The disposal of wastewater in water bodies has a negative impact in the
environment and the health of people who use such water bodies for either irrigation or
drinking purposes. In this study, we evaluated the parasitological profile of wastewater
from the Ahmadu Bello University Teaching Hospital sewage treatment plant, Zaria,
Nigeria using the magnesium sulphate floatation method. The parasite removal efficiency
of biosand filter was also tested in comparison with the sewage treatment plant. A total of
960 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.
Ova of
Ascaris
spp showed the highest count/litre of 307 (18.63%) followed by ova of
Taenia
spp (n=287; 17.42%). The least count per litre was exhibited by cysts of
Giardia
spp (n=58; 3.52%). The analysis revealed that 52.61% of the parasite eggs, cysts and
oocysts was removed by the sewage treatment plant while egg removal efficiency of the
biosand filter was 97.45%. 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. The results obtained therefore demonstrate that the raw wastewater was laden with
parasite eggs, cysts and oocysts and hence pose public health threat to the users of the
effluent downstream. The biosand filter was more efficient than the sewage treatment plant;
its effluent contains insufficient level of the ova, cysts and oocysts of parasites well below
the less than one (<1) helminth ova/protozoa cysts as recommended by WHO.