CALCIUM THIOSULPHATE INJECTION SYSTEM

AMENDMENT TWO

The purpose of this Amendment is to answer vendor questions and extend the due dates for quotes:

The due date for quotes is extended to August 17, 2026, at 10:00am EDT.

The Government offers the following supplemental process information in response to a vendor inquiry. No drawings, specifications, or P&IDs beyond the Statement of Need (SON) are available for release. This is a pump skid procurement to replace an existing sulfur dioxide gas dechlorination system. The new skid shall inject liquid calcium thiosulfate (CaTS) into the existing carrier line that discharges the dechlorination stream into the process water culvert/mixing basin; existing SO2 injection hardware is not compatible and shall not be reused. The SON remains the governing document for all requirements.



Q: Do you have drawings, specifications, or a P&ID available?

A: No. No additional drawings or P&IDs will be provided. A site walk is not being offered; the SON is sufficient to scope and quote the requirement. The supplemental process data below is provided to assist with pump sizing and quoting.



Application: Dechlorination of laboratory lake process water prior to discharge.

Chemical: Liquid calcium thiosulfate, 30% w/v (24% w/w), NSF-certified (reference basis: Tessenderlo Kerley CaTS/Captor, specific gravity approximately 1.22¿1.32, approximately 10.4 lb/gal).



Process configuration: Process water (125¿250 GPM, typical approximately 150 GPM) flows from the settling tank into a culvert/mixing basin. Dechlorination is performed on a separate branch (carrier) line that delivers a small slipstream of process water, carrying the metered CaTS, into the same culvert/mixing basin, where blending with the full process stream occurs. CaTS is metered into this carrier line, not into the full-flow process stream.



Chlorine load: Process water is chlorinated with 0.8% sodium hypochlorite to approximately 2.5 ppm free chlorine residual following a 1-hour dwell in the settling tank prior to dechlorination. Representative current reading is approximately 150 GPM at approximately 2.25 ppm free chlorine residual. Offerors should allow for excursions up to approximately 3 ppm at peak flow.

Existing dechlorination duty being replaced: approximately 9 lb/day sulfur dioxide gas.



Estimated CaTS dosing duty (per the manufacturer dechlorination dosage chart, approximately 5.1 gal per million gallons per ppm chlorine at neutral pH, based on the full process flow and chlorine load):

- Typical (150 GPM, 2.25 ppm): approximately 0.10 GPH (approximately 2.5 gal/day)

- Low flow (125 GPM, 2.5 ppm): approximately 0.10 GPH

- Peak (250 GPM, 2.5 ppm): approximately 0.19 GPH

- Peak with excursion (250 GPM, 3.0 ppm): approximately 0.23 GPH (approximately 5.5 gal/day)



The resulting operating band is approximately 0.10¿0.23 GPH, consistent with the high-turndown, low-flow peristaltic metering pump specified in the SON. Estimated values are provided for reference only and do not modify the salient characteristics in Section 4.0.



Chemical storage: Liquid CaTS is supplied and stored in a 275-gallon tote at the storage location; totes are delivered and removed by the chemical supplier as needed. Pump suction shall be configured for tote draw-down.



Utilities and interfaces:

- Power: 115V / 60Hz, single phase, standard NEMA 5-15 receptacle.

- Controls: Facility BMS is Siemens Desigo. Required signals are 4¿20 mA input (dosing speed control) and 4¿20 mA output (flow/status feedback), plus remote start/stop, alarm output, and run/status output.

- Suction: CaTS suction shall be run from the existing 275-gallon tote at the storage location.

- Discharge/injection: The new system shall tie into and inject CaTS into the existing 1/2" Schedule 80 PVC carrier line, which delivers the dechlorination stream into the culvert/mixing basin. The carrier line is a low-flow branch, not the full 125¿250 GPM process stream. Existing SO2 injection hardware is not compatible and shall not be reused; the offeror shall provide a new injection assembly (diffuser/injection quill, fittings, and all materials) suitable for liquid CaTS injection into the 1/2" Schedule 80 PVC carrier line.

All other requirements remain as stated in the Statement of Need.

No further questions will be accepted.
*********************************