Residents' willingness to pay for improved liquid waste treatment in urban Ethiopia: results of choice experiment in Addis Ababa

Abstract

This paper discusses residents’ willingness to pay (WTP) for improved liquid waste treatment in Addis Ababa based on data collected in 2011 using random parameter logit model. Findings indicate that respondents are willing to contribute for improved liquid waste treatment with higher quantity and quality. Their mean WTP for the medium improvement scenario is found to be 15.53 ETB (0.93 USD) per month. The compensation surplus tends to increase from the status quo to the alternative scenarios with aggressive improvement. Finally, the paper concludes by indicating the socioeconomic difference across households, and sub-cities need to be considered in designing environmental protection plans for the city.

Keywords:

• choice experiment
• random parameter logit
• willingness to pay
• liquid waste
• urban environment

Notes

1. Choice experiment scenario. You have been randomly selected from residents who are residing in Addis Ababa to participate in this survey. We are investigating households’ choices for various measures affecting improved sewage treatment plant (in terms of quantity and quality of treated waste water in Addis Ababa). We ask you to consider these factors and the costs for carrying out various measures in the choice questions that follow. There are no “correct” or “wrong” answers. However, priorities have to be made; we ask you to carefully choose between the alternatives below understanding these choices may be difficult, please consider the attributes: quantity and quality of treated waste water. Assume that the levels of these two attributes are independent of each other. Please mark the preferred alternative as if it is the only choice you make. Please feel free to go back and change your choice in a previous question.

The government has prepared a program of improving the waste water treatment facility in the city in order to reduce environmental and health damage that will arise due to direct or indirect contact with untreated domestic liquid waste. There are fundamentally two areas where the government plans to reduce health risk and improve the environmental quality of rivers and their surroundings: increasing the number and the capacity of STPs, the number of customers connected to the sewerage system in Addis Ababa. Improving the river water quality and controlling water pollution through installing sufficient treatment plants and a sewage network compatible with the growing urbanization and population of the city. Besides increasing the amount of treated domestic and non domestic waste water, there will be efforts for improving the removal efficiency of the current and coming STPs that will enable the discharge of very high quality of effluents to rivers.

Hence, such a measure is important for maintaining the overall quality of the environment and overcoming rivers from being highly polluted. Consequently, households and local communities will be protected from environmental and health hazards reduced with this program. If government implements these programs, the river and its surroundings can be used for unrestricted irrigation of crops to be eaten uncooked by consumers, sports fields and public parks and there will be an opportunity to use the sludge as a natural fertilizer. Having pungent /extensive smell and pathogen free surroundings also increases the scenic view of the river and its environment and increases the attractiveness of the area to tourists/visitors and hence other employment opportunities will be created. However, all these plans for the program cost money for the implementation of the program. The government/authority will set an appropriate implementation strategy. There will be stringent enforcement and regulation management systems that will be put in place. There will be essentially two versions of this Sewerage treatment plant improvement program, namely, the aggressive program scenario and a medium program scenario. Under the aggressive improvement program scenario, there will be a very high level quality of treated liquid waste and four STPs with 327 million liter/day working capacity. The medium water quality program brings about (250 million liter/day) coverage with two STPs and medium quality treated liquid waste. Currently, this municipality hosts a conventional STP built in 1985. The capacity of the local STP is 7.5 million liter/day and the workable capacity of 5.2 million liter /day that of the total volume of wastewater generated by the municipality. The concentration of total fecal coliforms, TP and TSS is high in the final effluent and all exceeded the WHO guideline standard. This study is not part of the project. Hence, we would like you to understand that the main objective of the questionnaire is to better understand what the major problems are and what could be done to alleviate these problems.