HBIS Shigang Runs on 100% Recycled Water with Zero Groundwater Intake: 1.6 m3 per Tonne of Steel, Fractional Crystallization Turns Brine into Industrial Salt

Tree-lined banks, clear water and shoals of fish — this is a corner of the plant site of Shigang, part of HBIS Group. What makes it remarkable is that all water used for landscaping and for the on-site landscape ponds comes from municipal reclaimed water supplied by Shijiazhuang's Jingxing mining district. Shigang relies on reclaimed water as its production source and, through advanced treatment, achieves 100% water recycling without extracting a single drop of groundwater.

The reclaimed water first enters an equalization basin that balances flow and homogenizes quality, then flows into MBBR (moving bed biofilm reactor) tanks, where thousands of white polymer carriers act as “housing” for microorganisms that biodegrade organic pollutants. The biologically treated water, still hard and insufficiently clear, passes through a high-rate clarifier and a V-type filter for further polishing and softening. The resulting effluent can be used for irrigating green belts and washing roads, but reuse in production still requires desalination.

In the production water advanced treatment workshop, ultrafiltration and reverse osmosis membranes perform the core desalination duty, with a filtration precision down to one ten-thousandth of a human hair. Membranes are easily scratched or fouled by impurities, so Shigang developed an efficient online integrated RO membrane sterilization technology, tightly controlling upstream pretreatment indicators to extend membrane life. Six years after commissioning the membranes are still the original ones, saving the company more than RMB 20 million on this item alone.

The water treatment system comprises 39 main process steps and 47 treatment units. Shigang converted years of operational know-how into digital algorithms and built a smart water treatment model that monitors water quality in real time, automatically matches the optimal process and predicts equipment risks — a shift from “experience-driven” to “algorithm-driven” water management. With the model in place, water consumption has been held steady at an average of 1.6 m3 per tonne of steel, among the lowest in China's steel industry, saving 3.5 million m3 of fresh water a year — roughly the annual household use of 25,000 families of three.

The last common industry hurdle on the way to full recycling is the brine rejected by the membrane system. Historically, once water was recovered from this stream, the remaining mixed salt was classified as hazardous waste that could not be reused and was expensive to dispose of. Drawing on experience from the coal chemical sector, Shigang developed a fractional crystallization process that separates the mixed salt into individual salt products. The recovered industrial salt is sold as a by-product to chemical companies, turning a treatment burden into a resource.