Challenge
One of the largest Denim Wash manufacturer in Bangladesh was facing challenges to meet even the flexible local discharge norms due to existing biochemical based treatment, also they were struggling to handle the huge sludge generated in the process.
Customer wanted to increase his existing plant (2.4 MLD to 3.6 MLD) within the limited available space, retrofit the existing plan and meet the stringent ZDHC aspirational discharge guidelines.
Solution
After several pilot studies, Veolia established that a biological based treatment provided by ZeeWeed 500D Membrane bioreactor (MBR) was an effective solution to treat the textile effluent, as it would generate treated water of such high quality that it could be recycled back to the process without any further treatment. Also, due to the space constrain the effluent treatment plant was installed within the building complex.
The treatment scheme includes - screening, pH correction, equalization, aeration, biological (MBR) and sludge treatment processes. ZeeWeed MBR based ETP is designed to receive demin wash effluent with high color, high COD and huge amount of thread and pumice stone.
The ZeeWeed membrane system with a pore size of 0.04 micros can operate in high MLSS concentrations of up to 10,000 mg/L. The membranes are also designed to operate with minimal air scouring using a patented cyclic aeration approach.
Result
- The water outlet quality met the Zero Discharge of Hazardous Chemicals (ZDHC) aspirational guidelines.
- Reduced dependency on fresh water, by recycling treated water back to the process
- Simpler operation and requires less chemical consumption, thus reduce operational cost by 50%.
- Removed color without any pretreatment chemical dosing, thus also reducing the amount of sludge generated.