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HomeMy WebLinkAbout08.a.1) (Handout) Plant Optimization for Ammonia Removal EvaluationItem No. 8.a.1)
Plant Optimization for Ammonia
Removal Evaluation
Element 1:
Plant Optimization
(near term w /existing facilities)
II Primary Baffle Study II
Samantha Engelage, P.E.
Assistant Engineer
Treatment Plant Planning
September 5, 2013
Central Contra Costa Sanitary District
Nutrient Facility Plan
& Site Characterizationli
Element 2:
utrient Visioning Plan
(long term w /new facilities)
Total Nitrification Study
(2010 HDR)
BioWin Configuration I '
Plant Optimization for Cutting -Edge Tact
Ammonia Removal Evaluation
Cyanide Study
Nitrification Rate Tests
vanide Removal Options
Element 3:
Site characterization
(contaminated soil disposaittreatment
for new facliftiesl
,�21_1 k
Aandmi�
Objectives
• Evaluate modifications to existing:
— Secondary treatment facilities that would enable
ammonia removal in the near -term with low capital
investments
— Plant -wide facilities that would increase ammonia
removal capacity
I
Current
Secondary
Configuration
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RAS flan North
S-dary CW im
II
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(C)
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it
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ecoMery Clarlh.n
LEGEND
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Figure 7
CURRENT CONFIGURATION
CENTRAL CONTRA COSTA SANITARY DISTRICT
Evaluation Summary
n.N�.,w c.Myv.Nn wnaaer.
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mu�.ns. vw�+mwwn..w�A S..pr an. us.�w INO A 60NM11C
CEN7RALCONN OSTAS AMiANY
067WCi
Secondary
Reconfiqurations
Description
',Near
Definition
Term Ammonia Removal Approach
Plug -Flow Activated Sludge
Scenarios
Minimal horizontal mixing of water, 100% of the flow
7
treated via suspended growth, conventional biological
ammonia removal (e.g. nitrification).
Step -Feed Activated Sludge
Plug -flow activated sludge with multiple feed points to
equalize the food -to- microorganism ratio and decrease
peak oxygen demand; 100% of the flow treated via
suspended growth, conventional biological ammonia
removal (e.g. nitrification).
Plug -Flow Activated Sludge, Split
2 parallel treatment streams (BOD and NH4); portion of
Treatment
the flow treated via plug -flow activated sludge; effluent of
2 streams are blended prior to discharge for overall
reduction in ammonia
Step -Feed Activated Sludge, Split
2 parallel treatment streams (BOD and NHJ; portion of
Treatment
the flow treated via step -feed activated sludge; effluent of
2 streams are blended prior to discharge for overall
reduction In ammonia
Upstream Improvements
Results
Bioaugmentation Sidestream biological ammonia removal on a high- strength stream;
used to seed the mainstream process with ammonia removing
rSidestream
microorganisms.
2^d
Removal
Remove screenings (i.e. rags, plastics, eta) from the wastewater
combined with performance improvement options); and
stream prior to primary treatment; Increases secondary treatment
required blower upgrades to meet peak aeration
capacity within the same footprint by removing inert solids earlier In
Step -Feed Activated Sludge
161
Operational Complexity
the process.
V
Near Term Preferred Ammonia Removal Approach
Chemically Enhanced Primary Treatment
Addition of coagulation chemicals upstream of primary treatment for
Scenario
Step-Feed Activated Sludge, Split Treatment
is
enhanced primary settling; increases secondary treatment capacity
within the same footprint by removing more solids earlier in the
1°
Not applicable as CCCSD does not digest sludge
Screenings Removal
process.
Preferred Performance Improvement Option
Chendcaliy Enhanced Primary Treatment
Ammonia Recycle Reduction
Reduce ammonia in the centrate recycle stream by limiting the
nitrification, Incinerator clinkers, UV fouling, eta)
retention time of the sludge blending tank; decreases the ammonia
1"
Loss of sludge storage capacity & operational flexibility
Primary Effluent Ammonia Load Equalization
load to the secondary treatment process.
Loss of wet weather capacity
Equalized Peak Wet Weather Reduction
Primary Effluent Ammonia Load Equalization
Diumai flow equalization to even out daily peak loads to the
Sludge Re- aeration
2ti
Compliance risk when combined with Scenario 1; not
secondary treatment process.
appicabe to preferred ammenla removal a roach
Equalized Peak Wet Weather Reduction
Increased peak wet weather bypassing to avoid biomass washout
and allow for higher biomass Inventory without Increased footprint.
Sludge Re- aeration
Temporarily operate secondary process in step -feed operation
during peak wet weather events to allow for higher biomass
inventory without increased footprint.
Evaluation
Results
Plug -Flow Activated Sludge
2^d
Compliance risk (unstable nitrification even when
combined with performance improvement options); and
required blower upgrades to meet peak aeration
demands
Step -Feed Activated Sludge
161
Operational Complexity
Plug -Flow Activated Sludge, Split Treatment
V
Near Term Preferred Ammonia Removal Approach
Scenario
Step-Feed Activated Sludge, Split Treatment
is
Operational Complexity
Sidestream Bicaugmentation
1°
Not applicable as CCCSD does not digest sludge
Screenings Removal
3"
Preferred Performance Improvement Option
Chendcaliy Enhanced Primary Treatment
2n0
Cost prohibitive, operationally complex (e.g. unstable
nitrification, Incinerator clinkers, UV fouling, eta)
Ammonia Recycle Reduction
1"
Loss of sludge storage capacity & operational flexibility
Primary Effluent Ammonia Load Equalization
1"
Loss of wet weather capacity
Equalized Peak Wet Weather Reduction
to
Loss of wet weather capacity
Sludge Re- aeration
2ti
Compliance risk when combined with Scenario 1; not
appicabe to preferred ammenla removal a roach
Plug -Flow AS, Split Treatment
/N1 P0.51rom North /�
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01* = 10- 8'pmg FJ i = 20111 o
N rth Clanfiers So ith Clari!ers z.
Exiclirp Gaze
t
FWS .,y South
x
Sonoary CWrifien
LEGENG Flgura 10
Ridogicat Se:xtor puwerazea) SCENARIO 3 F Pr.mary Etmwm roeee SPLIT TREATMENT, PLUG FLOW' [ P, _'V Emuom CENTRAL CONTRA COSTA SANITARY MSTRICT
Screenings Removal
• Description:
- Screenings = rags, plastics, non - biodegradable
material, etc.
- Currently 3/4" screens, ground screenings reintroduced
to main wastewater stream
- 2011 RMC Report recommended 3/8" screens with
removal at Headworks
• Benefits:
- Increase solids capacity of existing facilities
- Predicted annual NH4 removal increased by -7%
- Reduce O &M issues (e.g. clogging, UV transmittance)
- Currently in Capital Improvements Plan ($7.35M)
Limit Comparison
. Allowable .. ....
Recommended
....
Average Monthly` 65 27 15
(mg/L NH,-N)
Average Monthly
5,500
3,888
—
(kg /day NH3 N)
Maximum Daily
84
29
20
(mg/L NH3 -N)
'Calendar month
"Based on current NPDES permit limits
2011 data
" "Based on model simulations for 2030 flows and loads for both Plug -Flow Activated
Sludge, Split Treatment and Screenings Removal
aP_
Cost Estimates
"Association for the Advancement of Cost Engineering International, Recommended Practices & Standards
(T)
Conclusions
• Interim ammonia limits:
> 15 m /L monthly
average
> 20 mg /L max. daily
4 use Plug -Flow AS, M�
Split Treatment & ,r
Screenings Removal
Next Steps
Field verification of assumptions and
limiting parameters
— Redundancy /complications of running 2 systems
— Modeling predictions
— Clarifier capacities (North vs. South)
— Site - specific nitrification rate (bench vs. full - scale)
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Questions?
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