page 1

UV

C LED

s for

Deco

ntam

inatio

n o

f Water

page 2

Sterilization

of w

ater with

ultravio

let ligh

t

Facts a

nd

Figu

res

U

V sp

ectrum

: 100 400 nm

U

VA

(315 380 nm

)

U

VB

(280 315 nm

)

U

VC

(100 280 nm

)

U

nlike U

VA

and

UV

B,

UV

C is ab

sorb

ed in

the atm

osp

here

Ad

va

nta

ge

of U

V ra

dia

tion

D

NA

of m

icroo

rgan

isms is d

eactivated

M

Os cant d

evelop

resistance

m

ost effective d

eactivation

at 270 nm

w

aveleng

th [n

m]

deactivatio

n o

f cells

Re

fere

nce

: SEDLM

EIER, K

.: Wasserau

fbereitu

ng

mit U

V LED

s. 2008

Re

fere

nce

: http

://imag

es.nailsm

ag.co

m/p

ost/M

-na0911-LED

-UV

-Ligh

tSpectru

m-1.jp

g

page 3

Gen

eration

of U

VC

Ligh

t

Lo

w-p

ressu

re m

ercu

ry v

ap

or la

mp

co

nven

tion

al

lig

ht em

ission

at 254 nm

wavelen

gth

lim

ited life exp

ectancy

d

epen

den

ce on

AC

to

xic

h

igh

disp

osal co

sts

La

ser

excim

er laser, Nd

:YA

G laser, Ti:sap

ph

ire laser

exp

ensive

U

V LE

Ds

h

igh

life expectan

cy

ru

n o

n D

C

co

mp

act

en

viron

men

tally friend

ly

p

ortab

le R

efe

ren

ce:

http

://ww

w.led

s24.com

/bild

er/pro

du

kte/gro

ss/50-x-UV

-LED

s-5mm

-2000mcd

-30-UV

-LED-u

ltraviolett_b

2.jpg

Re

fere

nce

: h

ttp://h

almap

r.com

/new

s/han

ovia/files/2007/07/

han

ovia-u

v-lamp

_blo

g.jp

g

page 4

Desig

n o

f UV

water p

urifiers

LED

s circular aro

un

d w

ater or w

ateraro

un

d LED

s

len

gth

of lig

ht so

urce an

d w

ater flow

rate determ

ine exp

osu

re time

d

iameter o

f the p

urificatio

n ch

amb

erto

be co

nsid

ered

w

ater itself abso

rbs U

V en

ergy

w

ith 10 W

up

to 4 l/s can

be

desin

fected

UV

Trea

tme

nt o

f ultra

pu

re w

ate

r

d

isinfectio

n

w

aveleng

th 200 280 n

m

red

uctio

n o

f TOC

(total o

rgan

ic carbo

n)

w

aveleng

th 185 n

m

Re

fere

nce

: http

://ww

w.fresh

watersystem

s.com

/imag

es/mig

hto

per.jp

g

page 5

UV

LED Perfo

rman

ce Data

DO

WA

Do

UV

LEDs

M

OD

EL DF7V

series

265n

m N

aked B

are Die (Flip

chip

form

)

200m

W

page 6

Safety Asp

ects

O

ptical d

ang

er:

Effect o

n Eyes

K

eratitis

co

nju

nctivitis

Effect o

n Skin

su

nb

urn

risk o

f skin can

cer is very low

becau

se of sm

all dep

th o

fp

enetratio

n o

f UV

C rad

iation

dep

th o

f pen

etration

of U

VC

radiatio

n in

to th

e hu

man

skin

dep

th

In

m

th

resho

ld valu

e of 6 m

J/cm, an

d/o

r 60 J/m d

aily radiatio

n d

osag

eresp

ectively, is recom

men

ded

by th

e EU (EU

Directive 2006-25-EC

) (with

254 nm

)

n

o electrical d

ang

er

page 7

Test-Set-Up

top

cover

safety switch

UV

C LED

water

UV

C

intran

sparen

t casin

g

mag

netic ag

itator

at 500 rpm

d

efined

con

tamin

ated w

ater with

E.Co

li ind

ifferent co

ncen

tration

s

ag

itator fo

r ho

mo

gen

ou

s micro

org

anism

distrib

utio

n in

the test so

lutio

n

casin

g to

pro

tect enviro

nm

ent fro

m U

VC

radiatio

n

Pilz M

agn

etic No

n-C

on

tact Safety Switch

es,PSEN

MA

G Series

PSEN

ma1.4a-50/PSEN

ma1.4-10m

m/ 1u

nit

IP65/IP67 o

r IP69k Protectio

n

A

s the p

rocess is ru

nn

ing

, they en

sure th

atth

e mach

ine o

perates p

rovid

ed th

e safetyg

ate is closed

. If the m

ovab

le gu

ard is

op

ened

, they w

ork in

con

jun

ction

with

Pilzevalu

ation

devices to

ensu

re that th

em

achin

e is shu

t do

wn

qu

ickly.

page 8

UV

-transp

arent p

lastics

UV

LED em

its radiatio

n in

a narro

wb

eam. A

lense is req

uired

to exp

and

the b

eam

U

VC

-transp

arent p

lastic is necessary

U

VC

-radiatio

n d

oes n

ot p

ermeate

solid

bo

dies - even

no

win

do

w g

lass(b

oro

silicate, du

ran) o

r transp

arent

plastics (acrylic g

lass, po

lystyrene,

etc.)

Plexig

las Sun

active GS:

Fo

r 265 nm

wavelen

gth

and

3mm

thickn

ess: 15 % Tran

smissio

n

Tran

smissio

n can

be in

creased b

yad

ditives

Transm

ission

of Plexig

las Sun

active GS:

Spectral transmittance in %

Wavelen

gth

in n

m

3 mm

, un

irradiated

3 mm

, 1000 h irrad

iated

8 mm

, un

irradiated

8 mm

, 1000 h irrad

iated

page 9

Test Plan an

d A

ssessmen

t

Fix Test Parameters

m

icroo

rgan

isms u

sed: E.C

oli

w

ater qu

ality and

qu

antity: tap

water, 250m

l

Varied

Test Parameters

co

ncen

tration

: 10E+6 to

10E+10 p

er cm

resid

ence tim

e: 0min

to 30m

in

tests with

and

with

ou

t agitato

r

Step-b

y-Step Test

Proced

ure

d

etermin

ation

of in

itial E.Co

li-con

centratio

n b

efore treatm

ent

U

VC

LED treatm

ent

ag

ar platin

g o

f Water after treatm

ent

in

cub

ation

for 36 h

ou

rs

cou

ntin

g o

f CFU

s (Co

lon

y Form

ing

Un

its)

Assessm

ent

calcu

lation

of th

e redu

ction

efficacy of E.C

oli in

the w

ater test solu

tion

with

the co

ncen

tration

s befo

re and

after the treatm

ent

tim

e dep

end

ent killin

g rate o

f E.Co

li

Overall G

oal

feasib

ility stud

y to assess to

wh

at extend

the U

VC

LED treatm

ent can

be u

sedto

pu

rify con

tamin

ated w

ater

analysis if su

ch a system

cou

ld b

e used

un

der stan

dard

enviro

nm

ental

con

ditio

ns w

itho

ut an

y safety issues

page 10

Test Resu

lts: CFU

s per m

L

0 m

in

2 m

in

5 m

in

10

min

1

5 m

in

Parameter

Set 1 1,1 x 10

6 (in

itial con

centratio

n)

no

t assessable

no

t assessable

no

t assessable

no

t assessable

Parameter

Set 2 1,1 x 10

6 (in

itial con

centratio

n)

no

t assessable

no

t assessable

no

t assessable

no

t assessable

Parameter

Set 3 1,1 x 10

6 (in

itial con

centratio

n)

no

t assessable

1,6 x 104

1.4 x 102

2 x 102

Parameter Set 1:

30mA

@10.25V

, 15 min

, no

agitato

r, no

direct co

ntact b

etween

water an

d LED

no

assessable resu

lts, i.e. no

micro

bio

lPgical red

uctio

n

Param

eter Set 2:35m

A@

10.35V, 15 m

in, ag

itator, d

irect con

tact betw

een w

ater and

LED

no

assessable resu

lts, i.e. no

micro

bio

log

ical redu

ction

Param

eter Set 3:40m

A@

10.45V, 15 m

in, ag

itator, d

irect con

tact betw

een w

ater and

LED

assessable resu

lts, sign

ificant m

icrob

iolo

gical red

uctio

n after 5 m

inu

tes

page 11

Test Resu

lts: CFU

s per m

L

y = 732875e

-0,75x

1,00E+00

1,00E+01

1,00E+02

1,00E+03

1,00E+04

1,00E+05

1,00E+06

1,00E+07

02

46

810

1214

16

CFU concentration (CFU/cm)

Time

in M

inu

tes

Ou

tloo

k and

next step

s:

suitab

le setting

s: 40m

A@

10.45V, 15 m

in, ag

itator (d

ue to

coo

ling

effects of th

e water, th

e maxim

um

specified

Vo

ltage is

requ

ired)

d

irect con

tact betw

een LED

and

water is req

uired

selectio

n o

f suitab

le auto

no

mo

us en

ergy su

pp

ly for th

e UV

C-LED

p

ossib

le encap

sulatio

n m

aterials for th

e UV

C-LED

(UV

C tran

sparen

t)

d

esign

of su

itable an

d safe set-u

p fo

r stand

ard d

aily use