Biofiltration of fish farm effluents in Crete- the
role of macroalgae in nutrient stripping
Manolis Tsapakis, Eugenia Apostolaki, Vivi Pitta, Ioannis Karakassis
Amsterdam, 29-30/1/03
Institute of Marine Biology of Crete
Objectives - Strategy
1.
When should we deploy the
filters
2. When should we replace
the filters
3. How many filters should
we deploy
… in order to remove the
maximal amount of N & P
and fine particles from the
system.
Filters standing and sampling
Biotic succession on Biofilters
wet biomass
gross wet biomass
1500
4000
1000
may
2000
july
sept
1000
july
july
sept
sept
500
0
may
may
g/m 2
g/m 2
3000
0
noe
may
july
Biofilters biomass
Stress: 0.08
4(J-N)1
6(M-N)1
6(M-N)2
2(S-N)1
4(J-N)2
2(S-N)2
4(M-S)1
2(J-S)1
2(M-J)3
sept
noe
Biotic succession on Biofilters
flora coverage
wet biomass
1600
2,5
TOTAL FLORA
1400
2
TOTAL FAUNA
% coverage
1200
g m-2
1000
800
600
400
1,5
1
0,5
200
0
0
2(M-J)
2(J-S)
2(S-N)
4(M-S)
4(J-N)
2(M-J)
6(M-N)
100
80
may
60
july
40
sept
20
0
sept
noe
individuals no/m 2
species no/m2
120
july
2(S-N)
4(M-S)
4(J-N)
6(M-N)
individuals
species
may
2(J-S)
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
may
july
sept
may
july
sept
noe
Sampling of mesocosms
Dissolve oxygen
0.40
2(M-J)
0.35
Reference
mmole lt
July
Experiment
-1
0.30
0.25
0.20
0.15
0.10
0.05
6
5
4
3
2
1
0
ht
6
Ni
g
5
4
3
2
1
Da
y
0
0.00
0.40
2(J-S)
0.35
4(M-S)
0.30
Reference
0.25
0.20
0.15
0.10
0.05
4
3
2
1
0
3
2
1
0
ni
gh
t
m
or
ni
af
te
rn
oo
n
4
3
2
0
1
0.00
ng
Sept.
Experiment
mmole lt -1
time (h)
time (h)
0.45
2 (S-N)
4 (J-N)
0.40
Nov.
Experiment
mmole lt -1
6 (M-N)
0.35
Reference
0.30
0.25
0.20
D
ay
0
1
2
t
3
N
h
ig
time (h)
0
1
2
3
Ammonia trends
12
μΜ
10
8
2(M-J)
6
Reference
4
2
6
5
4
3
2
1
N
0
6
ig
ht
5
4
3
2
1
D
0
ay
0
Time (h)
2(J-S)
20
4(M-S)
15
Reference
μΜ
25
10
5
3
2
1
0
ht
3
af
ter
Ni
g
2
1
0
no
on
4
3
2
1
m
or
ni
n
0
in
g
0
Time (h)
1.4
1.2
6(M-N)2
4(J-N)2
0.8
0.6
2(S-N)2
0.4
0.2
N
Time (h)
2
1
0
ig
ht
3
2
1
0
A
Y
0.0
D
μΜ
1.0
Phosphate Trends
1.0
μΜ
2(M-J)
0.5
Reference
0.0
D
ay
0
1
2
3
4
5
6
N
h
ig
t
0
1
2
3
4
5
6
Time(h)
1.6
μM
1.2
2(J-S)
0.8
4(M-S)
Reference
0.4
3
2
1
0
3
ig
ht
N
2
1
0
af
te 4
rn
oo
n
3
2
1
m
or
ni
ni
ng
0
0.0
Time (h)
0.20
6(M-N)2
0.15
4(J-N)2
2(S-N)2
0.10
0.05
N
ig
h
Time (h)
2
1
0
t
3
2
1
0
AY
0.00
D
μΜ
0.25
Oxygen fluxes: Two months biofilters
NIGHT
DAY
O 2 (mmole/h)
O 2 (mmole /h)
10
0
8
-2
6
-4
4
-6
2
-8
0
-10
July
Sept
Nov
July
Se pt
Nov
NH4 fluxes: Two months biofilters
NIGHT
DAY
NH 4 (μmole /h)
NH 4 (μmole/h)
350
300
250
200
150
100
50
0
0
-50
-100
-150
-200
-250
-300
-350
July
Sept
Nov
July
Se pt
Nov
PO4 fluxes: Two months biofilters
NIGHT
DAY
PO 4 (μmole/h)
PO 4 (μmole /h)
5
25
0
20
-5
15
-10
10
-15
-20
5
-25
0
July
Sept
Nov
July
Se pt
Nov
-1
Oxygen fluxes (mmoles h )
Oxygen fluxes during the night experiment vs
water temperature
0
-1
y = -0.82x + 14.32
-2
R2 = 0.93
-3
-4
-5
-6
18
19
20
21
22
T (0 C)
23
24
25
26
NH4 fluxes during the day experiment vs Solar
irradiation
-1
Oxygen fluxes (mmoles h )
300
500
700
900
0
-20
-40
-60
-80
-100
-120
-140
-160
1100
y = -0.13x - 2.44
R2 = 0.83
Solar irradiation (W m-2 )
Mass Balance of Nitogen in Sitia fish farm
Fish Biomass: ~1000tn
Feed per Day: 1000kg
Nitrogen (8%): 80kg
Released as NH4 (~20%): 16 kg
Released as total dissolve N (60%): 48kg
Released as fine particulate matter (4-6%): 3.2-4.8kg
Then
The estimated consumption of dissolve NH4 during
a day of a two month Biofilter is approximately 1.3
mg N
Conclusions
• During the day the biofilters uptake dissolve inorganic
nutrients (N, P) & fine particulate matter and release
oxygen
• The uptake rate of dissolve N is depending from the
solar irradiation
• During the night the biofilters consume fine particulate
matter and release NH4 and PO4.. In addition, they
consume oxygen
New design
• Do you think that the micro
bioassay experiment in large
scale could be a good
biofiletr?
• What to you think if we fill
the dialysis bag with high
density phytoplankton?
• The product may can be used
by the fish farm hatchery.
Dialysis Bag
High density
phytoplacton