Transcript 1 g /40 ml wastewater
Effects of Biochars from Different Feed Stocks on Wastewater N and P Adsorption
H. Ren
1
, Q. Wang
1*
, Y. Li
1
, A.K.Alva
2
, B.Gao
3 1
University of Florida, TREC-Homestead,
3
Department of ABE-Gainesville, FL , and
2
USDA-ARS, Prosser, WA
INTRODUCTION
Wastewater from industrial, agricultural and municipal sources is usually hazardous to human beings and the environment, if disposed inappropriately. Biochar produced from slow pyrolysis for bio-fuel has potential adsorption of heavy metals and harmful organic compounds in wastewater and soil, such as lead (Mohan et al., 2007; Cao et al., 2009; Liu and Zhang, 2009), arsenic (Mohan et al., 2007), cadmium (Mohan et al., 2007), naphthalene, 1-naphthol (Chen and Chen, 2009), atrazine (Cao et al., 2009) and dye (Qiu et al., 2009). Phosphorous (Mortula et al., 2007), copper and zinc (Wilson et al., 2002), and some macro- and micro-nutrients, can also be absorbed by biochar. This study compared the adsorption of N and P in municipal wastewater by application of 4 biochars produced from different feed stocks: a commercial biochar (Dynamotive Canada), Peanut Hull, Bagasse and Hardwood compared to commercially activated carbon as a control.
MATERIALS AND METHODS
Five Char
Type
treatments with 3 replications
: Dynamotive Canada (Commercial Biochar), Peanut Hull, Bagasse, Hardwood, Activated Carbon (CK)
Treated with 7-Char
Rates
(ratio of biochar : water):
0 g, 0.1 g, 0.2 g, 0.4 g, 1 g, 2 g and 4 g in 40 ml wastewater. The wastewater sample used in this experiment was collected from the municipal wastewater treatment facility at Tropical Research and Education Center, University of Florida, Homestead, FL. The above mixtures in 60 ml polypropylene tubes were shaken at 100 rpm for 24 h.
Table 1 Concentrations of elements in the wastewater (mg/L)
Ortho-P 1.94
± 0.07
NH 4 + -N 24.40
± 0.96
NO 3 -N 0.00
± 0.00
F 0.40
± 0.13
Cl 147.21
± 3.15
SO 4 2 27.15
± 0.58
Br 2.56
± 0.96
Table 2 Properties of different biochar types and activated carbon
Processing temperature (℃) NH 4 + -N (mg/L) NO 3 -N (mg/L) Ortho-P (mg/L) Dynamotive 400-450 0.277
± 0.044
0.044
± 0.002
0.221
± 0.046
Hardwood 400 0.260
± 0.031
0.015
± 0.015
0.119
± 0.017
Peanut Hull 600 0.182
± 0.021
0.013
± 0.002
4.737
± 0.131
Bagasse 300 0.386
± 0.032
0.059
± 0.019
0.079
± 0.006
Activated Carbon — 1.020
± 0.537
0.058
± 0.051
0.036
± 0.046
The result was obtained by adding 1 g of biochar to 40 ml DDI water in a 60 ml polymeric tube, shaken for 24 hour at a speed of 100 rpm, and analyzed as other samples.
(
N
,
P
)
ads
[
C
(
N
,
P
)
i
C
(
N
,
P
)
e
]
V wastewater
/
m biochar
(
N
,
P
)
ads
-N or P adsorbed by biochar
C
(
N
,
P
)
i
-Initial concentration of N or P in wastewater
C
(
N
,
P
)
e
-N or P concentration after 24 hours shaken
V m wastewater
biochar
-Volume (ml) of wastewater -Weight (g) of biochar in the tube (
N, P
)
ads
> 0: Net adsorption; and < 0: Net desorption.
Reducing rate
(
C i
C e
) /
C i
100%
Ci > Ce net adsorption occurs, Ci < Ce net desorption occurs.
RESULTS 1500 1000 500 200 0 0 Dynamotive Hardwood Peanut hull Bagasse Activated carbon -500 0 0.2 0.4
1.0
2.0
Biochar rate (g/40 ml wastewater)
Fig. 1 NH 4 + -N adsorption with different biochar rates and types
4.0
Table 3 NH 4 + -N reduction rate of different biochars to wastewater ratios
Biochar rate g/40 ml wastewater 0.0
0.1
0.2
0.4
1.0
2.0
4.0
Dynamotive 0.0
7.5
10.1
22.1
42.9
64.1
80.4
Hardwood 0.0
5.8
16.8
33.6
72.0
58.1
18.6
Peanut hull % 0.0
3.9
4.9
14.5
28.9
45.0
65.8
Bagasse 0.0
12.5
23.1
44.4
63.1
0.8
13.0
Activated carbon 0.0
-3.3
-4.2
-4.8
4.0
11.7
35.6
800 600 Dynamotive Hardwood Peanut hull Bagasse Activated carbon 400 -200 0 0.2 0.4
1.0
2.0
Biochar rate (g/40 ml wastewater)
Fig. 2 Ortho-P adsorption with different biochar rates and types
4.0
Table 4 Ortho-P reducing rate of different material to solution rate of different biochar types
Dynamotive Hardwood Bagasse Activated carbon Biochar rate g/40 ml wastewater Peanut hull % 0.0
0.0 0.0 0.0 0.0 0.0 0.1
17.5 46.0 -16.3 79.1 -1.3 0.2
19.6 72.0 -31.6 98.1 1.3 0.4
46.3 95.6 -47.6 98.1 5.8 1.0
79.1 89.1 -42.3 95.1 22.0 2.0
87.3 93.7 -42.6 94.6 41.3 4.0
78.7 91.8 -96.6 86.0 59.9
CONCLUSIONS
•
NH 4 + -N adsorption by application of biochars made from Dynamotive and peanut hull increased significantly with the biochar rate, while that of activated carbon did not show any increase until the rate of 1:100 (0.4 g /40 ml wastewater).
•
The adsorption of bagasse and hardwood increased from the rate of 1:400 (0.1 g /40 ml wastewater) and decreased from the rates of 1:40 (1 g /40 ml wastewater) to 1:10 (4 g /40 ml wastewater) significantly.
•
The ortho-P adsorption by biochars from Dynamotive, hardwood, bagasse and activated carbon increased with application rates and these materials follow the order of bagasse > hardwood > Dynamotive > activated carbon. The peanut hull was found releasing P significantly to the wastewater.
•
The highest NH 4 + -N and ortho-P decreased in the wastewater by biochars reached up to 80.4% and 98.1%, which showed a great potential being used as wastewater treatment materials.
REFERENCES
Cao, X., L. Ma, B. Gao, and W. Harris. 2009. Dairy-manure derived biochar effectively sorbs lead and atrazine. Environ. Sci. Technol. 43:3285-3291.
Qiu, Y., Z. Zheng, Z. Zhou, and G.D. Sheng. 2009. Effectiveness and mechanisms of dye adsorption on a straw-based biochar. Bioresour. Technol. 100:5348–5351 Mortula, M., M. Gibbons, and G. Gagnon. 2007. Phosphorus adsorption by naturally occurring material and in dustrial by products. J. Environ. Eng. Sci. 6:157-164 Liu, Z., F. Zhang. 2009. Removal of lead from water using biochars prepared from hydrothermal liquefaction of biomass. J. Hazard. Mater. 167:933–939 D. Mohan, C.U. Pittman Jr., M. Bricka, F. Smith, B. Yancey, J. Mohammad, P.H. Steele, M.F. Alexandre-Franco, V. Gómez-Serrano, and H. Gong. 2007. Sorption of arsenic, cadmium, and lead by chars produced from fast pyrolysis of wood and bark during bio oil production. J. Colloid Interface Sci. 310:57–73 Wilson, J.A., I.D. Pulford and S. Thomas. 2003. Sorption of Cu and Zn by bone charcoal. Environ. Geochem. Health 25:51–56.
Chen, B., and Z. Chen. 2009. Sorption of naphthalene and 1-naphthol by biochars of orange peels with different pyrolytic temperatures. Chemosphere 76:127–133