The wastewater treatment technologies of catering and tourism industry include biological rotary table method, biochemical aeration method, contact oxidation method, air floatation method, oil and slag separation method, etc. However, after years of practice, it is found that some commonly used wastewater treatment methods have different degrees of defects, especially the large area, high power consumption, difficult equipment management or treatment effect is not obvious, which makes it difficult to promote.

It has good economic and environmental benefits to treat the sewage from catering industry with polymeric ferric sulfate. At present, the price per ton of PFS is 600 yuan. According to the amount of 200ml per ton of wastewater, the cost of treating water reagent per ton is 0.12 yuan, which is lower than that of air flotation, biological rotary table and biochemical aeration. This method has the advantages of convenient operation, less floor area, fast sedimentation speed and easy filtration, and has low requirements for equipment. On the basis of oil and slag separation, the sewage treatment can be completed by adding agitator and sedimentation tank, and adding filter or filter cotton at the outlet. On the other hand, PFS is a by-product of pickling waste liquid, which will play a positive role in comprehensive utilization, pollution control and environmental improvement.