The client, a leading Pulp and Paper mill in India enjoying the status of being largest Pulp and Paper premises of Asia for a long time, has a biological wastewater treatment process comprising MBBR as Pre treatment unit followed by Conventional activated sludge for the treatment of Pulping effluent. The plant has a capacity of 30-35 MLD. Existing MBBR has been filled with plastic BioChip MBBR media having 900 m2/m3 surface area. The MBBR is expected to achieve 50-60% COD reduction while remaining COD is to be reduced in the Activated sludge process downstream of MBBR.
Due to inherent issues related to the production, the plant is continuously receiving varying qualitative and quantitative fluctuations of wastewater which is disturbing the process in the MBBR and reducing its COD reduction capability. Further, the production facilities are also undergoing continuous expansion for higher production which requires higher treatment capacity for the biological wastewater treatment plant.
Major Problems Faced:
- Shock loads disturbing the process
- Reduced COD reduction
- Poor process recovery after the shock load disturbance
Due to presence of activated carbon and higher inner porosity with very high surface area, Levapor carriers offer much better protection against toxic shock loads.
Based on our previous experience, following solution was offered:
- Transfer all existing plastic Bio Chip to MBBR2 making its filling ratio to 20%
- Add Levapor carriers in MBBR1 at 10% filling ratio with 320 m3 media
Over the past one year, the process has now stabilized much and the results are improved to as per the clients requirement achieving consistent COD reduction at the MBBR outlet.
COD reduction achieved
Amit Christian, having MSc degree in Environmental Science from UK university is in the field of water and wastewater treatment from 1998. He has expertise in MBBR and IFAS process design, engineering and process start up /commissioning.