Abstract : Research on the Nature-by-Nature Process for wastewater treatment can provide significant economic, social, and environmental benefits to the Laem Phak Bia Environmental Research and Development Project. The project has been on-going since 1991, but there has not yet been any meaningful quantitative studies of the aforementioned benefits, particularly those focusing on potential contributions to making management of the project (budgetary management or implementation of the stated policy goals) more efficient, or to assess its impacts. Generally, comprehensive quantitative evaluation of the impacts of research is crucial to determine the success of research investments. Consequently, the over-arching objective of this study was to assess the impact of this research work based on the benefits derived from the project. The benefits were categorized and aligned by user group: Phetchaburi Municipality, Laem Phak Bia Environmental Research and Development Project, the local community and immediately surrounding area, residents within the project area, and individuals interested in learning about wastewater treatment systems. Evaluation of the research benefits evidenced a net present value of approximately 155 million THB (Thai baht), with a 2.02 ratio of benefit to cost, and 36% internal rate of return. Although this assessment focused on benefits within one province within Thailand, this type of research project has global significance and value.