Thermodynamic Studies of the treatment of wastewater from brewery industry using powdered snail shell

Abstract

Thermodynamic studies of the treatment of wastewater from brewery industry were carried out. The change in standard Gibb's free energy (ΔG°) for pH were 0.71, 0.72, 0.45 and 0.49 kj/mol, while for dissolved oxygen were 0.93, 0.96, 0.98, 0.97 and 0.95 kj/mol.K The values of change in standard entropy (ΔS°) and standard enthalpy (ΔH°) were -1.21 and 542.5 kj/mol.K respectively. Other parameters of the wastewater had negative values in standard Gibb's free energy (ΔG°), among which were -1.13, -048, -0.94, -0.70 and -0.73 kj/mol. Turbidity had values of ΔG° as -2.62, -1.82, -1.87, -1.78 and -1.76 kj/mol, while electrical conductivity values were -2.12, -2.17, -2.23, -2.20 and -2.23 kj/mol. Total solids had values of ΔG° as -0.41, -0.39, -0.38, -0.38 and -0.32 kj/mol, while biochemical oxygen demand values were -0.39, -0.37, -0.33, - 0.24 and -0.19 kj/mol, and of ΔG° for chemical oxygen demand were -0.68, -0.66, -0.62, -0.62 and -0.65 kj/mol, nitrate-nitrogen had values of -0.95, -0.88, -0.87, -0.86 and -0.87 kj/mol. ΔG° for phosphate were -5.42, -5.52, -5.62, -5.78 and -6.09 kj/mol; for sulphate the values were -9.42, -9.42, -9.89, -10.14 and -10.60 kj/mol. The values of change in standard entropy (ΔS°) was negative for most parameters with the exception of turbidity, total solids and biochemical oxygen demand and change in standard enthalpy (ΔH°) was positive for electrical conductivity, total suspended solid, phosphate and sulphate, but negative for other parameters. This showed that the reduction of most parameters during treatment at different temperature was spontaneous, except for pH and dissolved oxygen that have positive values for standard Gibb's free energy.