Material Flow Analysis (MFA)

Compiled by:
Lydie S.A. Yiougo (International Institute for Water and Environmental Engineering, 2iE), Dorothee Spuhler (seecon international gmbh)

Executive Summary

Material Flow Analysis (MFA) is the quantification and assessment of matter (water, food, excreta, wastewater...) and substances (nitrogen, phosphorus, carbon...) mass flows and processes, in a system (city, country, etc.) during a defined period. The principle of MFA is based on the law of matter conservation; flows are expressed in kg/year or in kg/capita/year. The method allows identifying problems and quantifying the impact of potential measures on resource recovery and environmental pollution. It can be used to compare different sanitation technology options regarding their environmental and financial impacts in order to support decision-making for choosing within different sanitation options.

What Is the Material Flow Analysis (MFA)?

The material flow analysis (MFA) method is described in the “Practical Handbook of Material Flow Analysis” by BRUNNER & RECHBERGER (2004). Material flow analysis contains the following main steps:

 

  1. Identification of the key (material flow related) issues.
  2. System analysis (selection of the relevant matter, processes, indicator substances (elements), and system boundaries).
  3. Quantification of mass flows of matter and indicator substances.
  4. Identification of weak points in the system.
  5. Development and evaluation of scenarios and schematic representation, interpretation of the results.

 

Indicator substances”considered for MFA are generally chemical elements such as nitrogen (N) and phosphorus (P), carbon (C) or CO2 and NH3. These substances can be either pollutants (e.g. eutrophication) or resources (e.g. fertiliser in agriculture).

“Goods”represent a substance or a mixture of substances with a function valued by man such as food, solid waste and wastewater.

“Processes” describe the transformation, transport or storage of “goods” and “substances” such as households, wastewater treatment plants or agricultural soils.

 

     FORSTER et al. (2010)

Example of system analysis.The boxes designate processes and the arrows represent the flows. Source: FORSTER et al. (2003)    

How to Do a MFA?

The first and second step of MFA consists in the identification of the key material flows and the setting of system boundaries (selection of the relevant matter, processes, indicator substances). For the indicator substance nitrogen, for example, the relevant “goods” are the inputs and outputs to and from the household, which contain nitrogen: that implies food, excreta, blackwater, greywater and organic solid waste. In order to have an overview of nitrogen pathways at household level, the processes are the household (food and water consumption, digestion, and kitchen wastes) and the on-site sanitation system. Nitrogen containing “goods” are being transformed in these two processes. For example, nitrogen enters the human organism as food (household) and leaves it, after digestion, with the excreta (on-site sanitation system). The system boundaries includes all household activities and the on-site sanitation system.

 

        processes comprise the household and the on-site sanitation system. YIOUGO (2010)

Example of system boundaries at the household level: processes comprise the household and the on-site sanitation system. Source: YIOUGO (2010)       

The third step consists in quantifying “goods” and substance flows in the system. Only the substance-flows (nitrogen-flows in this example) are of interest in this case. “Substance” flows are often calculated based on the mass flows of “goods” and substance concentrations in these “goods”. For example, the nitrogen flow in excreta can be assessed by multiplying the quantity of excreta produced per capita per day with the nitrogen concentration in excreta. Source data can be obtained from literature, estimations, measurements or calculations.

In the fourth and fifth step, the assessed “good” and/or substance flows are represented graphically and interpreted (see picture below). The software STAN (Software for Substance Flow Analysis), which is open source can be used for graphic representation. STAN was developed by the Vienna University of Technology and can be downloaded on the internet for free. It can be used as a base for modelling material flows for the assessment of the economic resources and environmental values of materials (CENCIC & RECHBERGER 2008). The Vienna University of Technology also offers workshops on the use of MFA and STAN; you can subscribe to their newsletter to stay informed. 

 

          Material Flow Analysis with graphic representation of the mass flows. YIOUGO (2010)

Material Flow Analysis with graphic representation of the mass flows. Source: YIOUGO (2010)          

Combating Lack of Data with Expert Judgements

Because of the amount of data needed, the implementation of MFA is difficult in the contexts of developing countries. MONTANGERO (2006) suggested therefore using the method of “eliciting expert judgement” to deal with this problem. Eliciting expert judgement consists in the translation of expert knowledge (subjective judgements) into probabilities for real values (data). Eliciting expert judgement comprises seven steps, the first step consists in the identification of the parameters for which expert assessment is needed; the second step consists in the recruitment of experts; followed by motivating experts; the development of a general model that reflects the experts’ thinking; the training of the experts in probability assessment; the required probability assessments and a documentation of the reasoning behind the assessments; and finally the aggregation of experts’ probability distributions (i.e. if experts’ views on the same parameter differ, it is important to try to understand why they reach different conclusions). Additional knowledge subsequently gained through measurements for example can be combined with expert knowledge.

Applicability

MFA can be used for environmental impact assessments, development of environmental policy for hazardous substances, nutrient management in watersheds, waste management and for sanitation planning.

MFA allows gaining a critical view on resource management including excreta, faecal sludge, wastewater and kitchen waste management and nutrient and water requirements in a city or a country. It is applicable for evaluating the environmental soundness of sanitation options by calculating and comparing the quantity of nitrogen or phosphorus flows within the city for each sanitation technology options. In this way, decision makers can choose the best options which do not pollute groundwater surface water and allow nutrient recycling.

Advantages

  • MFA allows having a critical view of sanitation/water management current status in a city
  • MFA helps to evaluate the environmental soundness of sanitation options
  • MFA can be used as a decision tool to choose sustainable sanitation technology
  • MFA is an ideal technical basis for planning and decision making, especially in developing and emerging countries with limited technical and financial resources
  • In developing countries, MFA has been proven to be a suitable tool for early detection of environmental problems and development of appropriate solutions

Disadvantages

  • Needs a lot of data to be implemented; there are only limited, reliable data available for developing countries
  • There is a need to deal with uncertainties

References Library

BELEVI, H. (2002): Material flow analysis: a planning tool for organic waste management in Kumasi, Ghana. Eschborn: German Technical Cooperation (GTZ) GmbH.

BINDER, C.; SCHERTENLEIB, R.; DIAZ, J.; BADER, H.P.; BACCINI, P. (1997): Regional water balance as a tool for water management in developing countries. In: International Journal of Water Resources Development 13, 5-20.

BRUNNER, P. H.; RECHBERGER, H. (2004): Practical Handbook of Material Flow Analysis. Advanced Methods in Resource and Waste Management. Boca Raton: Lewis Publishers.

CENCIC, O.; RECHBERGER, H. (2008): Material flow analysis with Software STAN. In: Journal of Environmental Engineering and Management 18, 3-7. PDF

LU, L. T.; CHANG, I. C.; HSIAO, T. Y.; YU, Y. H.; MA, H. W. (2007): Identification of pollution source of cadmium in soil: Application of material flow analysis and a case study in Taiwan. In: Environmental Science and Pollution Research 14, 49-59.

MONTANGERO, A. (2006): Material Flow Analysis for Environment Sanitation Planning in Developing Countries: an approach to assess material flows with limited data availability. (= PhD thesis). Innsbruck: Faculty of Civil Engineering, Leopold-Franzens-University Innsbruck.

FORSTER, D.; SCHERTENLEIB, R.; BELEVI, H. (2003): Linking Urban Agriculture and Environmental Sanitation. Duebendorf: Swiss Federal Institute for Environmental Science (EAWAG). URL [Accessed: 18.11.2010]. PDF

Further Readings Library

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CENCIC, O.; RECHBERGER, H. (2008): Material flow analysis with Software STAN. In: Journal of Environmental Engineering and Management 18, 3-7. PDF

This paper explains how to use the Stan Software for the graphic representation of material flows under consideration of data uncertainties.


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MONTANGERO, A.; ANH, N. V.; LUETHI, C.; SCHERTENLEIB, R.; BELEVI, H. (2006): Building the Concept of Material Flow Analysis into the Household- Centred Environmental Sanitation Planning Approach. Conference of Renewed Efforts to Plan for Sustainable Development. European Academy for the Urban Environment and Technical University Berlin, Germany. URL [Accessed: 18.10.2010]. PDF

The paper discusses very first ideas how the method of material flow analysis could be integrated in the Household-Centred Environmental Sanitation Planning Approach.


Case Studies Library

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DAHLMAN. K (2009): Modelling sanitation scenarios in developing countries: a case study in Kumassi, Ghana. Sweden: Uppsala University. URL [Accessed: 22.04.2012]. PDF

This document explains how a model-based on material flow analysis (MFA) and life cycle assessment (LCA) was constructed to evaluate the environmental performance of the scenarios. The variables were nitrogen, phosphorus and organic carbon. The evaluation focused on eutrophication and potential reuse of nutrients in agriculture.


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DO-THU, N.; MOREL, A.; PHAM-DUC, P.; NGUYEN-VIET, H.; KOOTATTEP, T. (2010): Material Flow Analysis – A Tool for Nutrient Resource Management. In: Sandec news 11, 28. URL [Accessed: 18.10.2010]. PDF

This paper shows a case study in Vietnam where a material flow analysis is applied in a rural area.


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KOANDA, H.; GALIERE, P.; YIOUGO, L.; WETHE, J. (2010): Evaluating the impacts of sanitation options on urban water quality by using the Material Flow Analysis method: case of Fada N’Gourma, Burkina Faso. Stockholm, Sweden: Stockholm Water Week. URL [Accessed: 30.10.2010]. PDF

This paper describes how the material flow analysis can be used as a tool to evaluate the environmental friendliness of sanitation options in a middle size city in Burkina Faso.


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KOFFI, P.K.; DONGO, K.; NGUYEN-VIET, H.; CISSE, G. (2010): Optimising Environmental Sanitation in Yopougon, Coete Ivoire. In: Sandec news 11, 28. URL [Accessed: 18.10.2010]. PDF

This document highlights how the material flow analysis method can be use to analyse N and P flows in a district of Abidjan in Côte d’Ivoire in order to develop sustainable sanitation options for wastewater management.


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SCHAFFNER, M.; KOOTTATEP, T.; SCHERTENLEIB, R. (2005): Assessment of Water Quality Problems and Mitigation Potentials by using Material Flow Analysis - A case study In the Tha Chin River Basin, Thailand. Ubon Ratchathani, Thailand: Role of Water Sciences in Transboundary River Basin Management. URL [Accessed: 18.10.2010]. PDF

The paper presents the methodological approach of material flow analysis, as it is used in the specific context of assessing nutrient pollution problems in a tropical, lowland river system, on the basis of scarce and uncertain data.


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THITIPHON, S.; THAMMARAT, K.; MONTANGERO, A. (2005): Material Flux Analysis for Planning of Domestic Solid Waste and Wastewater Management: A Case Study in Pak Kret Municipality, Nonthaburi, Thailand. Thailand: URL [Accessed: 18.10.2010]. PDF

This publication describes problems as well as potential solutions in the field of environmental sanitation based on the analysis of nitrogen flows in the city of Pak Kret, Thailand.


Training Material Library

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FORSTER, D.; SCHERTENLEIB, R.; BELEVI, H. (2003): Linking Urban Agriculture and Environmental Sanitation. Duebendorf: Swiss Federal Institute for Environmental Science (EAWAG). URL [Accessed: 18.11.2010]. PDF

The poster presents material flow analysis as a method to assess the material and nutrient flows in a given system and thus to link urban agriculture and environmental sanitation: The case of Kumasi, Ghana.


Important Weblinks

http://www.iwa.tuwien.ac.at/ [Accessed: 18.10.2010]

STAN software for the graphic representation of material flows can be downloaded for free on this homepage.

http://www.eawag.ch/ [Accessed: 18.10.2010]

This website contains some case studies of material flow analyses in developing countries.