JECET : Journal of Environmental Science, Computer Science and Engineering & Technology. E-ISSN : 2278-179X

      JECET : Journal of Environmental Science, Computer Science and Engineering & Technology

Research Papers in Env Science

Comparative study of the reproduction of Synodontis punctifer (Daget, 1964) upstream and downstream of the Taabo hydroelectric dam, Côte d'Ivoire

Oussou Koffi Hervé, Soro Yaya, Diaha N’guessan Constance, N’guessan Yao, N’Da Konan,[DOI: 10.24214/jecet.A.8.1.00113.]

Synodontis punctifer is an endemic species in Ivory Coast. Its breeding strategies have been determined in Taabo Lake for sustainable management of stocks. In January and December 2016, 848 specimens were harvested, of which 367 downstream against 481 upstream. The sex ratio was 1: 1.1 downstream and 1: 1.4 upstream in favor of females. The upstream landed fish consisting of all stages of development were large (13.82 ± 2 cm LF) compared to those downstream (12.31 ± 1.49 cm LF) where no mature individual was captured. There is a migration of juveniles from downstream to upstream for spawning. The first maturity size of males 16.5 cm (LF) is greater than females (16.1 cm LF). The evolution of the gonado-somatic ratio (RGS) and frequency of gonad maturation stages showed that S. punctifer breeds between August and September and is believed to be due to flooding in the lake. The absolute fecundity (Fa) of S. punctifer at Taabo lake was estimated at between 2735 to 20218 oocytes, an average of 6757 ± 4094.67 oocytes for females between 13 cm and 20.5 cm (LF) in size. These oocytes have diameters ranging from 0.6 to 1.2 mm, an average of 0.97 mm ± 0.09 at the time of egg-laying. As for relative fertility (Fr), it varied from 28,000 oocytes to 35,000 oocytes, an average of 123,000 ± 58,75 oocytes per kg of body weight. S. punctifer is a less prolific fish producing large size oocytes.

Etude comparée de la reproduction de Synodontis punctifer (Daget, 1964) en amont et en aval du barrage hydroélectrique de Taabo, Côte d’ivoire

Oussou Koffi Hervé, Soro Yaya, Diaha N’guessan Constance, N’guessan Yao, N’Da Konan,[DOI: 10.24214/jecet.A.8.1.00113.]

Synodontis punctifer est une espèce endémique à la Côte d’ivoire. Ses stratégies de reproduction ont été déterminées dans lac de Taabo en vue d’une gestion durable des stocks. Entre janvier et décembre 2016, 848 spécimens ont été récoltés dont 367en aval contre 481 en amont. La sex-ratio a été de 1 : 1,1 en aval et 1 :1,4 en amont en faveur des femelles. Les poissons débarqués en amont, constitués de tous les stades de développement ont été de grande taille (13,82 ± 2 cm LF) par rapport à ceux en aval (12,31 ± 1,49 cm LF) où aucun individu mature n’a été capturé. Il existerait une migration des juvéniles de l’aval vers l’amont pour le frai. La taille de première maturité des mâles 16,5 cm (LF) est supérieure à celle des femelles (16,1 cm LF). L’évolution du rapport gonado-somatique (RGS) et des fréquences de stades de maturation des gonades ont montré que S. punctifer se reproduit entre août et septembre et serait dû aux crues dans le lac. La fécondité absolue (Fa) de S. punctifer au lac de Taabo a été estimée entre 2735 à 20218 ovocytes soit une moyenne de 6757 ± 4094,67 ovocytes pour des femelles de taille comprise entre 13 cm et 20,5 cm (LF). Ces ovocytes ont des diamètres mesurant entre 0,6 et 1,2 mm soit une moyenne de 0,97mm ± 0,09 au moment de la ponte. Quant à la Fécondité relative (Fr), elle a varié de 28000 ovocytes à 350000 ovocytes soit une moyenne de 123000 ± 58,75 ovocytespar kg de masse corporelle. S. punctifer est un poisson moins prolifique, produisant des ovocytes des grandes tailles.

Spent Catalyst Coming Out from Ammonia Synthesis Fertilizer Plant and Impact on Environment

R. P. Prajapati ,[DOI: 10.24214/jecet.A.8.1.01422.]

Ammonia is primarily used as nitrogenous fertilizer and as a raw material of inorganic compounds including nitric acid, ammonia salts, cyanide and organic compounds, such as amines, sulfanilamide and so on. In addition, ammonia is also an excellent refrigerant. Since ammonia is a key raw material for industry and agriculture, the process of ammonia synthesis has an extremely important position in any economy. During ammonia synthesis in nitrogenous fertilizer plant for production of nitrogenous fertilizer and other products, the major reactions of production and purification of synthesis gas and the synthesis of ammonia, all the carried out over different catalysts (Prajapati, R. P., Sharma Anand and Tiwari, D. R., 2010) . At least eight kinds of catalyst used in the whole process, where natural gas or naphtha is used a feedstock and steam reforming is used to produce synthesis gas. These catalyst, are Co-Mo hydrogenation catalyst, zinc oxide desulfurizer, primary and secondary, steam reforming  catalysts, high and low temperature shift catalysts, methanation catalyst and ammonia synthesis catalyst etc. In every catalytic operation, activity of the catalyst gradually decreases. Due to structural changes, poisoning, or deposition of extraneous material. A catalyst, which can no longer perform its original duty is referred to as “spent catalyst”. In such cases fresh catalysts have to be substituted and the spent catalyst will be discarded as solid waste material. Disposal of spent catalyst is a problem as it falls under the category of hazardous industrial waste. Environmental laws concerning spent catalyst disposal have becomes increasingly more serve in recent years. Metals such Ni, Mo, Fe, Co, Cu, Zn and Cr present in the spent catalyst can leached by water after disposal and pollute the environment. These metals exert wide variety of adverse effects on human being. Some of the metals have extremely long biological half-life that essentially makes it a cumulative toxin. Also some metals are carcinogenic in nature. Hence these solid waste materials which are causing serous environmental problems can act as artificial ores. The valuable metals can be recovered from these spent catalyst waste1. Recovery of metals from spent catalysts solid wastes has been an important issue not only from economic aspect but also for recycling rare natural sources and reducing the spent catalyst waste to prevent the environmental pollution.


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