ZERO LIQUID DISCHARGE IN RCF BASED PAPER MILL A CASE STUDY A CASE STUDY VAIBHAV PAPER BOARDS PRIVATE LIMITED Vapi, Gujarat. Presented By Mr. Suresh C. Desai

Total Recycling of Process Water i.e. Zero Discharge of Industrial Effluent resulting conservation of natural resources OBJECTIVE

TECHNIQUES ADOPTED TO ACHIEVE ZERO LIQUID DISCHARGE PAPER MACHINE WIRE PART Number of ShowersOnly one Low Pressure shower drilled to use back water on wire part as knockdown shower. Pressure2 to 3 kg/cm 2 Hole Dia.1.5 mm No. of HolesPitch 3 mm Operation hoursContinuous

PAPER MACHINE PRESS PART No showers utilized on press felts, either fresh or back water. Only chemical cleaning is adopted during shutdown. Fresh water used, is for rinsing. TECHNIQUES ADOPTED TO ACHIEVE ZERO LIQUID DISCHARGE

FRESH WATER ADDITION POINTS Gland cooling at Fan Pump, Refiners and Pressure Screen. All chemicals preparations. Trim nozzles (Edge cutters). The quantum of fresh water is controlled at above points and the fresh water addition is maintained as per the evaporation at dryer part of paper machine. Fresh water is not used in showers at any place of the plant. TECHNIQUES ADOPTED TO ACHIEVE ZERO LIQUID DISCHARGE

RECYCLING SYSTEM ADOPTED GENERATION POINTS OF RECYCLED WATER Decker ThickenerFourdrinier Wire part Press PartVacuum Separators

TECHNIQUES ADOPTED TO ACHIEVE ZERO LIQUID DISCHARGE RECYCLING SYSTEM ADOPTED APPLICATION POINTS OF RECYCLED WATER Pulper. Decker Thickener Shower. Turbo Separator dilution. High Density cleaner fibremizer. Certicleaners rejects pits. Hose tapping for stock preparation, wire part and press part. Knock down shower at wire part.

CIRCULATION OF WATER WAS TOTALLY MODIFIED TO HAVE SHORT & CLOSED LOOP A holding tank collects the recycling water which is excess at (i) all closed loops, (ii) vacuum pump sealing water and (iii) press part drainage. Pulper Thickner Centrifugal Cleaning System Wire Part TECHNIQUES ADOPTED TO ACHIEVE ZERO LIQUID DISCHARGE

OVERALL USE OF RECYCLED WATER 1.White water of wire part drainage is taken at three places i.e. (i) Fan Pump Silo, (ii) Seal Pit No. 1, (iii) Seal Pit No The Fan Pump silo delivers white water along with stock to centricleaner, head box and finally to wire. 3. Seal Pit No. 1 delivers the white water to vacuum pump sealing. 4.Seal Pit No. 2 deliver the white water to knock down shower on wire and starch preparation tank. 5.The over flow water from silo goes to holding tank. 6.The squeezed water from press part goes to holding tank. TECHNIQUES ADOPTED TO ACHIEVE ZERO LIQUID DISCHARGE

OVERALL USE OF RECYCLED WATER 7.The sucked water from felt and sealing water from vacuum pump goes to holding tank. 8.Finally the recycled water from holding tank is utilized completely in pulper. 9.The drained water from decker thickner in excess is collected in a tank and is utilized continuously to decker thickner shower, turbo separator dilution, high density fibermizer, dilution to centricleaner pits and hosing purposes at pulp mill and paper machine. TECHNIQUES ADOPTED TO ACHIEVE ZERO LIQUID DISCHARGE

CHECK LIST FOR MAINTAINING ZERO DISCHARGE 1.Daily monitoring of stock chests level and Decker Thickener water tank level. This will help for increasing or decreasing fresh water addition. 2.Two water samples from wire part on daily basis a) Tray sample from formation zone to find out S.S. P.P.M. b) Sample from fan pump silo to find out S.S. P.P.M. (This is for increasing and decreasing Coagulant, Flocculent and Bentonite dosages.)

CHECK LIST FOR MAINTAINING ZERO DISCHARGE 3.Motor load on wire part for counter checking of degree of refining. This is for control on fines formation. 4.Water consumption of 24 hours for comparison with respect to production and point No.1. 5.Steam consumption of 24 hours for determining condensate usage and fresh water used in boiler house. 6.Holding tank circulation for keeping recycling water continuously in motion to avoid stagnancy. 7.Deposits in system to be checked during shut downs and if found, it is removed with the help of high pressure jets. TECHNIQUES ADOPTED TO ACHIEVE ZERO LIQUID DISCHARGE

THE EFFECTS OF RECYCLING SYSTEM 1.Temperature of recycled water gone up by 48° C to 52° C reducing viscosity, resulting increase in drainage at every point of filtration. 2.Foam generation reduced. 3.Paper quality improved remarkably.

TECHNIQUES ADOPTED TO ACHIEVE ZERO LIQUID DISCHARGE BENEFITS ACHIEVED AFTER RUNNING THE SYSTEM 1.Increase in Yield. 2.Fresh water consumption is reduced. 3.Saving in Electric consumption. 4.Man power saving. 5.Stream pollution eliminated. 6.ETP discontinued. 7.Elimination of slime (Bacterial Growth) resulting in odour free environment. 8.Reduction in chemical consumption.

RECOGNISATION This technology has been investigated, accepted and awarded with National Award for Prevention of Pollution by Department of Environment and Forest and Climate Change, Government of India on World Environment Day, 2014.

I Will Be Happy.... I will be happy and glad to share this innovative and sustainable technology developed inhouse, with all the interested mills and individuals to adopt and replicate the Zero Liquid Discharge in their unit, to save our mother earth and conserve natural resources. Mr. Suresh C. Desai

Thank you ……