Water purification system

A water purification system, comprising:

• a composite filter cartridge comprising a pretreatment filter cartridge and a filter membrane assembly inserted into the pretreatment filter cartridge, the composite filter cartridge being provided with a raw water inlet, a pretreated water outlet connected to the pretreatment filter cartridge, a pretreated water inlet connected to the filter membrane assembly, a pure water outlet and a waste water outlet;
• a raw water inlet pipe connected to the raw water inlet;
• a pure water outlet pipe connected to the pure water outlet;
• a waste water outlet pipe connected to the waste water outlet;
• a pretreated water pipe connected to the pretreated water outlet and the pretreated water inlet, respectively;
• a booster pump connected to the pretreated water pipe;
• a first conductivity sensor connected to the raw water inlet pipe and a second conductivity sensor connected to the pure water outlet pipe, wherein each of the first conductivity sensor and the second conductivity sensor is configured to detect a water flow impedance and generate a frequency signal according to the water flow impedance;
• and
• a single chip microcomputer that is electrically connected to the first conductivity sensor and the second conductivity sensor and configured to receive the frequency signals from the first conductivity sensor and the second conductivity sensor, determine a total amount of dissolved solid materials in the water flow according to the frequency signals, and determine a remaining service life of the composite filter cartridge according to the total amount of dissolved solid materials and a predetermined service life of the composite filter cartridge.