Seshasayee Paper And Boards Ltd

Interview with Mr.K.Shanmugam, Sr. G M (Environment), Seshasayee Paper And Boards Ltd

Seshasayee Paper & Boards is engaged in the business of manufacture and sale of printing and writing paper. SPBL is the flagship company of SPB-ESVIN Group headquarted at Erode. The company was incorporated in the year 1960, has six decades of experience in the Indian paper industry with a total installed capacity of 255,000 tonnes per annum (tpa)

Paper Desk : How much water is typically used in your paper mill’s production process, and how do you measure and monitor water usage across different stages of production?

K.Shanmugam :

• Venturi type flow meter available to measure intake water for the process from the Cauvery River
• The company has installed Electromagnetic Flow meters to measure and monitor the consumption of water in all the department
• Stringent internal norms have also been fixed for consumption of water by individual department
• A high level water consumption Monitoring cell has been constituted to monitor the water consumption by individual departments regularly.
• In the production Review Meeting being conducted every day, water consumption is also reviewed and proposals, if any, for further reduction of water consumption are also discussed and implemented.
• Continuous efforts are being made by the company to further reduce water consumption.
• The present water consumption is @38-40 m3/ton of paper

PD : What technologies and strategies has your mill implemented to reduce water consumption effectively?

KS :

• Installation of high efficiency Poly disc save all in paper Machine 4 & 5 for back water recycling and fiber recovery
• De-collator for vacuum pump seal water recycling
• Recycling of Bagasse thickener filtrate
• Separate treatment for White water from paper machine 4 and 5 in a Clariflocculator with coagulant dosing
• Collection of RO plant UF and RO reject water in Raw water sump for further treatment
• System for Re use of MF1 and MG paper machine save-all clarified water in wire showers, edge knock off showers, sheet knock off showers in paper machines.
• Installation of new save all system in Yankee paper machine for fiber recovery and fresh water reduction.
• Sealing water collection system for recycling back to the process
• Collection of the raw water clarifier underflow water for further treatment in HRS Clarifier with chemicals
• Installation of a sealing water collection system comprising disc filters
• Installation of mist cooling system for cooling secondary condensate for water recycling.
• Diversion of all the filter backwash water from utility to raw water tank for further treatment and reuse.
• The colored whitewater from MFI,MG and Yankee machines are treated in a separate clariflocculator and reused in ETP, bagasse slushing and in wood log washing

PD : How does your mill approach water recycling, and what percentage of water is generally reused within your production process?

KS :

• All the individual section water consumption is measured with Electromagnetic flow meters and recorded .This is being reviewed in shop floor level and in management production meetings daily.
• A total water audit is made to study the various quality of water from each section for its quality and quantity.
• The quality requirement for the process is studied and areas were identified for replacing fresh water by recycling the treated effluent at source.
• The SRP evaporator primary condensate water sent to condensate polishing unit installed and used in Boiler feed along with DM water.
• The entire evaporator secondary condensate is reused in bagasse pulp mill and in caustisisers by replacing fresh water.
• Reuse of paper machine non colored white water is treated in a separate clariflocculator and the treated water used for RDH pulp dilution replacing fresh water
• Recycling of Paper machine colored effluent is treated in a separate clariflocculator and the treated water used for log washing, ETP and in bagasse preparation..
• All the utility Filters back wash water recollected in raw water sump and treated for reuse.
• RO and UF reject water diverted to raw water sump instead of going to drain.
• In RDH plant pump sealing water is collected filtered and reused.
• All the Machine back water after treating in save-all are taken back to the system
• Totally about 38-40 % of water is collected at source and recycling back to back to the suitable process
• The shower nozzles size is reduced from 1mm to 0.8 mm in VHP Shower to reduce fresh water.
• The filtrate from wet lap machine is recycled back to process

PD : What types of final water treatment processes does your mill use, and how do you ensure compliance with environmental standards?

KS : The mill has approached the treatment of the mill waste water into three categories 1.Low BOD, 2. Medium and 3. High BOD

Low BOD effluent

The white water from all, the paper machines are treated separately in separate clariflocculators with necessary coagulant addition for recycling back to process

High BOD effluent

The bagasse waste water enriched with high COD is filtered in side hill screens with screw press for removal of suspended solids is subjected to anaerobic treatment in the anaerobic lagoon along with the high COD foul condensate from chemical recovery.

The treatment efficiency is 90% reduction of BIOD and COD .The biogas generated is collected in a balloon and burnt in the rotary lime kiln replacing part of furnace oil.

Medium BOD effluent

• Effluent from Recovery, Power house Pulp mill and anaerobic lagoon outlet are collected in the equalization tank and pumped to the primary clarifier of 180 feet dia with 14 feet SWD. The suspended particles settle down and taken to a belt filter and filtered under vacuum
• The removed ETP sludge is being consumed by the mill board manufacturers
• The primary overflow from the clarifier is taken to an aeration basin fitted with 12 nos of 50 HP twin lobe surface aerators to provide dissolved oxygen required for the activated sludge process
• The MLSS, F/M ratio and dissolved oxygen is maintained for efficient working of the process. This is followed with a secondary clarifier to settle the MLSS and recycled back to aeration.
• A portion is treated in the sludge thickener and is wasted after processing through decanter centrifuge.
• Spill control systems are installed in Recovery and pulping areas to collect the liquor spills and recycle the same to process.
• The treated effluent is monitored by Real time data monitoring system connected to TNPCB and  CPCB 24X7
• The clarified final effluent is disposed to lift irrigation societies where the treated effluent is used for raising sugarcane and tree crops like Casuarinas Eucalyptus etc. eliminating the river discharge.
• Final treated effluent is monitored by TNPCB personal and the results are within the stipulated standards prescribed.
• Once in a year this is verified through NABL accredited laboratory.

PD : How does your team maintain water quality throughout the production process, and what challenges do you face in doing so?

KS :

• The Intake well is equipped with good screening system to contain foreign matter like polythene and floating matters.
• The input raw water is subjected to Jar tests to assess the dosing of chemicals and based on the trial result coagulant and flocculent dosing is optimized to achieve process water quality.
• The water quality is poor during summer months and to keep the stringent water quality for boiler feed a separate system with HRSCClarifier, chemical dosing system MGF, Untrafiltration followed with RO. Dm plant etc are installed to cater the needs of ultrapure water.

PD : What are the primary sources of water pollution in your mill’s papermaking process, and what measures are in place to mitigate these effects?

KS : River upstream have dying and tannery industries.

(1) The major pollutants are from pulping of wood and bagasse.

(2) Spill control systems are installed for collection of liquor spills and reuse.

(3) Wasting losses are kept to barest minimum.

(4) The bagasse effluent, starch spills and foul condensate are subjected to Anaerobic treatment to minimize the organic load.

PD : How do fluctuations in water availability, such as during droughts, impact your production process, and what contingency plans does your mill have in place?

KS :

• A barrage is constructed before our intake and sustained water availability will be there for 11 months and during that period our water level will be minimum at our intake point.
• During this period we will additional pumps in intake well to meet out the process demand.
• Restriction of supply of process water to all process department
• We may run colored varieties to restrict fresh ware consumption.

PD : How does your mill handle wastewater, and what methods do you use to minimize its impact on local ecosystems?

KS :

• An innovative lift irrigation scheme is established in the year of 1984 to irrigate about 2140 acres dry and barren lands.
• The treated effluent is being pumped by the lift irrigation societies to their land elevated through HDPE piping network system.
• A water cycle of 10 days once wetting is being done.
• Regular monitoring of soils is being done by Tamil Nadu agricultural University.
• The soil type is sandy loam suited for sugar cane cultivation.
• The scheme envisages availability of sustained availability of irrigation water, availability of Sugarcane raw material for Sugar industry and Raw material bagasse for paper industry.
• Up liftment of rural economy with a vast green cover in the nearby vicinity.

PD : What role does regulation play in water management at your mill, and how do you adapt to changing regulations on water usage and discharge?

KS : Year after year the water consumption of the mill is reduced taking into consideration of the availability of the precious water Trials are already being made by adoption of membrane technology to recover water from the effluent to make it fit for the process applications.

PD : Could you share any recent innovations your mill has implemented in water management, and how have they affected sustainability and operational costs?

KS : Trials are being made with recycling of the EOP filtrate to recover chemicals as well as water with membrane technology to meet out any issues in future.