Acton Wastewater Treatment Plant Expansion Design Presentation
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Transcript Acton Wastewater Treatment Plant Expansion Design Presentation
WEF SDC 2011
Expansion of Acton WWTP
University of Guelph Team:
Alexandra Chan
Adam Erb
Cynthia Mason
Julia Veerman
October 16, 2011
Outline
Introduction
Population Analysis
Process Selection
Phase 1 Design
Modeling
Noise & Odour Control
Construction
Phase 2 Design
Economic Evaluation
Conclusions and Recommendations
Review of Existing Facility
Problem Statement
Current WWTP operating near peak
capacity
Need to increase capacity to
accommodate projected growth in two
phases
Meet projected effluent criteria
Design Basis
Parameter
Average Daily Flow (dry weather)
Maximum Daily Flow (dry
weather)
Instantaneous Peak Flow (wet
weather)
Current
(m3/day)
4610
Phase 1 Given
(m3/day)
5600
Phase 2 Given
(m3/day)
7000
6160
9690
14307
15980
14955
21452
Parameter
Existing
Effluent
Objective/Limit
Proposed
Effluent
Objective/Limit
BOD5 (mg/L)
2/5
2/5
TSS (mg/L)
3/5
3/5
0.2/0.3
0.1/0.2
1.0/2.0
1.0/4.0
-/0.1
1.0/2.0
1.0/4.0
-/0.016
-/0.08
100/150
100/150
Total Phosphorus (mg/L)
(Ammonia + Ammonium) Nitrogen (mg/L)
Non-freezing period (May 1 to Nov 31)
Freezing period (Dec 1 to April 30)
Unionized Ammonia (monthly average) (mg/L)
Unionized Ammonia (any single sample) (mg/L)
Escherichia Coli (monthly geometric mean
density) (#of organisms/100mL)
Population Analysis
Predicted linear growth
Assumed water saving devices at 10%
Infiltration/Inflow at 204 L/c/d
Parameter
Current
Phase 1
Given
Phase 1
Calculated
Phase 2 Phase 2
Given
Calculated
ADF
4610
5600
7628
7000
8574
MDF
6160
9690
10193
14307
11456
Peak
15980
14955
26442
21452
29721
Process Selection
Constraints
Accommodate design flows
Meet effluent discharge limits
Use available land
Be compatible with existing facility
Criteria
Cost effectiveness
Integration with existing facility
Environmental impact and footprint
minimization
Phase 1 Design
Process Flow
Primary Clarifier
Primary Clarifier
Add two rectangular clarifiers
New volume 256 m3
ADF SOR of 27.5 m3/m2/day
Maximum day flow
62.5% TSS removal
40.3% BOD removal
Chain & scraper sludge collector and
scum removal system
Secondary Treatment
Aeration System
Two conventional plug flow
activated‐sludge system with
nitrification
Accommodate 1275 m3/d required
Target MLSS = 4000 mg/L
SRT = 12 days
Fine bubble aeration
Positive displacement blower
Designed for max day flow + additional
feedback flow
Secondary Clarifier
Two additional secondary clarifiers
Limiting solid flux concept
MLSS = 6620 mg/L
Overflow = 31 m3/m2d
Chain & scraper sludge collector and
scum removal system
Max day flow design
Tertiary Treatment
Chemical Addition
85 mg/L liquid alum with 45% purity –
824 kg/d
Addition point in activated sludge tank
Plant B Alum Dose Determination
1,000
Alum Dose (mg/L)
At 95%, alum
dose = 85
mg/L
100
10
1
10
Percent of values equal to or less than indicated
value
100
Filtration
Dual media deep bed filtration
Existing filters work well to meet limits
Widely accepted in WWT
Easily retrofit
Leopold™ Type S™ Underdrain
Air scour + surface wash backwash
Max day flow design with one filter out
of commission
SLR of 7.2 m3/m2/h
http://www.wateronline.com/product.mvc/Universal-Type-S-Underdrain-0002
UV Disinfection
UV selected as best disinfection
method
Trojan UV3000Plus™ system
LP/HI lamp
Automatic and continuous dose pacing
Automated mechanical/chemical cleaning
Automatic level controller
Sized for peak flow
Solids Handling
Bio-Solids Digester
Sequential dual-stage digester series
Add new series in parallel
Methane gas collected for heating
Thermophillic Stage 1
SRT 2 days
Recirculation pump mixing
Mesophillic Stage 2
SRT 8 days
Sludge Drying
Belt press drying after digester
Polymer addition
Increases solids concentration from
~3% to ~25%
Cost-effective in disposal
Reduces footprint
Mass Balance
System Controls and Instrumentation
Control strategy
Increased control and monitoring
Small relative capital cost
Significant efficiency improvements
Biological treatment
Aeration accounts for up to 50% energy
consumption
Matched oxygen demand profile
Intelligent feedback control for aeration,
RAS, WAS
System Controls and Instrumentation
Clarifiers
Monitoring
Sludge pumping control mechanisms
Digesters
Control for feeding rates, recirculation,
heating, withdrawal
Tertiary Treatment
Flow splitting
SCADA
Interfacing with SCADA for remote
monitoring
Hydraulic Profile
Phase 1 – Model Inputs
Projected peak influent concentrations
and flows
Proposed plant sizing
Clarifier modeling based on Lessard
and Beck dynamic model
Activated sludge modeling completed
using the IAWQ1 model
Phase 1 – Model Results
BOD and NH3 water quality
requirements met
Model Shortcomings:
Chemical phosphorous treatment or
tertiary filtration not accounted for
Odour and Noise Control
Currently no odour or noise issues
Reduce odour and noise
Buffer zone
Housing potential equipment
Construction
Completion in 24 months
Best management practices:
Construct in phases
Protect waterways
Provide training
Conduct inspections
Phase 2 Conceptual Design
Phase 2 Conceptual Design
Modify Plant B aeration basin
configuration to plug flow + BNR
Investigate:
Membrane technology
Phosphorus extraction
Phase 1 – Capital Cost
Total Capital Cost Estimate
= $24M
Phase 1 – O&M Cost
Annual O&M Cost Estimate
= $1.2M
Phase 2 – Capital Cost
Total Capital Cost Estimate
= $12M
Conclusions
Expansion design to increase the Acton
WWTP capacity
Preliminary Phase 1 design
Additional clarifier, disinfection, and
anaerobic digestion trains
CAS + nitrification
Deep bed dual media filter
Belt press
Conceptual Phase 2 design
Recommendations
Implement sewer system improvement
plan
Conduct more simulations
Obtain more cost-specific information
from manufacturers
Conduct pilot tests
Acknowledgements
Dr. Hongde Zhou, P.Eng., University of
Guelph – Faculty Advisor
David Arsenault, P.Eng., CH2M Hill –
Consulting Advisor
Rafiq Qutub, P.Eng., WEAO – SDC SubCommittee Chair
Lauren Zuravnsky, P.E., WEF – Design
Competition Sub-Committee Chair