Pennsylvania Geothermal Well: Floc Logs Drop Turbidity from 5,000+ to 2 NTU

Geothermal drilling often brings crustal water to the surface loaded with dirt, rock, and sediment. Pennsylvania Ground Water Association asked Applied Polymer Systems to design a treatment train for a geothermal well demonstration in State College during PGWA’s 2010 Summer Field Conference. The approach mirrored stormwater dewatering: settle heavies first, then mix site-tested polymer in a ditch, then capture floc on a dispersion field.

A settling pit dropped larger particles before water entered a plastic- and jute-lined mixing ditch with APS Floc Logs® in series. Log type, reaction time, and process came from site water and soil analysis. Treated flow then entered a pipe to a larger jute-lined dispersion field; Silt Stop® powder on the field boosted capture of fine, polymer-charged particles that cling to jute while clear water runs off.

Initial well discharge exceeded 5,000 NTU. After Floc Logs in the mixing ditch and the jute dispersion field, runoff measured 2 NTU; a photo caption in the original case study records another discharge reading of about 7.5 NTU. Polymer-charged sediment remained attached to the matting. All APS Floc Logs and powders have been tested by an EPA-certified laboratory and were shown to be nontoxic to aquatic organisms. The same ditch-and-dispersion-field approach is laid out in the APS mixing system design guide, and a larger dewatering train appears in mixing and reaction chambers along a 300-mile pipeline; browse all APS case studies.