scholarly journals Evaluation of the efficiency of some disinfectants on the viability of Hymenolepis nana eggs isolated from wastewater and faecal sludge in Yaounde (Cameroon): importance of some abiotic variables

Author(s):  
Fotseu Kouam Arnold Landry ◽  
Ajeagah Gideon Aghaindum ◽  
Amoah Isaac Dennis ◽  
Okoa Amougou Thérèse Nadège ◽  
Tsomene Namekong Pierre

Abstract Hymenolepis nana is responsible for many parasitic infections in tropical areas, with its persistence in aquatic environments as major contributory factor. A study aimed at demonstrating the effectiveness of some disinfectants on the viability of Hymenolepis nana eggs was conducted in microcosm. Sampling consisted of taking wastewater and sewage sludge samples in sterilized containers and then transporting to the laboratory of Hydrobiology and Environmental Sciences for the determination of Hymenolepis nana eggs using standard protocols. The experimental set-up consisted of five replicates, four tests and a control. The test samples were successively treated with four disinfectants (calcium chlorite, hydrogen peroxide, gypsum and sodium hypochlorite). The physico-chemical parameters were measured before and after disinfection. The samples were then observed under an optical microscope after concentration of the sample through sedimentation and McMaster technique. The viability of the eggs was determined using incubation and staining techniques. The analysis revealed that, the selected disinfectants significantly reduced the physico-chemical parameters with an average yield ranging from 79.24 ± 19.43% to 99.24 ± 1.47%). These physico-chemical parameters can significantly influence the treatment of Hymenolepis nana eggs either by absorbing the disinfectant or by constituting a protective barrier for the eggs, and the physico-chemical nature of the disinfectant strongly influences the formation of disinfection by-products. Calcium chlorite showed a greater effectiveness in reducing eggs viability with efficiency rates of 93.12 ± 9.12% followed by hydrogen peroxide (89.57 ± 14.55%), sodium hypochlorite (82.51 ± 14.39%) and gypsum (80.85 ± 12.88%). The results obtained with gypsum are almost similar to those obtained with other disinfectants (calcium chlorite, hydrogen peroxide and sodium hypochlorite) and clearly show that this disinfectant can be used in water treatment because, unlike other chemical disinfectants, it has no known toxic effects.

2020 ◽  
Vol 10 (2) ◽  
pp. 335-346
Author(s):  
Arnold Landry Fotseu Kouam ◽  
Gideon Aghaindum Ajeagah

Abstract The aim of this study is to determine the effectiveness of disinfectant on the viability of eggs from three nematode species (Ascaris, Trichuris, Ankylostoma). It was conducted in a microcosm from June 2018 to June 2019. The wastewater scan was sampled using 5 L sterile containers, the sample was arranged in four replicas, three tests and one control. The test samples received three disinfectants (Moringa, calcium hypochlorite and Moringa associated with calcium hypochlorite) at varying concentrations. The physical and chemical parameters were measured before and after the application of each disinfectant. The samples were then observed under an optical microscope. The viability of the eggs was determined by incubating the Petri dish samples at 30 °C for 30 days. The analyses show that some physicochemical parameters can significantly influence the efficacy of disinfectant on the eggs. The calcium hypochlorite associated with Moringa at 0.6 g/L showed greater efficacy on reducing viability and inactivation of eggs with 100% efficacy yield rates on Ankylostoma and Trichuris trichiuria and 97% on Ascaris lumbricoides eggs; this efficacy is significantly different from that observed on samples treated with Moringa and simple calcium hypochlorite. Of the three parasites tested, A. lumbricoides showed greater resistance to the disinfectant.


2019 ◽  
Vol 11 (2) ◽  
pp. 77
Author(s):  
Abba Paltahe ◽  
Tsamo Cornelius ◽  
Balkissou Sambo ◽  
Djaoyang Christian ◽  
Téri Téri ◽  
...  

This paper presents the variation in physico-chemical properties of a local Maroua tannery effluent before and after a flocculation treatment. Tanning is a process that consists of the transformation of the animal skin into leather by using different baths which contain many chemical reagents and produces high quantity of liquid and solid waste. The used water of traditional tannery of Maroua is directly thrown in nature without any pre-treatment posing a potential risk to the environment and human health. Physico-chemical parameters such as temperature, pH and conductivity, Total suspended solids, Total hardness, chlorides, sulfides, nitrates,COD, BOD5 , ammonium ion, dissolve oxygen, turbidity, colour and odour were determined before and after aluminum sulfate powder flocculation treatment for effluents collected from soaking, liming, deliming and vegetable tanning stages of the tannery process. The results obtained showed that most of the physico-chemical parameters are higher than the international standard. The results obtained made it possible to classify these four effluents in order of toxicity as follows: Liming water > vegetable tanning water > deliming water > soaking water. The treatment of these waste waters by flocculation reduces the concentrations of certain pollutant loads such as TSS, turbidity, hardness, COD, BOD5, sulfate; but remains less effective on others such as nitrate, chloride and ammonium ion (8%). There is also a decrease in pH, an increase in dissolved oxygen and conductivity. The flocculation treatment thus considerably reduced the toxicity of these effluents, especially its organic load.


Author(s):  
Suganthi Ranganathan ◽  
Chaitra Koppal Renukanath

ABSTRACT Aim The aim of this study is to compare the various cold sterilization techniques for sterilizing dental burs and diamond points by assessing the microbial growth in culture media on them before and after sterilization. Materials and methods The following four disinfectants were used: 2% glutaraldehyde, 5.2% sodium hypochlorite, hydrogen peroxide, and 70% ethanol. There were two main groups taken as group I-carbide burs and group II-diamond burs. A total of 48 samples were collected, 12 samples per disinfectant. Each sample has two burs collected from same patient. One acts as control group which means only microbial count was deter- mined without disinfection. The other one would be determined as microbial count before and after disinfection. The microbial assessment was done using brain heart infusion (BHI) broth and counted by plating in chocolate blood agar and MacConkey agar. Results The obtained results were statistically analyzed by one-way analysis of variance (ANOVA) test and post hoc test. The results revealed that there was statistically significant difference between sodium hypochlorite and surgical spirit, sodium hypochlo- rite and hydrogen peroxide. There was no statistically significant difference between sodium hypochlorite and glutaraldehyde. Conclusion The results of this study revealed that sodium hypochlorite and glutaraldehyde are most effective than hydro- gen peroxide, and surgical spirit is the least effective disinfectant. However, there was clinical significance in level of disinfection of all four disinfectants. How to cite this article Ranganathan S, Manvi S, Gopalakrishna S, Renukanath CK. Comparison of Various Cold Sterilization Tech- niques on Routinely used Carbide Burs and Diamond Points. Int J Prosthodont Restor Dent 2017;7(3):97-102.


2019 ◽  
Vol 13 (1) ◽  
Author(s):  
L. Ovsiannykova ◽  
L. Valevskaya ◽  
V. Yurkovska ◽  
S. Orlova ◽  
O. Sokolovskaya

The article proves how practical it is to use whole-milled millet grain to improve the quality of bakery products. Samples of bread with the addition of different amounts of milled millet grain before and after microwave treatment have been evaluated by sensory (surface, shape, and colour of bread, porosity, structure and colour of the crumb) and physico-chemical parameters. To determine the organoleptic evaluation of bread samples with the addition of 5%, 10%, and 15% whole-milled millet grain before and after microwave treatment, a scoring scale and the profiling method were used. According to the results of the research, the advantages of introducing milled millet grain into wheat flour has been substantiated, and it has been shown that adding it to the formulation of 5–15% improves the organoleptic characteristics of the bread, namely, giving it a harmonious taste and aroma, an attractive colour, a pronounced smell, and a porous structure, comparatively with standard bread made from wheat flour. The best characteristics were observed after whole-milled millet grain that had undergone microwave treatment was added to the flour. When 15% of whole-milled millet grain is added to wheat flour after microwave treatment, there is a slight decrease in the porosity of the bread. So, the introduction of more than 15% of whole-milled millet into the formulation is considered inappropriate. It has been found that the physical-chemical parameters of bread (humidity, acidity, porosity, mass fraction of sugar and fat), when adding whole-milled millet in the amount of 5–15% before and after microwave treatment, practically do not change. The introduction of 5–15% of whole-milled millet grain into the composition of bread recipes allows you to obtain high quality bread, of high nutritional and biological value, which can be recommended for consumption by all social groups, including children, adolescents, and elderly people. These studies can be used in the future in developing a technology of obtaining bakery products of functional purpose with high consumer properties.


2021 ◽  
Author(s):  
Arnold Landy Fotseu Kouam ◽  
Ajeagah Aghaindum Gideon ◽  
Isaac Dennis Amoah ◽  
Tsomene Namekong Pierre ◽  
Okoa Amougou Thérèse Nadège

Abstract This study is aimed at highlighting the risks associated with the reuse of faecal sludge and proposed a sustainable treatment method. The sampling consisted of collecting samples of faecal sludge in 5L of sterilized containers and then transporting to the laboratory in a refrigerated chamber for the determination of helminth eggs using standard protocols. The experimental device consisted of two replicates, one test and one control. The test samples received active charcoal at different concentrations (C1, C2, C3, C4, C5, C6). The physico-chemical parameters were measured before and after treatment. The samples were then observed under the optical microscope at the 40X objective for morphological identifications. Molecular analysis was carried out using the Polymerase Chain Reaction technique. The viability of the eggs were determined using incubation and staining techniques. Analyses showed that the sludge used for irrigation contained eggs and larvae of 6 helminth species (S. stercoralis, A. duodenale, N. americanus, T. trichiuria, H. nana and Ascaris spp.) with viability percentages ranging from 57.72% to 74.46%. Treatment with active charcoal allowed significant adsorption of these parasites with yields ranging from 95 to 100%. In addition, the carbon used has favoured the alkaline stabilisation of the medium, which increases its absorption potential. It can therefore be used in the treatment of sludge because, unlike other chemical disinfectants, it does not present any toxic effects.


Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.


2012 ◽  
Vol 2 (10) ◽  
pp. 1-3
Author(s):  
Gyaneswar Bhuyan ◽  
◽  
Dr. R. Anandhan Dr. R. Anandhan ◽  
V. kavitha V. kavitha

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