Case Study · Site Water

Holding pond water: recycle-ready without pH adjustment.

Treatability test on red-coloured industrial holding pond water. The objective was to confirm the E-Cell could treat the water for recycle without requiring pH adjustment or chemical addition. Two test runs at different power settings; both produced clear water with dark green flocculant that settled rapidly.

Power Setting #1

100%single chamber

Clear water

110V × 6A

Power Setting #2

50%single chamber

Clear water

110V × 4A

6.90raw

7.73treated

No adjust

Floc Behaviour

Red colour

Dark green/black

Fast settle

The sample

Company personnel provided NEAT with two five-gallon containers of pond water taken from their industrial holding pond. ICP metals analysis was not performed on this sample — previous testing on water from the same source had shown no significant metal concentrations, so the focus of this work was on developing the treatment procedure for the visible colour and turbidity.

The raw pond water had a red colouration and a limited amount of sludge that became visible when the water in the pail was stirred. Initial pH was 6.90 with no odor.

Red-coloured industrial holding pond water sample, pH 6.90 — Raw pond water as received — red colouration, pH 6.90, no odor.

The treatment

The treatment objective was specifically to test whether the pond water could be E-Cell treated without pH adjustment — eliminating the need for a pH probe, caustic metering pump, and associated maintenance in the eventual field installation.

The first five-gallon run used a single-chamber configuration at 110V x 6A, approximately 100% amperage power. Treated water and floc flowed cleanly over the weir — clear water with dark green to black floc that precipitated very quickly.

Powell Water E-Cell chamber with overflow treated water and forming floc — E-Cell chamber during treatment — clear water with dark floc forming.

The second five-gallon run used the same single-chamber configuration but at 110V x 4A, approximately 50% amperage power. The lower power setting also produced clear treated water with the same dark green floc, indicating that the higher power setting was overshooting and that single-chamber operation at reduced power is sufficient.

Comparison of E-Cell treated pond water at two power settings — Comparison columns — 100% power treatment on right, 50% power treatment on left. Both produce clear water.

Floc settling characteristics

The floc generated from both treatment runs settles quickly — useful for sizing the downstream clarification tank in a production system. The dark green-to-black coloration is consistent with iron-based floc forming from the electrocoagulation reaction, encapsulating whatever colour-causing compounds were in the raw pond water.

Detail of dark green floc precipitation — Floc precipitation detail.

Settled treated pond water sample — Settled treated water.

Final treated pond water for recycle — Treated water suitable for recycle.

Multiple treated pond water samples — Treatment series — consistent clear water.

Results

The single-chamber treatment at 50% power was confirmed as the operating point for a production system handling this pond water. Treated water at pH 7.73 is suitable for recycle without further pH adjustment, and the dark floc settles fast enough to be handled in a conventional clarifier.

For shop owners with industrial holding ponds — whether they're collecting site runoff, process water, or stormwater — this configuration provides a path to closed-loop operation without the equipment overhead of a full chemical treatment system.