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Full-Text Articles in Engineering
Moving Bed Biofilm Reactors: Evaluation Of Geometry, Attachment Surface Material And Biofilm Populations On The Uptake Of Ammonia And Synthetic Organic Contaminants In Wastewater., Patrick D. Mclee
Civil Engineering ETDs
Plastic biofilm carriers are used in biological wastewater treatment to encourage the attachment and retention of microorganisms that metabolize pollutants. The following research was conducted to better understand how different characteristics of the biofilm carrier affect the treatment performance of the attached biofilms in moving bed bioreactors. Lab scale reactors were used in this study to grow nitrifying biofilms in reactors with contrasting and controlled conditions. The effect of surface geometry on nitrification performance was evaluated by testing commercially available moving bed bioreactor media that contrast in physical design, and by varying operational parameters. Additionally, mature biofilm from a similar …
Hydrogeochemical Investigation Of Recharge Pathways To Intermediate And Regional Groundwater In Cañon De Valle And Technical Area 16, Los Alamos National Laboratory, Brendan W. Brady
Civil Engineering ETDs
In aquifers consisting of fractured or porous igneous rocks, as well as conglomerate and sandstone products of volcanic formations, silicate minerals actively dissolve and precipitate (Eby, 2004; Eriksson, 1985; Drever, 1982). Dissolution of hydrated volcanic glass is also known to influence the character of groundwater to which it is exposed (White et al., 1980). Hydrochemical evolution, within saturated zones of volcanic formations, is modeled here as a means to resolve the sources feeding a perched groundwater zone. By observation of solute mass balances in groundwater, together with rock chemistry, this study characterizes the chemical weathering processes active along recharge pathways …
Rejection Of Low Molecular Weight Neutral Organics By Reverse Osmosis Membranes For Potable Reuse, Lauren N. Breitner
Rejection Of Low Molecular Weight Neutral Organics By Reverse Osmosis Membranes For Potable Reuse, Lauren N. Breitner
Civil Engineering ETDs
Factors such as increasing population, urbanization, and climate change have made the management of water resources a challenge for many municipalities. Water reuse, especially direct potable reuse (DPR) of treated wastewater, is increasingly seen as a potential source of water for communities facing water shortages. Due to improvements in analytical capabilities as well as concerns regarding toxicology of contaminants of emerging concern (CECs), the need for investigating the removal of CECs has become crucial for further DPR considerations. Reverse osmosis (RO) has been demonstrated to remove many CECs. Many studies, however, have investigated the removal of well-known CECs, often with …
Comprehensive Silica Removal With Ferric Compounds For Industrial Wastewater Reuse, Ehren D. Baca
Comprehensive Silica Removal With Ferric Compounds For Industrial Wastewater Reuse, Ehren D. Baca
Civil Engineering ETDs
Cooling towers, integrated circuit (IC) manufacture and reverse osmosis (RO) generate copious amounts of wastewater high in colloidal and reactive silica inhibiting on-site or synergistic reuse. Silica present in cooling water can reach solubility limits via evaporation and form impervious scale on heat transfer surfaces that decreases efficiency. When water is treated by RO operating at high rejection, silica forms difficult-to-remove scale on the membrane feed side in the form of glassy patches and communities of aggregate particles, inhibiting aspirations for zero liquid discharge. Current methods for silica scale mitigation include abundant dosing with chemical antiscalents or complex operating schemes. …