View
6
Download
0
Category
Preview:
Citation preview
CNP NUTRIENT
RECOVERY
TECHNOLOGIES
Josh Gable – Regional Sales Manager
MWEA Sustainability Seminar
Discussion Outline
• AirPrex Deep Dive
• How it works
• Review of data
• Review of key benefits
• CNP CalPrex – Basics
• History
• Brushite basics
• Summary
History of CNP and AirPrex
Where AirPrex Plugs In
So Why There?
So Why There?
1. Dewatering is always the problem area for nuisance struvite formation
- Get it to form before dewatering and eliminate the issue
2. We want to mitigate sidestream phosphorus
3. Removing the soluble P upstream of dewatering improves the cake
dryness and reduced the polymer requirement
So Why There?
MAP precipitation area
Mg2+ in solution
PO4-P Concentration (mg/L)
7
7,5
8
8,5
9
10 20 30 40 50 60 70 80 90 100 110 120 130 140
ortho-Phosphat [mg/ l]
pH
Raw Sludge (WAS & PS) Biogas
Digester
Magnesium-Dosage
AirPrex®Reactor
Dewatering
Air stripping
Struvite output
How it Works
1 Aeration to strip out CO2+recirculate sludge
2 Addition of Magnesium Chloride (MgCl2)
3 MAP- Crystallisation and sedimentation
4 MAP- Separation and washing
MgCl2
1
2
34 Struvite
Sequestration - OPTIONAL
How it Works
Notable Pilot Tests
What to Expect as a Result
Struvite sample collected during
Airprex Pilot in Miami-Dade
Improvement Cake Dryness
2 to 5 percentage points
Reduction in Polymer
10 to 40 % reduction
15%
17%
19%
21%
23%
25%
27%
29%
25 35 45 55 65
Ca
ke
TS
(%
TS
)
Active Polymer Dose, lb/dt
15 gpm 90% Target Removal
AirPrex
UntreatedDigestate
Data Collected during Denver Metro Pilot Test, Summer 2016
What to Expect as a Result
Struvite sample collected during
Airprex Pilot in Miami-Dade
90% Reduction of Sidestream OP
0
100
200
300
400
500
600
10/22 10/27 11/1 11/6 11/11 11/16
Co
ncen
tria
tio
n P
O4
-P (
mg
/L)
Date
Inflow
Outflow
AirPrex Cent
Digested Cent
Data Collected during Sun Prairie, WI Pilot Test, Fall 2016
What to Expect as a Result
Struvite sample collected during
Airprex Pilot in Miami-Dade
90% Reduction of Sidestream OP
Subsequent Reduction in Digester TP
0
100
200
300
400
500
600
10/22 10/27 11/1 11/6 11/11 11/16
Co
ncen
tria
tio
n P
O4
-P (
mg
/L)
Date
Inflow
Outflow
AirPrex Cent
Digested Cent
Data Collected during Sun Prairie, WI Pilot Test, Fall 2016
What to Expect as a Result –Reduction in Digester influent Phosphorus as Observed at the SunPrairie, WI
Pilot Test
Pre Pilot Test Average
490 mgP/L
At Conclusion of AirPrex Test
398 mgP/L
19% reduction in 16 days
HRT of digester 25-50 days
200
250
300
350
400
450
500
550
10/22/2016 10/27/2016 11/1/2016 11/6/2016 11/11/2016 11/16/2016
mg
P/L
Digestate P Conc’n
Pilot
Test
Modeling completed by MWH based on Denver Metro Pilot
Suggests 30% Reduction in Digester TP Concentration when System Reaches
Steady State.
Pilot Testing Summary
Example Installation
• Amsterdam, Netherlands – Installed 2014
Amsterdam-West WWTP (170 mgd)Struvite production: 2.5 t/dStart-up: 2014
AirPrex® - Amsterdam WWTP (Netherlands)
Disposal: $ 400,000/yr
Polymer savings: $ 350,000/yr
Maintenance: $ 40,000/yr
Revenue from Struvite pays for MgCl2
ROI 7 Years
AirPrex® - Savings for Amsterdam
AirPrex Installations
As of June 2017 – Denver Metro Announced AirPrex Selected
as Technology of Choice for their Nutrient Recovery Project
CNP CalPrex for Pre-Digestion Recovery
Why Acid Phase Digestion –Soluble Ions During Anaerobic Digestion
Sample from 8 Aug 2007
0
100
200
300
400
500
600
Acid Thermo Meso GBT Filtrate
pp
m
P Ca MgFlow
Phosphorus
precipitated
with calcium
and
magnesium
0%
10%
20%
30%
40%
50%
60%
70%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Re
co
ve
ry P
ote
ntia
l (%
To
tal P
)
% Total P solubilized
Veolia Struvia™ CNP AirPrex® Ostara Pearl® CNP CalPrex™
Phosphorus Recovery Potential
Post
Digestion
Filtrate
Max
WAS
Max
Acid
Digest
Max
Brushite (dicalcium phosphate or dical) forms in slightly
acidic conditions of pH 4.5 – 6.5 and is a good fertilizer.
Ca2+ + H2PO4- + 2H2O CaHPO4·2H2O + H+
Struvite (magnesium ammonium phosphate) forms in slightly
alkaline conditions of around pH 8 and is a good fertilizer.
NH4+ + Mg2+ + HPO4
2- + 6H2O NH4MgPO4·6H2O + H+
Hydroxylapatite forms under alkaline conditions of pH 9 and is
NOT a good fertilizer.
3Ca2+ +2HPO42- + xH2O Ca3(PO4)·2xH2O + 2H+
What is Brushite?Distinction of Phosphorus Minerals
What is Brushite?Distinction of Phosphorus Minerals
0
2
4
6
8
10
12
14
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
0.040
0 0.01 0.02 0.03 0.04 0.05
pH
Con
ce
ntr
atio
n [m
ol/L
]
Added calcium hydroxide [mol/L]
P Precipitation from Acid Digest
Dissolved-P Brushite Struvite calcite pH
What is Brushite?Distinction of Phosphorus Minerals
Brushite is a higher value product Commercial value = $250 - $300 / ton
versus
$100 / ton for Struvite
Fertilizer Comparison Statistical AnalysisBrushite and struvite were compared to MAP, DAP, and TSP
Various application rates to a P-deficient soil
Corn yield and P in above ground dry matter were measured
CNP CalPrex Pilot
CNP CalPrex Pilot
CNP CalPrex Pilot
Key Benefits of CalPrex
• Lower chemical cost for Ca(OH) 2 versus MgCl2• ~ $0.06 per lb
• Roughly 10-20% the cost of MgCl2 on a per lb. of P-removed basis
• Where acid digester used
• Can remove highest amount of TP of currently available
technologies
• Brushite has higher commercial value than Struvite
Summary
• Implementation of AirPrex
• Reduce sidestream OP by 90%
• Reduce digester influent TP by estimated 30% at steady state
• Improve Cake DS by 3 to 5 percentage point
• Reduce polymer requirement by 10 to 40%
• Implementation of CalPrex
• TP removal rates of over 50% possible as a separate stream
• Key to success is good P-release, best achieved via acid phase
digester
• Produce higher value fertilizer
• Combined Solution
• Maximize TP diversion and fertilizer production while maximizing
solids dewaterability
Questions?
Recommended