Ten facts to guide municipal waste management thinking

Key components. I illustrate the effect of geographical location on municipal waste composition by using the key components food scraps and paper. For developed countries in Europe, North America and Pacific Asia, the average fraction of food scraps is 0.30, whereas in developing countries of Latin America and Central and South Asia it is 0.70. Paper accounts for an average fraction of 0.31 in the developed countries, and of 0.11 in the developing countries. These are facts to consider when devising or comparing waste management philosophies. As an example, the fight against the landfills in Latin America can only succeed by recycling food scraps.

Long-term targets. Solid waste is an integral part of urban sanitation and as such is subject to numerical targets set out by successive world summits. The global target valid at this time is “Halve, by the year 2015, the proportion of authorized urban settlements not served by sewage and garbage collection”. This target originates from the Millennium Development Goals of 2000 and the World Summit of Sustainable Development of 2002; and the United Nations Conference on Sustainable Development of 2012 tacitly endorsed it. This latter summit invited local governments to move forward beyond 2015 with their own targets. Any city administration that attained the target in the 13 years from 2002 to 2015 can now move on with exactly the same effort and complete sewage and garbage collection in the 13 years from 2015 to 2028. This is a fact. Beyond 2028, there will be no excuse for not collecting all garbage. The summits did not mention destinations for collected garbage. Here is the opportunity for municipal administrations to set their own targets, and bulk tipping should not be an option.

Composition paradigm. The classical method of reporting municipal waste composition takes samples of unsorted material and divides them by substances. This type of data is not suited for reaching management decisions simply because it remains unknown how much of each substance can be separated at the source. Research in Brazil has shown that, after intense coaching, families are able to separate 67% of their trash into 47% biodegradable material and 20% packaging material. This is the fact. It represents what I call the recycling threshold attainable by private initiative. The city administration can direct its efforts to the 33% of trash that is not ‘source-separable’ at this time.

Reverse logistics. This expression refers to a large and very diverse community of private operators who thrive on source-separated material. The fact is that source separation and reverse logistics are interdependent. One cannot function without the other. Research in Brazil has shown that there are customers for all source-separated material. The secret resides in identifying them and organising the collection. Consequently, 67% of municipal waste does not need to go to landfill. It remains for the municipal administration to create the proper stimuli to make it happen.

Learning curves. Source separation is an educational problem and we have to face and solve it as such. Research in Brazil produced the learning curve for lay populations. It provides the number of person-years of sustained guidance to reach and maintain a certain percentage of target behaviour. It also shows that 90% of target behaviour is the maximum expected result. The fact is that coaching is a long-term process. As an example, to bring 150,000 inhabitants of a city up to the point of 85% source-separation of their trash, 82.5 person-years of coaching are required. This is a pragmatic guide for policy makers.

Decentralised composting. This option of recycling biodegradable discards is always alive, but does not happen by decree. Public relations talent is needed to induce the procedure. Research in Brazil has provided precedents of composting operations in schools and condominium complexes. Good quality compost for immediate use in gardening resulted. The bottleneck arises with the need for continuing dedication. This is the fact.

Marketing of horticultural produce. The distribution chain for fruits and vegetables from the farm gate to the dinner table incurs losses that go directly to landfill. Research in Brazil has shown those losses to reach 18% of wholesale turnover. This is the fact. Administrative support is required for both storeowners and consumers to reduce the losses. This support is available in the form of score sheets that tell the stakeholders how to manage the flow of produce with minimum losses.

Proactive legislation. Proactive legal scriptures anticipate undesirable situations. In the case of domestic waste, e.g. a proactive law puts the responsibility for waste on the citizens who produce it. As the ‘product’ waste can only have a noble destination if separated at the source, this separation becomes an unavoidable responsibility of the citizens. As a fact, a proactive law obliges the city administration to reach certain landfill diversion targets in a certain time and to publish regular progress reports. In order to remain modern, the law itself dictates provisions for its regular revision.

Performance indexes. These are an appropriate tool for fostering competition between institutions within the city, such as schools, private clubs, condominium complexes and the like. The competition occurs not only between institutions, but also within any institution that wishes to improve its own index. If used shrewdly by the city administration, the concept of performance indexes can contribute to diversion of waste from landfill. So far, research in Brazil has experimented with the following indexes: food scraps index (bio-waste/purchased food), waste production index (kg/(person × day), waste sorting index (sorted waste/total waste). The results are facts that do not leave room for excuses.

Large-scale composting. This item is appropriate for closing the list, because it determines success or failure of landfill diversion in emerging economies, now and in the future. The present thinking model of waste managers rejects the idea of centralised composting for economic reasons. The argument is that the compost price does not support the production facilities. Consequently, all biodegradable material in Brazil (70% of municipal waste) ends up in the landfills. With this attitude, landfill diversion stagnates or simply fails. Here resides the greatest challenge to waste management thinking. Research has produced some encouraging preliminary results. Accounting procedures for compost sales and avoided tipping fees at landfill have shown that source-separated biodegradable matter can compete favourably on the recycling market with cardboard and steel cans. This is the fact. If the opportunity cost of the landfill were included in the calculation, the situation would improve further. At this level of revenue, existing composting enterprises can consider entering the market for domestic food scraps. Admittedly, the challenge lies in collection. Research in Brazil has produced a set of preliminary procedures. Creative thinking and exchange of ideas will move us forward.