Step up on sewage treatment

Despite the dangerous consequences that untreated sewage has for our health and environment, Karnataka is leaving much of its sewage untreated. According to the National Green Tribunal’s Central Monitoring Committee (CMC), the state is treating 1,513.5 million litres per day (MLD) of sewage, leaving a larger fraction of some 1,843 MLD untreated. In other words, just 45% of the roughly 3,356 MLD of sewage generated by Karnataka’s cities is being treated, the CMC report says. So where does all the untreated sewage go? It pours into our lakes and rivers. Untreated sewage is the leading polluter of water sources in India, and although this contaminated water is unsafe for consumption by humans or animals or for use in irrigation of crops, it ends up getting used for these very purposes. Contaminated water causes diseases like diarrhoea, cholera, typhoid fever and rotavirus. Diarrhoea alone is responsible for 297,000 deaths per year of children under the age of five, and while the problem of water contamination due to untreated sewage is a global problem, its magnitude is most severe in countries like India, where millions of people living in hutments along ‘rivers’ that carry high levels of sewage consume this water daily.

Read | Only 45% of Karnataka's urban sewage water is treated

Water authorities often say that there is a shortage of sewage treatment plants (STPs). The BWSSB has 24 STPs. This is said to be inadequate to treat the massive amounts of sewage the city produces daily. But even so, the problem seems to be one of under-utilisation of existing capacity because much of that infrastructure is not functional. While authorities build STPs with great enthusiasm, little is done about maintaining them. According to the Central Pollution Control Board, less than half of India’s STPs work effectively. Besides, frequent power cuts result in STPs lying idle for hours.

Treated sewage water can be used for recharging lakes and for industrial and horticultural use. Moreover, experts describe treated sewage as ‘liquid gold’, for which there is demand from industry. By not treating a large fraction of sewage daily, we are not putting sewage to good use. Can its economic dividend at least drive our municipal authorities to pursue sewage treatment more assiduously? While civic bodies need to do more to step up use of available STP capacity, there is also a need to put in place systems and capacity for the long term. Our current sewage treatment system is highly centralised and capital intensive. Governments and municipal authorities must consider treatment systems that are localised and less expensive. They must focus on treating sewage close to the point of generation and enabling its more effective use for toilet flushing and gardening?