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.
The drives for UV application
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
The drives for UV application
Municipal wastewater treatment
The drives for UV application
The ratio of municipal wastewater treated
The drives for UV application
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
The drives for UV application
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
The drives for UV application
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
The drives for UV application
UV disinfection used in WWTP
The drives for UV application
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
The drives for UV application
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 drives for UV application
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
The drives for UV application
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
The drives for UV application
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)
紫外线剂量(mJ/cm2)
UVT=80%UVT=85%UVT=90%UVT=95%
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
)
紫外线剂量(mJ/cm2)
UVT=80%UVT=85%UVT=90%UVT=95%
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)
紫外线剂量(mJ/cm2)
UVT=80%UVT=85%UVT=90%UVT=95%
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 )
UVT=95%UVT=90%UVT=85%UVT=80%
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)
UVT=80%UVT=85%UVT=90%UVT=95%
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 )
UVT=95%UVT=90%UVT=85%UVT=80%
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
Microbe pollution of DW in Chifeng
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
Microbe pollution of DW in Chifeng
Advanced Water Supply Engineering
The Culprit: SalmonellaRain water flooded into the No. 9 well, resulting in excessive coliform and salmonella detected
Microbe pollution of DW in Chifeng
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.