When India declared itself open-defecation-free, it marked a critical step toward safe sanitation. However, a pressing challenge remains—the effective treatment, disposal or reuse of wastewater and biosolids. Without addressing this, groundwater, waterbodies and rivers remain vulnerable to pollution. This gap is pronounced in small and medium towns that lack faecal sludge treatment plants (FSTPs) and in larger towns where sewerage systems have not kept pace with urban expansion. Tackling this issue requires the installation of stand-alone FSTPs and well-designed co-treatment infrastructure, enabling sewage treatment plants to handle faecal waste.
Faecal sludge management in India has made progress since 2017 when the National Faecal Sludge and Septage Management Policy was released, and the country’s first FSTP was set up in Devanahalli, Karnataka. Today, over 1,500 FSTPs have been built, the majority based on decentralised treatment systems that employ nature-based solutions, such as sedimentation and anaerobic processes, without requiring electro-mechanical treatment.
Uttar Pradesh embarked on its faecal sludge management journey in 2018, starting with FSTPs in Jhansi and other cities under the Namami Gange programme. By 2019, plans were in progress to construct 54 FSTPs and co-treatment facilities in towns identified under the Atal Mission for Rejuvenation and Urban Transformation (AMRUT).
Today, Uttar Pradesh has 59 treatment plants spread across 56 cities. However, the rollout of these FSTPs has revealed significant design flaws. One critical issue is the one-size-fits-all approach to design capacity. Under the AMRUT mission, 35 FSTPs were constructed with a fixed treatment capacity of 32 kilolitres per day, regardless of city size or population. This uniformity disregards the varying sludge loads and population densities in cities like Orai (200,000 population) and Jhansi (700,000 population), resulting in underutilised or overburdened systems.
Moreover, many FSTPs in Uttar Pradesh are over-designed, with redundant modules performing the same function. For instance, 23 of the 39 FSTPs in the state have both screw press machines and unplanted drying beds for dewatering sludge. This redundancy not only escalates capital costs but also adds to operational burdens. In cities like Jhansi, where the dry climate would suffice for natural dewatering through drying beds, the inclusion of mechanical presses was unnecessary.
The issue extends to co-treatment plants as well. Of the 20 co-treatment facilities in Uttar Pradesh, nine have been over-engineered with redundant secondary treatment modules. Co-treatment is meant to dewater septage and send the liquid waste to sewage treatment plants (STPs) for further processing. However, in places like Gorakhpur, the addition of secondary modules—such as anaerobic baffled reactors (a type of septic tank) and phytorid beds (a technique using porous media like crushed stones for wastewater treatment)—unnecessarily duplicates the work of existing secondary treatment processes. The partially treated liquid from these modules is then sent to the STP inlets, where it mixes with untreated sewage, defeating the purpose of waste management.
Another key flaw lies in the design of inlet points at several FSTPs. In cities like Agra, Varanasi, Prayagraj, Ghaziabad and Meerut, the inlet points were incompatible with the desludging vehicles’ outlet pipes. This oversight, unanticipated at the planning stage, led to operational inefficiencies that required additional construction, such as screening chambers, to address the mismatch.
Despite these design flaws, Uttar Pradesh’s experience offers valuable lessons for future projects. Primary treatment, where solid-liquid separation occurs, needs careful consideration based on climate and sludge characteristics. In arid regions, natural drying beds are often sufficient, while humid or cold areas require mechanical dewatering.
Additionally, secondary treatment modules must be appropriately scaled to avoid unnecessary cost escalations. An incremental approach may work better for small and medium towns, starting with smaller-capacity plants that can be expanded as needed.
Co-treatment plants, in particular, should focus solely on dewatering septage, without the secondary treatment of liquid waste. Streamlining this process would reduce both capital and operational costs, making co-treatment a cost-effective option for septage management.
This was first published in the 1-15 November, 2024 Print edition of Down To Earth