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New Mexico State University (2021)

Recovering Microbially and Chemically Safe Effluent from Domestic Wastewater : Algal Pathway Towards United Nations Sustainable Development Goals

Delanka Pedige, Himali Madushani Kanchanamala

Titre : Recovering Microbially and Chemically Safe Effluent from Domestic Wastewater : Algal Pathway Towards United Nations Sustainable Development Goals

Auteur : Delanka Pedige, Himali Madushani Kanchanamala

Université de soutenance : New Mexico State University

Grade : Doctor of Philosophy (PhD) Civil Engineering 2021

Résumé
Today, water scarcity has become a conspicuous challenge not limited to arid regions but a global concern due to ever-increasing population, rapid urbanization, lack of affordable and sustainable water management strategies, climate change impacts, etc. In recent years, reuse of treated wastewater has been recognized as a source of nontraditional and renewable source of water to circumvent potable water shortage to a certain extent while conserving available freshwater sources. However, current approaches for reclaiming reuse-quality effluent continue to rely on the traditional energy- and resource-intensive wastewater treatment technologies and retrofitting them with a series of downstream processes for refining the effluent, rendering the multi-step system cost-prohibitive and unsustainable. On-going work at New Mexico State University has demonstrated an algal-based wastewater treatment (A-WWT) system that has the potential to treat domestic wastewater in a single-step and recover its energy- and nutrient-contents for beneficial use. Even though the A-WWT system has been well-evaluated for energy-efficient wastewater treatment and downstream resource recovery, its potential for recovering reuse-quality effluent has not yet been studied. The current study was undertaken to evaluate the feasibility of producing microbially and chemically safe reuse-quality effluent from the A-WWT system in a sustainable manner. In the first part of this study, a process model was developed and validated to predict algal biomass production and the fed-batch cycle time, t*, required to meet the chemical water quality standards under varying influent concentrations of organics and nutrients. Reasonable agreement was found between the predicted and measured day-to-day concentrations of biochemical oxygen demand (r2 = 0.97 ; n = 40), ammoniacal-nitrogen (r2 = 0.90 ; n =120), and phosphate-phosphorus (r2 = 0.95 ; n =120). The quality of the predictions in this study is comparable to that reported in the literature, but with fewer model parameters. Sensitivity analysis indicated the kinetic coefficient for phosphate-phosphorus reduction as the most sensitive parameter in predicting the fed-batch cycle time to meet all the chemical water quality standards. In the second part, microbial water quality of the effluent produced by the A-WWT system within the fed-batch process time of t* was assessed in detail. Previous studies have documented that the A-WWT system was able to achieve superior removals of pathogenic bacteria.

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Aperçu du document (ProQuest)

Page publiée le 3 décembre 2021