Date of Publication

2025

Document Type

Master's Thesis

Degree Name

Master of Science in Environmental Engineering and Management

Subject Categories

Chemical Engineering

College

Gokongwei College of Engineering

Department/Unit

Chemical Engineering

Thesis Advisor

Kathleen B. Aviso

Defense Panel Chair

Michael Angelo B. Promentilla

Defense Panel Member

John Frederick D. Tapia
Michael Francis D. Benjamin

Abstract (English)

With increasing water scarcity driven by climate change and rising demand for water, reusing treated wastewater for irrigation offers a sustainable alternative to reduce pressure on freshwater sources. However, this requires extensive wastewater treatment system planning, which involves trade-offs between cost, environmental impact, and reuse potential. This study developed a multi-objective optimization model that simultaneously considers treatment technology and scale selection, flow allocation, and uncertainties in decision-making. The model aims to minimize overall cost, reduce greenhouse gas emissions of the system, and maximize reuse for irrigating green spaces. A fuzzy goal programming model with imprecise hierarchies is applied to overcome the challenge of prioritizing competing objectives. Flexible presentation of priority structures or hierarchies alleviates the burden on the decision-makers in determining the exact numerical combination of weights for all objectives. A case study in Hillsborough County, Florida, demonstrates the effectiveness of the model in selecting optimal wastewater treatment locations, technology, service areas, and reuse areas. Results show that using two achievement functions – degree of achievement of fuzzy goals and degree of satisfaction of the fuzzy importance relations provides the decision-makers the flexibility to balance the financial feasibility, sustainability, and reuse for green areas depending on their preference. This study presents a robust and practical tool for optimizing wastewater management planning that considers uncertainties on the perceived relative importance relations among the goals.

Abstract Format

html

Abstract (Filipino)

None

Abstract Format

html

Language

English

Format

Electronic

Keywords

Fuzzy decision making

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Embargo Period

2026

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