The new article about “Application of UAV Photogrammetry for Landfill Management in Developing Countries” has been released.
Application of UAV Photogrammetry for Landfill Management in Developing Countries
Kokusai Kogyo Co., Ltd.
Hiroshi TSURUTA
The Urban Development and Management Group of Kokusai Kogyo Co., Ltd., which leads international consulting in the area of waste management, has been working on the application of unmanned aerial vehicle (UAV) photogrammetry in landfill management.
This article briefly provides some background and introduces some cases in which UAV photogrammetry has been applied in the past five years.
Utilization of ICT in Japan and Application of UAV
In Japan, the concept of “i-Construction” is promoted by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT), with the aim of enhancing productivity at construction sites through the use of Information and Communication Technology (ICT).(1) Demographic issues facing Japan form the backdrop to this, caused by a declining population and an aging society. It is estimated that the working-age population (15-64 years old), which was approximately 75.09 million as of the 2020 population census, will fall to 45.35 million in 2070, according to a medium-fertility projection.(2) In response, a variety of ICT tools are being examined as countermeasures to deal with the future labor shortage that is anticipated. These tools can help reduce the amount of labor expended in time-consuming field work. UAVs are among the ICT tools used in surveying to obtain the shape of the ground surface of areas of interest.(3) In relation to waste management, landfill surveying is often required for landfill management in order to monitor landfill operation and estimate remaining landfill volume.
Landfill Operation in Developing Countries
Globally, about 37 percent of waste is disposed of in some type of landfill, 33 percent is openly dumped, 19 percent undergoes materials recovery through recycling and composting, and 11 percent is treated through modern incineration.(4) Compared with high income nations where material recycling and incineration are emphasized, for economic reasons low income nations can only afford the dumping of waste.(5) While the technology used for waste management systems varies from country to country and city to city, final disposal is an essential component. The first step in improving waste management is the provision of landfills.
One priority for landfill operation is strategically securing sufficient landfill volume by understanding the lifespans of existing landfills and preparing new landfill sites before existing ones become full. This is a top priority for waste management authorities to enable them to prevent open dumping, ensure public health, and create a healthy living environment for communities.
However, there are some cases where landfills are operated without a landfill plan or regular monitoring, and some where the waste management authority does not even have data to calculate the remaining volume and lifespan of its own landfill site. These are critical issues because generally, in order to calculate the remaining volume of a landfill, the following datasets are required: (1) a present ground surface model of the landfill, acquired through surveying; and (2) a final surface model of the landfill when the landfill operation is completed, acquired through the landfill plan. The remaining volume of a landfill is obtained by calculating the space between these two models. Moreover, for the estimation of the lifespan of a landfill, the remaining volume of a landfill is divided by the volume of incoming waste for one year. The volume of incoming waste is obtained by dividing the weight of incoming waste by the density of landfilled waste. Thus, the calculation process is quite simple, but collecting the necessary data is challenging in many cases.
Regular monitoring of field operations is crucial for the safe and sustainable operation of landfill sites over their long lifespans. Further, landfill managers need to take necessary and immediate action when issues are identified. In developing countries, however, many landfill sites are visually monitored only on a day-to-day basis. While such monitoring may be effective for detecting daily issues, it can overlook issues that become apparent over longer time periods. Moreover, a landfill operation typically lasts more than 10 years, and to evaluate it over such extended periods, it is quite important to keep records of the landfill that can be visually understood. The simplest approach is taking photos from the same point and same angle on a regular basis. However, it is not always possible to find points which have a stable ground surface and have a good view for monitoring the situation over the years of landfill operation, since the shape of a landfill site changes over time as operation continues.
UAVs can offer a solution to overcome the above-mentioned difficulties.
Application of UAV Photogrammetry in Waste Management in Developing Countries
The next two sections introduce cases in which UAV photogrammetry was applied in waste management, conducted through technical cooperation projects funded by the Japan International Cooperation Agency (JICA).
Case 1: Monitoring landfill operation in Samoa through the project, “Promotion of Regional Initiative on Solid Waste Management in Pacific Island Countries Phase 2 (J-PRISM2)”
In Samoa, landfill management is under the supervision of the government, while field operation is conducted by private contractors. The government is responsible for supervising the contractors’ performance to ensure sound operation. The duty of the government’s landfill officer is to give directions to the field operator and monitor operation.
In Case 1, a 3D ground surface model based on UAV photogrammetry was utilized for monitoring landfill operation.
For instance, the landfill officer gave firm instructions for soil cover to be applied to improve the situation after a fire accident occurred in 2018. In order to evaluate the progress after 10 months had passed, aerial photogrammetry using a UAV was applied.
By comparing before and after 3D ground surface models, the expansion of an area with soil cover can be visually confirmed.
Fig. 3D ground surface model (left: model as of July 2018; right: model as of May 2019).
<Source> Produced by the Expert Team of “Promotion of Regional Initiative on Solid Waste Management in Pacific Island Countries Phase 2 (J-PRISM2)”.
In contrast to a single photo, a 3D ground model can be freely rotated and the viewpoint can be changed accordingly (zooming in and out). Therefore, with this model a detailed discussion of a specific area of a landfill can be conducted, even off-site.
Case 2: Estimation of the lifespan of six landfills in Indonesia through the project, “Technical Cooperation for Development Planning Project on Regional Solid Waste Management in Gerbangkertosusila Area”
Surabaya Metropolitan Area in East Java Province in Indonesia, where wide-area waste management is under consideration, is facing a shortage of landfill sites. However, because there was no landfill plan before, there was also no quantitative understanding of the remaining volume and lifespans of the existing landfills. In Case 2, six landfills were surveyed using a UAV. Based on aerial photos taken from the UAV, a ground surface model was computed using Structure from Motion (SfM) software and a landfill plan then developed based on the ground surface model. Lastly, the remaining volume and the lifespan of the landfill sites were calculated using the calculation process described above.
In this case, it only took less than an hour to take comprehensive aerial photos of a landfill site and two to three hours to compute the ground surface model with a computer. The only resources required were one drone operator with a consumer model UAV, one to two field assistants, and a computer with SfM software installed.
The figures below show the output from calculating the volume of one of the six landfills surveyed. The results show the remaining volume of the landfill as approximately 304,000m3 if the final height of the landfill is 15 m, and approximately 437,000 m3 if the final height is 20 m.
Fig. 3D ground surface model for landfill volume calculation. Top: current ground surface contour model. Bottom left: Landfill Plan Model (final height: 15 m). Bottom right: Landfill Plan Model (final height: 15 m).
<Source> JICA, “Technical Cooperation for Development Planning Project on Regional Solid Waste Management in Gerbangkertosusila Area Final Report”.(6)
Based on the results of analysis, the decision-maker of Sidoarjo Regency, one of the target municipalities of this project and where the landfill explained above is located, understood that the existing landfill can be used for approximately two to 2.5 years and that they need to start operation of the new one by that time.
Summary
The application of a UAV can thus be a solution to improve landfill operation, as well as for waste management planning in developing countries.
However, there are some points to be considered in utilizing a UAV, such as the following:
- If there are restrictions on the importation of a UAV or the utilization of a UAV in the country;
- If it is possible to obtain permission to operate a UAV above the area of interest;
- The availability of technical staff who have knowledge and technical skills for mission planning, flight operation, 3D data analysis, and landfill volume calculation;
- The availability of basic data on solid waste management (incoming waste amount data, landfill plans); and
- The availability of a budget to procure, maintain, and update a UAV and its software.
It would be desirable for the above points to be clarified so that UAV surveying can effectively assist landfill management in developing countries.
References
(1) Sasaki et al., “Promotion of i-Construction”, 2019 Annual Report of NILIM, p. 91, 2019. Available at: https://www.nilim.go.jp/english/annual/annual2019/pdf_file/3_014.pdf (accessed 28 June 2024).
(2) National Institute of Population and Social Security Reasearch, “Population Projections for Japan (2023 revision): 2021 to 2070 Appendix: Auxiliary Projections 2071 to 2120”, 79p., 2023. Available at: https://www.ipss.go.jp/pp-zenkoku/e/zenkoku_e2023/pp2023e_Summary.pdf (accessed 28 June 2024).
(3) Tateyama, “Special Contribution A New Stage of Construction in Japan – i-Construction”, IPA News Letter, Vol. 2, Issue 2, pp. 2-11, 2017.6. Available at: https://www.press-in.org/_upload/files/Newsletter/Newsletter%20vol.2%2C%202.pdf (accessed 28 June 2024).
(4) Kaza et al., “What A Waste 2.0: A Global Snapshot of Solid Waste Management to 2050”, World Bank Group, 272p., 2018, Available at: https://openknowledge.worldbank.org/entities/publication/d3f9d45e-115f-559b-b14f-28552410e90a (accessed 28 June 2024).
(5) Agamuthu et al., “Do we need landfills?”, Waste Management & Research: The Journal for a Sustainable Circular Economy, Vol. 38, Issue 10, pp. 1075-1077, 2020. 10, Available at: https://journals.sagepub.com/doi/10.1177/0734242X20943036 (accessed 28 June 2024).
(6) JICA, “Technical Cooperation for Development Planning Project on Regional Solid Waste Management in Gerbangkertosusila Area Final Report” (Japanese), pp. 2-70 – 2-71, 2021 April. Available at: https://libopac.jica.go.jp/images/report/12348330.pdf (accessed 28 June 2024).