Abstract: A method for treating fluoride-containing waste water is disclosed. The method includes, first, inducing fluoride-containing waste water and calcium compound into a crystallization reaction tank having a plurality of crystallizing webs so as to conduct a reaction between the fluoride-containing waste water and the calcium compound to form calcium fluoride crystals on the crystallizing webs; meanwhile, stirring the fluoride-containing waste water and the; then, discharging the fluoride-containing waste water out of the crystallization reaction tank for conducting a successive treating step.

Abstract: A system of sludge dewatering is described. The system comprises of a filter press, a sludge fee pipe, and acid feed pipe, and exhaust pipe and a discharge pipe. The sludge feed pipe is configured on the filter press. The acid feed pipe is connected with the sludge feed pipe. The exhaust pipe is connected with the sludge feed pipe. The discharge pipe is configured on the filter press. The system of the present invention can lead the acid solution into the filter press by the acid feed pipe so as to use in situ way to proceed filter cloth washing of the filter press.

Abstract: A drained water recovery system of a process device and recovering method thereof is provided. The recovering method includes using a conductivity meter to measure the conductivity of the drained water so that the drained water with different degrees of conductivity are channeled to different pipelines. Furthermore, another conductivity meter and a total organic carbon analyzer together with an interim tank liquid level controller sorts out the recovered water. Thereafter, according to the properties of the recovered water, the drained water is re-used to improve recycling efficiency.