Oxygen, ozone and carbon dioxide in waste water treatment

Oxygen, ozone and carbon dioxide in waste water treatment Meeting EU regulations …. Directive 91/271/EEC Parameter > 100.000 P.E. > 2000* - 100.000 ...
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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

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