Method for treating waste liquid produced during on-line chemical oxygen demand (COD) determination with potassium dichromate method

The invention discloses a method for treating waste liquid produced during on-line chemical oxygen demand (COD) determination with a potassium dichromate method, and belongs to the field of waste liquid treatment. The method is characterized in that a certain proportion of reducing salt is adopted to react with the waste liquid into which an interference removing solvent is added; then alkali is added into the waste liquid and a precipitation reaction is conducted; and finally, the waste liquid stands still to precipitate, and a supernatant can be emitted up to standard after the pH (potential of hydrogen) value is regulated. The method has the advantages as follows: through using the interference removing solvent the utility model effectively solves the problems that high-concentration sulfuric acid in the waste liquid participates in the chemical reactions to produce SO2 to harm the physical health of an operator, and as SO42 minus ions in the waste liquid interferes following chemical reaction steps, the a