Challenges in planning faecal sludge management systems

Empty faecal sludge drying bed (Image: Lars Schoebitz; Flickr Commons)
Empty faecal sludge drying bed (Image: Lars Schoebitz; Flickr Commons)

Sanitation targets for SDG 6 can only be met if the focus expands from just access to the full cycle of sanitation – access, conveyance, treatment and re-use. Fecal sludge treatment or septage management is increasingly being recognised as an effective and appropriate method to scale urban sanitation systems to achieve safe sanitation, particularly in small towns and cities. As implementation progresses, data-based evidence is emerging, highlighting the challenges faced on the ground, and the requisite planning necessary to address them.

A recent paper ‘Planning fecal sludge management systems: Challenges observed in a small town in southern India’ presents the findings, challenges and possible ways ahead from a study conducted to provide data for Fecal Sludge Management (FSM) planning for a small town in a state in southern India.

With the idea of understanding the nature of containment structures and on-ground desludging practices, 8,001 households and 1,667 establishments were studied in Periyanaicken-Palayam (PNP), a non-sewered Town Panchayat in Coimbatore District, Tamil Nadu, to provide evidence for effective decision-making.

This study was undertaken to help the urban local body to design, plan and execute an effective fecal sludge management plan for the town. It targeted 100 per cent coverage of all households and establishments, complemented by a mapping exercise. Given this, the objectives of the study were:

  • To understand access, containment and on-ground desludging practices to enable more effective planning.
  • To prepare a GIS-linked database of properties (households and establishments) and help build a spatially explicit database of containments and networks for conveyance and access that could be updated/tracked over time.
  • To provide spatial and non-spatial inputs for effective decision-making.
  • To validate the appropriateness of the selected locations and sizing of the treatment systems.


The findings show that considerable progress has been made in the provisioning of access to toilets. Only a small percentage of households practice open defecation, and need to be provided with individual, shared or community toilets. The key challenge in PNP (and illustrative of urban India) is to move households up the sanitation ladder.

FSM planning needs to be cognizant of variations in containment systems

While the corrections for some deviances such as ensuring access to containment systems by putting a removable lid are easier to carry out, other design deviances are more complicated. For example, many structures reported as septic tanks did not have a soakaway, but most of these structures behaved like leach pits, and hence would not require a soakaway. Single pits could be an adequate solution in the interim if adequate distances are maintained from drinking water sources Containment systems require improvement, but rather than recommending the construction of new septic tanks, a more nuanced plan for retrofitting and improvement is required.

The findings highlight the need to pay attention to the containment systems, and this necessitates a two-pronged strategy: to ensure that new containment systems are built according to standards (BIS, 1985aBIS, 1985b), and that existing ones are retrofitted or upgraded. This still leaves open the question of retrofitting existing on-site sanitation systems. A requisite containment improvement plan at the household level with technology options and low-cost improvements could be devised.

It must be recognised that any containment improvement plan would require substantial time and effort for scaling. The immediate priority should be to safely secure the fecal sludge that is being emptied by ensuring proper conveyance and treatment. In addition, FSM planning for other parts of the chain – de-sludging and treatment – needs to account for the variance in containment systems, until they are retrofitted/upgraded.

Methodological difficulties exist in data collection on containment systems.

The findings highlight a ‘response bias' (Lavrakas, 2008) in household surveys about containments – where containment structures that are reported as ‘septic tanks’ may not function like septic tanks.

The respondent bias is due to multiple reasons: inadequate understanding amongst residents about technical terms used to describe containment systems; respondents not being in a position to observe the construction or repair of the containment; and a high proportion of tenants in the study area who may not know details about the construction. All these biases affect survey results, as well as estimations such as dimensions of containment systems and their functioning.

Data collection regarding containment systems is further complicated by the fact that they are located underground. Data regarding the structures e.g., size and porosity of the structure, and presence of partitions is household reported data which the team tried to cross-verify through observation. However, only some features could be ‘observed’; for the other, the septic tanks need to be opened, and there was resistance to do so from households.

One of the ways to overcome/compensate for this is to triangulate data collected at the property level (households and establishments) by gathering information from other stakeholders. Discussions with masons are likely to reveal local practices of construction, as well as a sense of dimensions. Further, to understand de-sludging frequency, information can be triangulated by speaking with de-sludging operators.

ULBs, who require such data for planning, may not be able to conduct a Census or detailed study. A simpler database could possibly be built through a sample study based on transects (Center for Applied Transect Studies, 1988). One could also start with a basic database of containment structures such as a simplified version of the current study and refine the database with data collected as and when each unit is de-sludged.


The learnings from the study point to a series of checks and steps that need to be taken to achieve and sustain SDG 6. Providing access to toilets, which government programmes such as Swacch Bharat Mission have kickstarted, and inculcating/ensuring their use which has been emphasised earlier as well, are only the beginning. The wider mandate of the SDGs, which includes the treatment of wastewater, requires practitioners, planners and administrators to broaden the scope of urban sanitation.

The findings confirm what is generally accepted by practitioners based on anecdotal evidence – that there is significant deviance from prescribed standards in construction practices of OSS. Responses recorded as ‘septic tanks’ could actually be structures that behave as ‘holding tanks’ or ‘leach pits’. As the first link in the FSM chain, containments are a vital point of fecal disposal. Any variation in containment systems will have cascading implications for design and planning for subsequent parts of the chain. These findings are thus critical to design an appropriate scaling strategy for FSM.

This paper highlights the need to pay more attention to containment systems, a part of the chain often ignored. More work needs to be done to devise methods and practices to ensure that new containments are built to a standard, and those old ones are retrofitted. Further, it is necessary to understand the implications of containment systems for FSM planning to avoid the over-estimation of capacities.

This paper also points to a larger point that planning for relatively new areas like FSM must be grounded in the local context and realities. While thumb rules and standards are useful and can provide a baseline, it is essential to validate these with practices on the ground given local contexts.

Also, any containment improvement plan will require engagement with households and establishments. Therefore, there is an increasing need to pay attention to the communication around FSM; the Kakkaman campaign in Tamil Nadu is a good example.

Finally, this paper calls for increased attention to data collection methods to ensure effective planning. Large scale data sets like the Census in India are based on resident reported data, and hence are likely to be affected by respondent bias, in particular in the reporting of ‘septic tanks’. For instance, Census (2011) reports that 67 per cent of households in PNP are connected to septic tanks; but this study undertaken in PNP shows that in reality, most of these are not likely to function as septic tanks.

A case could be made that large, generic data sets like those of the Census need to be supplemented by local data collection efforts for planning. There is a strong need to develop and implement methods for measurement which are simple and scalable, incorporating aspects of socio-economic nature of households/neighbourhoods and sub-surface character. While possibilities have been suggested in the paper, this is an area that requires much research and innovation.

The full report can be accessed here