The basic principle of effective wastewater management is a strict limit on the discharge of hazardous liquids to
sewers. Chemical waste, especially photochemicals, aldehydes (formaldehyde and glutaraldehyde), colorants and
pharmaceuticals, should not be discharged into wastewater (see Figure 9.2) but should be collected separately and
treated as a chemical health-care waste. Pretreatment is recommended for wastewater streams from departments
such as medical laboratories. Ths pretreatment could include acid–base neutralization, fitering to remove
sediments, or autoclaving samples from highly infectious patients. Non-hazardous chemicals such as syrups,
vitamins or eye drops can be discharged to the sewer without pretreatment.