oxygen, ozone and carbon dioxide in waste water treatment ... · dr. hermans 1 / 09-05 oxygen,...

Dr. Hermans 1 / 09-05

Oxygen, ozone and carbon dioxide in waste water treatment

Meeting EU regulations ….

70 - 801070-8015Total nitrogen **

801802Phosphorus **

903590 (70)35 (60)Suspended solids

7512575125COD

70 - 902570 - 9025BOD5

[% reduction][mg/l][% reduction][mg/l]

> 100.000 P.E. > 2000* - 100.000 P.E.Parameter

* Coastal water > 10.000 p.e. ** Sensitive areas, one or both parameters

Biologicaltreatment

More stringent treatment

Directive 91/271/EEC



....easily by using Oxygen, Ozone or Carbon dioxide in water treatment

Neutralisation of industrial waste water: CO2

Prevent corrosion in canalisation and in treatment plant : O2

Capacity increase in activated sludge process: O2

Cracking of persistent COD with ozone: O3

Remediation of surface waters: O2



Neutralisation of alkaline waste waters

pH 1 pH 7 pH 14

acid neutral alkaline

Effluent discharge legislationin Europe: 6,5 < pH < 9,5



epp 0200/9/1

CO2 consumption

Phase I

dischargelimits

Phase IIImineral acid

CO2

pH

2 OH_ + CO2

2 HCO3_

CO32_ + CO2 + H2O

CO32_ + H2O

Phase II

Neutralisation curves of mineral acid and CO2



Characteristics of CO2 and mineral acids

HCl & H2SO4

• strong acids difficult regulation

• difficult to storeand handle

• release of noxious fume• corrosion• consent levels for discharge

CO2

• week acid, no over-acidification

• storage and handling simple and safe

• inert gas• no corrosion• no salting up, ecologic



CO2 injection in waste or process water

Pumped tube reactor with static mixer *Pumped tube reactor with multiple loops *Gas-liquid injector nozzles dH > 40 oDiffusers Pressure vessel Submerged aeratorsHose mats

* suited for injection of liquid CO2



Neutralisation of alkaline waste water with CO2



Compact units for gaseous CO2

50 kg/h CO2 75 kg/h CO2



Advantages of Neutralisation with CO2

Safe and simple pH control, overdosing not possibleLow investment costs No impact on salt content; reduced discharge feesAvoids corrosion problems when recycling effluents



CO2 Neutralisation References

• Beverage industry

• Dairies

• Pulp & Paper Mills

• Textile industry (Leather!)

• Galvanic processes

• Concrete handling



Oxyduct: Oxygen addition in sewersPrevents sewer corrosion and hydrogen sulphide emissions



0

2

4

6

8

10

12

0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9

Pipe Diameter [m]

Oxy

gen

dem

and

[kg/

h*10

00m

]Calculated oxygen demand for pressurized sewersAfter Lohse 1987, ATV M 168



Oxygen injection through socket



Oxygen injectionwith pump-venturiin bypass

In Budapest



Advantages of oxyduct process with oxygen

Proven technology

High oxygen solubility

Small gas flow compared to air

Economic compared to nitrate and hydrogen peroxide

Fast reaction compared to nitrate



Pure oxygen increases capacity and saves energy

Messer offers• Re-engineering of activated

sludge process• Retrofitting• Oxygenation systems• Gas supply• Coached start-up

BIOX-Process: first application at the WWTP ´Emschermündung´in 1980. Since then our technology has been introduced in over

150 plants.



Ct

Cs- air

Cs- Oxygen

* i.e. set point 2 mg/lunder atmospheric conditions

0 10 20 30t [°C]0

2*

10

20

30

40

50

60

70

80

90

C [m

g/I]

Solubility of air and Oxygenin water

Oxygen mass transfer rate is one of the main factors influencing the performance of the activated sludge process.

Power of mass transfer is pro-portional to saturation deficiency: “Cs – Ct”



epp 0200/9

Oxygen bulk vaporizer controlstorage tank system

activated sludge basinaeration

pure oxygenpure oxygenOxygen probe

fine bubbles of oxygen are introduced over a wide area through specially developed oxygenation hose

BIOX Process



WWTP Ilsfeld (D): increased loads from textile industry



WWTP Beggen (Lux): Peak loads from a dairy



WWTP Leer (D): 120.000 P.E.Deep shaft operated with pure oxygen; Waste water 50 % municipal and 50 % oil mill



WWTP Leer: 120.000 P.E.

Deepshaft operated withpure oxygen

Increases capacity

Saves energy



Fillmixing, aeration

COD degradationNitrificationaeration, mixing, oxygenation

Denitrificationmixing

Sludge separationsedimentation

Effluent drawSurplus sludge withdrawal

Industrial waste water

Sequencing Batch Process



Sequencing Batch ReactorsOxygen Demand Profile

Time [minutes]

Oxy

gen

flow

[m3 /h

]

Oxygenation, D.O. controlled

Fill1h,10min

7 h 00min Sedimentation2h 20min

Draw1h 10min



Sequencing Batch Reactorsoxygen for cycle start in a dairy



High rate SBR plant for treatment of sludge liquor

Advantages of the oxygenprocess•Low investment costs•Flexible operation mode •optimised sedimetation of sludge

WWTP Lingen (D)



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: Short residence time Very high oxygenation rate

Aerobic selector in WWTP Overward (AT)



0

50

100

150

200

250

300

350

januaryfeb

ruary

march

april may

june

julyau

gustse

ptember

octobernovem

berdece

mber20002001

Selector operatedwith pure oxygen

Municipal + potato-processing waste waterSl

udge

inde

x[m

l/gra

m]

WWTP Hankensbüttel (D)



Membrane bioreactors

• superior effluent quality• compact treatment

exploit full potentialwith pure oxygen

Industrial waste water: membrane bioreactor



Membrane Bioreactor

additional oxygen increasescapacity by > 50 %

NH4 controlled oxygen dosageLandfill leachate treatmentHorm (D)



epp 0200/2

Nitrogen removal : FundamentalsNitrification

nitrifyingbacteria

heterotrophicbiomass

Denitrification

NH4+

O2

NO3-

NO3-

N2



Conversion to Messer’s BIOX® N process

epp 0200/3

primary settling tank aeration tank final clarifier

before BIOX N return sludgeexcess sludge

inflow outflow

inflow outflow

Denitrification Nitrification final clarifier

Primarysettingtank internal recirculation

return sludge excess sludgeBIOX N process



Conversion to Messer’s BIOX® N process : Retrofitting

epp 0200/4



Sewage treatment plant Neustadt a/d Weinstrasse

epp 0200/6

Outlet values of nitrogen before and after conversion to BIOX® NTo

tal i

norg

anic

N (m

g/l)

before BIOX® N

BIOX® N process

wine harvest

start-up BIOX N

limit18 mg/l

16. april 05. june 25. july 13. sept. 02. nov. 22. dec.

60

50

40

30

20

10

0



The BIOX process-This is how oxygen saves costs

Advantages:Increases treatment capacityFlexible operation mode Costly enlargements are avoidedReduction of yearly costsNo additional energy demandRealised at short notice

oxygen, ozone and carbon dioxide in waste water treatment ... · dr. hermans 1 / 09-05 oxygen,...

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