vations in Oxidation Technologi o treat difficult wastewaters Dr Peter Barratt Business Manager Environmental & Clean Technology Air Products (Europe)
Dec 16, 2015
Innovations in Oxidation Technologiesto treat difficult wastewaters
Dr Peter BarrattBusiness ManagerEnvironmental & Clean TechnologyAir Products (Europe)
2 TNAV April 2005
Oxidation:The range of technologies
11 22 33 44 55 1010
OrganicOrganic ComponentComponent
Non- or poorly-Non- or poorly-biodegradablebiodegradable
BiodegradableBiodegradable
OzoneOzone&&
BiologicalBiological
ThermalThermalWetWet
OxidationOxidationIncinerationIncineration
Aerobic BiologicalAerobic BiologicalStabilizationStabilization
ororThermal Wet OxidationThermal Wet Oxidation
AerobicAerobicBiologicalBiological
Organics Concentration (%)Organics Concentration (%)Requiring DestructionRequiring Destruction
OzoneOzone
3 TNAV April 2005
High Purity Oxygen in Water for Aerobic Biology… why?Increased Saturation Concentration (Cs)
– Oxygen in Air = 9.1mg/l @ 20oC– Oxygen = 43 mg/l @ 20oC
Rate of Oxygen Mass Transfer– dC/dt = KLa (Cs - C)– Pure oxygen maximises the oxygen
deficit, so oxygen dissolves faster
Process benefits– Microbes enjoy well oxygenated
conditions
4 TNAV April 2005
Treated water
Excess Sludge
ClarifierFeed
Mixed Liquoror“Sludge”
Returned Activated Sludge (RAS)
Settled Sludge
The Activated Sludge ProcessThe Activated Sludge Process
5 TNAV April 2005
Treated water
Excess Sludge
ClarifierFeed
Mixed Liquoror“Sludge”
Returned Activated Sludge (RAS)
Settled Sludge
The Activated Sludge ProcessThe Activated Sludge Process
OXYGEN
OXYGEN
6 TNAV April 2005
Pure Oxygen
Classical Oxygenation bysidestream oxygen injection
Recirculation Pump Activated Sludge Basin
Water Water IntakeIntake
Secondary EjectorSecondary Ejector
Venturi-typedevice
The OXY-DEP® processTypically fromLiquid Oxygen
7 TNAV April 2005
Paper Industry lagoon
8 TNAV April 2005
Technology– Oxygen generator (Vacuum Swing
Absorption) linked to a low energy mixer– Standard sizes:
• 150 lpm (262kg/d)• 500 lpm (875kg/d)• 2800 lpm (5000kg/d)
– Simplicity and cost in line with aeration– Process benefits of oxygen
New developmentOXY-DEP® VSAOn-site generated oxygen
9 TNAV April 2005
OXY-DEP® VSA
OXYGEN GENERATOR
MIXER-OXYGENATOR
10TNAV April 2005
Aerobic Biological Treatment
Aeration• Typically 1 - 2kgCOD/m3/day
– MLSS 1.5 – 5g/l• Up to 0.5kgNH3-N/m3/day
Oxygenation• High Rate Biological Treatment
processes– Typically 2 – 5kgCOD/m3/day
• MLSS 3 – 20g/l– Up to 5kgNH3-N/m3/day
11TNAV April 2005
OXY-DEP® MB Process
Feed
Washtank
EffluentOXY-DEP reactor
Membrane
O2 Inlet
12TNAV April 2005
OXY-DEP® MB benefitsRefractory COD is treatable
High rate system– Above 30kgCOD/m3/day
Low waste sludge production rate– zero in 3 months (rendering)
Provides potentially re-usable water
13TNAV April 2005
Oxygen - common uses in aerobic biological treatment
Increase treatment capacity of an existing aerated plant
Reduce odours, foams and aerosols
Cater for peak organic and ammonia loads as required
Improve sludge quality
Reduce regulatory risk and improve environmental image
14TNAV April 2005
Direct Ambient Oxidation
Oxidation Processes• Rising Main Injection (sewers)
– avoids H2S and corrosion• Sulphide (S-) Oxidation
– e.g. lagoons• Ozone
– Hard COD and colour removal
O2 & O3
15TNAV April 2005
Ozone
Unstable oxidant
Generated on site
Precursor to .OH
Water treatment
In conjunction with biological treatment
16TNAV April 2005
CHEMOX Reactor for O3
GasOutflow
LiquidOutflow
Pump
Gas InflowLiquid Feed
Main Tube
ImpingingZone
Guide Tube
Nozzle
17TNAV April 2005
CHEMOX - landfill leachate
CHEMOX 1.8 O3 :COD ratio*
4 hours HRT
500 mg/l CODin
<150 mg/l CODout
4 kWh/kgO3 Powerdiss
Existing PlantExisting Plant > 2.2> 2.2
10.3 hours10.3 hours
500 mg/l500 mg/l
<150 mg/l<150 mg/l
8 kWh/kgO8 kWh/kgO33
** : ozone applied/COD removed : ozone applied/COD removed
18TNAV April 2005
CHEMOX - landfill leachate
CHEMOX 1.8 O3 :COD ratio*
4 hours HRT
500 mg/l CODin
<150 mg/l CODout
4 kWh/kgO3 Powerdiss
Existing PlantExisting Plant > 2.2> 2.2
10.3 hours10.3 hours
500 mg/l500 mg/l
<150 mg/l<150 mg/l
8 kWh/kgO8 kWh/kgO33
** : ozone applied/COD removed : ozone applied/COD removed
COST ADVANTAGECOST ADVANTAGE
17% lower in capital17% lower in capital
29% lower in operation29% lower in operation
19TNAV April 2005
Other Ozone Applications
Sludge solids oxidation– Activated sludge in-process
Pathogen removal in reused water
Alternative clean oxidant in chemical synthesis
Selective destruction of problem bacteria e.g. bulking
20TNAV April 2005
Oxygen reuse technology after ozone productionNormally, conversion of O2 to O3 is
6% to 12% by weight. Therefore:– Oxygen off-gas use in other
processes– Long Loop Recycle (LLR)– Short Loop Recycle (SLR)
• O2 and O3 separated after the ozoniser, and O2 recycled to produce O3
• 98% conversion of O2
21TNAV April 2005
SLR Benefits - example
Straight Through
Total
OxygenPower
Capital
SLR Total
40% Savings
15% Savings
4 8 12 16Ozone Concentration [wt%]
$0.50
$1.00
$2.00
$2.50
Cost
tell me morewww.airproducts.com
Please see our web-based Wastewater Treatment Plant Risk Assessment tool