The impact of ozone treatment on the removal effectiveness of various refractory compounds in wastewater from petroleum refineries

Figures & data

Figure 1. Raw FFS PRW samples.

Figure 2. Equipment set-up in the laboratory.

Figure 3. Ozone treatment reactor loaded with FFS PRW.

Table 1. Experiments design for the ozone treatment reactions.

Component	Run 1	Run 2	Run 3	Run 4	Run 5
Air flowrate (L/min)	1	1	1	1	1
Ozone output (mg/min)	8.05	8.05	8.05	8.05	8.05
pH	9.67	5	11	9.67	9.67
Temperature (°C)	25	25	25	2	40
Treatment time (min)	0-60	0-60	0-60	0-60	0-60

Table 2. GC operating conditions during analysis.

Parameter	Value and units
Column flow	2.5 mL/min
Split flow	100 mL/min
Velocity of carrier gas	48 cm/s
Injector temperature	220 °C
Detector temperature	250 °C
Analysis time	20 min
Column maximum temperature	250 °C (isothermal)

Table 3. Characterization of FFS PRW for organic compounds.

Compound	Concentration (µg/L)
Gasoline range organics
Methyl Tert Butyl Ether (MTBE)	<50
Benzene	1786.88
Toluene	2560.32
Ethylbenzene	522.87
m + p-Xylene	812.49
O-Xylene	930.35
1, 3, 5-Trimethylbenzene	402.04
1, 2, 4-Trimethylbenzene	1241.64
Naphthalene	1918.71
C8–C10	<10
Diesel range organics
C10–C28	53,791
Oil range organics
C28–C36	188,209

Table 4. The FFS PRW’s COD as compared to other PRW.

Parameters
pH	COD (mg/L)	Reference
8.3–8.9	3600–5300	^[^16^]
2.5	21,000	^[^31^]
8.48	7896	^[^18^]
9.5	4050	^[^21^]
9.67	48,524	Current study

Figure 4. Effect of ozone treatment on benzene.

Figure 5. Effect of ozone treatment on toluene.

Figure 6. Effect of ozone treatment on ethylbenzene.

Figure 7. Effect of ozone treatment on m-xylene and p-xylene.

Figure 8. Effect of ozone treatment on o-xylene.

Table 5. Zone I ozone treatment reaction kinetics and removal efficiency.

	Zone I
Compound	k (s^−1)	R^2	% Removal
1,3,5-Trimethylbenzene	6.128 × 10^−4	0.936	66.82
Ethylbenzene	5.080 × 10^−4	0.937	59.93
O-xylene	3.365 × 10^−4	0.916	45.44
Benzene	2.072 × 10^−4	0.876	31.13
m + p-xylene	1.618 × 10^−4	0.806	25.26
COD	1.165 × 10^−4	0.932	18.92
Toluene	7.604 × 10^−5	0.989	12.79
Naphthalene	7.502 × 10^−5	0.879	12.63
1,2,4-Trimethylbenzene	6.868 × 10^−5	0.817	11.63

Table 6. Zone II ozone treatment reaction kinetics and removal efficiency.

	Zone II
Compound	k (s^−1)	R^2	% Removal
Benzene	1.412 × 10^−3	0.908	63.44
Toluene	7.455 × 10^−4	0.949	64.42
COD	4.799 × 10^−4	0.989	46.97
1,2,4-Trimethylbenzene	3.886 × 10^−4	0.987	44.46
m + p-xylene	5.012 × 10^−4	0.959	44.42
Naphthalene	2.511 × 10^−4	0.963	31.77
O-xylene	2.528 × 10^−4	0.957	19.94
Ethylbenzene	1.378 × 10^−4	0.935	9.10
1,3,5-Trimethylbenzene	3.979 × 10^−5	0.902	2.29

Table 7. Zone I and Zone II ozone treatment pseudo-second-order reaction kinetics.

	Zone I		Zone II
Compound	k (mM^−1 s^−1)	R^2	k (mM^−1 s^−1)	R^2
COD	2.671 × 10^−9	0.921	2.000 × 10^−8	0.953
Benzene	1.097 × 10^−2	0.858	4.123 × 10^−1	0.799
Toluene	2.933 × 10^−3	0.985	6.480 × 10^−2	0.877
Ethylbenzene	1.687 × 10^−1	0.887	7.926 × 10^−2	0.922
m + p-xylene	2.454 × 10^−2	0.799	1.423 × 10^−1	0.911
O-xylene	5.279 × 10^−2	0.884	6.695 × 10^−2	0.933
1,3,5-Trimethylbenzne	3.344 × 10^−1	0.877	3.716 × 10^−2	0.898
1,2,4-Trimethylbenzne	7.077 × 10^−3	0.813	6.162 × 10^−2	0.958
Naphthalene	5.364 × 10^−3	0.872	2.427 × 10^−2	0.940

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Data availability statement

The data presented in this study are available on request from the corresponding author.