A municipal water treatment facility in South Dakota needed to replace aging lime slaking equipment. The new system had to handle quicklime conversion, slurry aging, and soda ash preparation simultaneously, with each tank configured to exact dimensional tolerances matching the facility’s existing piping layout. Eleven separate vessels. Customer-supplied drawings. Twenty-four thousand pounds of stainless steel. One fabrication shop that could do all of it to spec.
Project Snapshot
GSM Industrial fabricated 11 custom stainless steel vessels for a municipal water treatment facility in Brookings, SD: 2 lime slaker tanks with water jackets, 2 slurry aging tanks with water jackets, 1 soda ash solution tank, 1 soda ash prep tank, 1 fine grit classifier, and 4 dosing assemblies. Total material: 24,000 lbs of stainless steel. All welds performed to AWS standards and dye tested for watertightness. All 4 jacketed tanks pressure tested at 40 PSI for 48 hours. Completed and delivered in 14 weeks from receipt of order.
| Client Type | Municipal water treatment facility |
| Project Type | Custom stainless steel tank fabrication |
| Industry | Municipal water treatment |
| Location | Brookings, SD (fabricated in Lancaster, PA; shipped to site) |
| Completion Date | July 2023 |
| Schedule | 14 weeks from receipt of order |
| Primary Material | Stainless steel (multiple grades and thicknesses) |
| Total Weight | 24,000 lbs |
| Number of Vessels | 11 (7 tanks + 1 classifier + 4 dosing assemblies) |
| Weld Standard | AWS; all welds watertight and dye tested |
| Pressure Test | 40 PSI, 48-hour hold on all jacketed tanks |
| Drawings | Customer-supplied |
Water treatment lime slaking systems are not catalog items. Every installation has a different footprint, different connection sizes, different process flow requirements, and different operating pressures for the water jacket circuits. The facility in Brookings had a specific layout that dictated the diameter, height, and nozzle configuration of each vessel. Working from customer-supplied drawings, the GSM team had to break each vessel down into its component parts, fabricate those parts to dimensional tolerances that would allow proper assembly, and then build eleven separate units that all had to fit the same piping and structural layout at the other end of a 1,400-mile delivery.
The lime slaker tanks added a layer of complexity beyond standard vessel fabrication. Each unit required a water jacket, a secondary outer shell that surrounds the tank and circulates water to control process temperature. Every weld on every jacketed vessel had to be watertight to AWS standards and dye tested before the unit could advance to pressure testing. Then each completed jacket assembly had to hold 40 PSI for 48 hours without leaking. Any leak meant the weld was repaired and the 48-hour clock started over. There was no shortcut and no partial pass. The jacket either held pressure for two full days or it did not ship.
The fabrication team began by reviewing the customer drawings in detail before cutting the first piece of material. On a project with eleven units and strict dimensional requirements, fit-up decisions made at the drawing review stage determine whether the assembly goes together cleanly or requires rework. The team identified the critical dimensions for each vessel type, established the fabrication sequence, and set the inspection hold points before shop work began.
The water jacket vessels were built from the inside out. The primary tank shell was formed, fitted, and welded first. The jacket was then fitted around the completed primary vessel, with the connection nozzles aligned and tacked in position before any final welds were run. Every weld was performed to AWS standards and dye tested for watertightness before the jacket assembly advanced to pressure testing. Each completed jacket was then pressurized to 40 PSI and held for 48 hours. Any weld that showed a leak was repaired and the pressure test restarted from zero. No unit moved to final fit-up until it had passed the full 48-hour hold without issue.
The soda ash tanks, the fine grit classifier, and the four dosing assemblies ran parallel to the jacket vessel builds. Staggering the work across all eleven units kept the shop floor moving without creating bottlenecks at any single fabrication step. Final dimensional inspection on every vessel confirmed compliance with the customer drawings before the units were prepared for shipment.
All 11 vessels were fabricated to the customer’s dimensional specifications and delivered to Brookings, SD in July 2023, 14 weeks from receipt of order with no delays. Every weld was performed to AWS standards and dye tested. All 4 jacketed tanks passed the 40 PSI, 48-hour pressure test before leaving the shop. The complete system included 2 lime slaker tanks with water jackets (4 ft. 6 in. diameter), 2 slurry aging tanks with water jackets (5 ft. 8 in. diameter), 1 soda ash solution tank (4 ft. 8 in. diameter), 1 soda ash prep tank (3 ft. 2 in. diameter), 1 fine grit classifier, and 4 dosing assemblies. Total stainless steel: 24,000 lbs. The fabricated equipment supports the facility’s lime slaking process, including pH adjustment, bacteria and virus reduction, heavy metal removal, and water softening for the municipal water supply.
Municipal water treatment equipment does not have room for approximation. The vessels that process drinking water have to meet the dimensional requirements of the installation exactly, and the welds have to hold up in a continuous-operation environment. A fabricator that cuts corners on fit-up or skips pressure testing on the jacket circuits creates problems that show up after startup, not before it.
GSM Industrial has been fabricating custom stainless steel tanks and process vessels since 1983. The team that handled this project has experience across a wide range of tank configurations, including jacketed vessels, classifier systems, and dosing equipment. Working from customer-supplied drawings is standard practice at GSM. When the drawings call out a dimension, that dimension is what gets built.
The facility in Brookings got 11 tanks that met their specifications, shipped to South Dakota on a schedule that supported their installation timeline. That is what a fabricator is supposed to do.
“Jacketed tanks have to be right twice: once when you build them and once when you test them. Every jacket on this job was pressurized to 40 PSI and held for 48 hours. That’s the standard we hold ourselves to on water treatment work. Fourteen weeks from order to delivery, no issues.”
Tom Busser, Account Manager – GSM Industrial
A lime slaker tank is a vessel used to convert quicklime (calcium oxide) into slaked lime, or calcium hydroxide, by reacting it with water. The resulting lime slurry is used in municipal water treatment for pH adjustment, disinfection support, heavy metal removal, and water softening. Lime slaker tanks are typically jacketed to control the heat generated during the slaking reaction.
The reaction between quicklime and water is exothermic, meaning it generates heat. A water jacket, a secondary outer shell that circulates water around the main tank, manages that heat to keep the slaking process within the required temperature range. Without temperature control, the reaction can become unstable, affecting slurry quality and equipment longevity. On this project, every jacketed tank was pressure tested at 40 PSI with a 48-hour hold before shipment to confirm weld integrity under operating conditions.
Yes. GSM regularly fabricates custom vessels, tanks, and process equipment from customer-supplied drawings. The team reviews drawings in detail before fabrication begins to identify dimensional hold points and confirm that the fabrication sequence will produce the required geometry. Customer-supplied drawings are common on replacement projects where new equipment must match an existing installation footprint.
GSM works with a range of stainless steel grades depending on the application, including 304, 316, and 316L. For water treatment equipment, 316L is often specified for its improved corrosion resistance in contact with process chemicals. Material selection is driven by the customer’s specification and the chemical environment the vessel will see in service.
GSM can fabricate complete multi-vessel systems, as on this project, or individual replacement vessels. For system projects, fabricating all vessels in a single shop run ensures dimensional consistency across the units and allows the team to manage the delivery schedule as a single coordinated project rather than multiple separate orders.
This project drew on GSM Industrial’s custom stainless steel fabrication capabilities and experience with complex multi-vessel process equipment. Learn more about our stainless steel fabrication services and custom metal fabrication capabilities, or contact GSM Industrial to discuss your water treatment equipment project.
GSM Industrial provides custom stainless steel tank fabrication, water treatment equipment fabrication, and related industrial fabrication and field services across Pennsylvania, New Jersey, Maryland, Delaware, and Ohio. Based in Lancaster, Pennsylvania since 1983, GSM holds ASME U and R Stamp certification, AISC certification, and AWS certification. For industrial fabrication projects in the Mid-Atlantic region, contact GSM Industrial at 717-207-8985 or visit gsmindustrial.com.
