Cookie tracking notice
Are we allowed to crumble with cookies and anonymous tracking?

We use cookies on our website. Some of them are essential for the operation of the site (so called session cookies), while others help us to improve this site and the user experience (tracking cookies). We use the application Matomo and the external service etracker to analyze your behavior on our website anonymously. Because we value your privacy, we are here with asking your permission to use the following technologies. You can change your settings any time via this link or the menu item in footer menu. For more information visit our Data Policy

Development of an In-Situ Faecal Sludge Solar Dryer at Pilot-Scale - WRC Final Report of the Project K5/2897


Published in: 2023
Pages: 140

Water Research Commission


Uploaded by:
Santiago Septien Stringel

Partner profile:
University of KwaZulu-Natal


 Location of library entry

The present project (K5/2897) was about the development, testing and evaluation of two prototype solar thermal drying technologies for the treatment of faecal sludge, namely a greenhouse-type solar dryer and a screw conveyer, and it included a pre-feasibility study.
The prototype testing showed that, temperatures between 35 and 45°C could be obtained with peaks up to 50°C, as well as relative humidities lower than 40%, leading to favourable conditions for drying. The prototypes were capable to handle material from viscoelastic consistency (paste-like aspect) to granular solids, but they were not adapted to a too watery feedstock. Under the most favourable weather and operating conditions, the feedstock could be dried in the prototypes at drying rates around 1-2 kg/h/m2, efficiencies up to 30-70% and a specific energy consumption of 100-400 kWh/ton, which is lower than the typical values found in conventional thermal driers (800 and 1000 kWh/ton). The drying rate drastically slowed down at the last phase of drying and the specific energy consumption increased to values superior than 800 kWh/ton, which was presumed to be due to remaining moisture being tightly bounded to the solid matrix. The screw conveyer solar drier shown a higher performance than the greenhouse, but it experienced serious stickiness issues that can compromise the long-term operation of the prototype. This stickiness issues were attempted to be mitigated by mixing the sludge with additives. So far, lime addition to the sludge was observed to diminish the stickiness problem but not yet in a significant way.
Based on a techno-economic analysis, it was estimated that the cost to treat one tonne of sludge would be approximately ZAR600 and ZAR150 for the greenhouse and screw conveyor solar thermal drying prototypes, respectively. Some potential technical challenges and areas of improvement were identified after the testing of the prototypes. The operation of the prototypes can be further optimised, which will lead to a further decrease of specific energy consumption, as well as the design specification for the reduction of the construction costs.
This study confirmed that solar thermal drying is an interesting cost-effect alternative for faecal sludge treatment. In the developed solar driers, the drying of faecal sludge is expected to occur at the optimal time and at low energy consumption when the weather conditions are favourable, and with the correct operating conditions. The process could be stopped at low moisture content before reaching a high level of moisture boundness where drying progresses very slowly and the process becomes inefficient.

Bibliographic information

Santiago SEPTIEN STRINGEL, Pareshin NAIDOO, Akhil RAMLUCKEN, Freddie INAMBAO, Craig MCGREGOR, Jon POCOCK, Anusha SINGH (2023). Development of an In-Situ Faecal Sludge Solar Dryer at Pilot-Scale - WRC Final Report of the Project K5/2897. Water Research Commission

Filter tags

Camps (emergency or longer term) Energy: fuel (liquid or solid) English Faecal sludge treatment processes Faeces or faecal sludge Fertiliser Peri-urban Practitioners Recommended by SuSanA (other than SuSanA publications) Research publications Rural Sanitation systems and technology options (WG4) Schools Sub-Saharan Africa Urban (entire city) Urban informal settlements (slums)


Development of an In-Situ Faecal Sludge Solar Dryer at Pilot-Scale

Format: pdf file
Size: 9.61 MB

Share this page on    

Follow us on    

SuSanA Partners  currently 400 partners

Networks Circle


Latest SuSanA Blog Articles

  • 26-03-2024Alice Brandt ,Mascha Kaddori:
    Let’s get wild: Water, sanitation and hygiene at the human-wildlife interface »
  • 21-03-2024Tabeer Riaz:
    Empowering Young Women Water Professionals in South Asia: Leading the Wave of Change »
  • 12-03-2024Beauty Mkoba:
    Unlocking the potential of African Women in STEM through mentorship »
  • 08-03-2024Gloria Mariga :
    Mentorship empowers African women to lead environmental stewardship »
  • 05-03-2024Josphine Gaicugi:
    Achieving access to adequate and equitable sanitation for all is no mean feat »
  • 01-02-2024Sanitation for Millions:
    Toilets Making the Grade® school competition – A Competition where all Participants are Winners »
  • 24-01-2024Anne Fetscher,Jörg Felmeden:
    The sustainable use of tap water (in Germany) and the power of education. An Interview with Dr.-Ing. Jörg Felmeden »

SuSanA Blog »

SuSanA newsletter

Stay informed about the activities of SuSanA and its partners. The SuSanA newsletter is sent out around four times per year. It contains information about news, events, new partners, projects, discussions and publications of the SuSanA network.

Subscribe to newsletter »




Resources and publications

Our library has more than 3,000 publications, factsheets, presentations, drawings etc. from many different organisations. It continues to grow thanks to the contributions from our partners.

Add item to library »

The three links below take you to special groups of items in the library for more convenient access:


The project database contains nearly 400 sanitation projects of many different organizations dealing with research, implementation, advocacy, capacity development etc. Advanced filtering functions and a global map are also available. Information on how and why this database was created is here.

People working for SuSanA partners can add their own projects through their partner profile page. You might need your SuSanA login upgraded for this purpose. Please contact us if you would like to add a project.

Trainings, conference and events materials

Missed important conferences or courses? Catch up by using their materials for self study. These materials have been kindly provided by SuSanA partners.

Shit flow diagrams, excreta flow diagrams (304 SFDs worldwide)

Shit flow diagrams (SFDs) help to visualize excreta management in urban settings. Access SFDs and more through the SFD Portal.

Emersan eCompendium

Humanitarian Sanitation Hub

Sanitation Workers Knowledge and Learning Hub




Discussion forum

Share knowledge, exchange experiences, discuss challenges, make announcements, ask questions and more. Hint: Your discussion forum login is the same as your SuSanA login. More about the forum's philosophy »

Integrated content

We are hosting content from some other communities of practice and information-sharing portals. This section also provides a link to SuSanA's Sanitation Wikipedia initiative.

Suggest content to add »

SuSanA partners

Not yet a SuSanA partner? Show your organisation's support to SuSanA's vision and engage in  knowledge sharing by becoming partners.

Apply to become a partner »

Individual membership

Register as an individual member of SuSanA free of charge. As a member you can interact with thousands of sanitation enthusiasts on the discussion forum.  You can also get engaged in one of our 13 working groups and our regional chapters. Our FAQs explain the benefits further.

By getting a SuSanA login you can fully participate in the SuSanA community!

Register as a member


Forgot your password?
Forgot your username?