Success Factors and Challenges: Implications of Real Options Valuation of Constructed Wetlands as Nature-Based Solutions for Wastewater Treatment

Abstract

Constructed wetlands (CWs) are engineered water treatment systems that mimic the features and functions of natural wetlands. As a nature-based solution (NBS) for wastewater treatment, CWs are sustainable and cost-effective while providing various ecosystem services. However, their widespread application faces several uncertainties, particularly in developing countries. This study aims to analyze the success factors and challenges in implementing CW projects. Using the case of successful CWs in Bayawan City in the Philippines, this study surveyed 270 household heads from the community benefiting from the CWs and interviewed various CW stakeholders, including the project planner, management, community leader, social workers, and CW workers. The results showed that 89% of the respondents were aware of the existence of CWs in the community and 73% believed in their long-term sustainability. Among the identified factors for the successful implementation of the CW project were government support (43%), good governance (32%), and public support (14%). On the other hand, the implementation was challenged by improper maintenance (63%), overcrowding in the community (11%), foul smells (4%), funding (4%), and climate-related uncertainties, including natural calamities (4%), flooding (7%), earthquakes (4%), and sea level rise (11%). The implications of these success factors and challenges were discussed in the application of real options valuation to CW projects by incorporating the identified uncertainties into flexible decision making in the scaling up and widespread implementation of a more sustainable NBS to water resources management.

Diesel to Solar Irrigation System: Economic, Environmental, and Social Acceptability Analyses by Small-Scale Farmers of Calapan, Oriental Mindoro

“…These results would play a significant role in understanding the barriers and other challenges that hinder the adoption of solar irrigation among marginal farmers. Hence, proper information dissemination is needed to make the farmers more aware of this technology's nature, costs, advantages, and disadvantages to better help them make informed decisions on its adoption [14,42].…”

Household Willingness to Pay for Constructed Wetlands as Nature-Based Solutions for Wastewater Treatment in Bayawan City, Philippines

“…The locally available reed called 'tambok' (Phragmites karka) is used as the vegetation, which is regularly trimmed by phase [26]. The facility was designed for a flow rate of 50 L/person/day for 600 households, with an average of 5 people/household [25]. There are 67 septic tanks, with each serving 6 to 10 houses.…”

“…These also related their monthly incomes with 61% below PHP 5 thousand a month, 32% between PHP 5 thousand and ten thousand, and only 7% above PHP 10 thousand. On the other hand, this reason allowed them to avail of the social services of Bayawan City to stay in the Fishermen's Gawad Kalinga Village [25].…”

“…It can be noticed that the water supply has the highest value among other ecosystem services. This is because the community receives free water from CWs for other household purposes such as construction, ornamental gardening, backyard cleaning, and others [25]. Additionally, the table shows that biomass is another provisioning service, with 33.33% of respondents acknowledging the potential for biomass production within constructed wetlands.…”

“…It can be noticed that this value is lower than the wastewater treatment service of the CWs. This is because the main purpose of the CWs in the Gawad Kalinga Village is to treat the domestic wastewater from toilets and kitchen sinks for ornamental gardening or finally disposing the treated water in the ocean [25]. While the quality of the treated water from CWs is monitored and tested regularly, results should be communicated to the community to avoid biases on these two terms.…”