Unit 7: Faecal Sludge Management

Expected Study Load : 8 hours.


This unit deals with the transport and treatment of faecal sludge produced from conventional on-site sanitation (mainly pit latrines and septic tanks).

This unit goes hand in hand with the earlier unit on Conventional on-site sanitation (C2U2_Lecture_Presentations).

Faecal sludge is produced at household level or from public toilets, institutions and businesses which use toilet types related to conventional excreta management systems, i.e. mainly flush toilets connected to septic tanks, pit latrines, VIP latrines and pour flush latrines.

Faecal sludge production from conventional on-site sanitation systems will increase in the future, due to an increase of non-sewered informal settlements in cities in developing countries. Also the fact that the improved pit latrines are taken up in the list of the MDGs, but the treatment of the sludge is not, will add to the problems related to faecal sludge.

One remaining problem of faecal sludge treatment is how to treat the liquid fraction in such a way that it has a quality suitable for discharge or reuse. The biggest issue related to the liquid fraction is the high ammonia concentration in combination with a high salinity. This stems of course mainly from mixing with urine.

Now, it is possible to take up faecal sludge management (FSM) in an ecological sanitation concept. Codigestion with organic solid waste is studied more and more, and biogas production is very well possible (see assigned readings and extra material).

FSM Closed Loop Approach

Transport of faecal sludge is already a well know source of income. Also the digging of a new pit next to the old one including shifting of the FS from the old pit to the new is a business opportunity. The trick now is to make also the management of FS into a business opportunity, rather than the transport alone.

The material was put together by Doulaye Kone, who is from Burkina Faso but used to work for Sandec in Switzerland.

Learning Objectives:

After completing this unit, you will:

  • understand the main problems with the current (lack of) faecal sludge management in most cities of developing countries
  • know the characteristics of different types of faecal sludge and how these are produced
  • know the aims of an appropriate (sustainable) faecal sludge management (FSM) system (creating barriers to disease transmission and closing the loop)
  • know of possible faecal sludge treatment options (for the solids and the liquid fraction), including some basic design and performance parameters
  • have an overview of the financial, legal and institutional challenges in FSM
  • understand how FSM can be integrated into an ecosan approach (e.g. safe reuse of treated faecal sludge in agriculture)

Frequently Asked Questions:

  1. What is faecal sludge management and why is it important?
    Faecal sludge management is the safe management of faecal sludges from on-site sanitation systems such as septic tanks and pit latrines. The sludges can be of different consistencies as they may include only excreta or a mixture of excreta and water. The safe and efficient transport, treatment and reuse of the faecal sludge are all parts of the management system. An efficient, well established and sustainable faecal sludge management system is essential in cities where pit latrines, septic tanks and other on-site sanitation systems are widely used.
Last modified: Saturday, 8 May 2010, 12:50 PM