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Effect of sewage on biodegradability of hydrocarbons in refinery wastewater
Environment International, Vol. 7, pp. 309-311, 1982 Printed in the USA. All rights reserved.
0160-4120/82/040309-03503,00/0 Copyright©1982Pergamon Press Ltd.
EFFECT OF SEWAGE ON BIODEGRADABILITY OF HYDROCARBONS IN REFINERY WASTEWATER Mohamed M. EI-Abagy and Ahmed S. Moursy water PollutionControl Laboratory, NationalResearchCentre, Dokki, Cairo, Egypt (Received 4 December 1981; Accepted 25 January 1982)
The effect of the microbial flora of municipal sewage, with special referenceto faecal coliform and faecal streptococcigroups, on the hydrocarbons biodegradationof the refinerywastewater from the Moustorod Oil Refinery has been studied. The results indicate that sewage with its microbial flora seems to have a significant role in the biodegradation of hydrocarbons in refinery wastewater. In addition, the early degradation in the wastewater seeded by sewage reveals that faecal streptococci, in addition to other microbial flora, have a significant role in the biodegradation of hydrocarbons.
Introduction Hydrocarbons have drawn attention for their toxicity on aquatic life. Moursy and EI-Abagy (1981) recorded that the use of Ps. aeruginosa enhanced the biodegradation of hydrocarbons after 7 days. The effect of mixed bacterial culture on biodegradation of hydrocarbons has been studied by several investigators (Kator et al., 1971; Atlas and Bartha, 1972; Cundell and Traxler, 1973); however, these studies did not investigate the effect of the sewage flora, which may be discharged together with hydrocarbons into a body of water. Thus, the present study is devoted to the investigation of the effect o f bacterial parameters on the biodegradation of the hydrocarbons of Moustorod Oil Refinery waste, with special reference to faecal coliform and faecal streptococci groups. Materials and Methods Two 10-1 flasks were filled with 8 1 of the refinery wastewater. One of these flasks was seeded with 8 ml of sewage from the main Giza pumping station. The flasks were aerated by air bubbling and kept at room temperature ( - 25 °C). Samples were taken from each flask twice per week and were subjected to bacteriological and hydrocarbon analysis. Bacteriological examination For the total viable bacterial counts, the poured plate technique was employed according to A P H A (1975).
Temperature o f incubation was 22 °C. For faecal coliform density, direct M P N for faecal coliform, as recommended by E1-Abagy et al. (1980), was employed. For measurment of faecal streptococci density, a presumptive test was employed, using Azide dextrose broth, followed by EVA broth as a confirmation test (Saleh and EI-Abagy, 1976). Hydrocarbons recovery Hydrocarbons recovery and its analysis by gas chromatography was carried out as recommended by Moursy and E1-Abagy (1981).
Results and D i s c u s s i o n In refinery wastewater seeded by sewage, the two faecal indicators, faecal coliform and faecal streptococci, survived more than those recorded in refinery wastewater without sewage (Figs. 1-3). This is due to the high level o f the two microorganisms as well as the required nutrients present in sewage. In addition, the biodegradation o f hydrocarbons may add sublimentary substances which encourage the persistence of the two parameters, especially faecal streptococci. It can be observed from Fig. 1 that faecal streptococci increased in density after 12 days, then slightly decreased, and finally persisted along the period o f investigation. Despite the obvious decrease in faecal coliform density in the first 4 days, the density fluctuated within the same power (102) throughout the period o f investigation. 309
310
Mohamed M. EI-Abagy and Ahmed S. Moursy 4
Totol viable counts
14
16
2O
,
~
I
•
J
.
L
I
L
.
i
B
i
29 3O 31
103
-
32
33
.
Faecal streptococci
2
6
10
14
18
22
26
30
3~4
Time d a ~ 1 Fig, I. The density of bacterial parameters in refinery wastewater
seeded by sewage.
These results revealed that faecal streptococci has a role in biodegradation of hydrocarbon, especially in high density. The microbial degradation of the hydrocarbons in the wastewater seeded by sewage is shown by the chromatograms in Fig. 2. The concentration of hydrocarbons started to decrease after 4 days. Individual components of low and high molecular weight of hydrocarbons were degraded at different rates within 7 days. However, some of these hydrocarbons were fairly resistant and disappeared after 12 days. The chromatograms show that the high molecular weight of hydrocarbons (n-paraffins) were degraded much faster than those of low molecular weight. Results indicated that many of the hydrocarbon components in the original wastewater were completely degraded, while others were attached to a partial degradation. The chromatogram shows that the most of hydrocarbon components were completely degraded after 21 days. The percentages of degradation were 62.5°70 and 97070 after 7 and 21 days, respectively. In the refinery wastewater (without sewage), faecal coliform increased directly during the first 7 days and then decreased afterwards (Fig. 3). This indicated that there ar~" some factors that dramatically affect faecal coliform density in refinery wastewater seeded by sewage. These results are in agreement with those reported
12 ~ys
21 days
Fig. 2. Progressof microbial degradation of chromatographed hydrocarbon compoundsin refinery wastewaterseededby sewage. by Rutler et al. (19.57) and Mitchell et al. (1967), which reported that the presence Of Ps. aeruginosa, as well as the density of bacterial population, had a strong effect on the density of faecal coliform. The microbial degradation of the hydrocarbon components in the wastewater without sewage is shown by the chromatograms in Fig. 4. The hydrocarbon concentrations started to decrease after 4 days. The chromatograms in this figure show that all hydrocarbon components in the original wastewater were slightly degraded within 7 days; after 12 days all components decreased and some of them disappeared. After 14 days some of low molecular weight hydrocarbons had disappeared, while others were fairly resistant. Complete degradation of some hydrocarbon components were achieved after 21 days. The percentages of degradation were 46°70 and 79°70 after 7 and 21 days, respectively. In general, faecal streptococci and other microbial flora seem to play a significant role in the biodegrada-
Effect of sewage on hydrocarbon biodegradability
311
1 4
10 tn
14 16 18
> 104
22 | 2 4 26 28 r
i
i
i
i
J
l
I
1
29 21
Faecal coliform
102
"T
10~
I
I
I
1
I
I
= I
I
1
25
30
Faecal streptococci
2
6
10
14
18
22
34
T;me days-1
Fig. 3. The density of bacterial parameters in refinery wastewater.
tion of hydrocarbons. On the other hand, faecal coliform was affected dramatically by hydrocarbon density. These results merit faecal streptococci as an indicator of pollution. In addition, it is in agreement with other investigators whose work found that faecal streptococci survived more faecal coliform in various environmental conditions (Saleh and E1-Abagy, 1976; E1-Ahagy et al., 1981). Acknowledgements-This study was supported in part by the funds provided by the "Multidisciplinary Environmental Studies." Research project sponsored by the Egyptian National Research Centre, Dokki, Cairo, and the U.S. Environmental Protection Agency.
References American Public Health Association (1975) Standard Methods for the Examination of Water and Wastewater, 14th ed. American Public Health Association, Washington, DC. Atlas, R. M. and Barth, R. (1972) Biodegradation of petroleum in sea water at low temperature, Can. J. Microbiol. 15, 18151. Cundell, A. M. and Traxler, R. W. (1973) The isolation and characterization of hydrocarbon-utilizing bacteria from Chedabucto Bay, Nova Scotia. Proceedings, Joint Conference on the Prevention and Control of Oil Spills, pp. 421. E1-Abagy, M. M., EI-Zanfaly, H. T., and E1-Hawaary, S. (1980) Direct MPN for faecal coliform, Zent. Bakt. II. Abt. 135, 396.
-
~
12 days
15 days
21 days
.------"
Fig. 4. Progress of microbial degradation of chromatographed hydrocarbon compounds in refinery wastewaters.
El-Abagy, M. M., EI-Hawaary, S., and Mawaheb Abou El-Azm (1981 ) Survival of bacterial indicators and Salmonella typhimurium during methanogenesis. Bull. N.R.C., Egypt ( in press). Kator, H., Openheimer, C. H., and Miget, R. J. (1971) Microbial degradation of a Louisiana Crude Oil in closed flasks and under simulated field conditions. Proceedings, Joint Conference on the Prevention and Control of Oil Spills, pp. 287. Mitchell, R., Yankafsky, S., and Jannash, H. W. (1967): Lysis of E. coil by marine microorganisms, Nature (Land.) 215, 891. Moursy, A. S. and EI-Abagy, M. M. (1981) Biodegradability of hydrocarbons in the refinery wastewater from Moustorod Oil Refinery, Environ. Int. 5, 39. Reitler, R. and Seligman, R. (1957) Pseudomonas aeruginosa in drinking water, J. Appl. Bacterial. 20, 145. Saleh, F. A. and EI-Abagy, M. M. (1976): The density of coliforms and faecal streptococci in Nile waters prior to impoundment. Presented at the Symposium on Nile Water and Lake Dam Project, Cairo, Egypt, Session 2 pp. 102.
0160-4120/82/040309-03503,00/0 Copyright©1982Pergamon Press Ltd.
EFFECT OF SEWAGE ON BIODEGRADABILITY OF HYDROCARBONS IN REFINERY WASTEWATER Mohamed M. EI-Abagy and Ahmed S. Moursy water PollutionControl Laboratory, NationalResearchCentre, Dokki, Cairo, Egypt (Received 4 December 1981; Accepted 25 January 1982)
The effect of the microbial flora of municipal sewage, with special referenceto faecal coliform and faecal streptococcigroups, on the hydrocarbons biodegradationof the refinerywastewater from the Moustorod Oil Refinery has been studied. The results indicate that sewage with its microbial flora seems to have a significant role in the biodegradation of hydrocarbons in refinery wastewater. In addition, the early degradation in the wastewater seeded by sewage reveals that faecal streptococci, in addition to other microbial flora, have a significant role in the biodegradation of hydrocarbons.
Introduction Hydrocarbons have drawn attention for their toxicity on aquatic life. Moursy and EI-Abagy (1981) recorded that the use of Ps. aeruginosa enhanced the biodegradation of hydrocarbons after 7 days. The effect of mixed bacterial culture on biodegradation of hydrocarbons has been studied by several investigators (Kator et al., 1971; Atlas and Bartha, 1972; Cundell and Traxler, 1973); however, these studies did not investigate the effect of the sewage flora, which may be discharged together with hydrocarbons into a body of water. Thus, the present study is devoted to the investigation of the effect o f bacterial parameters on the biodegradation of the hydrocarbons of Moustorod Oil Refinery waste, with special reference to faecal coliform and faecal streptococci groups. Materials and Methods Two 10-1 flasks were filled with 8 1 of the refinery wastewater. One of these flasks was seeded with 8 ml of sewage from the main Giza pumping station. The flasks were aerated by air bubbling and kept at room temperature ( - 25 °C). Samples were taken from each flask twice per week and were subjected to bacteriological and hydrocarbon analysis. Bacteriological examination For the total viable bacterial counts, the poured plate technique was employed according to A P H A (1975).
Temperature o f incubation was 22 °C. For faecal coliform density, direct M P N for faecal coliform, as recommended by E1-Abagy et al. (1980), was employed. For measurment of faecal streptococci density, a presumptive test was employed, using Azide dextrose broth, followed by EVA broth as a confirmation test (Saleh and EI-Abagy, 1976). Hydrocarbons recovery Hydrocarbons recovery and its analysis by gas chromatography was carried out as recommended by Moursy and E1-Abagy (1981).
Results and D i s c u s s i o n In refinery wastewater seeded by sewage, the two faecal indicators, faecal coliform and faecal streptococci, survived more than those recorded in refinery wastewater without sewage (Figs. 1-3). This is due to the high level o f the two microorganisms as well as the required nutrients present in sewage. In addition, the biodegradation o f hydrocarbons may add sublimentary substances which encourage the persistence of the two parameters, especially faecal streptococci. It can be observed from Fig. 1 that faecal streptococci increased in density after 12 days, then slightly decreased, and finally persisted along the period o f investigation. Despite the obvious decrease in faecal coliform density in the first 4 days, the density fluctuated within the same power (102) throughout the period o f investigation. 309
310
Mohamed M. EI-Abagy and Ahmed S. Moursy 4
Totol viable counts
14
16
2O
,
~
I
•
J
.
L
I
L
.
i
B
i
29 3O 31
103
-
32
33
.
Faecal streptococci
2
6
10
14
18
22
26
30
3~4
Time d a ~ 1 Fig, I. The density of bacterial parameters in refinery wastewater
seeded by sewage.
These results revealed that faecal streptococci has a role in biodegradation of hydrocarbon, especially in high density. The microbial degradation of the hydrocarbons in the wastewater seeded by sewage is shown by the chromatograms in Fig. 2. The concentration of hydrocarbons started to decrease after 4 days. Individual components of low and high molecular weight of hydrocarbons were degraded at different rates within 7 days. However, some of these hydrocarbons were fairly resistant and disappeared after 12 days. The chromatograms show that the high molecular weight of hydrocarbons (n-paraffins) were degraded much faster than those of low molecular weight. Results indicated that many of the hydrocarbon components in the original wastewater were completely degraded, while others were attached to a partial degradation. The chromatogram shows that the most of hydrocarbon components were completely degraded after 21 days. The percentages of degradation were 62.5°70 and 97070 after 7 and 21 days, respectively. In the refinery wastewater (without sewage), faecal coliform increased directly during the first 7 days and then decreased afterwards (Fig. 3). This indicated that there ar~" some factors that dramatically affect faecal coliform density in refinery wastewater seeded by sewage. These results are in agreement with those reported
12 ~ys
21 days
Fig. 2. Progressof microbial degradation of chromatographed hydrocarbon compoundsin refinery wastewaterseededby sewage. by Rutler et al. (19.57) and Mitchell et al. (1967), which reported that the presence Of Ps. aeruginosa, as well as the density of bacterial population, had a strong effect on the density of faecal coliform. The microbial degradation of the hydrocarbon components in the wastewater without sewage is shown by the chromatograms in Fig. 4. The hydrocarbon concentrations started to decrease after 4 days. The chromatograms in this figure show that all hydrocarbon components in the original wastewater were slightly degraded within 7 days; after 12 days all components decreased and some of them disappeared. After 14 days some of low molecular weight hydrocarbons had disappeared, while others were fairly resistant. Complete degradation of some hydrocarbon components were achieved after 21 days. The percentages of degradation were 46°70 and 79°70 after 7 and 21 days, respectively. In general, faecal streptococci and other microbial flora seem to play a significant role in the biodegrada-
Effect of sewage on hydrocarbon biodegradability
311
1 4
10 tn
14 16 18
> 104
22 | 2 4 26 28 r
i
i
i
i
J
l
I
1
29 21
Faecal coliform
102
"T
10~
I
I
I
1
I
I
= I
I
1
25
30
Faecal streptococci
2
6
10
14
18
22
34
T;me days-1
Fig. 3. The density of bacterial parameters in refinery wastewater.
tion of hydrocarbons. On the other hand, faecal coliform was affected dramatically by hydrocarbon density. These results merit faecal streptococci as an indicator of pollution. In addition, it is in agreement with other investigators whose work found that faecal streptococci survived more faecal coliform in various environmental conditions (Saleh and E1-Abagy, 1976; E1-Ahagy et al., 1981). Acknowledgements-This study was supported in part by the funds provided by the "Multidisciplinary Environmental Studies." Research project sponsored by the Egyptian National Research Centre, Dokki, Cairo, and the U.S. Environmental Protection Agency.
References American Public Health Association (1975) Standard Methods for the Examination of Water and Wastewater, 14th ed. American Public Health Association, Washington, DC. Atlas, R. M. and Barth, R. (1972) Biodegradation of petroleum in sea water at low temperature, Can. J. Microbiol. 15, 18151. Cundell, A. M. and Traxler, R. W. (1973) The isolation and characterization of hydrocarbon-utilizing bacteria from Chedabucto Bay, Nova Scotia. Proceedings, Joint Conference on the Prevention and Control of Oil Spills, pp. 421. E1-Abagy, M. M., EI-Zanfaly, H. T., and E1-Hawaary, S. (1980) Direct MPN for faecal coliform, Zent. Bakt. II. Abt. 135, 396.
-
~
12 days
15 days
21 days
.------"
Fig. 4. Progress of microbial degradation of chromatographed hydrocarbon compounds in refinery wastewaters.
El-Abagy, M. M., EI-Hawaary, S., and Mawaheb Abou El-Azm (1981 ) Survival of bacterial indicators and Salmonella typhimurium during methanogenesis. Bull. N.R.C., Egypt ( in press). Kator, H., Openheimer, C. H., and Miget, R. J. (1971) Microbial degradation of a Louisiana Crude Oil in closed flasks and under simulated field conditions. Proceedings, Joint Conference on the Prevention and Control of Oil Spills, pp. 287. Mitchell, R., Yankafsky, S., and Jannash, H. W. (1967): Lysis of E. coil by marine microorganisms, Nature (Land.) 215, 891. Moursy, A. S. and EI-Abagy, M. M. (1981) Biodegradability of hydrocarbons in the refinery wastewater from Moustorod Oil Refinery, Environ. Int. 5, 39. Reitler, R. and Seligman, R. (1957) Pseudomonas aeruginosa in drinking water, J. Appl. Bacterial. 20, 145. Saleh, F. A. and EI-Abagy, M. M. (1976): The density of coliforms and faecal streptococci in Nile waters prior to impoundment. Presented at the Symposium on Nile Water and Lake Dam Project, Cairo, Egypt, Session 2 pp. 102.