Pre-treatment (coagulant, algaecide) and filter resistance.
Transcript of Pre-treatment (coagulant, algaecide) and filter resistance.
Pre-treatment (coagulant, algaecide) and filter resistance.
Filamentous diatom :Melosira
Scale of midge, midge are abundant.
In long filter run,filamentousgreen algae are found. Cladophora, Spirogyra, Hydrodictyon,
Mollusk is also found.
Short filter run : filamentous diatom :pioneer of succesion.
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N D J F M A M J J A S O N D J F
水温(
Inflow water temperature: from Dec, 2003 to Dec.2004.
Wakata plant., Takasaki city.℃)
Dominant algaeMidge larvae is a grazing animal of Melosira.
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APR
FEB MARJAN
MAY JUN
JUN AUG SEP
OCT NOV DEC
Filter does not clog in all the year.
NH
L, c
m
Filter run days
Observed head loss and Normalized head loss(NHL)
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(cm)
(cm)
Filter run in days Filter run in days
Observed HL
Observed HL
NHL
NHL
+0.59
+0.18
+0.50
-0.07
Observed Head Loss gradually increases. It is due to increase of flow rate. Real resistance of NHL is almost same or it becomes slightly small resistance in warm period (August). These resistance change is influenced with the biological activity.
Sum of turbid matter (load of SS to filter bed) and NHL
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FEB
AUG
Load of SS to the filter.
NHL(cm)
NHL(cm)
FEB (Cold season)
Low Biological Activity
Filter Resistance (NHL) increases.
AUG (Warm season)
High Biological Activity
Filter Resistance (NHL) does not increase.
Development of Algal Mat as Chl. a.
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Chl‐a(mg/㎡)
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8月
Run Days
Growth rate 0.054
Melosira varians 2.5E+09cells/㎡
Growth rate 0.174
Chl‐a(mg/㎡)
Melosira varians 2.6E+10cells/㎡
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Health Index (%) of Algae:Chl.a/(Chl.a+Phe.a)
(%)
(%)
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8月
Run Days
Active algae M.varians
Chironomide midge larvae graze diatom.
Dead algae of fecal pellet M.varians
Algal development in summer. Filamentous diatom of Melosira grew rapidly and decreased after 10 days. It was caused by the grazing activity. This phenomena is clear in warm period.
DAYS OF FILTER RUN
Chl
orop
hyll
a,
mg
m -2
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%
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A
B
A
B
A ; Active algae
B ; In-active algae
Alg
al B
iom
ass
Hea
lth In
dex
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Comparison of Load of SS and Filter Resistance, and Algal Development in Winter (FEB) and in Summer (AUG).
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AUG
Load of SS (mg/m2) along the filter run
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lgal
Bio
mas
s:C
hlor
ophy
ll a,
mg
m -2
Filter Run in Days
AUG
FEB
Low Biomass: Easily Clog in Cold Season.
Low growth rate of algae
High Biological Activity: High Temperature: No Clog in warm period.
Rapid growth of algae, then rapid decrease.Fi
lter
Res
ista
nce NHL:
Nor
mal
ize
Hea
d L
oss (
cm)
Filter resistance is related with temperature. This is due to biological activity.
2001: Deep depth, large scrap of upper sand layer.
1992: Shallow depth, small amount of scrap.
Scrap
↓
鋤取り(取り除く厚みが大きい)
汚泥(汚砂):生物群集を取り除く
Biomass and Run days
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生体量(㎎/㎝
2)
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生体量(μg/㎝
2)
Algal Biomass
Animal Biomass
:100cm~140cm:140cm~200cm
▲:Less than 7 daysBiomass: Bio-volume as weight : Specific gravidity = 1.
Growth rate of algae was low in deeper filter. Algal biomass still grew even on 24 days and it did not reach the stationary phase.
Population of small animals (ciliate, rotifer, midge etc.) grew with filter run.
Difference of biomass of algae and animals are 1000 times.
Run Days
Bio
mas
s, m
g/cm
2B
iom
ass,
mic
ro-g
/cm
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September, Takasaki, Gumma
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水深(㎝)
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水深(㎝)
Depth and Biomass
Algal Biomass
Animal Biomass
:100cm~140cm:140cm~200cm
After 7 days of filter run, algal biomass is related with depth. Shallow: large biomass Deep: small biomass.
Algae and animals are abundant in shallow depth filter.
Active diatom is abundant in shallow filter
Dead and empty diatom is abundant in deep filter.
Biomass, mg/cm2
Biomass, micro-g/cm2
Dep
th, c
m2
Dep
th, c
m2
SSF is not mechanical filter.It is really ecological purification system. This system is similar with the ecosystem of soil in the natural forest. Microbial organisms and small animals are active in the forest soil.
Shallow depth for active algal growth. Small animals are necessary. Long filter run is better. Large size of sand particle. Faster filter rate gives better condition of aerobic condition for small animals. Less amount of removal of upper sand is necessary to keep heterotrophic organisms in the filter.
There are so many bacteria.→Medical doctor touches with patient.→Doctor is safe.
106 104105
Logarithmic bacteria number in 1 ml
107108
Risk of germ bacteria in water.
10-1 10-2 10-3 10-4 10-5103 102 101 100
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water
RSF
EPS (SSF)
Dust in air
Wash hand
100 years ago, when the number of general bacteria was less than 100 colonies in 1 ml, Cholera patient did not appear.
Coli-form bacteria are abundant in soil and are not germ bacteria.
Please compare the size and number of Cryptosporidium with bacteria in water. Risk?
100 1101,000 0.1 0.0110,000 0.001 0.0001
soil
0.00001100,0001,000,000
10,000,000100,000,000
Sterilize by chlorine
Toxicity of chlorine?
Gen
eral
ba
cter
ia
Gen
eral
ba
cter
ia
Gen
eral
ba
cter
ia
Gen
eral
ba
cter
iaG
ener
al
bact
eria
Col
i-for
m
bact
eria
Col
i-for
m
bact
eria
Col
i-for
m
bact
eria
Col
i-for
m
bact
eria
Col
i-for
m
bact
eria
Feca
l C
oli-f
orm
Feca
l C
oli-f
orm
Feca
l C
oli-f
orm
Feca
l C
oli-f
orm
Feca
l C
oli-f
orm
Ger
m :
Cho
lera
Ger
m :
Cho
lera
Ger
m :
Cho
lera
Ger
m :
Cho
lera
Ger
m :
Cho
lera
Elimination by chemical
Elimination by biological community
Acceptable risk is essential for practical life.
100 % safe is not good for practical life.
This is natural ecological sense.
SSF(Ecological Purification System) is the suitable environment for filamentous algae.
Filamentous algal growth experiment by use of natural stream water: the best food for animal
Roughing filter experiment for SSF system and algal culture to reduce suspended matter from the surface water of a stream.
Sapporo
Ueda
Tokyo
Tokyo
NaganoSuzaka
Suwa
JICA excursion, Summer, 2007