The Role of Inorganic Metal Salts in Wastewater Clarification

An investigation into the ability of four inorganic coagulants namely; alum (Al2(SO4)3.18H2O), ammonium aluminum sulphate (NH4Al(SO4)2.12H2O), ferrous sulphate (FeSO4) and ammonium ferrous sulphate (NH4)2Fe(SO4)2.6H2O) in clarifying wastewater was examined. Results obtained from conventional standard ‘jar-test’ experiments indicated that alum was the most effective coagulant since it reduced turbidity of the wastewater to 0.64 NTU at a contact time of 300 min. Ferrous sulphate was the least effective coagulant, reducing turbidity of the wastewater to 3.45 NTU only at 240 min contact time, but when the contact time of the experiment was increased from 240 to 300 min, re-coloration of the solution was observed indicating re-stabilization of suspended particles. These findings tend to support the claim that alum is a choice coagulant for wastewater clarification.  Â

Kinetic Study of Aluminum Sulphate and Ammonium Aluminum Sulphate Coagulants in Wastewater Treatment

An investigation into the kinetics of two inorganic coagulant namely: aluminum sulphate octadecahydrate (Al2(SO4)3.18H2O) an ammonium aluminum sulphate dodecahydrate (NH4Al(SO4)2.12H2O) was studied to determine the effect of certain kinetic parameters on coagulation performance of the above mentioned coagulants. Results of analysis obtained revealed that the rate constant (k) for Al2(SO4)3.18H2O was 5.727s-1, while that for NH4Al(SO4)2.12H2O was 2.282s-1. However, the order of the reaction (xn) of Al2(SO4)3.18H2O and NH4Al(SO4)2.12H2O with the wastewater was 1.0 and 1.0, respectively, indicating that both reactions were first order. Considering the mechanism of the reaction, the general trend observed indicated that the Al2(SO4)3.18H2O reaction was thrice as fast as the NH4Al(SO4)2.12H2O reaction. This fact together with the larger value of k for Al2(SO4)3.18H2O obtained in the experiment lend credence to the widely held believe that Al2(SO4)3.18H2O is a more effective coagulant than NH4Al(SO4)2.12H2O in wastewater treatment

Level of Total Petroleum Hydrocarbon in Fish Samples Smoked with Different Combustible Materials

The determination of total petroleum hydrocarbon (TPH) in smoked fish samples were studied using six combustible materials, such as tyres, lubricating oil, polyvinyl chloride (PVC), plastics, iroko (chlorophoraexcelsa) wood and black velvet (dialiumguineense) wood.  The result of the analysis indicates high TPH of mean value 0.8172g for fish sample smoked with tyre. The low TPH of mean value 0.0679g was obtained from fish sample smoked with iroko wood. This study established the formation of TPH during incomplete combustion of combustible materials used during smoking of fish samples. The associated health hazard of smoked fish were examined. Keywords: Fish samples, Total petroleum hydrocarbon, Combustible materials, Toxicity. DOI: 10.7176/JEES/9-2-0