Tannery ZLD

Tannery ZLD

Tannery ZLD****Tannery Industrial Wastewater Treatment with Zero Liquid Discharge — Saudi Arabia

Capacity: 500 m³/day · Recovery rate: ≥95% water · 0% liquid discharge

Tanneries produce some of the most challenging industrial wastewater on earth — laden with chromium, sulfides, high salinity, intense organic load, and dyes. For this Saudi tannery, environmental regulations demanded zero liquid discharge. We delivered an end-to-end ZLD train that turns toxic effluent into reusable water and a stable solid salt cake.

The Treatment Train:

1.Pretreatment — DAF for fats and suspended solids · chromium oxidation/reduction (Cr⁶⁺ → Cr³⁺) and precipitation for selective recovery · sulfide oxidation

2.Biological treatment — high-MLSS MBR for COD/BOD removal and biological nitrification, producing membrane-grade effluent

3.Membrane concentration — multi-stage RO recovers ~75–80% of permeate as reusable water

4.Brine concentration — MVR (mechanical vapor recompression) evaporator further concentrates RO reject

5.Crystallization — forced-circulation crystallizer produces a dry salt cake for offsite disposal or potential resale

Outcomes: 100% of treated water reused in tannery process operations, cooling towers, and sanitary applications · zero liquid discharged to environment · chromium recovered for potential reuse · solid waste only — no liquid effluent · full compliance with Saudi General Authority of Meteorology and Environmental Protection (GAMEP) standards · significant reduction in groundwater consumption.