Sediment Cleaning of Water Tanks

[Paragraph on water tanks] Return to contents

Problem Statement
The Energy Plant of the University of Idaho is looking for a solution to sediment cleaning for chilled water tank. The current approach is time consuming, expensive, and the chilled water service must be stopped during the cleaning process. The current method requires the tank to be drained to a certain level. Scuba divers are hired to go in the tank and remove the sediment with a vacuum. The total cost of the operation is close to $300,000. Water is wasted when it is removed, and the water needs to be chilled to the correct temperature once the tank is operating again. Return to contents

Project Goals

 * Identify the components and properties of the sediment
 * Design a device to remove sediment from tank
 * Create device that can clean sediment while tank is operating
 * Separate the sediment from the water and return the water to the tank
 * Find a way to make it a self-powered system
 * Build a small scale prototype
 * Create detailed drawings of the full scale model with bill of materials

Design Specifications
Small Scale Prototype Design Specifications Full Scale Prototype Target Specifications
 * Create a semi-transparent tank (no more than 50 gallons) that can validate proof of concept
 * Identify surrogate sediment with comparable density/viscosity
 * Create method for separating surrogate containment from a flow stream that is returned to tank
 * Remove 90% of sediment (by weight) in one hour
 * Devize system for collecting and disposing of sediment
 * Select components/processes that can be scaled up to a size of the chilled water tank
 * Create non turbulent suction in removal device
 * Create evenly distributed suction between each perforation
 * Create automated sediment level detection


 * Bill of materials, drawing, and system diagram that can be implemented by UI facilities staff
 * Means of controlling depth at which contamination is being processed
 * Location for return stream that does not compromise the separation process
 * Remove 95% of sediment (by weight) each time system operates
 * Achieve flow rates of ZZ gpm
 * Reduce sediment load by YY% in WW hours
 * Components fit within the existing tank structure and penetrations

Design Challenges
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 * Obstacles along tank bottom
 * Turbulence can mix sediment into tank water
 * Large amounts of sediment extracted from tank
 * Ability to use design on multiple tanks (some without flat bottoms)

Preliminary Designs
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Team Members
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[[File: .pdf]]
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