Techniques and technologies for decontaminating chemically contaminated premise plumbing infrastructure
Notice bibliographique
Résumé
Recent large-scale drinking water chemical contamination incidents in Canada and the U.S. have affected more than 1,000,000 people. In all cases premise plumbing has become contaminated and disparate plumbing decontamination approaches have been applied. Premise plumbing components include the service line and piping within the building as well as various appurtenances (i.e., tanks, valves, fixtures). The overall research goal was to identify techniques and technologies that can be used for premise plumbing decontamination. To achieve this goal two separate studies were conducted and are presented as two independent thesis chapters. The study described in Chapter 1 was designed to understand current knowledge associated with premise plumbing contamination and create a rationale for science based water flushing protocols. Objectives were to (1) review past premise plumbing contamination incidents and the decontamination approaches applied, and (2) develop and test a mass balance water heater model. Thirty-nine drinking water contamination incidents were identified that involved a wide range of contaminants. Results showed that plumbing system design, operational conditions, contaminant properties, as well as building inhabitant safety have not been fully considered in premise plumbing flushing protocol design. Flushing could decontaminate some, but not all plumbing systems and poorly designed procedures likely caused residents to become ill during some incidents. Several water heater modeling scenarios showed that contaminant levels could exceed drinking water health limits after flushing and water saving fixtures, devices, water heater size, and flow rate affected contaminant removal efficiency. The study described in Chapter 2 was conducted to examine the effectiveness of surfactants to decontaminate plastic plumbing components. Objectives of this study were to: (1) determine the impact of Alconox® detergent, Dawn® soap, and MAG IT DG 100 surfactant solutions on the strength, dimension, and mass of ethylene propylene diene monomer (EPDM), cross-linked polyethylene (PEX), high-density polyethylene (HDPE), and low-density polyethylene (LDPE) plastics, and (2) determine the effectiveness of Alconox® detergent solution for decontaminating PEX-a and copper pipes exposed to crude oil contaminated water. Results showed that MAG solution constituents, at room temperature, permeated all plastics within 3 days, but EPDM was the most affected (+45% weight; +43% volume; -82% tensile strength). Results of these studies provide a better understanding of premise plumbing contamination as well as decontamination techniques, approaches, and technologies. In response to future drinking water contamination incidents, premise plumbing decontamination procedures should be based on water heater modeling, pilot-, and field-testing. Also recommended is that flushing procedures be developed that consider system design, operation, organic contaminant properties, and building inhabitant safety. In particular, plastic components exposed to crude oil contaminated water pose a unique challenge to returning contaminated plumbing to safe use. Additional decontamination studies are recommended that involve other plastics, contaminants, and surfactants. Studies should also examine the role of temperature and flow/mixing on decontamination effectiveness. Results from this study show that current decontamination practices can degrade plastics (e.g., mechanical strength, oxidative resistance) and can leave residual surfactant compounds in the plastics. While in-situ cleaning of plastic plumbing components is preferred, component removal and replacement should be considered. (Abstract shortened by ProQuest.)
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,001 |
| Méta-épidémiologie (sens large) | 0,000 | 0,001 |
| Bibliométrie | 0,002 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,002 | 0,002 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».