음용수수준의물재생을위핚 하수처리방류수초고도처리env.seoul.go.kr/files/2012/03/4f541ce9de4276.01005449.pdf · 2013-01-08 · •Hydranautics ESPA-2 Membranes

미래를 선도하는 서울의 스마트 물 순환, 2011 물순환 회복 학술 심포지움

프레스센터 국제회의장, 2011.5.31

음용수 수준의 물재생을 위핚하수처리 방류수 초고도 처리

UV/H2O2 Oxidation of Endocrine Disruptor Chemicals for Water Reclamation and Reuse

고광백연세대학교 토목환경공학과 교수



Indirect Potable Water Reuse

GWR System

NEWater

Advanced Oxygen Processes (AOPs)

UV/H2O2 Process

UV/O3 Process

Degradation of Emerging Contaminants via UV/H2O2 Process

NDMA, 1,4-Dioxane

MIB, MTBE, Atrazine

Pilot-scale AOP Operation

Objective of Study

Results and Discussion

Conclusions



Pacific OceanIrvine

Fullerton

Ocean

Outfall

OCWD

Groundwater Basin

Santa Ana River

Santiago Creek

OCSD

Treatment

Facilities

HuntingtonBeach

Future Mid-Basin

Injection/Recharge

SeawaterIntrusion

Barrier Pumping

Facilities

Advanced

Water Purification

FacilityN

Source: SCAG, 2008

Indirect Potable Water Reuse: GWR System Components



Ultraviolet Light

(UV) with

H2O2

Brine Treated

in OCSD Outfall

Backwash

Sent to OCSD

Microfiltration

(MF)

Reverse

Osmosis

(RO) Expanded

Seawater

Barrier

Recharge

Basins in

Anaheim

OCSD

Secondary

Effluent

Normally

Goes to

Ocean

Source: SCAG, 2008

Indirect Potable Water Reuse: GWR System



• 86 MGD (325,500 m3/day)

Siemens CMF-S Microfiltration

System

• Tiny, straw like hollow fiber

polypropylene membrane

• Removes bacteria, protozoa, and

suspended solids 0.2 micron pore

size

• In basin submersible system

Source: SCAG, 2008

Indirect Potable Water Reuse: Microfiltration System



• 70 MGD (265,000 m3/day)

Reverse Osmosis System –

3stage

• Hydranautics ESPA-2

Membranes

• Recovery Rate: 85%

• Removes dissolved minerals,

viruses, and organic compounds

(incl. pharmaceuticals)

• Pressure range: 150 – 200 psi

Source: SCAG, 2008

Indirect Potable Water Reuse: Reverse Osmosis System



• 70 MGD (265,000 m3/day)

Trojan UVPhox System

• Low Pressure – High Output

lamp system

• Destroys trace organics

• Uses Hydrogen Peroxide to

create an Advanced Oxidation

Process

• After treatment, water is so pure

we need to add minerals back -

lime

Source: SCAG, 2008

Indirect Potable Water Reuse: UV/H2O2 process



ParameterPermit

Requirement

2008

Q1

2008

Q2

2008

Q3

Reportable

Detection

UV% T-254 <90% 98.0 98.6 97.6 % T

Turbidity <0.2 / 0.5 NTU 0.04 0.1 0.16 NTU

Total Nitrogen 5 mg/L 1 1.5 1.6 0.3 mg/L

Total Organic Carbon 0.7 0.26 0.14 0.12 0.05 mg/L

pH 6 – 9 8.5 8.3 8.4 1 pH unit

Electrical Conductivity NA 85 65.6 72 1 µm/cm

Oil and Grease 1 mg/L <5 <5 <5 5 mg/L

Tetrachloroethene 5 µg/L <0.5 <0.5 <0.5 0.5 µg/L

Atrazine 1 µg/L <0.1 <0.1 <0.1 0.1 µg/L

bis (2-ethylhexyl) phthalate 4 µg/L <2 <2 <2 2 µg/L

2, 3, 7, 8 – TCDD (Dioxin) 30 µg/L <5 <5 <5 5 µg/L

n – Nitrosodimethylamine (NDMA) 10 µg/L <2 <2 <2 2 µg/L

1, 4 – Dioxane 3 µg/L <1 <1 <1 1 µg/L

Simazine 4 µg/L <0.1 <0.1 <0.1 0.1 µg/L

Methyl – tert – butyl ether (MTBE) 5 µg/L <0.2 <0.2 <0.2 0.2 µg/L

IndirectPotable WaterReuse: GWRSystemProduct WaterQuality

Source: SCAG, 2008



NEWater pipeline

NEWater Plant

Service Reservoir

Legend

Kranji

(17 mgd, 2007)Seletar

(5 mgd, 2004)

Ulu Pandan

(32 mgd, 2007)

Bedok

(18 mgd , 2008)

Changi

(50 mgd , 2010)

Source: I2 Water Tech’s Int’l Symposium, 2008

Indirect Potable Water Reuse: NEWater System



Rainwater

Raw water

ImportReservoir

Waterworks

Population

Industries

Commercial

Water

Reclamation

Plant

NEWater

Factories

NEWater

Desalted Water

Mixing

Sea

Indirect Potable Water Reuse: NEWater System




Indirect Potable Water Reuse: NEWater System Components




AOPs involve the generation of hydroxyl radicals (2.8 eV), highly reactive

and unselective species, in sufficient quantities to oxidize the majority of

organics present in the effluent water.

Name of oxidant Oxidation potential (eV)

Fluorine 3.0

Hydroxyl radical 2.8

Ozone 2.1

Hydrogen peroxide 1.8

Potassium permanganate 1.7

Chlorine dioxide 1.5

Chlorine 1.4

Table. Oxidation potential of different oxidants (Parsons and Williams, 2004)

Advanced Oxidation Processes (AOPs)

Chemicals with high positive oxidation potential, such as ozone (2.1 eV) and

hydrogen peroxide (1.8 eV), attacks selectively certain functional groups of

organic molecules.



Table. Most common AOPs evaluated for water and wastewater treatment

(Gültekin and Ince, 2007)

Photochemical processes Non-photochemical processes

UV oxidation processes Ozonation

UV/H2O2 Fenton

UV/O3 Ultrasound (US)

UV/H2O2/O3 US/H2O2, US/O3, US/Fenton

UV/Ultrasound Electrochemical oxidation

Photo-Fenton Supercritical water oxidation

Photocatalysis Ionizing radiation

Sonophotocatalysis Electron-beam irradiation

Vacuum UV (VUV) Wet-air oxidation

Microwave Pulsed plasma

Advanced Oxidation Processes (AOPs)

The major advantages of AOPs include (a) complete mineralization of

organics, (b) removal of recalcitrant compounds, and (c) easy combination

with biological processes.



UV-based AOPs also transform pollutants in two ways.

- Organic chemicals absorb UV light directly.

=> some organic chemicals do not degrade very quickly or efficiently by

direct UV photolysis.

- H2O2 absorbs UV light and breaks down into •OH, degrading the

contaminants via •OH oxidation.

H2O2 + hv → 2•OH

H2O2 + •OH → •HO2 + H2O

H2O2 + •HO2 → •OH + H2O + O2

2•OH → H2O2

2•HO2 → H2O2 + O2

•OH + •HO2 → H2O + O2

Pollutants + •OH → by-product formation

Pollutants + •HO2 → by-product formation

•OH generation

Radical combination

Decomposition of pollutants

(Huang and Shu, 1995)

UV/H2O2



During ozonation, organic contaminants are oxidized in two ways.

- Ozone itself can directly react with dissolved chemicals at varying rates.

=> However ozone is a highly selective oxidant.

- When hydrogen peroxide is added to the ozone system, the decomposition

of O3 into •OH is accelerated.

O3 + HO– → O2 + HO2–

O3 + HO2– → •HO2 + •O3

–

•HO2 ↔ H+ + •O2–

O3 + •O2– → •O3

– + O2

•O3– + H+ → •HO3

•HO3 → •OH + O2

•HO + O3 → •HO2 + O2

H2O2 ↔ H+ + HO2–

2O3 +H2O2 → 2•OH + 3O2

(Staehelin and Hoigné, 1982)

O3/H2O2



Hydroxyl radicals are produced via the ultraviolet photolysis of ozone to

produce electronically excited singlet oxygen atoms.

(Ray et al., 2006)

O3 + H2O + hv (< 310) → H2O2 + O2

H2O2 + H2O → H3O+ + HO2

–

O3 + HO2– → O2 + •O2

–+ •OH

O3 + •O2– + H2O → 2O2 + OH– + •OH

O3 + •OH + H2O → O2 + H3O + •O2–

UV/O3



(Mark and Bolton, 1999).

The photolysis of NO2– or NO3

– is known to result in the formation of •OH.

NO3– + hv (<250)→ [NO3

–]*

[NO3–]* → NO2

– + O (3P)

[NO3–]* → •NO2 + •O– + H2O → •NO2 + •OH + OH–

NO2– + hv(<250) → [NO2

–]*

[NO2–]* → •NO + •O–

At pH<12, •O– protonate to form •OH.

•O– + H2O ↔ •OH + OH–

Effects of nitrate on hydroxyl radicals



(Mark and Bolton, 1999).

As NO2– accumulates, it can react with •OH, and acts as an •OH scavenger.

These reactions greatly limit the steady-state concentration of •OH

available to take part in oxidation reactions with organic pollutants.

NO3– + hv → NO2

– + O

NO2– + hv → [NO2

–]*

[NO2–]* → •NO + •O–

•NO + •OH → HNO2

•OH + NO2– → •NO2 + OH–

Effects of nitrate on hydroxyl radicals



Chemical

Name

N-

Nitrosodimethyl

amine (NDMA)

Chemical

FormulaC2H6N2O

Molecular

Weight74.08

Water

SolubilityHighly Soluble

Specific

Gravity1.006

Vapor

Pressure2.7 mm Hg

Volatility Semi-volatile

(Mitch and Sedlak, 2002)

Emerging Contaminants : N-Nitrosodimethylamine(NDMA)

• A semi-volatile, yellow oily liquid with very

little odor in its pure form

• Produced until the mid 1970s as a component

of liquid rocket fuel

• Formed in drinking water and wastewater

disinfection with chlorine and chloramine

(classified as a disinfection by-product)

• Formed in rubber, printed circuit board, and

pesticide manufacturing processes

• Has a high chronic and acute toxicity:

USEPA's IRIS one-in-a-million cancer risk

concentration is 0.7 ppt.

• An Action Level (AL) for Max contaminant

limit (MCL): 0.01 ppb in California



Chemical

Name1,4-Dioxane

Chemical

FormulaC4H6O2

Molecular

Weight88.12

Water

SolubilityHighly Soluble

Specific

Gravity1.033

Vapor

Pressure29 mm Hg

Volatility Semi-volatile

(Mohr, 2001)

Emerging Contaminants : 1,4-Dioxane

• A semi-volatile, colorless liquid with a mild

ethereal odor

• Currently being produced as a stabilizer in

chlorinated solvents such as trichloroethylene

(TCE) and 1,1,1-trichloroethane (TCA)

• Has a moderate chronic toxicity and a low

acute toxicity, as a probable human carcinogen

• An Action Level (AL) set by California

Department of Health Services (DHS): 3.0 ppb.

(In current water treatment application in

California, permits have been issued for

discharges limits as low as 1.0 ppb.)



• Common odorous chemicals such as

Geosmin (trans-1,10-dimethyl-trnas-9-

decalol) and MIB (2-methylisoborneol),

which some species of algae and

bacteria naturally produced inside the

cells (Cyanobacteria and Actimycetes)

• Actinomycetes, spore-forming bacteria

that grow as branching filaments in

water: microcystin, cylindrospermopsin

and anatoxin-a

• Cyanotoxins, which certain species of

cyanobacteria produce toxins, that can

cause harm to animals and humans

• A microcystin guideline in freshwater

set by WHO: 1.0 ppb

Taste or Odor Source

Earthy Geosmin

Musty

MIB, isopropylemethoxy-

pyrazine(IPMP),

isobutylmethoxy-

pryrazine(IBMP)

Turpentine,

oily

Methyl teriary butyl

ether(MTBE)

Fishy / rancid2,4-Heptadienal,

decadienal, octanal

Medicinal Chlorophenols, iodoform

Oily, gas-like,

paint

Hydrocarbons, volatile

organic compounds( VOCs)

MetallicIron, copper,

zinc, manganese

Grassy Green algae (Heohn, 2002)

Taste and Odor-Causing Compounds in Drinking Water



(Powell, 1968)

Emerging Contaminants : Fuel and Fuel Additives

Chemical

Name

Methyl tertiary-Butyl

Ether(MTBE)

Chemical

FormulaC5H12O

Molecular

Weight88.15

Vapor

Pressure245 mm Hg at 25 ºC

Henry’s

Law

Constant

0.587 L-atm/mol

at 25 ºC

Solubility

in water43,000~50,000 mg/L

MTBE –Chemical summary • MTBE, the most widely used as a fuel

oxygenates

• A semi-volatile, chemically unreactive

molecules that has a distinct, unpleasant

odor, highly soluble in water and low

volatility

• designated a possible human carcinogen

by the USEPA

• Several routes to the environment:

leaking underground storage tanks,

accidental spills of fuels and releases

from recreational vehicles in reservoirs

• Non-enforceable drinking water advisory

levels by USEPA: 20 ppb



Emerging Contaminants : Pesticides

Triazine Herbicides

Atrazine, Cyanazine,

Simazine

Chloroacetamide Herbicides

Alachlor, Metolachlor,

Acetochlor

Phenyl-urea Herbicides

Diuron, Fenuron,

Isoproturon

Organophosphate Insecticides

Diazinon, Malathion,

Chlorpyrifos

Examples of Pesticide Chemical Classes• Atrazine, the most widely used

pesticide in US

• Alachlor, metolachlor and chlopyrifos

(insecticide) also widely used in US

• Alachlor and dieldrin are classified "

probable human carcinogen"

• USEPA's National Primary Drinking

Water Regulations (i.e., Max. Conc.

Levels, MCLs): 3.0 ppb for Atrazine,

2.0 ppb for alachlor

• Under European regulation, the total

conc. of pesticide in drinking water may

not exceed 0.5 ppb, while the conc. of

any one pesticides may not exceed 0.1

ppb

(Battaglin and Fairchild, 1999)



Evaluate the oxidation efficiency of DEP for the UV irradiation alone, the

UV/H2O2 process, the O3 oxidation , and the O3/H2O2 process by performing

a pilot-scale AOP system, into which a portion of the effluent from a pilot-

scale MBR plant was pumped. The effluent was used as the influent for the

AOP system.

Neither the temperature nor the pH level in the system was controlled. The

identification of the intermediates from the DEP oxidation was beyond the scope of

this study.

Pilot-scale AOP Operation: Objectives of Study



DEP is used as plasticizer for cellulose ester plastic films, sheets and molds

and as an ingredient in 67 cosmetic formulations (Page and Lacroix, 1995).

Phthalates have been classified as estrogenic chemicals that have adverse

effects on organisms even at low concentrations (Sharp et al., 1995).

various etiological diseases such as disorders of the male reproductive

tract, breast and testicular cancers, and dysfunction of the neuroendocrine

system (Parkerton and Konkel, 2001).

Monitoring surveys conducted from 2000 to 2004 revealed that phthalates

were the major micro-pollutants in the Han River Basin. The concentration

of DEP ranged from 0.0 (not detected) to 6.5 ug/L at some sampling sites

(Oh, et al., 2006).

Pilot-scale AOP Operation: Diethyl Phthalate



-Very water soluble

-Very low vapour

pressure

- Very high boiling

point (295 °C)

- Very high KOW

=> bio-accumulation

Parameters Value

CAS number 84-66-2

Molecular weight (g/mol) 222.24

Molecular formula C12H14O4

Water solubility at 25 °C (mg/L) 1000

Log KOW 2.47

Henry’s law constant (kPa) 7.9 x 10-5

Chemical structure

Table. Chemical and physical characteristics of DEP

(Xu et al., 2007)

Pilot-scale AOP Operation: Diethyl Phthalate



In- line Mixer

Ozone Generator

Pump

Flow meter

Flow meter

Ozone Destructor

Pump

PG

Gas Trap

Air Vent

Ozone Injector

Treated Water

Level sensor

Level sensor

Influent

Valve Flow meter

Valve

Inflow watertank

H2O2

tank

UVlamp

UVlamp

OzoneReactor

In- line Mixer

Ozone Generator

Pump

Flow meter

Flow meter

Ozone Destructor

Pump

PG

Gas Trap

Air Vent

Ozone Injector

Treated Water

Level sensor

Level sensor

Influent

Valve Flow meter

Valve

Inflow watertank

H2O2

tank

UVlamp

UVlamp

OzoneReactor

Figure. Schematic diagram of the pilot-scale AOP system.

(Park, et al., 2008)

Pilot-scale AOP Operation: the AOP system

• Flow capacity (24 m3/day)

• Influent pump

• Stainless-steel H2O2 holding tank

• H2O2 in-line mixer

• Ozone generator (WHOZ-10,

Pacific Ozone)

• Ozone injector (#584, Mazzei)

• Ozone reactor (30 L)

• UV chamber

• Gas trap (30 L)

• Air vent (11 AV, Armstrong)

• Ozone destructor (WHOD-150H,

Pacific Ozone)

• Two UV lamps (01AM10,

• Trojan; UVP-L-3908VB/VH,

UV Plus)



The SPME method is a solvent-free isolation technique that is known to be

distinctly faster and simpler to perform compared with conventional pre-

treatment methods (Prokupkova et al., 2002).

The DEP concentrations were measured using GC/MS (Varian Saturn 2000),

which was operated by the Saturn 2000 Workstation (ver. 6.41).

Items Conditions

SPME fiber Polydimethylsiloxane, 7 μm film

Adsorption 20 min at 50°CInjector split/splitless, 280°C (closed 4 min)

DetectorMS, scan range m/z=45-465 at 0.6 sec/

scan

Column DB-5 30 m 0.25 mm ID, 0.25 μm

Carrier gas Helium, 40 cm/sec at 60°COven temperature 60°C (3 min) to 320°C at 10°C /min

Table. Operating conditions for GC/MS

Pilot-scale AOP Operation: Analytical methods



ComponentsConcentration (mg/L)

Average Range

BOD5 1.7 0.1 – 15.1

COD 9.8 4.7 – 17.0

Total nitrogen (TN) 6.7 1.9 – 16.7

Ammonium nitrogen (NH4+-N) 1.3 0.1 – 15.2

Nitrate nitrogen (NO3–-N) 2.6 0.6 – 6.5

Total phosphorus (TP) 2.7 0.1 – 6.5

Orthophosphates (PO43–-P) 2.2 0.1 – 5.4

pH (median value) 7.1 6.6 – 7.4

Turbidity (in units of NTU) 0.05 0.04 – 0.09

Diethyl phthalate (in units of μg/L) 13.9 *ND – 50.6

Table. Major components of the effluent from the pilot-scale MBR plant

0.1 μm hollow fiber membrane

Pilot-scale AOP Operation: Results and discussion

Characteristics of the effluent from the MBR



UV dose (mJ/cm2)

400 500 600

Oxid

ati

on

Eff

icie

ncy(%

)

0

20

40

60

80

100

H2O

2 10mg/L

H2O

2 20mg/L

H2O

2 30mg/L

H2O

2 40mg/L

Figure. Oxidation efficiencies

(%) of DEP as functions of UV

doses (400, 500 and 600 mJ/cm2)

at the four different H2O2

concentrations. The operating

conditions for this pilot-scale

operation were the following:

water temperature: 17.0°C, NO3–

-N concentration: 5.0 mg/L, DEP

concentration in influents: 10.2-

10.7 μg/L with an average

concentration of 10.4 μg/L.

UV dose(500mJ/m2)

+ H2O2 (40 mg/L)

Pilot-scale AOP Operation: Oxidation efficiency of DEP



Figure. Profiles of DEP

concentrations (μg/L) resulted

from a pilot-scale AOP

operation; Inf.: influent into the

WWTP, PE: primary effluent

from the WWTP (i.e., influent

for a MBR), MBR Eff.: effluent

from the MBR (i.e., influent for

the pilot-scale AOP system),

UV: UV irradiation alone

without H2O2 addition, O3: O3

oxidation alone without H2O2 ;

water temperature: 19°C,

average NO3– -N concentration:

4.6 mg/L, UV dose: 400 mJ/cm2,

H2O2 concentration: 40 mg/L,

O3 concentration: 3.0 mg/L,

DEP concentration in MBR Eff.:

7.98 μg/L

Inf. PE MBR Eff.

UV UV/H

2O

2

O3

O3/

H2O

2

0

3

6

9

12

15

18

DE

P c

on

cen

trati

on

(

g/L

)

9.098.967.98

4.27

(46%)

5.40

(32%)

7.02

(12%) 6.50

(16%)

Pilot-scale AOP Operation: DEP concentrations



Figure. Profiles of DEP

concentrations (μg/L)

resulted from a pilot-scale

AOP operation; water

temperature: 18°C, average

NO3–-N concentration: 6.0

mg/L, UV dose: 400 mJ/cm2,

H2O2 concentration: 40

mg/L, O3 concentration: 3.0

mg/L, DEP concentration in

MBR Eff.: 7.69 μg/L.

Inf. PE MBR Eff.

UV UV/H

2O

2

O3

O3/

H2O

2

0

3

6

9

12

15

18

DE

P c

on

cen

tra

tio

n (

mg

/L)

13.17

11.14

7.69

2.99

(61%)

3.68

(52%)4.44

(42%

)

5.02

(35%)

Pilot-scale AOP Operation: DEP concentrations



Bench-scale Operation: Nitrate scavenging effect on the DEP oxidation

Figure. Oxidation efficiencies (%)

of DEP with the respect to

different initial concentrations of

NO3–-N with the initial H2O2

concentration of 30 mg/L at the

UV dose of 954 mJ/cm2; UV: UV

irradiation without H2O2 addition,

and UV/H2O2: UV oxidation of

H2O2; initial concentration of

DEP: 85±15 μg/L.

Ox

ida

tion

Eff

icie

ncy

(%)

0

20

40

60

80

100NO

3--N : 0mg/L

NO3--N : 5 mg/L

UV/H2O

2UV



• The UV photolysis of H2O2 was most effective for DEP oxidation, with the

initial H2O2 concentration of 40 mg/L at the UV dose of 500 mJ/cm2. About

48% of the influent DEP, which was naturally contained in the treatment stream

was oxidized under theses operating condition, even though a relatively high

NO3--N concentration of 5.0 mg/L was observed in the influent.

• The O3 oxidation with H2O2 addition was also most effective for DEP

degradation with the initial H2O2 concentration of 20 mg/L, when the initial O3

concentration was 3.0 mg/L in the pilot-scale AOP system.

• The proposed water reclamation system, consisting of the MF/UF membrane

process (without RO membrane process) followed by the advanced oxidation

processes (AOPs using UV/H2O2 or O3/H2O2), appeared to be a desirable

alternative for DEP oxidation in treatment effluent streams.

Pilot-scale AOP Operation: Conclusions



Gui, T. (2008) New-water Project, in I2 Water Tech’s International Symposium on Water Reclamation and

Reuse.

Gültekin, I., Ince, N. H. (2007) Synthetic endocrine disruptors in the environment and water remediation by

advanced oxidation processes. Journal of Environmental Management, 85, 816-832.

Huang, C. R., Shu, H. Y. (1995) The reaction kinetics, decomposition pathways and intermediate formations

of phenol in ozonation, UV/O3 and UV/H2O2 processes. Journal of Hazardous Materials, 41, 47-64.

Mack, J., Bolton, J. R. (1999). Photochemistry of nitrite and nitrate in an aqueous solution: a review. Journal

of Photochemistry and Photobiology A: Chemistry, 128, 1-13.

Oh, B. S., Jung. Y. J, Oh,Y. J., Yoo, Y. S., Kang, J. W. (2006) Application of ozone, UV and zone/UV

processes to reduce diethyl phthalate and its estrogenic activity. Science of the Total Environment, 367, 681-

693.

Page, B. D., Lacroix, G. M. (1995) The occurrence of phthalate ester and di-2-ethylhexyl adipate plasticizers

in Canadian packaging and food sampled in 1985-1989: a survey. Food Addit. Contam., 12, 129-151.

Park, C. G., et al. (2008) Advanced H2O2 Oxidation for DEP degradation in treated effluents: effect of nitrate

on oxidation and pilot-scale AOP operation, Water Science and Technology, Vol. 58, No. 5, pp.1031-1037.

Park, J. H., et al. (2010) Degradation of DEP in treated effluents from a MBR via advanced oxidation

processes: Effects of nitrate on oxidation and a pilot-scale AOP operation, Environmental Technology, Vol.

31, No. 1, pp. 15-27.

Southern California Association of Government (2008) Groundwater replenishment system, scag.ca.gov.

It is noted that some other research papers and documents, which are not listed above, were actually reviewed

and cited for the preparation of this presentation.

REFERENCE



Thank you for your attention

Documents

음용수수준의물재생을위핚 하수처리방류수초고도처리env.seoul.go.kr/files/2012/03/4f541ce9de4276.01005449.pdf · 2013-01-08 · •Hydranautics ESPA-2 Membranes