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Alsen Remediation Project


The NYS Department of Environmental Conservation (DEC) hired us to install a water treatment facility on land owned by a construction company that was shut down in the mid-1990s. The issue was the company used a type of cement that, when mixed with water, creates a highly caustic byproduct with a high pH level. Because the land is on the Hudson River, whenever it rained, the byproduct would flow into and pollute the river. Our task was to build a 3 million-gallon retention pond to collect the rain water, repair a smaller retention pond, and build a pump station to pump the water to an acid treatment facility that lowers the pH to neutral, making the water safe to release into the river.


An aggressive schedule (we started in mid-August and had a deadline of November 30) combined with a record 40 inches of rain, a tropical storm, and an earthquake, contributed to making this project challenging. In addition, to install the 20,000- pound pump station, we had to dig down 30 feet, which was about 17 feet below the water table. This, coupled with the tough site conditions caused by the weather, required us to closely monitor the excavation and keep the site dewatered.


To keep the job moving forward despite the weather, we made sure our schedule remained flexible and could change based on the weather conditions. We also kept a list of tasks we could do on rainy days to ensure the project stayed on schedule and we met our deadline.


Between the two retention ponds, our client now has a 4 million-gallon water storage facility that treats 200 gallons of water a minute. Before we built the larger retention pond, the smaller pond would fill with polluted water and then overflow into the river, resulting in severe fines from the DEC.

“The second retention pond more than doubles our client’s holding capacity.”

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