The treatment plant mechanism

Sensing this danger, the guidelines in the Bio Medical Waste (Management and Handling) Rules, 1998, explicitly state that hospitals should set up Effluent Treatment Plants (ETPs), for treating water that can be reused.

In hospitals that do not have ETPs, the water is chemically treated and released in the common sewage pipeline, provided it is connected to the BWSSB water treatment facilities. Liquid bio-medical waste from the points of generation like the operation theatre, labour ward, laboratory, canteen, laundry and toilet is segregated and let into a common disinfection facility. Here, sodium hypochlorite is added in the required quantity for a prescribed amount of time, so that it is safe to be released into the common sewage pipeline.

In hospitals that have ETP facility, the liquid bio-medical waste is treated using a special scientific process. The water treated here can be reused for practically anything, except drinking. However, different ETPs use different  methods to treat the liquid waste.

The ETP at Jayadeva Hospital is considered a model one. Dr Ravi Shankar, state nodal officer for environment, Karnataka Health Systems Development and Reform Project, who designed the plant, explains that the entire liquid waste from the hospital is collected in a sump that is three-and-half metres deep. It then goes to a collection well that is six-and-half metres deep.

The collection well is next to the ETP and both are located at least 500 metres away from the hospital. From the collection well, the liquid is pumped to the roof of the ETP. From there, using gravitational force, the water first enters the anaerobic and then the aerobic reactors for treatment. When the water is treated in the aerobic reactor, it emits biogas as a byproduct. Through this process, 95 per cent of the pollutants in the water are removed.

The treated water is then released into two filtration units at the ground level, from where it is let out into an area where Cattal plants are grown. These plants absorb the remaining pollutants as nutrition. Finally, the treated water is let into a small well to recharge the water table. The sterile water can also be used for gardening, toilets and laundry.