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BIOFILM START-UP ON DIFFERENT BIOFILM START-UP ON DIFFERENT
FILTER MEDIAFILTER MEDIA
Min Jiang, Weiwei Miao, Chunfang LuoMin Jiang, Weiwei Miao, Chunfang Luo
Shanghai Ocean UniversityShanghai Ocean University
Apr 21, 2023Apr 21, 2023
AquaFish CRSPUSAID
Travel funding for this presentation was provided by
AquaFish Collaborative Research Support
Program
The Aquaculture CRSP is funded in part by United States Agency for International
Development (USAID) Grant No. EPP-A-00-06-00012-00.The opinions expressed herein are those of the authors and do not necessarily reflect
the views of the US Agency for International Development.
• Introduction
• Materials and methods
• Results and discussion
• Conclusions
Filter media
• Introduction
Aquaculture industry
Environmentally friendly technologies
Recirculating system
Water quality
diseases
Environmental impacts
Bio-filter system
• Materials and methods
Aquaculture waste water
pH 8.12
TAN-N (mg/L) 32.95
NO2-N (mg/L) 6.69
NO3-N (mg/L) 2.81
PO4-P (mg/L) 5.60
CODMn (mg/L) 82.37
Alk (mmol/L) 2.62
HT (mmol/L) 4.92
General conditions of the recirculating system
Volume of Waste water: 10L
Volume of Filter: 220mL
Velocity of flow: 63.3L/h
DO: 7.5±0.23mg/L
Water quality of the initial aquaculture waste water
for biofilm start-up
Bio-fiber fill Netlike plastic fill plastic ball
coral sand porcelain ring
Five kinds of
filter media
During the first 108h, water samples for quality analyses were collected from the tank every 12h. (8:30 & 20:30)
After that, samples were collected every 24h. (8:30)
The whole experiment lasted for 22days.
pH
Environmental quality standards
for surface water
GB 3838—2002
People’s Republic of China
TAN-N
NO2-N
NO3-N
PO4-P
CODMn
Alk
HT
• Results and discussion
Concentrations of TAN,NO2-N and NO3-N in thebiofilter with coral sand media
0
10
20
30
40
50
60
0 5 10 15 20 25Time(d)
Con
c.(m
g/L
)
TAN
Nitrite-N
Nitrate-N
Nitrite increased corresponding to the rapidly decreasing of TAN during the first phase of start-up and kept growing up for 6 days after TAN had reached a steadily low level. While nitrate increased during all the experimental period.
Concentrations of TAN, NO2-N and NO3-N in the biofilter with coral sand media changed regularly.
Same situation happened in biofilters with the other four media while the days needed to reach the stable low concentration of NO2-N were different.
Fig.2 Nitrite-N concentrations in the biofilterswith different media
0
10
20
30
40
50
60
0 5 10 15 20 25Time(d)
NO
2-N
(mg/
L)
bio-fibre fill
netlike plastic fill
plastic ball
coral sand
porcelain ring
During the start-up period, coral sand media showed the best efficiency of turning TAN to NO2-N and then NO3-N. NO2-N was less than 1.0 mg/L after 12 days.
Netlike plastic fill and porcelain ring were the worst.
The intervenient were plastic ball and bio-fibre fill.
Bio-fiber Netlike plastic
plastic ball
coral sand
porcelain ring
pH and Total alkalinity decreased rapidly during first several days and then increased slowly to stable values. The biofilter with coral sand media had higher pH and alkalinity than others.
Changes of pH duri ng bi ofi l mstart- up peri od
4
5
6
7
8
9
0 2 4 6 8 10 12 14 16 18 20 22 24
t i me(d)
pH
bi o- fi bre fi l lnet l i ke pl ast i c fi l lpl ast i c bal lcoral sandporcel ai n r i ng
Changes of Al kal i ni ty
0. 00
1. 00
2. 00
3. 00
4. 00
0 2 4 6 8 10 12 14 16 18 20 22 24
t i me d( )
Amm
ol·
L-1
()
bi o- fi bre fi l lnet l i ke pl ast i c fi l lpl ast i c bal lcoral sandporcel ai n r i ng
pH and Total alkalinity decreased rapidly during first several days and then increased slowly to stable values. The biofilter with coral sand media had higher pH and alkalinity than others.
Hardness in five filters nearly doubled after 22 days. Hardness in filters with coral sand, bio-fibre fill and porcelain ring were higher than the other two.
Changes of Hardness
0
2
4
6
8
10
12
0 2 4 6 8 10 12 14 16 18 20 22t i me d( )
Htmm
ol·
L-1
()
bi o- fi bre fi l lnet l i ke pl ast i c fi l lpl ast i c bal lcoral sandporcel ai n r i ng
Phosphate-P was consumed. Biofilters with coral sand and porcelain ring had less phosphate-P than others.
Changes of PO43- - P
0. 00
2. 00
4. 00
6. 00
8. 00
10. 00
0 2 4 6 8 10 12 14 16 18 20 22
t i me d( )
PO43-
-Pmg
·L
(-1
)
bi o- fi bre fi l lnet l i ke pl ast i c fi l lpl ast i c bal lcoral sandporcel ai n r i ng
Different ability of COD removal was approved in 5 biofilters.
Removal rate of COD
0
20
40
60
80
100
0 5 10 15 20 25
time(d)
rem
oval
rate
(%)
bio-fibre fill
netlike plastic fill
plastic ball
coral sand
porcelain ring
• conclusionsChange of water quality: regularity
Biofilm start-up: coral sand media> plastic ball≈ bio-fibre fill > Netlike ≈ porcelain ring
Advantage(1)Biofilm forming rapidly(2)Alkalinity and pH buffer(3)Higher consumption of
phosphate(4)Relatively higher COD
removal
Disadvantage (1)Increasing hardness(2)Heavy
coral sand
Thanks for your attention