Measurement of saltness of reactive dyed wastewater using light refractive index method

In order to efficiently reuse reactive dyed wastewater,the salt concentration of wastewater was measured by light refractive index method. The relationship between salinity and salt concentration of single salt and mixed salt solution and the influence of dye concentration were studied. There is a good linear relation between the concentration of sodium chloride,sodium sulfate,sodium carbonate and salinity,and R2 0. 99. The salinity exhibited good additivity in the solution of mixed salt with the error of less than 5%. Dye concentration had little effect on the salinity of single salt and mixed salt and the error is below 4%.