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Continuous Operation of Clarifier as “Save All”

Description

'Save-all' devices (typically drum or disc filter or dissolved air flotation units etc.) that separate solids (fibres and filler) from the process water. An efficient save-all system that produces clarified water with a low suspended solid content is essential to use process water instead of fresh water for select applications. This case study addresses how an efficient ‘Save All’ makes good environmental sense in the paper production process.

Implementing Industry

Daman Ganga Paper Mills is a medium sized company engaged in recycled packaging products. Company produce a range of recycled products such as Paper, Core-Board, Cores & Tubes, Fibre-Drums, Partition Boards, Insulation Boards, Acoustic Boards, etc. The company started its operation in the year 1982, with present production capacity of Kraft Board 60 Tons per day, with annual turnover of 50 Crores.

Implemented technology / technique

 

BEFORE:

  • The surplus flow from different storage / holding systems was going to ETP and was intermittent, thus the clarifier operation was not continuous.

  • The recirculating water quality from ETP to process was very poor due to stagnation of organics resulting in bio-fouling.

  • There was hardly any recovery of fibre, which in turn increased solid sludge generation at sludge dewatering system.

AFTER:

  • The existing clarifier was made into continuous operation as “save all” since March 2014, due to which recirculating water quality is improved from overflow of clarifier. The clarified water is now recirculated to process.

  • Underflow of clarifier is now passing through Sliding Screen for recovery of fibre which is reused into the system. 

  • This reduces the TSS up to 40% in non-recoverable impurities which were earlier going directly to the filter press and finally as sludge.

  • The problem of high sludge generation and its eventual disposal is also resolved. The actual savings are not yet accounted.

  • The recirculating water quality from ETP to process was very poor due to stagnation of organics resulting in bio-fouling.

  • There was hardly any recovery of fibre, which in turn increased solid sludge generation at sludge dewatering system.

Environmental benefits

The capital cost invested was negligible, since the TSS level has been reduced by 40 %, the value of recovered fibre is significant.

Contact details 

Mr. Banjul Shah, Director; banjul.shah@damanganga.com