Snake style COD reactor

The utility model relates to an environment monitor. A snake-shaped tube is arranged in an outer sleeve tube; a resistance wire is coiled out of the outer sleeve tube; one end of the snake-shaped tube is connected with a mixing pool; the other end of the snake-shaped tube is provided with a water cooler; one end of the snake-shaped tube in the water cooler is inserted into a spectrophotometer. The utility model has the advantages of simple structure and principle, realization of automatic, continuous and on-line monitoring in a flowing state, obvious electricity saving, short checking and analyzing time, etc.