Agriculture Reference
In-Depth Information
Solution:
Conduct a black box mass balance:
[A
acc
]
=
[A
in
]
−
[A
out
]
+
[A
prod
]
−
[A
cons
]
where
A
acc
=
mass of A per unit time accumulated
A
in
=
mass of A per unit time in
A
out
=
mass of A per unit time out
A
prod
=
mass of A per unit time produced
A
cons
=
mass of A per unit time consumed
The materials A are, of course, the three VOCs.
Barrels must be converted to cubic meters, and the density of each chemical
must be known. Each barrel is 0.12 m
2
, and the density of the three chemicals
is 1548, 1326, and 1476 kg m
−
3
. The mass per year of carbon tetrachloride
accumulated is
1548 kg m
−
3
186 kg yr
−
1
12 m
3
[A
acc
]
=
1 barrel
/
yr
×
0
.
/
bbl
×
=
Similarly,
8916 kg yr
−
1
[A
in
]
=
48
×
0
.
12
×
1548
=
The mass out is in three parts: the mass discharged to the wastewater treatment
plant, the mass leaving on the trucks to the hazardous waste disposal facility,
and the mass volatilizing. So
343 gm
−
3
076m
3
s
−
1
86400 s day
r
−
1
365 days yr
−
1
[A
out
]
=
[0
.
×
0
.
×
×
10
−
3
kg g
−
1
]
×
+
[48
×
0
.
12
×
1548
×
0
.
80]
+
A
air
=
822
.
1
+
7133
+
A
air
where A
air
is the mass per unit time emitted to the air. Since no carbon
tetrachloride is consumed or produced,
186
=
8916
−
(822
.
1
+
7133
+
A
air
]
+
0
−
0
775 kg yr
−
1
.
If a similar balance is performed for the other chemicals, it appears that the
loss to air of methyl chloride is about 16,000 kg yr
−
1
and that of trichloroethy-
lene is about 7800 kg yr
−
1
.
and A
air
=
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