Data Center Greywater Tank: Capturing And Storing Non-Potable Reuse

A data-center greywater tank stores the lightly used water from staff amenities - hand basins, showers, kitchens - that would otherwise go to drain, holding it as a non-potable reserve for cooling-tower makeup or irrigation. Greywater is cleaner than black water but still carries organics and microbes, so the tank and its pre-treatment must protect the cooling loop. Center Enamel supplies Glass-Fused-to-Steel, Fusion-Bonded Epoxy and stainless bolted tanks with the inert finish and sealed roof that greywater duty requires, delivered to 100-plus countries. The right tank is sized from the amenity load and the makeup balance, not a generic estimate.

Data-center greywater comes from staff amenities rather than IT cooling, so its volume tracks occupancy and shift patterns rather than IT load. The recoverable amount is the amenity flow minus black-water separation, scaled by the makeup demand and storage-loss allowance. Because greywater carries higher organic and microbial load than rainwater, the collection path and pre-filtration must be cleaner than for stormwater to keep pretreatment light before the tank.

• Amenity flow, not IT load, drives volume.
• Occupancy and shift patterns set recovery rate.
• Black-water separation is mandatory.
• Cleaner collection than stormwater reduces pretreatment.

Water stored for reuse, process or fire duty spends most of its life idle, so the internal finish decides reliability more than the shell rating. Glass-Fused-to-Steel panels are fired at 820-930 °C to give a smooth inert skin at 0.25-0.45 mm thickness, adhesion above 3,450 N/cm2 and 100 percent 1,500 V DC spark testing per panel. Fusion-Bonded Epoxy bolted tanks (Resicoat R4-ES interior 180-280 micrometres, Interpon D2015 exterior 150-250 micrometres, adhesion above 16 MPa) and hot-dip galvanized bolted tanks cover specified or cost-sensitive duties. Stainless 304 or 316 is chosen where the recovered water is low-mineral and a factory vessel is preferred. A caveat applies: the right lining depends on the recovered-water chemistry, so the engineer should confirm pH and halide load rather than assume one coating fits every reuse stream.

• GFS bolted: inert enamel, Ra below 0.8 micrometres, no field recoating.
• FBE bolted: documented epoxy lining for specified duty.
• Hot-dip galvanized: lower cost, zinc shell protection.
• Stainless 304 or 316 for low-mineral recovered water.

Sizing starts from the actual duty calculation - rainfall capture volume, cooling-makeup balance, greywater generation rate or fire hydraulic demand - not a catalogue number. The coating thickness of 0.25-0.45 mm for GFS or 180-280 micrometres for FBE, the tank lifecycle of 30-50 years, the NSF/ANSI 61 or WRAS potable-contact option and the freeze or tropical duty margin then set the shell, roof and appurtenances. Every figure below is confirmed against the applicable standard and the local authority having jurisdiction.

The figure below is a REAL Center Enamel delivery used here as manufacturing-capability evidence for the tank type discussed, NOT as a claimed data-center, rainwater, greywater, reclaimed, condensate or ice-storage project. Center Enamel's verified project record (case_library.csv) holds no data-center water-reuse, greywater, reclaimed-water, condensate-recovery or ice-storage delivery, so this reference demonstrates the ability to engineer large coated and stainless water tanks for demanding duty, not a claim about this specific application. Where the source did not record a diameter or height, the field reads Not Provided and is never estimated.

Separate black water at source, screen and bio-filter the greywater, then store it in a sealed tank with an inert lining that resists the organic and microbial load. Keep the greywater loop isolated from potable by air-gap or backflow protection, and balance the tank volume against the amenity recovery and makeup demand so the reserve neither overflows nor runs dry. Confirm the internal finish and the treatment train with the authority having jurisdiction.

• Separate black water at source.
• Screen and bio-filter the greywater.
• Sealed inert-lined tank resists load.
• Balance volume against recovery and makeup.

Lightly used water from staff amenities such as hand basins, showers and kitchens, separated from black water and recovered as a non-potable reserve.

Staff amenities, not IT cooling, so its volume tracks occupancy and shift patterns rather than server load.

Greywater carries higher organic and microbial load than rainwater, so it needs cleaner collection and more pre-treatment before tank storage.

Screening and bio-filtration to control organics and microbes, with disinfection sized to the cooling-tower makeup quality target.

GFS enamel gives an inert skin resisting the organic load; FBE and stainless are alternatives where the recovered water chemistry directs.

Yes - an air-gap or backflow protection must separate the greywater loop from potable systems.

From the amenity recovery rate and the makeup demand, so the tank smooths variable inflow without overflowing or running dry.

Yes - GFS, FBE and stainless bolted tanks with the inert finish and sealed roof that greywater duty requires, delivered to 100-plus countries.

AWWA D103-09 and ISO 28765 for the bolted structure, with NSF/ANSI 61 or WRAS available where recovered water contacts potable-adjacent systems.

About 30 days ex-works for a 1,000-10,000 m3 tank, with on-site bolted erection in weeks versus months for concrete.

A verified single shell of 20,000 m3 was delivered in 2016, establishing the upper bound for one bolted tank.

A sealed, covered roof keeps the recovered water from picking up dust and biological load and limits odour, preserving quality before treatment.

Yes - the lining, not only the steel, should be warranted, because greywater duty stresses the coating over a 30-50 year life.

No - the fire reserve is a separate code-referenced volume and must stay isolated from the greywater loop.

Periodic internal inspection of the lining and verification of screening and bio-filtration support a 30-50 year service life.

A data-center greywater tank stores amenity water as a non-potable reserve, separated from black water and protected by pre-treatment and an inert lining before it feeds cooling-tower makeup. The source separation, buffer volume and air-gap isolation decide whether greywater actually offsets potable draw, and those figures must come from an amenity-and-demand balance rather than a generic estimate.

Suggested CTA: Design a data-center greywater tank with black-water separation, pre-treatment and an inert sealed lining, and balance volume against amenity recovery.