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How Do You Clean a Stormwater Management Pond (SWMP)?

Jul 17, 2012

 

 

The Challenge - Cleaning a stormwater management pond (SWMP) without having to drain the pond first.

 

The Aquatech Solution The simple answer is that we combine the pumping and excavation into one process. As Aquatech always stays current with new technologies to service its clients, in this case we would employ Dragflow Pumps which are designed to pick up solids, mix them into a high density slurry and pump them all in one straightforward operation. This equipment can pump as much as 70% solids by weight and readily handle up to 5” diameter solids. It’s an excellent solution for those looking to better manage tailings ponds as well as SWMPs.

 

The Traditional Approach

The conventional method of sediment removal would involve setting up a pumping system to pump or drain the SWMP and filter before then releasing it to an outlet storm pipe. Excavated sediment would then be loaded into trucks “wet”. However if a storm refills the pond, the draining process would then have to start again, and would require the use of filters to protect the storm outlet and creeks. The cycle of pump-off, filter, excavate and transport would continue until the pond sediment was completely removed.

 

The New Method

Prior to starting a complete assessment of the pond sediment area is completed to determine sediment type, density, estimated drying time and total quantity. Site assessment must also conclude whether flocculent will be required and what level of dosage if so. To ensure optimum safety, geo-tubes or tanks must be positioned on level ground. Next, mount the Dragflow Pump with agitator and cutters directly onto the excavator or barge system and initiate pumping.

 

The agitators and cutters are designed to pump large quantities of solids, even when very heavy sediment laden slurries are involved. The pumping goes directly to the holding/drain-off tank or Geo-tubes for appropriate draining and drying. Note that the pumping should be strategically layered for maximizing the compression and draining of sediment. For the final stage, remove the tank or Geo-tube and replace, if required. Thanks to the draining/drying process, the resulting volume and weight of the sediment is dramatically reduced, which naturally shrinks the trucking costs.