② comprehensive medical institutions and other medical institutions disinfection contact pool contact time ≥ 1h, contact pool outlet total residual chlorine 3-10 mg / L.
③ If discharged directly into surface waters and marine areas, should be dechlorinated, so that the total residual chlorine of less than 0.5 mg / L, the use of other disinfectants on the total residual chlorine is not required.
Free chlorine means chlorine in the form of hypochlorous acid, hypochlorite ion and dissolved monomer chlorine.
Combined chlorine combined chlorine means chlorine in the form of chloramines and organochloramines.
Total chlorine means chlorine in the form of "free chlorine" or "combined chlorine", or both.
Chloramines chlorinated derivatives of ammonia with one, two or three hydrogen atoms replaced by chlorine atoms (e.g., monochloramine, dichloramine, nitrogen trichloride) and chlorinated derivatives of organic nitrogen compounds, as determined by standard methods.
Chlorine dioxide interferes with the determination of free and total chlorine, and chlorite interferes with the determination of total chlorine. Chlorine dioxide and chlorite can be corrected by determining its concentration, its determination method see GB/T 5750.11 and GB/T 5750.10.
Two, the use of ultraviolet disinfection, sewage suspension concentration should be less than 10mg/L, irradiation dose of 30-40mJ/cm2, irradiation contact time should be greater than 10s or determined by the test.
Third, the use of ozone disinfection, the concentration of suspended solids in the sewage should be less than 20mg / L, ozone dose should be greater than 10mg / L, contact time should be greater than 12min or determined by the test.
In addition, due to the impact of the epidemic, the ecological and environmental departments to strengthen the supervision of the treatment and disinfection of hospital wastewater, online testing of total residual chlorine in drainage water to meet the requirements of infectious diseases, tuberculosis health care institutions containing chlorine disinfectants, that is, disinfection of the contact pool of the contact time ≥ 1.5h, the total residual chlorine in the contact pool outlet 6.5-10 mg / L. The use of chlorine dioxide disinfection of hospitals is the same requirements, moreover, regardless of whether the discharged into a body of water or into a sewage treatment plant.