The Research and Application of UV Disinfection ... · PDF fileThe Research and Application of UV Disinfection Technologies in China Wenjun Liu, Ph.D., Professor ... IIIIIIIVV劣V

The Research and Application of UV Disinfection Technologies in China

Wenjun Liu, Ph.D., Professor

School of Environment Tsinghua University

Green Technology Forum in Tokyo, 2012

Outlines

The drives for UV applicationResearch review of UV for water and waste water disinfectionApplication of UV technologies in China The challenges and prospective

Water Pollution

Tianjin

Dalian

Beijing

wuhan

Shanghai

Guilin Shenzhen

The drives for UV application

Water Pollution

China is a country which is short of water resources and with average amount of 2200 m3 water per person, which is 1/4 of the world’s average.

Of 660 cities all over the country, more than 400 are short ofwater. 160 million people are influenced by the lack of water.

More than 190 million people living in rural areas are hard to access safe drinking water.


Water Pollution

3%18%

19%

22%

10%

28%

I II III IV V 劣V

7%

22%

4%

19%

48%

II III IV V 劣V

Seven main watersheds severely polluted

70% of 200 lakes in eastern and southwestern euthophicated

Half of urban drinking water sources can not meets stardards

I II III IV V 劣V

2 4 6 10 15 >15


Municipal wastewater treatment


The ratio of municipal wastewater treated


New standard for municipal waste water discharge

Primary A Primary B Secondary

1, 000 CFU/L 10, 000 CFU/L 10, 000 CFU/L

Fecal E. Coli Standards for municipal wastewater Discharge (GB18918-2002)

E. Coli Standards for municipal wastewater reused in general purposes (GB18920-2002）

E. coli. <3 CFU/L


New standard for reclaimed water

River and Lake Waterscape

landscape purpose( not directly touched by human)

10, 000 CFU/L 2, 000CFU/L

Recreation purpose(directly touched by human)

500CFU/L Below MDL

Fecal E. Coli Standards for reclaimed water (GB18921-2002)

E. Coli Standards for reclaimed water used in general purposes (GB18920-2002）

E. coli. <3 CFU/L


Outbreak of SARS (Severe Acute Respiretory Syndrome) in 2003

Before outbreak of SARS, no full-scale WWTP used disinfection process except very few experimental sets

After outbreak of SARS, the importance of disinfection unanimously recognized by government offices, industry, academia, and public.

Because of some disadvantages of UV technologies, UV disinfection became the first choice of the disinfection process


UV disinfection used in WWTP


More than 600 sets of the capacity above 50, 000m3 /d installedManufactures from both inside and outside China

UV disinfection for drinking water

Much stringent standards for drinking water quality was promulgated in 2006

Old standards: 35 parameters (GB 5749-85)

New standards: 106 parameters (GB 5749-2006), have been effective from 1st, July, 2007


Comparison of two version standards 71 new parameters：Microbiological: 2 → 6Disinfectants : 1 → 4Toxicological: Inorganic:10 → 21

Organic:5 → 53Aesthetical：15 → 208 parameters modified ：Total coliform：3 CFU/L →no detected （CFU/100 mL）As: 0.05mg/L → 0.01mg/LCd：0.01mg/L → 0.005mg/LPb：0.05 mg/l → 0.01mg/LNitrate：20 mg/L → 10mg/LCCl4：0.003mg/L → 0.002mg/LTurbidity：3 NTU→ 1 NTUTotal αradioactivity：0.1 Bq/L → 0.5 Bq/L 。

UV disinfection for drinking water


The drive from new standards

Biological parameters

Cryptosporidium oocysts and giardia cysts

< 1/10L)

Total coliform: < MDL/100mL

E. coli: < MDL/100mL

Fecal coli: < MDL/100mL

Total bacterial count: < 100cfu/mL


DBP regulations

THMs（mg/L）

HAA5（mg/L）

Chlorine（mg/L）

Chloramines（mg/L）

USA 0.080 0.060 4 4CHina 0.100 0.060 4 3

ClO2（mg/L）

Chlorite（mg/L）

Bromate（mg/L）

Acetaldehyde（mg/L）

USA 0.8 1.0 0.01 --China 0.8 0.7 0.01 0.9


Ensure water safe for drinkingThe drives for UV application

To provide drinking water safe for direct drinking

Traditionally, Chinese are used to drink tea or boiled water

Up to now, no city provides drinking water be directly drinked at POU

New standard requires drinking water safe for all users, including urban residents and rural residents.

validate the efficiency of UV for different organisms

investigate the options to control the bio-stability in distribution systems following UV disinfection

Evaluate the mutagenicity of water from different disinfection technologies.

Assess the cost-effective feasibility

Research of UV disinfection for drinking water treatment

A 20-25 m3/h and a 5 m3/h pilot UV disinfection systems were installed in two WTPs at 2006 and 2007, respectively.

TBC, E. coli, B. subtilis and MS2 were chosen as the index organisms

Coffee was used to adjust the transmittance

Filtered water from conventional process was used to be disinfected.

Research of UV disinfection for drinking water treatment

booster pump

filtered waterwater tank

sample connection

dosage pump

dosage pumpMS-2 pot

coffee potUV system

mixer

sample connection

mixer

sample connection

BAR

simulated distribution system

simulated cleartank

chlorine pot

Flow diagram of pilot UV disinfectionFlow diagram of pilot UV disinfection

Water tankWater tank

Coffee organism

UV reactor and simulated UV reactor and simulated clearwellclearwell

Facility layoutFacility layout

Collimated beamCollimated beam

Facility layoutFacility layout

Water tank

UV reactor

Clear well

BAR

UV reactorUV reactor

Control panel

TBC number observedTBC number observed

0

50

100

150

200

250

300

2007-7-27

2007-8-6

2007-8-16

2007-8-26

2007-9-5

2007-9-15

2007-9-25

2007-10-5

2007-10-15

2007-10-25

2007-11-4

2007-11-14

2007-11-24

2007-12-4

2007-12-14

2007-12-24

2008-1-3

2008-1-13

2008-1-23

2008-2-2

2008-2-12

2008-2-22

2008-3-3

2008-3-13

2008-3-23

2008-4-2

2008-4-12

Date

TBC(CFU/ml)

influent

effluent

The TBC number from UV reactor were far fewer than the drinking water standard of China (100CFU/mL).

Total Total coliformcoliform number observednumber observed

0

200

400

600

800

2007-7-27

2007-8-6

2007-8-16

2007-8-26

2007-9-5

2007-9-15

2007-9-25

2007-10-5

2007-10-15

2007-10-25

2007-11-4

2007-11-14

2007-11-24

2007-12-4

2007-12-14

2007-12-24

2008-1-3

2008-1-13

2008-1-23

2008-2-2

2008-2-12

2008-2-22

2008-3-3

2008-3-13

2008-3-23

2008-4-2

2008-4-12

Date

Total coliform

(CFU/100ml) influent

effluent

The total colifrom number were below MDL in 100 days of 102day sampling

The impact of Water Temperature

0

5

10

15

20

25

30

2007-8-11

2007-8-21

2007-8-31

2007-9-10

2007-9-20

2007-9-30

2007-10-10

2007-10-20

2007-10-30

2007-11-9

2007-11-19

2007-11-29

2007-12-9

2007-12-19

2007-12-29

2008-1-8

2008-1-18

2008-1-28

2008-2-7

2008-2-17

2008-2-27

2008-3-8

2008-3-18

2008-3-28

2008-4-7

Date

Temperature(℃)

Room temperature

Water temperature

The water temperature could impact on the influent bacteria concentration, but it did not change the UV disinfection effect.

UV Intensity on-line monitoring

0.002.004.006.008.00

10.0012.0014.0016.0018.00

2007-7-27

2007-8-6

2007-8-16

2007-8-26

2007-9-5

2007-9-15

2007-9-25

2007-10-5

2007-10-15

2007-10-25

2007-11-4

2007-11-14

2007-11-24

2007-12-4

2007-12-14

2007-12-24

2008-1-3

2008-1-13

2008-1-23

2008-2-2

2008-2-12

2008-2-22

2008-3-3

2008-3-13

2008-3-23

2008-4-2

2008-4-12

Date

UVI(mw/cm2)

UVI

In most situations, UVI were above the deadline.

UV inactivation for the challenge organism in the pilotUV inactivation for the challenge organism in the pilot

E.coli TBC

B. subtilis MS2

30

0.00

1.00

2.00

3.00

4.00

5.00

0 20 40 60 80

大肠

杆菌灭

活率

Log（

N0/

N）

紫外线剂量（mJ/cm2）

UVT=80%UVT=85%UVT=90%UVT=95%

0.00

1.00

2.00

3.00

4.00

5.00

0 5 10 15 20 25

细菌

总数

灭活率

Log

（N

0/N）



y = 0.044x + 0.038R² = 0.941

0.00

1.00

2.00

3.00

4.00

5.00

0 20 40 60 80

枯草芽孢

杆菌灭活率

Log（

N0/N

）



y = 0.046x + 0.282R² = 0.983

0.00

1.00

2.00

3.00

4.00

5.00

0 20 40 60 80

MS2

灭活率

Log

（N

0/N）



Comparison of MS2 response curveComparison of MS2 response curve

0.00

1.00

2.00

3.00

4.00

5.00

6.00

0 20 40 60 80 100 120

UV dose (mJ/cm2)

MS2

Inac

tivat

ion

log(

N 0/N

)

No 9DongguanTrojanLinden

Under collimated beam test, the MS2 response curve was similar for different water.

0

10

20

30

40

50

60

5 7.5 10 12.5 15 17.5

Flow rate (m3/h)

UV

dos

e(m

J/cm

2 )


Designed dose: 40mJ/cm2 when flow rate was10m3/h，Bioassay dose：46±1 mJ/cm2 when flow rate was 10m3/h，12.5％safe margin.

Bioassay curve for Beijing No 9Bioassay curve for Beijing No 9

0

20

40

60

80

100

120

5 10 15 20 25 30

Flow rate(m3/h)

UV

dos

e(m

J/cm

2)


Comparison for bioassay curve of two pilots

0

10

20

30

40

50

60

5 7.5 10 12.5 15 17.5

Floe rate((m3/h)

UV

dise

z((m

J/cm

2 )


Beijing Dongguan

The bioassay curve of Beijing and Dongguan is in consistence. It was confirmed that UVT was an important factor for UV disinfection effect.

CleaningCleaning

CleaningCleaning

Control bio-stability following UV

Hydraulic retention time of distribution Hydraulic retention time of distribution system, system,

Disinfectant (chlorine or Disinfectant (chlorine or chloraminechloramine) ) residual residual

AOC levelAOC level

Pipe materials Pipe materials

UV doseUV dose

Control bio-stability following UV

Water tank

UV reactor

BAR

Parameter levelpH 7.2~7.8

UV254 (cm-1) 0.01~0.02

Turbidity (NTU) 0.1~0.2UVT 95%~98%TOC (mg L-1) 0.6~0.8AOC(μg L-1) 50~70Temperature(℃) 15-17

The influent water qualityThe influent water quality

2012-3-26

Impacts of UV dose on HPC on couponImpacts of UV dose on HPC on coupon

2~4days 8~10days

Biofilm densities on steel coupons are much less than PVC coupons

0

1

2

3

4

5

6

7

0 5 10 15 20 25 30

HPC concentration（

logCFU/cm2）

days

UV-steel-24hr

UV-PVC-24hr

undisinfected-steel-

24hr

steel-2hr

PVC-2hr

The impact of UV dose on the The impact of UV dose on the bioflimbioflim densitiesdensities

AOC=50µg/L；Temperature=16℃；Chorine residual=0

0

1

2

3

4

5

6

7

0 5 10 15 20

Bio

film

HPC

(logC

FU/c

m2 )

Operated days

UV dose=0 mJ/cm2

UV dose=10 mJ/cm2

UV dose=40 mJ/cm2

UV dose=80 mJ/cm2

The steady-state bioflim density had no obviously changing

The relationship of fluid HPC and chlorine residual The relationship of fluid HPC and chlorine residual

0.00

1.00

2.00

3.00

4.00

5.00

6.00

0 0.2 0.4 0.6 0.8Susp

ende

dH

PC(lo

gCFU

/mL)

Residual chlorine(mg/L)

2.7log (500CFU/mL)

AOC=50µg/L；T=16℃；UV dose= 40mJ/cm2；

0

1

2

3

4

5

6

0 5 10 15 20

Bio

film

HPC

(logC

FU/c

m2 )

Operated days

RT=0.5h

RT=1h

RT=2h

RT=24h

The impact of retention timeThe impact of retention time

AOC=50µg/L；Temperature=16℃；UV dose= 40mJ/cm2；

The HRT impact on the density on the coupon of BAR in a certain level.

0

10

50200

0

1

2

3

4

5

6

0 0.05 0.3 0.5 0.7 1 1.5

AOC (μg/L)

HPC

(CFU

/mL)

余氯(mg/L)

5-64-53-42-31-20-1

43

Coefficients t Stat P-value Down 95.0% Upper 95.0%alternatio

n2.910432 21.91405 5.54E-

262.643097 3.177767

AOC 0.006761 5.959354 3.33E-07

0.004477 0.009044

余氯 -2.20415 -14.3574 1.31E-18

-2.51317 -1.89513exp( )HPC a b AOC c RC= +

regression

15μg/L

AOC and Chlorine residual impact on HPC in DWDSAOC and Chlorine residual impact on HPC in DWDS

Chlorine residual

Chlorine residual

SEM after 20 day operation of BARSEM after 20 day operation of BAR

No disinfection UV disinfection only

UV+0.5mg/L chlorine UV+0.4mg/L chloramine

DGGEDGGEPCR-DGGE

results of BAR following UV with different slide materials

10.29 (R1392 968GC)

C A B C D C1 C2 P1 P3 q2 3 4 5 7

The chlorine resistant bacteriaThe chlorine resistant bacteria

Sphingomonas

formed dark-yellow colonies on R2A media

The SEM of the a chorine resistant bacteriaThe SEM of the a chorine resistant bacteria

TEM

Chlorine Chlorine inactivationinactivation for for SphingomonasSphingomonas

0%

20%

40%

60%

80%

100%

0 200 400 600 800

CT(mgmin/l)

Inac

tivat

ion

rate

The inactivation rate for the chlorine resistant bacteria is under 10% even the chlorine CT above 700 mg.min/L.

UV inactivation for UV inactivation for SphingomonasSphingomonas

0.00

1.00

2.00

3.00

4.00

5.00

0 40 80 120 160 200

UV dose(mJ/cm2)

Inac

tivat

ion

log(

N0/

N)

UV disinfection is effective for the inactivation of Sphingomonas, When the UV dose is 40mJ/cm2, the inactivation approxiamate 3 log.

UV application in rural areas in Beijing:UV application in rural areas in Beijing:to verify the impacting of UV disinfection on to verify the impacting of UV disinfection on distribution systemdistribution system

50

Shuangta

Ximafang

Wuzi

Nanliyuan

Zhoucun

Tongmafang

Baolinzhuang

Xihangzi

AquafineUV max

UV logic

UV application in rural areas

Schematic of the sampling pointsSchematic of the sampling points

Well1#

2#

5#

Effluent UV Influent

4# and 5# were the distribution ends (1200 m, 13000 m respectively).

3# 4#

Village Power/W

Flowrate/m3h-1

Lamp No

Service people

Pipe meterial

TOC/mgL-1

AOC/μgL-1 UVT Water

temperature

WUZI 280 35 2 2300 PVC 1.2 47 98％ 15

The parameters of UV system and water qualityThe parameters of UV system and water quality

For WUZI’s groundwater, The UVT was 98% and the AOC level was under 50 μgL-1, it is suitable for UV disinfection.

The bacteria parameter of samplesThe bacteria parameter of samples

TBC(CFU/mL) Total coliform(CFU/100mL) HPC (CFU/mL)network

pointspipe length

(m)08.1.19 08.4.4 08.1.19 08.4.4 08.1.19 08.4.4

influent 3 4 88 112 1905 1040

effluent 0 0 0 0 0 42 701 450 1 5 0 0 39 1342 800 0 4 0 0 20 2003 1100 0 5 3 15 32 2654 1200 1 4 1 1 109 3105 1300 2 5 11 0 103 85

HPC are all under 500CFU/ml in the distribution system

0

50

100

150

200

250

300

350

400

Jan-19-08 Apr-04-08 Apr-22-08 Jun-24-08 Sep-26-08 Nov-14-08 Jan-10-09

HPC

(CFU

/mL)

取样时间

出水

1#2#3#4#5#平均

MutagenicityMutagenicity evaluationevaluation

0

50

100

150

200

250

300

0 1 2 3 4 5 6

遗传毒性

( ng

4-N

QO

/L )

消毒剂投加量 ( mg/L,以Cl2计 )

UV剂量为40mJ/cm2

氯

氯胺

UV+氯

UV+氯胺

氯转氯胺

Evaluation of HAA formation Evaluation of HAA formation

Recommendation for UV based Recommendation for UV based disinfection process used in WTP disinfection process used in WTP

UV +chloramine Processe

Clearwell distribution

Chloramine

UV

Benefits:High disinfection efficiencyBio-stable distribution minimum mutagenicity

UV application in WTP

Tianjin

Shanghai

UV disinfection UV disinfection inTedainTeda WTP, Tianjin WTP, Tianjin

UV disinfection UV disinfection inTedainTeda WTP, Tianjin WTP, Tianjin

UV disinfection in UV disinfection in LianjiangLianjiang WTP, ShanghaiWTP, Shanghai

UV disinfection for ballast water treatmentUV disinfection for ballast water treatment

Challenges of UV in WTP in the future

Do we really need UV for WTPin China???

We drinking tea and boiled water, microbes is not of concerns

The city has an area of 90,000 km² and a population of 4.60 million (2004)

A prefecture-level city in southeastern Inner Mongolia

Microbe pollution of DW in Chifeng

Water for industrial and domestic use are all extracted from a groundwater source

Water usage in many parts of town are near maximum capacity

Water usage in some areas are past maximum capacity


Heavy rainstorm on July 23rd, 2009

Few days later, thousands of residents in the “new city”area reported cases of diarrhea, vomiting, dizziness, fever and other symptoms after drinking tap water

On July 26th, official statement was made on the cause of the outbreak: recent storm water along with sewage has intruded into water supplies causing contamination


Advanced Water Supply Engineering

The Culprit: SalmonellaRain water flooded into the No. 9 well, resulting in excessive coliform and salmonella detected


Preparation of the Standards for UVCoordination of preparing the first national standards regarding UV applications in water treatment which was promulgated by the National Standardization Administration Commission and has been effective since Jan. 1st 2006.Promotion of the creation of the National Technical Committee 299 on Ultraviolet Disinfection of standardization Administration of China. The committee consist of 26 members and Wenjun Liu has been appointed to the Chair.

Acknowledgement

Wenjun Sun, Ted Mao, Yanjiu Qie, LifengAll who have contributed to facilitate the UV knowledge distributed in China.

Documents

The Research and Application of UV Disinfection ... · PDF fileThe Research and Application of UV Disinfection Technologies in China Wenjun Liu, Ph.D., Professor ... IIIIIIIVV劣V