PARASITOLOGICAL ASSESSMENT OF WASTEWATER AND THE EFFICACY OF BIOSAND FILTER IN THE REMOVAL OF PARASITE OVA AND CYSTS
PARASITOLOGICAL ASSESSMENT OF WASTEWATER AND THE EFFICACY OF BIOSAND FILTER IN THE REMOVAL OF PARASITE OVA AND CYSTS
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Date
2011-10
Authors
OKOJOKWU, OCHEME JULIUS
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Abstract
In this study, the parasitological profile of wastewater from the Ahmadu Bello University
waste stabilisation ponds (ABU-WSP) and Ahmadu Bello University Teaching Hospital
sewage treatment plant (ABUTH-STP), Zaria, Nigeria were evaluated using the sucrose
floatation andKinyoun modified Acid-Fast(modified Ziehl-Neelsen) staining techniques. The
parasite removal efficiency of biosand filter was also tested in comparison with the waste
stabilisation ponds and the sewage treatment plant. A total of 1920 L of wastewater was
examined and a significant level of parasite eggs, cysts and oocysts were detected. In all,
1,648 parasites eggs, cysts and oocysts per litre were counted in sewage from ABUTH–STP.
Ova of Ascarislumbricoides had the highest count/litre of 307 (18.63%) followed by ova of
Taeniaspp (n=287; 17.42%). The least count per litre was for cysts of Giardia lamblia (n=58;
3.52%). The analysis revealed that 52.61% of the parasite eggs, cysts and oocystswere
removed by the sewage treatment plant while egg removal efficiency of the biosand filter was
97.45%. On the other hand, a total of 874 parasites’ eggs, cysts and oocysts per litre were
counted in sewage from ABU–WSP. Ascarislumbricoides accounted for the highest eggs/litre
(n = 198; 22.65%) followed by Taeniaspp (n = 155; 17.73%) and Hookworm (n = 123;
14.07%). Cysts of Giardialamblia had the least count/litre (n = 3; 0.34%). The mean egg or
(oo)cyst/litre of sewage from the ABU-WSP revealed that the raw sewage had 12.38 ± 0.93
Ascarislumbricoides egg/litre. Further comparison of mean parasite eggs/litre in the effluents
of biosand filter and the sewage treatment plant using Wilcoxon’s Signed Ranks Test
indicated a significant difference (p< 0.05) with biosand filter having lower counts per litre.
One-way analysis of variance (ANOVA) of the efficiencies of the three treatment methods
showed that biosand filter was significantly more efficient than the sewage treatment plant (p
<0.001) in the removal of helminth eggs and protozoan (oo)cysts. The results obtained
therefore demonstrated that the raw wastewater was laden with parasite eggs, cysts and
oocysts and hence posed public health threat to the users of the effluent downstream. The
biosand filter was efficient in removing oocysts of Cryptosporidium parvum and Giardia
lambliacysts and was more efficient than the sewage treatment plant; its effluent contained
insufficient level of the ova, cysts and oocysts of parasites well below the less than one (<1)
helminth ova/protozoa cysts as recommended by World Health Organization (WHO).
Description
A THESIS SUBMITTED TO THE
SCHOOL OF POSTGRADUATE STUDIES,
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
IN PARTIAL FULFILMENT OF THE REQUIREMENTS
FOR THE AWARD OF MASTER OF SCIENCE (M.Sc.) IN
MICROBIOLOGY
DEPARTMENT OF MICROBIOLOGY
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
OCTOBER, 2011
Keywords
PARASITOLOGICAL ASSESSMENT,, EFFICACY,, BIOSAND FILTER,, REMOVAL,, PARASITE OVA,, CYSTS.