Comparison of 2- and 3-compartment electrodialytic remediation cells for oil polluted soil from northwest Russia

Figures & data

Table 1. Sediment characteristics. Russian soil quality criteria (QC) for organic priority substances are included.

Characteristic	Units	Value	Russian QC
Carbonate	%	0.3 ± 13%
Organic matter	%	2.8 ± 8%
pH		3.9 ± 1.5%
Conductivity	mS/cm	0.08 ± 6%
Grain size <63 µm	%	1.7%
Acenaphtene	mg/kg	0.74 ± 40%
Acenaphtylene		0.02 ± 40%
Anthracene		0.33 ± 40%
Benzo(a)anthracene		0.28 ± 40%
Benzo(a)pyrene		0.12 ± 40%	0.02
Benzo(b)fluranthene		0.21 ± 40%
Benzo(ghi)perylene		0.05 ± 40%
Benzo(k)fluoranthene		0.06 ± 40%
Dibenzo(a,h)anthracene		<0.020
Phenanthrene		2.6 ± 40%
Fluoranthene		0.28 ± 40%
Fluorene		1.1 ± 40%
Indeno(1,2,3-cd)pyrene		0.02 ± 40%
Chrysene		0.95 ± 40%
Naphtalene		1.3 ± 40%
Pyrene		2.1 ± 40%
PAH16		10
PCB		n.d.
C5–C8		<5.0
C8–C10		130 ± 30%
C10–C12		890 ± 30%
C12–C16		7700 ± 30%
C16–C35		13,000 ± 30%
THC, total		22,000	1000

Table 2. Experimental design.

Exp.	Current density	Stirring	Light	Time	Cell design	Result
	(mA/cm^2)			(days)	compartments
1	+	–	–	28	3	y1
2	+	+	+	28	3	y2
3	–	–	+	28	3	y3
4	–	+	–	28	3	y4
5	0	+	+	14	3
6	+	+	+	28/42	2	z1
7	+	+	–	28/42	2	z2
8	–	+	+	28/42	2	z3
9	–	+	–	28/42	2	z4
10	0	+	+	21	2

Table 3. Removal efficiency for 3-compartment cell.

Exp.	Current density	Time	Stirring	Light	THC remaining
	(mA/cm^2)	(days)			%
Raw					100
1	0.64	28	Off	No light	83.2
2	0.64	28	On	Light	23.0
3	0.05	28	Off	Light	82.3
4	0.05	28	On	No light	87.5
5	0.32	14	On	Light	40.8

Notes: In all experiments, tap water was used as suspension liquid with an L/S ratio of 7 mL/g. Stirring rate was 250 rpm if turned on.

Table 4. Extended experimental domain for 3-compartment cell.

Exp.	Current density	Time	Stirring	Light	THC remaining
	(mA/cm^2)	(days)			%
Raw					100
A	1.28	2	On	Light	90.5
B	0.025	7	On	Light	70.0

Notes: In all experiments tap water was used as suspension liquid with a L/S ratio of 7 mL/g. Stirring rate was 250 rpm.

Table 5. Removal efficiency for 2-compartment cell.

Exp.	Current density	Light	THC remaining 28 days	THC remaining 42 days
	(mA/cm^2)		%	%
Raw				100
6	0.64	Light	93.0	91.0
7	0.64	No light	65.8	62.4
8	0.05	Light	111	139
8	0.05	No light	104	115
10	0.32	Light	83.0^a

Notes: In all experiments tap water was used as suspension liquid with a L/S ratio of 7 mL/g. Stirring rate was 250 rpm.

^aAfter 21 days.