Oxygen, ozone and carbon dioxide in waste water treatment Meeting EU regulations …. Directive 91/271/EEC Parameter
> 100.000 P.E.
> 2000* - 100.000 P.E. [mg/l]
[% reduction]
[mg/l]
[% reduction]
BOD5
25
70 - 90
25
70 - 90
COD
125
75
125
75
90 (70)
35
90
Suspended solids 35 (60) Phosphorus **
2
80
1
80
Total nitrogen **
15
70-80
10
70 - 80
* Coastal water > 10.000 p.e.
**
Sensitive areas, one or both parameters
Dr. Hermans 1 / 09-05
Biological treatment
More stringent treatment
Oxygen, ozone and carbon dioxide in waste water treatment
....easily by using Oxygen, Ozone or Carbon dioxide in water treatment ¾ Neutralisation of industrial waste water: CO2 ¾ Prevent corrosion in canalisation and in treatment plant : O2 ¾ Capacity increase in activated sludge process: O2 ¾ Cracking of persistent COD with ozone: O3 ¾ Remediation of surface waters: O2
Dr. Hermans 2 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
Neutralisation of alkaline waste waters pH 1
pH 7
acid
neutral
pH 14
alkaline
Effluent discharge legislation in Europe: 6,5 < pH < 9,5
Dr. Hermans 3 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment Neutralisation curves of mineral acid and CO2 Phase II
Phase I
Phase III mineral acid
CO2 pH discharge limits
_
2 OH + CO2
2
_
CO3 + CO2 + H2O
_
2 HCO3
CO32 + H2O
_
CO2 consumption epp 0200/9/1
Dr. Hermans 4 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
Characteristics of CO2 and mineral acids HCl & H2SO4
CO2
• strong acids difficult regulation • difficult to store and handle • release of noxious fume • corrosion • consent levels for discharge
• week acid, no over-acidification • storage and handling simple and safe • inert gas • no corrosion • no salting up, ecologic
Dr. Hermans 5 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
CO2 injection in waste or process water ¾ ¾ ¾ ¾ ¾ ¾ ¾
Pumped tube reactor with static mixer * Pumped tube reactor with multiple loops * Gas-liquid injector nozzles dH > 40 o Diffusers Pressure vessel Submerged aerators Hose mats
* suited for injection of liquid CO2
Dr. Hermans 6 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment Neutralisation of alkaline waste water with CO2
Dr. Hermans 7 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment Compact units for gaseous CO2
75 kg/h CO2
50 kg/h CO2
Dr. Hermans 8 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
Advantages of Neutralisation with CO2 ¾ Safe and simple pH control, overdosing not possible
¾ Low investment costs ¾ No impact on salt content; reduced discharge fees
¾ Avoids corrosion problems when recycling effluents
Dr. Hermans 9 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
CO2 Neutralisation References • Beverage industry • Dairies • Pulp & Paper Mills • Textile industry (Leather!) • Galvanic processes • Concrete handling
Dr. Hermans 10 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
Oxyduct: Oxygen addition in sewers
¾Prevents sewer corrosion and hydrogen sulphide emissions
Dr. Hermans 11 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment Calculated oxygen demand for pressurized sewers Oxygen demand [kg/h*1000m]
After Lohse 1987, ATV M 168 12
10
8
6
4
2
0 0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
Pipe Diameter [m]
Dr. Hermans 12 / 09-05
0,8
0,9
Oxygen, ozone and carbon dioxide in waste water treatment
Oxygen injection through socket
Dr. Hermans 13 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
Oxygen injection with pump-venturi in bypass
In Budapest
Dr. Hermans 14 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
Advantages of oxyduct process with oxygen 9 Proven technology 9 High oxygen solubility 9 Small gas flow compared to air 9 Economic compared to nitrate and hydrogen peroxide 9 Fast reaction compared to nitrate
Dr. Hermans 15 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
Pure oxygen increases capacity and saves energy BIOX-Process: first application at the WWTP ´Emschermündung´ in 1980. Since then our technology has been introduced in over 150 plants. Messer offers • Re-engineering of activated sludge process • Retrofitting • Oxygenation systems • Gas supply • Coached start-up
Dr. Hermans 16 / 09-05
Solubility of air and Oxygen in water
C [mg/I]
Oxygen, ozone and carbon dioxide in waste water treatment 90 80 70 60 50
Oxygen mass transfer rate is one of the main factors influencing the performance of the activated sludge process. Power of mass transfer is proportional to saturation deficiency: “Cs – Ct”
40
Cs- Oxygen 30 20
Cs- air 10 2* 0
Ct 0
10
20
* i.e. set point 2 mg/l under atmospheric conditions
Dr. Hermans 17 / 09-05
t [°C]
30
Oxygen, ozone and carbon dioxide in waste water treatment
BIOX Process
activated sludge basin aeration Oxygen bulk storage tank
vaporizer
control system
Oxygen probe
fine bubbles of oxygen are introduced over a wide area through specially developed oxygenation hose epp 0200/9
Dr. Hermans 18 / 09-05
pure oxygen
Oxygen, ozone and carbon dioxide in waste water treatment WWTP Ilsfeld (D): increased loads from textile industry
Dr. Hermans 19 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment WWTP Beggen (Lux): Peak loads from a dairy
Dr. Hermans 20 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment WWTP Leer (D): 120.000 P.E. Deep shaft operated with pure oxygen; Waste water 50 % municipal and 50 % oil mill
Dr. Hermans 21 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
WWTP Leer: 120.000 P.E. Deepshaft operated with pure oxygen
¾ Increases capacity ¾ Saves energy
Dr. Hermans 22 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment Industrial waste water
Fill mixing, aeration COD degradation Nitrification aeration, mixing, oxygenation Denitrification mixing
Sludge separation sedimentation
Sequencing Batch Process
Dr. Hermans 23 / 09-05
Effluent draw Surplus sludge withdrawal
Oxygen, ozone and carbon dioxide in waste water treatment
Oxygen flow [m3/h]
Sequencing Batch Reactors Oxygen Demand Profile
Fill
7 h 00min
1h,10min
Sedimentation 2h 20min
Draw 1h 10min
Oxygenation, D.O. controlled
Time [minutes]
Dr. Hermans 24 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
Sequencing Batch Reactors oxygen for cycle start in a dairy
Dr. Hermans 25 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
High rate SBR plant for treatment of sludge liquor
Advantages of the oxygen process •Low investment costs •Flexible operation mode •optimised sedimetation of sludge
WWTP Lingen (D)
Dr. Hermans 26 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
Aerobic selector improves sludge settling High concentration of „easy BOD“, e.g. waste water from potato processing or soft drinks, easily causes bulking sludge. Aerobic selector: ¾ Short residence time ¾ Very high oxygenation rate Aerobic selector in WWTP Overward (AT)
Dr. Hermans 27 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
350
300 2000 2001 250
200
150
100
Selector operated with pure oxygen
50
WWTP Hankensbüttel (D)
Dr. Hermans 28 / 09-05
no ve m be r de ce m be r
ob er oc t
au gu st se pt em be r
ju ly
ju ne
m ay
ap ri l
m ar ch
y fe br ua ry
0
ja nu ar
Sludge index [ml/gram]
Municipal + potato-processing waste water
Oxygen, ozone and carbon dioxide in waste water treatment Industrial waste water: membrane bioreactor
Membrane bioreactors
• superior effluent quality • compact treatment ¾ exploit full potential with pure oxygen
Dr. Hermans 29 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment Membrane Bioreactor
additional oxygen increases capacity by > 50 %
NH4 controlled oxygen dosage Landfill leachate treatment Horm (D)
Dr. Hermans 30 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment
Nitrogen removal : Fundamentals Nitrification NH4+ O2
nitrifying bacteria
NO3-
Denitrification
NO3-
heterotrophic biomass
epp 0200/2
Dr. Hermans 31 / 09-05
N2
Oxygen, ozone and carbon dioxide in waste water treatment Conversion to Messer’s BIOX® N process aeration tank
primary settling tank inflow
final clarifier outflow
return sludge
before BIOX N
Denitrification
Nitrification
excess sludge final clarifier outflow
inflow Primary setting tank
BIOX N process
internal recirculation return sludge
epp 0200/3
Dr. Hermans 32 / 09-05
excess sludge
Oxygen, ozone and carbon dioxide in waste water treatment Conversion to Messer’s BIOX® N process : Retrofitting
epp 0200/4
Dr. Hermans 33 / 09-05
Oxygen, ozone and carbon dioxide in waste water treatment Sewage treatment plant Neustadt a/d Weinstrasse
Total inorganic N (mg/l)
Outlet values of nitrogen before and after conversion to BIOX® N 60 ®
before BIOX N 50 ®
BIOX N process
40 30 20
wine harvest
limit 18 mg/l
10 0
start-up BIOX N
16. april
05. june
25. july
epp 0200/6
Dr. Hermans 34 / 09-05
13. sept.
02. nov.
22. dec.
Oxygen, ozone and carbon dioxide in waste water treatment
The BIOX processThis is how oxygen saves costs Advantages:
¾ ¾ ¾ ¾ ¾ ¾
Increases treatment capacity Flexible operation mode Costly enlargements are avoided Reduction of yearly costs No additional energy demand Realised at short notice Dr. Hermans 35 / 09-05