Kerala generates 596 million litres per day of untreated urban sewage

Kerala generates about 596 million litres per day (MLD) of untreated sewage in urban areas as of January 2026, according to the estimates by the Local Self-Government department (LSGD).

The State has set up sewage treatment plant (STP) projects for the treatment of 435.83 MLD. The remaining urban sewage of 596.17 MLD is currently treated through various onsite facilities such as septic tanks and bio-digestors, pointed out a report furnished by the Secretary, LSGD, before the Principal Bench of the National Green Tribunal (NGT) on February 13, 2026 in the case pertaining to the compliance of norms relate to solid and liquid waste management.

As per the projected population of 2026, the total liquid waste generated in Kerala is 4,043 MLD (1,032 MLD from urban areas and 3,011 MLD from rural areas). The total capacity of STPs currently existing is 247.08 MLD, including centralised and decentralised STPs at various establishments. According to the previous report submitted before the NGT last year (2025), the then existing capacity was 241.035 MLD, which has now been increased to 247.08 MLD. STPs with a capacity of 15.30 MLD are under construction, while STPs with a capacity 173.45 MLD have been proposed and are currently under various stages of implementation, the report said.

Strategy is ‘network-based STPs’

The government submitted that the strategy adopted is to set up “network-based STPs” at core sanitation zones of urban local bodies, faecal sludge treatment pants (FSTPs) in the fringe areas outside the core sanitation zones of urban local bodies and also rural local bodies.

Authorities have identified 65 land parcels for constructing the FSTPs and STPs with co-treatment facilities. Seven plants have become operational, while 10 are in various stages of construction. The remaining 48 plants are in different stages if implementation such as detailed project report preparation, tendering and land allocation.

The total capacity of such plants, including existing and proposed ones, is about 4,931 kilo litres per day (KLD).

The report stated that there has been an increase in the institutional and establishment-level treatment systems. The capacity has increased to about 105.3 MLD from 99.26 MLD earlier.

The LSGD observed that setting up STPs remained a challenge in view of the State’s unique settlement pattern, geographical diversity, and land availability constraints. Due to these challenges in implementing centralised STP, the State can only rely significantly on onsite sanitation (OSS) systems, including septic tanks and soak pits, it said.