TerrAqua Resource Management (TARM), subsidiary of Larson Design Group (LDG)

Natural gas wastewater re-use

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When it became apparent the natural gas industry in the Marcellus Shale was going to create a need for treating large quantities of wastewater, the Larson Design Group found itself uniquely positioned to fill that niche creating a subsidiary, TerrAqua Resource Management, which treats for re-use industry wastewater adjacent to its offices at Water Tower Square on Commerce Park Drive.

The company's work with and understanding of agencies such as the state Department of Environmental Protection and Susquehanna River Basin Commission allowed it to foresee the regulatory parameters it would have to work under, said Martin J. Muggleton, Larson vice president of marketing.

The company also had experience designing and permitting wastewater treatment plants, he said. The company applied for and received from the department a zero-discharge permit to treat gas industry wastewater.

Trucks take wastewater to the facility and leave with treated water that is taken to drilling sites, mixed with fresh water and re-used in the hydrofracturing process.

The 'generation one' plant, uses a 'physical-chemical' process to remove suspended solids from the water. A 'generation two' plant is planned and will create 'a high-quality water that can be discharged to the watershed,' Muggleton said. The company will be required to meet DEP discharge standards to do that. Such a plant could be up and running by 2014, he said.

The generation-one plant is 80,000 square feet and contains 98 tanks representing about 2 million gallons of storage. Its treatment capacity is 320,000 gallons a day.

Trucks drive to a spill-proof concrete pad at the back of the building, hook up to an inbound recepticle and unload the wastewater, which is filtered to remove items such as stones, mud and other debris.

The water then is filtered through a silt sack and stored in a lined concrete pit. Two trucks can unload and refill simultaneously in about 30 minutes.

According to Larson engineer Quay Schappell, every truck that pulls into the facility has to complete a manifesto showing the well from which its load was taken. A sample of the truck's contents is taken and analyzed for pH, solids and oil. It also is checked for levels of naturally occurring radioactive material, or NORM, he said.

Water entering the facility is put in tanks where its pH level is adjusted to a level in which chemicals added to the water can react to clean the water. Next, the water enters a 'flocculator' where magnesium, barium, strontium and other materials in the water attach themselves to chemical additives. That produces a material called 'floc' that resembles a gelatin or cottage cheese.

Water is then clarified and sent to holding tanks for re-use. The end product is a very salty water that can be mixed with fresh water to be used for further well development operations.

The floc is compressed to squeeze moisture from it. That process results is a chalky 'filter cake' that is sent as residual waste to a landfill permitted to receive it.

According to Muggleton the the gas industry recognises the importance of recycling drilling wastewater.

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