CACTUS aims to improve the quality of information available to decision makers who seek to make investment decisions relating to urban sanitation provision in cities and towns.  Decisions about investments in sanitation infrastructure and services are complex and driven by a wide range of factors.  CACTUS works on the principle that there is never a single ‘best’ solution to the question of how to provide effective, equitable and sustained sanitation – the decision will be driven by a variable number of factors, and that different cities and towns and indeed different stakeholders in a given city or town, would place different levels of emphasis on different factors. For example some decision makers would place a higher value on the mitigation of environmental impacts compared to financial costs, while others would have different priorities.  CACTUS addresses this problem by generating data on three broad characteristics of different sanitation service delivery options, namely, cost (in the form of greenhouse gas emissions), climate and welfare effects.

Funded by The Bill and Melinda Gates Foundation.




Assessment for functional sanitation infrastructure (from collection to treatment)

Developing a standard cost metric and globally-relevant cost comparators for modularized on- and off-site urban sanitation systems. Our comparators will be applicable across geographical regions and in cities and towns with differing demographic and physical characteristics. The metrics will include financial cost, and measures of climate and welfare effects.


Estimate of water use, energy use and GHG emissions in different urban sanitation systems


Assessment of skilled, unskilled and unpaid work in different urban sanitation systems

The Project

The purpose of this project is to develop and promote new tools which can be used to improve the efficiency and effectiveness of investments in urban sanitation in the context of ongoing climate change

Project Timeline

2016 November

Project initiated

Climate and Costs in Urban Sanitation was shortened to acronym ‘C-CUS’, but later changed to ‘CACTUS’
2017 April

Recruitment of 3 post-doctoral researchers

Tristano Sainati, Fiona Zakaria and Sally Cawood were recruited

2017 May

1st team meeting

Collaborated with Gunther Langergraber on CLARA costing tool

2017 August

Fiona and Sally joined in Leeds

2017 September

BMGF MEDS Convening

1st CACTUS poster

CACTUS poster 2018

2017 October

Work plan formulation, technology framework, literature reviews

Technology framework, cost data from literatures

2018 February

Fiona and Sally’s scoping visit to India

Visited BMGF funded FSTP in Dhenkhanal, Odisha – collaborated with Practical Action

2018 March

Comparing lifecycle costs of 4 cases from literature search, compilation of costs of sanitation components

Full system cases from Nonthaburi, Dakar and Cochabamba, ranges of sanitation components cases in USD 2016 (PPP&CPI)

2018 June

Sally-MSc student Mariam’s field research in Dhaka, Bangladesh

Dhaka cost data (emptying and transport), manual emptying welfare case

2018 July

Urban Sanitation Costing Workshop at WEDC Conference in Nakuru, Kenya

2018 September

BMGF MEDS Convening

2nd CACTUS Poster

CACTUS poster 2019

2018 October

Costing, Climate and Welfare Impact Workshop at UNC Water and Health Conference, Chapel Hill, US

One-page CACTUS description

2018 November

China cost data literature search, researcher Zhe Zhan was recruited

China cost data

2018 November

Climate impact from urban sanitation, recruited researcher Jake Johnson

Estimation of greenhouse gasses emissions from on-site sanitation, the case of Kampala City, Uganda

2018 December

Fiona attended Aquaya’s workshop in Nairobi and field research to Kisumu, Kenya

Collaboration with WSUP and Aquaya, Kisumu cost data

2019 February

Fiona’s field research to Nakuru, Kenya

Collaboration with WSUP, Nakuru cost data

2019 April

Fiona’s field research to Accra and Kumasi, Ghana

Ghana cost data (assisted by Water Aid, Clean Team, WSUP)

2019 May

Sally-Mariam’s field research to Khulna, Kushtia, Jhenaidah – Bangladesh

Collaboration with SNV, cost data from 3 cities

2019 June

Literature search for sanitation cost data from Spanish literatures, interns Guillermo was recruited

Contact and references

2019 July

Development of CACTUS database and website. Interns Anna (for database and website) and Valentina (for database programming) were recruited

2019 August

Tristano’s field research to Madagascar

Collaboration with Loowatt, cost data of Loowatt CBS system

Toilet Paper by Mourad Mokrane from the Noun Project
Toilet Paper by Mourad Mokrane from the Noun Project

Shit Flow Diagrams

Access to services underpins the human development project and infrastructure is central to the delivery of those services. We have been leading flagship research to map how unmanaged fecal flows in rapidly growing cities in the global south can travel throughout the city, resulting in high risk of disease and a significant deterioration in environmental conditions. Our 'Shit flow' diagrams are changing the way cities plan ‘Shit flow’ diagrams are changing the way cities plan for sanitation, drainage and water supply interventions.

View and build SFDs