Thompson, M J (2023) Environmental sustainability of small wastewater treatment systems and pathways for improvement. PhD thesis, University of Nebraska - Lincoln, USA.
Abstract
Wastewater treatment protects society and the environment by reducing pollutants generated from communities prior to discharge into local water bodies. Small water resource recovery facilities (WRRFs) represent the majority of centralized wastewater treatment systems, are resource intensive, and often lack resources needed to evaluate sustainability improvements. The goal of this dissertation was to identify primary sources and drivers of environmental impacts in small WRRFs and exploration of pathways to improve their environmental sustainability.Case study data collected from small WRRFs in Nebraska was analyzed using environmental life cycle assessment (LCA) to quantify the environmental impact of facilities and existing opportunities. This included comparing the use of mechanical WRRFs and lagoon systems, agriculture water reuse, energy efficiency improvements, on-site solar energy, improved design sizing, collection system rehab, and recycling.Lagoons exhibit smaller environmental impacts relative to mechanical WRRFs but use significantly more land. Construction phase impacts are larger for lagoons causing results to be sensitive to system lifespan and electric grid mix.Net positive environmental benefits were estimated for seven lagoons using treated water for agricultural with increased crop yields providing the most value. Design sizing and seasonal precipitation variations drive impacts due to coinciding effects on lagoon supply and cropland demand. Impacts are sensitive to changes in agriculture land air emissions.Data was collected for 35 site-specific energy efficiency (E2) recommendations and three on-site solar renewable energy systems. Improvements in energy efficiency (e.g., aeration control) showed the largest emission reduction per dollar invested and shortest paybacks. On-site solar systems provide the largest environmental footprint reduction while having less operational involvement, greater resiliency, and less uncertainty in terms of sustained benefit.Synthesis of six research studies that included a total of 52 WRRFs highlighted that most environmental impacts, both from embedded infrastructure and operations are effectively “locked in” during the conceptual and detailed design phase of a facility. Most notably, technology choice and detailed design decisions affect the process control capability and consequential operating resources.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Thesis advisor: | Williams, R; Zhang, T; Li, Y and Lane, K |
| Uncontrolled Keywords: | renewable energy; sustainability; uncertainty; water resource; construction phase; life cycle; precipitation; reuse; variations; energy efficiency; design decision; environmental impact |
| Index terms: | design phase, dissertation, construction phase, land, case study, renewable energy system, energy efficiency, recovery, life cycle, recycling, water resource, environmental footprint reduction, environmental impact, process control, payback, variation, exploration, renewable energy, precipitation, environmental sustainability, design decision, pollutant, society, lifespan, crop, solar energy, life cycle assessment |
| Subjects: | climate science, environmental impact, waste management, research dissemination and communication, economic analysis, professional practice, operations management, environmental resource management, land management, health safety and environment, sustainability assessment, communities and social development, control systems, value management, data collection methods, material degradation and durability, project delivery, energy systems, real estate economics, sustainability and energy, contractual condition, design practice, environmental engineering, environmental health |
| Topics: | Stakeholder Management, Business Strategy, Research Practice, Construction Materials, Contract Administration, Design Practice, Urban Studies, Sustainability, Health and Safety, Project Management, Engineering Principles |
| Descriptive scope: | 3 PCE |
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