DEVELOPMENT OF GUIDELINES FOR WATER CONSERVATION IN PULP AND PAPER SECTOR doc

Chapter 2: Industry Profil;e: Pulp and Paper 2.1 Status of Pulp and Paper Mills in India 5 2.2 Classification of Pulp and Paper Mills in the country 11 Chapter 3: Manufacturing Process

{Environment Group}

NATIONAL PRODUCTIVITY COUNCIL

New Delhi (March, 2006)

Chapter 2: Industry Profil;e: Pulp and Paper

2.1 Status of Pulp and Paper Mills in India 5

2.2 Classification of Pulp and Paper Mills in the country 11

Chapter 3: Manufacturing Processes

3.1 Generalised Paper /Paper board making process 16

3.2 Different industrial processes in pulp and paper sector 17

3.3 Chemical recovery from black liquor 36

Chapter 4: Water consumption pattern in other countries 48 Chapter 5: Present Water consumption pattern prevailing

in pulp and paper sector in India

5.3 Water consumption: Norms/Standards for paper and pulp 52

5.4 Water consumption: Latest Trends 54

Chapter 6: Unit Process/operation specific water

consumption factors

6.2 Existing Water Consumption Status 62

Chapter 7: Formulation of Standards for water

consumption by different categories of pulp and paper

manufacturing units

7.2 Proposed categaries of pulp anf paper mills for standards 78

7.3 Proposed types of Water consumption standards 82

7.4 Development of category specific water consumption standards 83

7.5 Proprosed category specific wastewater discharge standards 90

Chapter 8: Water conservation options identified for

different categories of pulp and paper mills

92

Annexure I: Copy of Questionnaire

Annexure II: List of pulp and paper mills in India

Annexure III: Compilation of Questionnaire data

Mr K K Sinha, Senior Consultant

Ms Shukla Pal, SeniorConsultant

Mr S Baskaran, Consultant

From other Regional Offices

Mr Kaliprasad V, Senior Consultant, RPMG, Hyderabad

Mr Hemantha S S, Consultant, RPMG Bangalore

SECRETARIAL ASSISTANCE

Mrs H K Sarna

Mr R.K Ahuja

LABORATORY ASSISTANCE

Mr S K Jain, Laboratory Analyst

Mr Bhupinder Singh Yadav

ACKNOWLEDGEMENT

National Productivity Council (NPC) places on record its sincere thanks to the Central Pollution Control Board for entrusting the study on “ Development of Guidelines for Water conservation in Pulp and Paper sector” NPC is grateful

to Shri P M Ansari, Additional Director, CPCB and Shri S K Gupta, Senior Environmental Engineer, CPCB for their cooperation and assistance at various stages of the project in collecting information from State Pollution Control Boards and in selecting representative pulp and paper mills NPC is also thankful to all State Pollution Control Boards for providing list of operating pulp and paper mills in their respective states

NPC places on record its sincere thanks to all the management of following pulp and paper mills for their full cooperations during conduction of field studies in their mills:

1 M/s Tehri Pulp & Paper Ltd, Muzaffarnagar

2 M/s Shreyan Industries Ltd., Ahmedgarh

3 M/s HNL, Kottayam

4 M/s ITC (PSPD) Ltd., Bhadrachalam

5 M/s Seshasayee Paper & Boards Limited, Erode

6 M/s Indo Afrique Paper Mills (P) Ltd., Pune

7 M/s Pudumjee Pulp & Paper Mills Ltd Pune

8 M/s Shalimar Paper Mills (p) Ltd., Muzaffarnaga

9 M/s The Simplex Mills Co Ltd (Paper Division), Gondia

10 M/s KAWATRA PAPER Mills Ltd., Dadri

NPC also extends its thanks to various pulp and paper associations for providing information on pulp and paper mills operating in India

Last but not the least, NPC is thankful to all those who have been associated with the project studies either directly or indirectly

The pulp and paper industry is one of India's oldest and core industrial sector The socio-economic importance of paper has its own value to the country's development as it is directly related to the industrial and economic growth of the country Although paper has many uses, its most important contribution to modern civilization is its use as a medium to record knowledge

Paper manufacturing is a highly capital, energy and water intensive industry It

is also a highly polluting process and requires substantial investments in pollution control equipment In India, around 905.8 million m3 of water is consumed and around 695.7 million m3 of wastewater is discharged annually

by this sector1

India’s current average fresh specific water consumption of about 150

m3/tonne of product is far above the global best specific water consumption of 28.66 m3/tonne (for large scale wood based pulp and paper mill) and this large gap is primarily attributed to the use of obsolete technology / equipments and poor water management practices

The large water requirements and consumption by the Indian pulp and paper industries has led to, water fast becoming a scarce commodity and lowering

of the groundwater table and thus increased pumping costs and more importantly water shortage in many regions Realizing the importance of water and excessive usages of water by pulp and paper sector, Central Pollution Control Board (CPCB) has taken initiative to develop the water conservation guidelines and water consumption standards and entrusted National Productivity Council to undertake the study to address these issues

India produces 5.96 million tones of paper per year (2003 – 2004) through

309 paper manufacturing mills at a capacity utilization of approximately 60 percent The number of paper manufacturing mills has increased consistently from just 17 in 1951 to around 600 in Year 2002 with an annual installed capacity of 6.2 million to meet the increasing demand However since 2001 –

02, the number of mills have fallen sharply to 309 in the year 2004 primarily due to increased environmental regulatory pressure, water shortage etc

The profile of Indian pulp and paper sector including the various aspects like product consumption pattern, operational scale, state wise industry inventory,

production process used, raw material used is presented in the Figures E-1

to E-3 and tables E-1 to E-3

Table E-1: Consumption pattern of paper and paper board products in

Industrial paper kraft paper, paper board – paper

board - single layer board, multilayer board, duplex board,

electrical grades of paper Newsprint glazed, non-glazed 12%

227

20 57

187 174

21 62

3

22

12 12 0

Producti

on, 104 TPA

Table E-2: Distribution of Pulp and Paper Mills (Number of Mills) Based

on Pulping Processes and Operational Scale

No of Mills Installed Capacity,

Small Scale

Grand Total

Large Scale

% Small Scale

%

1 Chemical Soda

54 0.666 4.26 0.106 18.2

Table E-3 : Summary of classification of pulp and paper sector in

Pape

r Mill3

Wast epap

er

Woo

d base

No type Agro

based

Integrated 2

Pape

r Mill3

Wast epap

er

Woo

d base

on operational scale, raw material used, pulping process, end product etc Detailed studies were conducted in these 10 mills to identify the water conservation measures and also to generate the water consumption profile

The detailed studies in conjunction with the data from questionnaire survey, literature search and international water consumption norms have been used

to develop water consumption standards in the country

Existing Water Consumption Norms / Standards: India

In India so far, no standards have been set for water consumption by any agency However CPCB has prescribed standards in terms of wastewater discharge for different categories of pulp and paper industry The wastewater discharge quantum with additional 21 % (towards evaporation losses) is generally used to give a fair picture of water consumption The wastewater discharge standard of 150 and 50 m3/tonne of product for small agro and wastepaper based mills respectively and 200 m3/tonne for large scale mills prescribed by CPCB do not appear appropriate as it does not cater to different categories of pulp and paper manufacturing mills prevailing in India presently Further, this standard in the current scenario seems to have outdated as the current average water consumption is itself 150 m3/tone of product

As per Corporate Responsibility for Environment Protection

(CREP)-2002, following water discharge standards have been agreed upon by

different pulp and paper manufacturing associations:

A Large scale pulp and paper mills:

¾ Less than 140 cum/tonne of paper within 2 years

¾ Less than 120 cum/tonne of paper in 4 years for mills installed before

1992

¾ Less than 100 cum/tonne of paper in 4 years for mills installed after

1992

This standard is also discharge specific but takes into consideration the operational scale and the age of the mill This standard also does not differentiate on the basis of pulping process, raw material used, end product etc

Centre for Science & Environment through their Green Rating Project has

reported significant reduction in water consumption in large-scale Indian paper mills and average figure has been reduced to 135 m3 per tonne paper

in the year 2002 due to increasing awareness regarding water conservation, ever increasing pressure from government regulatory agencies and also due

to increasing water scarcity in many regions The CSE finding gives an indication that most of the industries are already achieving the water consumption norms as agreed upon by them under CREP programme –

2002

Existing Water Consumption Norms / Standards: World

In developed countries, most of the pulp and paper manufacturing mills are wood based, however, due to environmental implications, trend is changing towards use of recycled fibre as is the case with India

The average water consumption for wood based large pulp and paper industries primarily producing paper & paper board products from 6 regions / countries namely United States, Australia, Europe, Canada Finland & Spain have been compiled from various documents available on the web and the

same is presented in the Table E-4 below :

Table E-4: Region / Country Specific Average Water Consumption in

Large Scale Wood Based Pulp and Paper Mills

Source

(Average value in the year 2000)

Appendix “W” of Report on Status of Pulp

& Paper in US by Michiel P H Brongers and Aaron J Mierzwa

2

Australia 28.66

( Average value for the year 2003)

APIC Public Eco-efficiency Report 2003

APIC Public Eco-efficiency Report 2003

5 Finland 40 Pulp Fact - Environmental Implications of

o

consumption (m3/T of product)

Stolton and Jean-Paul Jeanrenaud WWF International 1996

6

Spain 30 Pup Fact – Environmental Implications of

the paper Cylcle by Nigel Dudley, Sue Stolton and Jean Paul, Jean Renaud – WWF International 1996

The average water consumption for wood based large pulp and paper industries primarily producing paper & paper board products in developed countries varies from 30 – 70 m3/tonne of Product Whereas average water consumption in waste paper based pulp and paper mills

in developed countries varies from 8 – 10 m3/Tonne of product

Current Water Consumption: A Revisit - Questionnaire Response

In order to review present water consumption levels in pulp and paper sector

in India, questionnaires were circulated to all the pulp and paper manufacturing mills Based on the questionnaire responses by industries (44 mills responded out of total of 309), specific fresh water consumption range (excluding domestic) has been compiled and is as given below:

S.No Raw Material End Product

Specific Water Consumption

(M 3 /T of product) Min Max Remark

Large Scale category

3 Wood Based Newsprint only 74 There is only one mill

4 Wood Based Rayon pulp 130

Only one mill in this category responded

5 Agro Based Cultural - high grade 73 -do-

6 Agro Based

Cultural - low grade including newsprint 46 -do-

Medium Scale category

1 Agro Residue Cultural – high grade 102 219

2 Agro Residue Industrial grade 28

Only one mill in this category responded

3

Waste Paper

Based Cultural – high grade 40 -do-

Min Max Remark

based

5

Waste paper

Based Industrial grade 5.5 35

One mill reported 5.5 m3/T & operating with zero discharge system

Small Scale category

1 Agro Residue Cultural - high grade 156

Only one mill in this category responded

2 Agro Residue Industrial 7

Straw board making

mill

3 Waste paper Cultural - high grade 18

Only one mill in this category responded

4 Waste paper Cultural - low grade 14 25

5 Waste Paper Industrial 7 80

Current Water Consumption: In depth Study Findings

Keeping in view, the above mentioned variation prevailing in Indian pulp and paper sector, ten representative mills were selected in consultation with CPCB official for carrying out detailed field studies During the field studies, detailed water balance, material balance (with respect to fibre and water) audits were carried out And based on studies, specific water consumption in each mill was estimated The specific fresh water consumption estimated in

each representative mill is as given in table E-5 below:

Table E-5: Specific Water Consumption in Selected Field Study Mills

5 Agro & waste paper based Industrial grade 47

6 Waste paper based Cultural – high

Code Material consumption,

Proposed standards for water consumption in pulp and paper sector

Based on the detailed pulp and paper mill’s inventorisation and observations from the dry and detailed field studies conducted during the course of this study, it became evidently clear that water consumption varies significantly depending upon the raw material used, scale of operation and the end product Realizing these variation it was clear that one or two general standards would not suffice for the entire pulp and paper sector Accordingly, considering the prevailing characteristics of Indian pulp & paper mills in the country, following six categories of pulp and paper mills with respect to water consumption pattern have been proposed for formulation of standards:

A Large scale Wood based and integrated pulp and paper mills

manufacturing cultural grade paper & paper board and / or

Newsprint

B Small/Medium Scale Agro based pulp and paper mills

manufacturing high grade cultural paper

C Small/Medium Scale Agro based pulp and paper mills

manufacturing industrial grade paper

D All wastepaper based pulp and paper mills manufacturing high

grade cultural paper with “De-inking”

E All wastepaper based pulp and paper mills manufacturing cultural

grade paper without De-inking

F All medium / small scale waste paper based mills manufacturing

industrial grade paper

While developing the water consumption standards for the above referred categories following factors have been considered

¾ The standards developed should ensure continuous reduction in water consumption

¾ The standards should be such that they trigger technological interventions as well as reuse / recycling opportunities and thus lead to quantum reduction in water consumption in long term

¾ The standards should be India specific and practicable and feasible to implement

¾ The standards should also even out the huge water consumption

• Benchmark Standard: This standard refers to minimum water

consumption required after implementation of best available technology (economically viable and currently practiced / demonstrated in India), recycle and reuse practices This standard has been developed by identifying the various mill operations involved in each specific category and also identifying the least water consumption actually achieved by any of the mills studied in that particular category The total of water consumption in each of the mill operation / process would be the benchmark standard for that specific category

The idea of developing this standard is to ensure

o Quantum reduction in water consumption: No mill in the above referred categories is currently operating at this level To achieve this level most of the mills would need to undertake certain technological modifications and complex recycling / reuse measures to achieve the quantum reduction in the water consumption and comply with these standards

o Development of feasible standards: Further these standards reflect the feasible and demonstrated mill operation specific water consumption norms already practiced in one or the other industry in India and thus expected to be appreciated and followed by industries

Since complying with these standards would need technological and complex recycling / reuse systems interventions, which require significant time and resources at the industries end, it is proposed that these standards to be considered for implementation after four years from the acceptance year of this report

• Best Achieved Standard: This standard refers to the minimum water

consumption already achieved by a mill (or can be achieved by implementation of simple recycling / reuse measures) simple in the specific category

This standard is developed with the perspective of bringing the other mills to the currently best achieved and demonstrated level in the country This standard can be achieved by implementation of simple water recycling and reuse practices and minor technological changes

This standard is proposed to be considered for implementation from two years from the acceptance year of this report The three years grace period is proposed to enable other industries to undertake technologies feasibility (technical, economical, environmental etc) and implementation

• Relaxed Standard: This standard provides 20 % relief over the best

achieved standard in each specific category This standard is proposed

water consuming industries and thus bridge the huge gap between

best performing and worst performing mills in a short time It is

estimated that this standard can be achieved by other industries in

each categories by implementing simple reuse, recycling and other

minor modification

This standard is proposed to be implemented after six months from the

acceptance of this report The six months grace period is proposed to enable

other industries to undertake the reuse, recycling and other minor

modifications

The process of developing above referred benchmark standards would also

identify mill operation / process or section specific water consumption

benchmark figures that can be used by the industries for continuous

improvements

The consolidated proposed water consumption/wastewater discharge*

standards for each category of the pulp & paper mills are compiled and

tabulated below in table E-6:

Table E-6: Proposed Water Consumption/Wastewater Discharge

Standards

Proposed water consumption/wastewater discharge standard in m 3 / Tonne of product

Benchmark Best

achievable

Relaxed

1 Large scale Wood based and integrated pulp

and paper mills manufacturing Newsprint,

Cultural grade paper and paper board

63 / 50 67 / 53 80 / 63

2 Small/Medium Scale Agro based pulp and

paper mills manufacturing cultural grade paper

38 / 30 80 / 63 95 / 75

3 Small/Medium Scale Agro based pulp and

paper mills manufacturing industrial grade

18 / 15 47 / 37 56 / 44

4 All wastepaper based pulp and paper mills

manufacturing high grade cultural paper and /

or news print with “De-inking”

19 / 15 41 / 32 49 / 38

5 All waste paper based pulp & paper mills

manufacturing high grade cultural paper without

“De-inking”

9 / 7 13 / 10 15 / 12

6 All Medium / Small scale wastepaper based

pulp and paper mills manufacturing industrial

grade paper

6 / 5 6 / 5 7 / 6

* Wastewater discharge standards have been evolved with an assumption that around 21% of the input fresh water is lost as vapour in fourdreineir machine (drier section) and in boiler section and the balance is discharged as wastewater

Further, it is recommended to reuse this wastewater as much as possible for irrigation purpose

Water Conservation Options Evolved and Recommended to Achieve Quantum Reduction in Fresh Water Consumption in Pulp and Paper

Sector

The high water consumption in Indian pulp and paper industry is mainly due to obsolete process technology, poor water management practices and inadequate wastewater treatment

In order to evolve techno economically feasible option, detailed field studies were carried out as mentioned earlier Depending upon the category and scale of operations, water conservation options have been recommended They are briefly described below:

Low – cost improvements

• General Housekeeping Measures: General housekeeping measures deals with low-cost improvements like leak detection, repair, production scheduling, use of press type tap, auto close valve hose to reduce wastage due to negligence, etc

• Using better quality raw material to achieve desired brightness: Manipulation of raw material quality enables use of lesser quantity of bleaching chemicals, hence requires less water quantity for bleaching and washing

• Dry de-dusting of straw for removal of fines and dust / Dry depithing of Bagasse / Dry debarking of Wood

• Collection of black liquor spills in a common tank: This reduces fresh water consumption required for floor washing

Design stage procedures (new plant/equipment)

• Use of Better pulp washing technology: Various technologies available

in decreasing specific water consumption are potcher washing, hydraulic washing, vacuum drum washing, Pressure washing, diffusion washing, chemi or belt washing, twin roll press washing Among all, potcher washing has maximum specific water consumption (55 - 60 m3/BDMT bleached pulp) and twin wire roll press has minimum specific water consumption (26 m3/BDMT bleached pulp) However, a

1081 million INR Where as a vacuum drum washer would cost only 10 – 25 million INR, hydraulic washer would cost 2.5 million (works good with lower capacity) Therefore, techno-economic feasibility is required before identification of suitable washer in the individual mill

• Use of More Efficient Deinking Plant : The clarified water is reused in different mill operations: Helicopulper, H D Cleaner, Pulp Dilution, Centricleaner, Pressure screen

• Membrane filtration technique in deinking process instead of conventional floatation method: Membrane separation technology is a potentially attractive method for the removal of flexographic ink residues from the wash filtrate effluent of deinking mills and thereby enabling recycle of wash filtrate

• Installation of Indirect & More Efficient Heat Transfer System for Blow Heat Recovery In Digestor Section: This avoids generation of contaminated wastewater (in direct heat transfer, waste gases are directly injected to water) and enables reuse of cooling wastewater

• Replacing barometric leg (direct) condensor cooling by surface (indirect) condensor cooling: The wastewater from barometric leg is generally discharged to ETP and cannot be completely recycled back

Process modifications including recycle/reuse

• Optimum use of cooling wastewater:

A Collection of once-through cooling water and reuse it in different process operation

B Converting once-through system into a closed –loop system by installing a cooling tower

• Recovery and re-cycling of clean water from vacuum pumps

• Installation of Vacuum flume tank to recycle vacuum pump sealing water

• Replacement of water seals in Process Pumps: Mechanical seal pumps can be used to avoid usage of sealing water Also seal less pumps are extensively used in chemical industries which can also be used pulp and paper manufacturing mill

• Use of modified design of nozzle in Decker thickener shower

• Use of efficient Decker thickener/ vacuum drum showers

• Use of efficient shower system and Regular monitoring of low pressure and high pressure showers and in the paper machine section

• Use of Enzymatic deinking process

• Recovery of bleaching chemicals through membrane separation & reuse (closed loop bleaching): For Mills with Elemental Chlorine free bleaching process

• Reuse of secondary condensate in raw material preparation section, Brown Stock Washing / Bleach Washing

• Reuse of barometric leg wastewater: This wastewater is suitable for reuse in Brown stock washing

• Reuse of wastewater from DM plant (regeneration & sandfilter backwash), softner (regeneration & sandfilter backwash) for ash conditioning / quenching

Process redesign which includes improvement in quality and management of paper machine wastewater

• Choosing right type of saveall system: There are different technologies

to clarify paper machine white water like polydisc saveall, Krofta saveall, sedimentation type saveall, drum filter, inclined or Hill screens, etc Depending upon the usage of clarified water and quality required, type of saveall needs to choosen In large scale mills, polydisc saveall

is advantageous The clear filtrate generated from the saveall can be directly used in high pressure paper machine showers

• Optimum use of paper machine clarified wastewater in sections other than paper machine: Various application areas are :Decker thickener showers, Vacuum washers, Centricleaner reject dilution, Pulp dilutions before bleaching stage, Johnson screen showers, etc this requires provision of sufficient storage capacity A modified storage capacity similar to ‘Stawford” separator helps in further separation of solids and fibres from the clarified water

• Use of back or recycled water in low pressure showers: Various locations in paper machine section where back water can be used are: Wire section - Breast roll, wire turning and wire-return rolls, knock – off shower, trim knock – off shower, wire cleaning shower ( low pressure).,Press section - Cleaning of rolls

Total system closure with zero liquid effluent

• Tertiary treatment of wastewater for recycling: In tertiary treatment, Aluminum oxide, ferric oxide and poly electrolytes assist coagulation of waste in the effluents, which are then sand filtered The quality of treated wastewater after the tertiary treated is fit for recycling back completely to the system especially in wastepaper based mills and partially for other mills

However, there is a limitation to continuous recycle of wastewater within the plant for a long period as it leads to slime generation This is prevented by optimized addition of biocide and chemicals in the water at regular intervals

Existing standards are passé

The questionnaire responses, CSE’s green rating project and the detailed field studies have clearly indicated that the majority of industries in-fact actually performing better than both the existing standards and the CREP standards they have agreed to

Common standard not far-sighted

It has also clearly emerged from the in depth studies that water consumption varies significantly based on the scale of operation, raw material used and the end products manufactured Hence a common standard for all type of industries would not be prudent and accordingly standards have been developed for six categories of pulp and paper industries considering operational scale, raw material used and the end product manufactured

Recommended standards a challenge already conquered

While comparing with the existing standards, the currently recommended standards may seem to be a challenging task to achieve but actual practice these have already been achieved in totality by an Indian enterprise (Best achieved standard) or partially i.e at a mill process level by one or the other Indian enterprise (benchmark standard) Hence the proposed standards are practical and feasible to achieve The industries may refer to the water conservation measures identified under the study to achieve the water consumption standards

Let’s not stop, we need to go further

The currently developed and recommended water consumption standards are still comparably high in light of the latest world wide trends on water consumption The currently developed standards should be treated as short term applicable for about 8 years It is further recommended that these standards should again be revisited after 6 years

***************

CHAPTER 1 BACKGROUND

Paper manufacturing is a highly capital, energy and water intensive industry It is also a highly polluting process and requires substantial investments in pollution

around 695.7 million m3 of wastewater is discharged annually by this sector1 Looking into the serious nature of pollution, the pulp and paper industry in India has been brought under the 17 categories of highly polluting industries

In global comparison on specific water consumption (the global best specific water

India is still far behind ( India’s average fresh water consumption in pulp and paper sector is 150 – 200 m3/tonne of product) and this is largely attributed to the use of obsolete technology / equipments and poor water management practices

At the same time, water has been increasingly becoming a scarce commodity and several industries are experiencing acute water shortages especially during non-monsoon periods While most large industries are located near abundant water supply source (the rivers), The majority of small / medium scale agro residue/waste paper based mills are in clusters and have to depend on groundwater The continuous exploitation of ground water by these industries has led to lowering of the groundwater table and thus increased pumping costs and more importantly water shortage in many regions This has forced many industries to curtail their production levels and some closed down their mills for want of adequate amounts of water

However, in large scale mills, the situation is slightly better with regard to water conservation and environmental compliance because of better technology / equipment employed by them, large scale of operation and also access to latest information / developments Despite this, water management is very poor in pulp and paper industry and it requires immediate attention as its excess use is affecting the water availability particularly during non-monsoon

1

Source: Estimated by CSE based on the wastewater discharged data published by CPCB in "Water quality in India (Status and trends) 1990 -

Central Pollution Control Board (CPCB) has therefore approached National Productivity Council (NPC) to develop suitable guidelines for water management in different types of pulp and paper mills through out the country

1.2 OBJECTIVE OF THE STUDY

The objective of the study is to evolve appropriate guideline for conservation of water based on the existing water management practices and identify optimum recycle/reuse options for water

For the above objective, following scope of work has been defined:

(i) Inventorisation of pulp and paper manufacturing mills through out the country

operation, raw material usage, products manufactured

(iii) Selection of 10 representative mills for detailed studies

(iv) Preliminary survey of the selected mills, followed by detailed studies Detail

study comprises of:

• Collection of background data regarding the raw material consumption, product output, installed and operating capacity of existing process and utilities etc

• Study of the manufacturing process

• Identification of the sources and characterisation of the wastewater generated from each process operation

• Compilation of material balance for complete process

• Identification of the water conservation, waste recycling/reuse options, if any adopted by the mill

• Compilation of the water balance for the complete mill and

• Generation of water recycle/ reuse and other conservation options with or without mild treatment

(v) Cost benefit analysis for optimum reuse and recycling of waste water in terms

of reduction in pollution load reaching ETP and fresh water consumption for each type of pulp and paper industry

assuming the optimum water consumption level for each type of industry

(vii) Formulation of guidelines for water conservation for each type of pulp and

paper industry

1.4 METHODOLOGY

The following methodology is being adopted to accomplish the above said scope of work:

Phase I

operation, production process, water management practices followed, etc was prepared in consultation with CPCB officials and Pulp and Paper manufacturing Association’s members A copy of questionnaire is placed as

Annexure I

(ii) The inventorisation of pulp and paper mills and other relevant information on

pulp and paper mills was compiled through various agencies, research institutes, pulp and paper manufacturing associations, state pollution control boards, and associated bodies

through out the country

Based on the responses, typical wastewater characteristics from pulp and paper mill has been generated

consumption, wastewater generation, etc for different types of pulp and paper mills has been procured from pulp and paper manufacturing associations, printed matters and internet

(vi) Based on the literature survey and questionnaire survey, criteria for selection

of representative mills has been developed

Phase II

(vii) Based on the information obtained from Pulp and paper mill associations and

other Institutions, pulp and paper mills through out the country have been classified according to scale of operation, raw material usage and product manufactured

(viii) Ten representative mills were identified as per the criteria developed in

consultation with CPCB and based on the questionnaire responses

(ix) Detailed studies at the individual mill were carried out as given below:

− Background data with respect to raw material consumption, product output, installed and processing capacity, existing process and utilities, etc were collected from stores and inventory, raw material preparation section, pulp mill section, chemical recovery section, stock preparation section, paper machine section, utilities department, engineering department, projects, quality control and technical services department

− The manufacturing process was studied in a detailed manner Following general process related information were collected:

- Yield

- Cooking temperature and time

- Makeup chemical type and amount

- Bleaching stages and time

- Temperature and charge to bleaching towers

- Dilution factor in washing

- Black liquor solids content before and after evaporation

- Black liquor quantity

- Product target data This was followed by collection of specific process related details, engineering drawings and verifying them by conducting a shop floor walk through Simultaneously, different input and output streams were identified

at each process step

− Different sources of wastewater generation was identified and marked Sampling and monitoring of wastewater at these points was carried out The samples were analysed for relevant parameters for characterization of inlet process water and wastewater stream

− Material balance for the complete process was compiled TSS balance was also carried out to ascertain the fiber loss from the process

− Water conservation measures as adopted by the mills were identified and the total water saved per unit of the product was computed

− Water balance for the complete mill along with the water used in the utility was made

− Water conservation techniques/technologies were identified and economic feasibility of the identified technologies/techniques were studied The impact of implementation of these were also ascertained so as to determine the effect on the pollution load

techno-Phase III

(x) On the basis of the studies carried out in all the ten mills, limits for water

consumption level for each type of industry was established

(xi) Subsequently, general guidelines for water conservation for each type of pulp

and paper industry were evolved

CHAPTER 2

INDUSTRY PROFILE : PULP AND PAPER

2.1 STATUS OF PULP AND PAPER MANUFACTURING MILL IN INDIA

The capacity utilization is estimated at around 60-65 percent of the total installed capacity The growth of paper mills from 1950 onwards along with average installed

capacity is as given in the Table 1

Table 1: Number of paper mills in India with installed capacity during 1950 to

2004 2

Mills

Installed Capacity (million tonnes/

annum)

Actual Production (million tonnes/ annum)

The low capacity utilisation in the industry is due to high incidences of sickness in many small / medium mills and thus most of these are operating either at lower capacity or closed The state wise distribution of the closed mills during 1999 to

2002 is given in Table 2 below

Table 2:No of mills closed between 1999 and 2002 3 State-wise Number of Paper Mills Closed Down in India

The major types of paper that are produced in the country along with main varieties

and their consumption pattern (demand indicator) are presented in the Table 3

below:

Table 3: Consumption pattern of paper and paper board products in India

consumptions

Type of paper Main varieties % of total

consumptions

Chromo paper

board - single layer board, multilayer board, duplex board,

43%

electrical grades of paper

4%

In India, the cultural varieties (writing and printing paper) account for about 41% of

the production, specialty papers including coated papers for about 4% and newsprint

for about 12 % This leaves about 43% for kraft and boards

The world consumption of paper and paperboard at present has been estimated to

be over 300 million tonnes a year which includes 30% of cultural papers, 14% of

newsprint, and the balance of kraft / packaging paper and specialty paper

State wise Distribution of Pulp & Paper Mills

The statewise distribution of pulp and paper mills (including further distribution based

on raw material used) in the country from 2000 to 2004 is given in Table 4 through

Table 6

Figure 1 depicts the present distribution of pulp and paper mills in India Annexure

II gives the list of industries operating in 2004

Table 4: No of pulp and paper mills as on 2000 4

State-wise Number of Paper Mills in India

Kerala 7 Karnataka 17

State-wise Number of Paper Mills in India

India 515

Table 5: No of Pulp and Paper Mills as on 2002 5

Table 6: No of Pulp and paper mills as on 2004 6

State Agro Wastepaper Wood PaperMill Integrated Sub Total

2.2 CLASSIFICATION OF PULP AND PAPER MILLS IN THE COUNTRY

At present, around 3098 pulp and paper manufacturing mills are operating in the country Out of these, 198 mills are operating under large scale category with actual capacity of 5.2 million tonnes per annum and 111 mills are operating under small scale category with actual capacity of 0.3 million tonnes per annum

(a) Based on Scale of operation

The pulp and paper mills based on the scale of operation are classified as those having an installed capacity of 25,000 tonnes per year & above as large scale and less than 25,000 tonnes but greater than 5,000 tonnes per year as medium scale and up to 5000 tonnes per year as small scale The distribution of large/medium and

small scale pulp and paper mills in the country is given below in Table 7

Table 7: Distribution of Large/Medium and Small scale pulp and Paper Mills

Sl

No

Scale of operation No of Mills Actual

Capacity, million tonnes per annum

(b) Based on Raw material Usage

The pulp and paper industry is segmented as wood/forest-based, agro-based and waste paper based with the former accounting for 21 %, agro-based 71 %, waste paper based 7% wood based and integrated for 1 % of the total actual production

The number of pulp and paper mills under each classification is given below in Table

8

Table 8: Distribution Pulp and Paper Mills Based on Raw Material Used

In Large/medium Scale Category

In the large/Medium scale category, 63% of the mills are wastepaper based, 25% agro based, 11% wood based and 1% integrated pulp and paper mills

Category No of Mills % Production,

In Small Scale category,

In the small-scale category, 83.6 % of the mills are wastepaper based, 15.3 % agro

based, and 0.1% integrated pulp and paper mills

(c) Based on Products manufactured

The Indian paper industry is classified broadly into two categories based on product

manufactured:

• Paper and Paper board products

• Newsprint

The number of pulp and paper mills producing Paper and Paper board and

Newsprint along with actual production in the country is given in Table 9 below:

Table 9: Distribution of Pulp and Paper Mills Based on Raw Material Used

In the Large/Medium Scale category, 28% are involved in manufacture of high

quality cultural paper and paper board while only 7.5% are involved in low quality

cultural paper, 1.51 % only pulp, 3% only specialty paper and rest industrial and

newsprint grade paper as shown below:

Category No of Mills % Production, million TPA %

In Small Scale Category, maximum mills (about 81%) are involved in the production

of industrial grade paper followed by 9% high grade cultural paper manufacturing,

4.5% are involved in low grade cultural paper manufacture, 9% are involved in high

quality Cultural grade paper, 5.45% specialty and rest industrial grade as shown

below:

The major producers of paper in the country along with their installed capacities are

given in Table 10

Table 10: Major players in paper board product segment

tpa (FY2002)

Product mix

paper, MG poster

board

The West Coast Paper

Mills

(ii) Newsprint

In the News print segment around 21 mills in Large scale category (4 in central public sector, 2 in state public sector and 15 in private sector) with an installed

capacity of about 0.658 million TPA are operating

The major mills in the newspaper/newsprint segment with their production capacities

are given in Table 11

Table 11: Major mills in Newsprint segment

(d) Based on Pulping Process

Generally speaking, the pulp and paper industry divides itself along pulping process lines: chemical pulping (e.g., kraft chemical pulping), mechanical pulping, and semi-

chemical pulping The pulping process affects the strength, appearance, and intended use characteristics of the resultant paper product Pulping processes are the major source of environmental impacts in the pulp and paper industry; each pulping process has its own set of process inputs, outputs, and resultant environmental impacts The different types of products resulting from various pulping processes are listed as below:

• Bleached Paper grade Kraft and Soda / Unbleached Kraft: Bleached or unbleached kraft process wood pulp usually converted into paperboard, coarse papers, tissue papers, and fine papers such as business, writing and printing

• Paper grade Sulfite: Sulfite process wood pulp with or without bleaching used for products such as tissue papers, fine papers, and newsprint

• Semi-chemical: Pulp is produced by chemical, pressure, and mechanical (sometimes) forces with or without bleaching used for corrugating medium (for cardboard), paper, and paperboard

• Mechanical pulp: Pulp manufacture by stone groundwood, mechanical refiner, thermo-mechanical, chemi - mechanical, or chemi-thermo - mechanical means for newsprint, coarse papers, tissue, molded fiber products, and fine papers

• Non-wood Chemical pulp: Production of pulp from textiles (e.g., rags), cotton linters, flax, hemp, tobacco, and abaca to make cigarette wrap papers and other specialty paper products

• Secondary Fiber Deink: Pulps from waste papers or paperboard using a chemical or solvent process to remove contaminants such as inks, coatings and pigments used to produce fine, tissue, and newsprint papers

• Secondary Fiber Non-deink: Pulp production from wastepapers or paperboard without deinking processes to produce tissue, paperboard, molded products and construction papers

• Fine and Lightweight Papers from Purchased Pulp: Paper production from purchased market pulp or secondary fibers to make clay coated printing, uncoated free sheet, cotton fiber writing, and lightweight electrical papers

The distribution of pulp and paper mills in the country based on pulping processes is

given in Table 12 and Table 13 based on number of mills and installed capacity

Table 12: Distribution of pulp and paper mills based on pulping processes ( number of mills)

No of Mills

Sl No Pulping Process Large Scale Small Scale Grand Total

Installed Capacity, million tonnes/yr

CHAPTER 3 MANUFACTURING PROCESSESS

This section describes the major industrial processes within the pulp and paper industry, including the materials and equipment used, and the processes employed This section specifically describes the details of commonly used production processes, associated raw materials, the products produced, and the materials recycled This discussion, coupled with schematic drawings of the identified processes, provide a concise description of where wastes may be produced in the process

3.1 Generalised Paper/Paper board making process

In general, paper is manufactured by applying a liquid suspension of cellulose fibers

to a screen, which allows the water to drain, and leaves the fibrous particles behind

in a sheet The liquid fibrous substrate formed into paper sheets is called pulp

Processes in the manufacture of paper and paperboard can, in general terms, be split into three steps: pulp making, pulp processing, and paper/paperboard production Paperboard sheets are thicker than paper sheets; paperboard is normally thicker than 0.3 mm Generally speaking, however, paper and paperboard production processes are identical First, a stock pulp mixture is produced by digesting a material into its fibrous constituents via chemical, mechanical, or a combination of both In the case of wood, the most common pulping material, chemical pulping actions release cellulose fibers by selectively destroying the chemical bonds in the glue-like substance (lignin) that binds the fibers together After the fibers are separated and impurities have been removed, the pulp may be bleached to improve brightness and processed to a form suitable for paper-making equipment Currently, one-fifth of all pulp and paper mills practice bleaching At the paper-making stage, the pulp can be combined with dyes, strength building resins,

or texture adding filler materials, depending on its intended end product Afterwards, the mixture is dewatered, leaving the fibrous constituents and pulp additives on a wire or wire-mesh conveyor Additional additives may be applied after the sheet-making step The fibers bond together as they are carried through a series of presses and heated rollers The final paper product is usually spooled on large rolls for storage

A typical process for the manufacture of paper is shown in Figure 2

Figure 2: A typical process for Paper manufacture

Raw material Wastewater Water

3.2 Different industrial processes in pulp and paper sector

Based on the type of raw material used, the manufacturing processes are classified into

− Wood Based Pulp and Paper manufacturing Process

− Agro residue based Pulp and Paper manufacturing Process

− Secondary fibre based Pulp and Paper manufacturing Process

Figure 3 shows the schematic diagram of different manufacturing processes of pulp

and paper making from raw material sources

Raw material Preparation section

Pulping Section

Pulp Washing &

Bleaching Section

Stock Preparation system

Paper Machine

Finished Paper

3.2.1 Wood Based Pulp and paper manufacturing Process

Pulp Production: Various Methods of Pulping

Wood consists of two primary components: cellulose and lignin Cellulose, which is the fibrous component of wood, is used to make pulp and paper Lignin is the “glue” that holds wood fibers together Pulping is the process, which reduces wood to a fibrous mat by separating the cellulose from the lignin

Pulping processes are generally classified as chemical, mechanical, or chemical

semi-Mechanical Pulp (yield 90%): semi-Mechanical pulp uses mechanical abrasion to

separate cellulose fibres which are held together by lignin In the process called

“Groundwood”, wet wood is ground by large stones In Thermo mechanical pulping (TMP), metallic plates rub steam heated chips at high speeds, separating fibers Mechanically produced pulp has a higher proportion of broken cell fragments (called 'fines') among the fibres Thus, when used to make paper, the long fibres form the matrix of the sheet within which the fines are trapped Paper derived from mechanical pulps, therefore, tend to be denser and is often a component of newsprint and other printing papers

However, because mechanical pulps are not chemically processed they still contain lignin and other natural wood substances, and paper with a high component of mechanical pulp tends to yellow quickly in sunlight

Mechanical pulping processes all use a lot of electrical energy and water However, they also provide 80-90% recovery of total fibre Mechanical pulp processes are cheaper to operate than more sophisticated chemical based systems There are also fewer environmental issues, such as chemical contamination of sites and unpleasant smells

Chemical Pulp (yield 50%): Chemical pulping achieves fiber separation by

dissolving the lignin that cement the fibers together In chemical pulping, fibres are less likely to be damaged than in other pulping processes Chemical pulp is more expensive then mechanical pulp, but it has better strength and brightness properties There are three chemical pulping methods known as Soda, Kraft (or Sulfate), and Sulfite The choice of the chemical pulping method depends upon the type of raw material available and the product end use

1 Soda Pulping

Soda pulp is the original chemical pulp and is produced by cooking chips of (usually) deciduous woods in a solution of caustic soda under pressure This leaves a relatively pure cellulose pulp which is then washed and bleached Soda pulp produces relatively soft, bulky papers (as a filler with other pulps) used in books, magazines and envelopes Caustic soda dissolves most of the lignin in wood while having little effect on the cellulose Cooking liquor is recovered during the washing process Currently this process is primarily used for agro residue based material pulping

2 Kraft / Sulfate Pulping

In a chemical pulping process, heat and chemicals are added to wood chips in a pressure cooker called the digester In the kraft process, an aqueous solution of sodium hydroxide and sodium sulfide, known as white liquor, selectively dissolve the lignin and make it soluble in the cooking liquid After 2 to 4 hours, the mixture of pulp, spent pulping chemicals and wood waste is discharged from the digester The pulp is washed to separate it from the black liquor - the pulping chemicals and wood waste Kraft pulping is a low yield process - only 45% of the wood used becomes pulp The pulp, called brownstock at this point in the process, is ready to be bleached Softwood pulp from a conventional cooking process contains about 4.5% lignin This lignin will be removed and the pulp will be brightened during the bleaching process

In response to concerns about the amount of organic waste in the effluent, as conventional pulping processes remove only about 95% of the lignin from the pulp, there are few mills that have started extended / oxygen de-lignification for further lignin removal Today, a well run oxygen de-lignification system can remove 55% of

the lignin from the unbleached pulp Figure 4 shows the oxygen delignification tower

installed in one of pulp and paper mill in India

The kraft process is applicable to almost any wood and produces a pulp with strong fibres, but which also takes more bleaching that other chemical pulps It is suitable for even quite resinous pine species Kraft pulp is used where strength, wear and

Fig 4: Oxygen De-lignification Tower

tear resistance and colour are less important the most obvious examples are brown paper bags, cement sacks and similar sorts of wrapping paper

3 Sulfite Pulping

Sulfite pulping uses sulfurous acid and an alkali to produce pulps of lower physical strength and bulk, but exhibits better sheet formation properties The yield on the basis of chipped wood is again about 45 percent These pulps are blended with ground wood for newsprint and are used in printing, bond papers, and tissue Sulfite pulping was originally designed with a recovery system similar to the older soda process still used in some plants Environmental pressures have often forced these plants to develop a recovery process The pulp produced is made up of longer, stronger and more pliable fibres and is favoured where strength properties are particularly important

Chemical pulping requires significant quantities of energy, mostly for process heat but uses less electrical energy than mechanical processes However, many modern kraft pulp mills are totally self-sufficient in energy, with combustion of residues and waste products meeting all heat and electrical energy needs

Semi-Chemical Pulps Semi-chemical pulps are essentially mechanical pulps

that have been pre-treated with a sulphite or sodium hydroxide liquor to improve breakdown and reduce energy requirements during processing Pulps tend to retain some of the properties of mechanical pulp, including good yields of fibre, but are also suitable for better classes of paper manufacture

Pulp & Paper Manufacturing Process

In general, pulping process is described in following 3-steps:

Step 1: Pulping

Raw Material Preparation

The wood logs are fed to a log chain conveyor and from log chain conveyor, the

wood is fed to the chipper by means of a belt conveyor (Figure 5) The wood after

chipping goes to a cyclone The chips from the cyclone are fed on the vibrating screen where oversize chips are removed and the accepted chips go to the silo via a conveyor belt The oversized chips are fed back to the crusher

Digester House

The chips from the silo are fed in the Digester through a belt conveyor There are two types of digestion processes employed; Batch digestion carried out in spherical digestors and Continuous digestion process carried out in a pandia type digester

A shuttle conveyor helps in filling up the digester The chips in a vertical digester provided with liquor circulation pumps and pre heaters In this process, wood is cooked in a “digester” at elevated pressure (upto 11 bar) with a solution of the appropriate chemicals, which dissolve the lignin and leave behind the cellulose The

cooking process results in emissions of a variety of hazardous air pollutants including formaldehyde, methanol, acetaldehyde, and methyl ethyl ketone

The cooked material is blown into a blow tank provided with blow heat recovery system The blown material from the blow tank is taken into the unbleached knotters where the uncooked chips are removed

Step 2: Pulp Washing

After the wood is pulped, the pulp that is created is washed to remove the dissolved lignin and chemicals In the washing process, the pulp is passed through a series of washers and screens The washing process occurs at high temperatures (above room temperature), which generates a large volume of exhaust gases containing hazardous air pollutants which are released to the atmosphere

The liquid that results from the washing process contains lignin as well as the chemicals used to separate the lignin from the cellulose The chemical recovery processes are used to recover these chemicals

Step 3: Pulp Bleaching

After washing, if a white product is desired, the pulp must be bleached to remove color associated with remaining residual lignin The three general approaches to bleaching are:

Elemental Chlorine Bleaching is the process currently in place at some existing

bleaching plants, and uses chlorine (Cl2) and twice hypochlorite to brighten the pulp

In addition, Sodium hydroxide with or without peroxide is used for extraction of chlorine from the pulp

When elemental chlorine and hypochlorite react with the lignin, they form chlorinated pollutants such as chloroform, dioxins, and furans in the wastewater stream

Elemental Chlorine Free Bleaching (ECF) replaces chlorine with chlorine dioxide

as a bleaching agent and hypochlorite in no longer used The use of ECF bleaching

results in reduced levels of chlorinated pollutants in the wastewater stream Figure 6

shows a ClO2 plant installed in one of Indian pulp and paper mill

Fig 5: Chipper Section