Social Return on Investment (SROI) and Operational Guidelines for Wastewater Treatment at Klong Lam Phak Chi: A Case Study of Ying Charoen Market

Abstract

This study aimed to 1) examine the key contextual factors influencing wastewater treatment at Klong Lam Phak Chi, using Ying Charoen Market as a case study, 2) assess the Social Return on Investment (SROI) of the Khid Jak Khlong canal project, and 3) develop operational guidelines for effective wastewater treatment in the area. A mixed-methods approach was employed, incorporating qualitative and quantitative research techniques. The qualitative component involved semi-structured interviews and focus group discussions with five key informants, while the quantitative data were collected from 400stakeholders using purposive sampling. Content analysis was conducted to evaluate inputs, activities, outputs, outcomes, users, and the overall impact of the Klong Lam Phak Chi project. The SROI calculation was based on four key factors: (1) deadweight, (2) attribution, (3) displacement, and (4) drop-off at a 3.5% discount rate. The findings reveal that between 2021 and 2024, the SROI for the Khid Jak Khlong canal project at Klong Lam Phak Chi was 5.2260, indicating that every 1 Baht invested in wastewater treatment yielded a social return of approximately 5.2260 Baht in terms of social benefits and sustainability. This research highlights the adaptability of SROI as a measurement tool, demonstrating its applicability across different organizations, investment contexts, and currencies. The proposed framework could be modified to suit specific projects, providing a valuable tool for decision-makers seeking to enhance social and environmental outcomes.