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Tools » Delivering services » Sanitation » Faecal Waste Flow Calculator

Please note: this is a beta-version of the Faecal Waste Flow Calculator; this tool is currently being tested in several countries. We invite you to use the tool and send us your feedback. You can send your questions or suggestions to baetings@ircwash.org

What is the tool about?

A pressing concern for authorities in cities worldwide is the ever-increasing volumes of faecal waste amassing in their cities. Even when everyone uses a toilet, human faecal waste captured in non-sewered onsite sanitation facilities often ends up in neighbourhoods, drains, rivers, fields and on beaches. How can cities improve their sanitation conditions? Mapping of shit flows is part of the solution.

This fast and simple-to-use tool offers an easily understood representation of the volumes of faecal waste safely dealt with in a city, at each stage of the sanitation chain and also a scorecard analysis of other more qualitative data on governance and enabling factors.

Why is it important?

Often municipalities and policy makers already know that there are problems with the management of faecal waste in the city. The advantage of the tool is that it is able to confirm these gut feelings by providing the required evidence. The findings of the rapid assessment can reveal some of these serious problems and help city planners raise a number of concerns relevant for sanitation planning. The tool is also able to quantify these challenges; it allows municipalities and decision makers to evaluate the current sanitation situation and see what is most in need of improvement. It helps them to identify possible solutions, map out scenarios and make the most effective use of available funds.

It is particularly useful as an advocacy or influencing tool. National and local government often see faecal waste management as an end-of-the-chain issue instead of an integral part of all the different steps in the sanitation service chain. When budget is allocated to sanitation it is often for infrastructure, like the construction of treatment plants, and much less on making sure the faecal waste actually gets there. Getting insight into what happens with the faecal waste flows from capturing it in a toilet until safe disposal or re-use is crucial to support local government. Thanks to the information generated by the tool local government can plan and budget for faecal waste management based on real problems and risks.

By continuing to use the tool after the initial assessment, there is the potential for a city's situation to be monitored over time. Reports generated can be compared easily since the results will be in the same format.

This tool was produced to fill a gap in the existing tools. At the time (mid-2015) there was no rapid assessment available which looked at faecal waste management in terms of the sanitation chain, and no tool which incorporates both quantitative volumes and the qualitative aspects. The tool was inspired by the visualisation example of the Shit Flow Diagram which was developed by the World Bank/WSP and further developed by the SFD Promotion Initiative.

How does it work?

The tool calculates volumes of faecal waste as well as faecal sludge volumes and assesses what needs to be in place for safe sanitation service provision.The volumes of faecal waste lost between each of the six links in the sanitation chain: capture, containment, emptying, transport, treatment, and safe use or disposal is the main focus of the tool since this will be the main aspect which affects public health and will therefore be of the greatest importance. The capture and containment sections incorporate not only household data but also out-of-home facilities for for instance commuters and travellers into a city. The volume calculations for each link show the decrease in faecal waste (and faecal sludge) volume along the chain, and the tool shows the link where most faecal waste is lost, posing the greatest threat to inhabitants. The tool is also able to quantify these problems, helping to identify possible solutions and map out scenarios. 

Secondary data - accepted by the local stakeholders - is used. This data is collected by working with local government and others involved in sanitation service provision. It is essential to have a cooperative municipality, willing and able to provide information and entry points/contacts for information and spot checks in the field.Then the whole exercise can be undertaken within ten days, including visual reporting.

Scorecards

Although the main focus of the tool is the volume section there are other considerations which have a marked impact on faecal waste management. Government planning, policies and permits all have a bearing on how well faecal waste is dealt with in a city. Detailed investigation for each of the different links will be useful so that the issues in the weakest links can be identified and addressed. These factors are mostly qualitative and as such cannot be studied easily and then represented. In order to show the presence and efficacy of these important considerations scorecards have been created which allocate an overall percentage to each issue showing how well a particular issue has been dealt with in the city.

Scorecards have been created for issues on standards, permits and budgets for each of the steps on the sanitation ladder, apart from the capture phase which is added into the containment scorecard sheet. A safety scorecard is added for emptying and transporting, since these are the links where people are most likely to come into direct and sustained contact with large volumes of faecal waste. Other scorecards are related to the planning of faecal waste management in a national or city-wide view.

How is the tool structured?

The tool is excel-based and consists of a number of sheets:

  1. Predefined input sheets for entering data needed to calculate the volumes and to generate the score cards
  2. Calculation sheets, these are worksheets that automatically calculate the volumes of faecal waste produced and passed on along the six sanitation service chain elements
  3. Overview sheets compiling data from the various sheets
  4. Reporting sheets presenting the findings (volume calculations and score card scores). For presentation purposes we also have worksheets that provide the information needed to develop the shit flow diagrams. These sheets are used to generate the (data for the) shit flow diagrams.

An interface has been developed to make it easier for the user to focus on the data that needs to be filled in and which is required for the calculations. The interface hides the calculations and underlying formulas. The interface has an input menu and a results menu.

The input menu is divided in two main areas: input questions to calculate the volumes and input questions for qualitative information. The input questions for faecal waste volume calculations collect city-wide information on population size, number and types of toilets, information on pit emptying and transportation methods, on treatment plant type and capacity. The questions on capture and containment take residents as well as temporary residents into account, which can be important in cities where there are many tourists, workers from outside the city or students for example. The score cards relate to (government) information on planning, budget, regulations, permits, standards and safety.

The results menu provides diagrams and summaries of the total faecal waste flows and also of faecal sludge flows separately. It also gives a scorecard overview and an overview of the facilities and volumes produced. 

Where has it been used?

So far the tool has been applied in four cities in Asia: Indonesia, India and Cambodia and two in Africa: Burkina Faso and Zimbabwe, as part of the development and field testing process. The whole rapid assessment can be carried out within ten days including the visual reporting. While the tool can be used by everyone - with some orientation - it is still being refined through testing in other locations.

In short

The faecal waste flow calculator:

  • is a tool for engineers, planners and decision makers to get a better understanding of the current situation in a city
  • calculates current and future faecal waste flows on the basis of current population and future predictions
  • provides insight where and how much faecal waste is lost along the sanitation service chain
  • provides the basis for setting sanitation priorities and developing scenarios

It does not, however, assess public health risks, nor is it a precise scientific analytical tool.  

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