar-08
Jun-08
Sep-08
Dec-08
Mar-09
Raw Water Hardness
Hardness
400
350
mg/L as CaCO3
300
16" RW
250
24" BW
200
Groundwater
150
36" FW
100
50
0
Apr-07
Jul-07
Sep-07
Dec-07
Mar-08
Jun-08
Sep-08
Dec-08
Mar-09
Status of Membrane Testing EffortCompleted Task 1, Initial Evaluation of
Task 2, Draft of Task 3
1.
2.
3.
4.
5.
CH2M HILL to identify TCEQ requirements. Summarize in TM.
CH2M HILL and BCMUD staff to define testing goals, including
flux rate or flow rate to be the target for the test. Confirm with
Pall the wash cycles and mode of operations. CH2M HILL to
summarize in TM.
CH2M HILL to develop a detailed protocol for 30-day test.
Submit to TCEQ for approval. Make changes as required by
TCEQ.
BCMUD staff to operate selected test rack for 30-day test
following approved protocol. CH2M HILL to provide limited
technical support.
CH2M HILL to prepare report outlining full-scale test results.
Submit to BCMUD and TCEQ for review/approval.
Initial Findings
• Staff has made some positive changes to adjust to changes
– change to a coagulant that has recently shown to be more
effective for membrane systems, added more modules
• Some foulants still continuing to require membrane
cleaning at higher rates than desired for capacity and
membrane life.
• With the addition of the modules and by addressing the
foulants, there is a significant opportunity for higher
capacity and less cleaning – thus meeting some important
goals – more capacity, better adjustment to changing water
quality, few cleans – which protects your investment and
extends its life.
Recommendation
• To get the best value of the plant, get the best
rating we can from TCEQ by making some
upgrades for capacity and treatability
Upgrades
Upgrade
Use
Benefit
Cost Range (capital)
Additional water
softener
Soft water must be used
for cleaning membranes
otherwise scale can
form
Higher wash volumes
for more capacity and
complete cleans quicker.
$40,000 to $45,000
Additional air scrub
capacity
Air is used to scrub and
clean membranes along
with chemicals – more
modules need more air
Better cleaning and
protection of
membranes
$75,000 to $85,000
Addition of sodium
permanganate to raw
water
Oxidizes manganese
and organic compounds
Reduces manganese
levels to the membranes
$60,000 to $80,000
Increase storage of
cleaning chemicals and
blend tank
Chemicals used to clean
membranes
More modules require
higher wash volumes –
need more storage that
is also makes it safer for
handling
$60,000 to $80,000
Backwash supply Tank
Water used to flush
membranes after
cleaning
Better cleaning and
protection of
membranes
$20,000
Upgrades
Upgrade
Use
Benefit
Cost Range (capital)
Spare Rack Mounted air
Solenoids -
Controls valve air on
racks
6 weeks to order – rack
would be down if not
working
$10,000
Improve Decant basin
solids settling
Basins settle solids and
recycle water back to
ponds
Reduce organic loading
to ponds – lower
disinfection byproducts
$20,000 to $30,000
Miscellaneous
Other ancillary needs
like air filters on racks,
lab instruments
Improved operations
$15,000 to $25,000
Total
$300,000 to $375,000
Does not include
engineering cost
Next Steps
•
•
•
•
Make Upgrades
Submit test plan based on upgrades
Test
Potential to get 2 mgd more capacity with
upgrades than if not done – that $0.19 per gallon
of treatment capacity – compared to new plant
that is $3 per gallon of treatment capacity.