| |
|
 |
Salamanca, Mexico -- A city of 500,000 people 130 miles northwest of Mexico City, faced a major wastewater dilemma. The city had to have a new municipal treatment facility to assure water safety and to manage its environmental responsibilities. The biggest industrial asset of the city is an oil refinery, which is also a source of large volumes of wastewater each year.
Normally, each entity would have had to find its own wastewater plant, at considerable expense. But through cooperation and careful planning, the city and the oil refinery found the needed solution by combing resources in one plant. The result is an example of how industry and government can work together to handle effluent costs-effectively. The installation was completed by some problem-solving technology and the staff of Columbian Steel Tank Company, a U.S. manufacturer of storage tanks for liquids and dry bulk matter.
The company provided 20 tanks for this project, which was designed and installed by Agua Mejor, an engineering, design and construction company headquartered in Guadalajara, Mexico.
All the tanks are of bolted construction, with concrete pad or steel flooring and open tops. They are used as clarifiers and digesters, biological reactors, aeration tanks, and dry bulk silos. The largest tank is 130 ft in diameter and 18 ft high. Four are 98 ft by 28 ft, three are 98 ft by 15 ft, and one is 68 ft by 28 ft high. Eleven others are of varying sizes.
The facility has a capacity of over 310,000 gpd, and is already running at 80 percent of capacity, with about 35 percent coming from the city and the balance from the refinery. An indication of the efficiency of the treatment plant is the fact that although the refinery has 38 water wells available to meet all the water needs, these wells are not tapped because it is convenient to simply recycle the water through the treatment plant over and over again.
Wastewater from both the refinery and the city is pumped into the equalization tank, which keeps the flow even throughout the purification process. The water is then moved into the dissolved air flotation (DAF) units, which inject the effluent with micro-bubbles of air in combination with a polymer. This traps the oil and lifts it to the surface, where it is raked to the trough collection systems of the tank. The oil mixture is then pumped into centrifugal chambers where gravity separates the oil from the water and polymer.
Effluent from the flotation units is passed to aerobic digester tanks. After this oxidation process, part of the sludge is removed and part is recycled.
After sludge removal, the water goes into the chemical phase of the process. Calcium carbonate is added to clean the water, which then moves to the chlorinator tanks. After chlorination, part of the water is recycled back to the refinery for use in the steam system and the remaining part goes back to the river that runs through the city.
The engineers specified these tanks on the basis of their factory coating, the fact that they can be assembled quickly without welding equipment and welders, the ease of handling and shipping, and competitive costs. Each has a corrosive-resistant factory baked-on epoxy coating and an enamel or urethane exterior. Each tank was shipped from the manufacturer's Kansas City, Kansas plant unassembled in sections, along with all the hardware needed to assemble it at the site. In all, 42 flatbed truck loads traveled to Laredo, Texas, where the tanks were unloaded, cleared through customs, re-loaded and driven to Salamanca.
Mark Workman, chief engineer, made several trips to Salamanca to coordinate technical aspects of the project.
"Agua Mejor's staff worked well with us to make certain the installations were going to match our drawings and specifications," he said. "Any surprises were minor, and usually were due to translation of engineering terms. Then there were the occasional construction snags you always run across, and those don't change much whether you're in the U.S. or Mexico."
Columbian TecTank
5400 Kansas Ave.
Kansas City, KS 66110
Telephone: 913-621-3700
Fax: 913-621-2145 Fax
Email: sales@columbiantectank.com
Web site: http://www.tectank.com
© Copyright 1998 - 2008 Water and Wastewater.com
Top of Page
|
|
| |
| Send news and case
histories to:
news@waterandwastewater.com |
|
|
| |
|
|
|
I Live Newsfeed
I |
|
Increase traffic and add
content to your website
with our exclusive
newsfeed generator.
Our live newsfeed
allows you to
include news
headlines from our
News Center, right
on your homepage.
Headlines update in
real-time, automatically.
Click here to create
your own newsfeed! |
|
| |
|
 |
