Industrial Chemistry Report on Pulp and Paper Industry
Leif Duncan S. Urdaneta
University of San Carlos Technological Center
Cebu City, Philippines

Abstract
Information about the pulp and paper industry that focuses mainly on kraft pulping using wood as raw material for paper production is covered in this report. Content includes a brief account of the global paper production status, a general overview of the kraft paper making process that is presented with a model mill PFD (with materials balance) from ÅForsk Engineering (2011) as well as actual information from Danao Paper Mill, general waste management practices recommendations by authoritative figures, actual waste management of Danao Paper Mill, future trends and direction of the industry in general and that of Danao Paper Mill, and finally, author’s conclusion and closing remarks.

Table of Contents

Introduction | 4 | Existing Industries | 5 - 8 | Manufacturing | General Overview | | | Pulp production | 9-11 | | Chemical Recovery | 12-13 | | Paper Making | 13-14 | | Danao Paper Mill | 14-15 | | Stock Preparation | 15 | | Repulping | 15-18 | | The Paper Machine | 18-20 | | Mass Balances | 21 | | Process Flow Diagrams | 22-23 | Waste Management | Overview | 24-25 | | Danao Paper Mill | 25 | Future Trends and Direction | Philippines | 26 | | Danao Paper Mill | 26 | Conclusion | 27 | Recommendations | 27 | References | 28-30 |

Introduction

Starting at around 1965, paper industries around the world have continued to strive, flourish and develop (“Andritz; Pulp and Paper Research and Development,” 2014; Confederation of European Paper Industries, 2010). The advent of the internet and modern computerization saw a 40%-increase in paper production when offices started using email in the 1990’s (“The Paper Chase,” 2013). A 2008 survey presents that the production growth of paper around the globe has been increasing by 2.8%, in the order of million tonnes, annually (Food and Agriculture Organization of the United Nations, 2009 in “The Paper Life Cycle,” n.d.).
Pulp and Paper Industry in the country has been identified as one of those that will be subject to upgrading and transformation in accordance with the Philippine Manufacturing Industry Roadmap (Lumawag, 2013). Danao Paper Mill is the only paper mill in Cebu; actual data and information from the mill will be included in this report.

Review of Existing Industries in the Region

There are but less than a handful of paper mills in the Visayas. Most paper mills in the Philippines are found up north in Luzon – mostly in Metro Manila. The following list compiles those paper mills that are easiest to manually find, as DTI does not provide a list of such industries online.

Asia Pulp and Paper Group (APP)
Products: Stationery, Duplex Triplex Carton, PPC, Carbonless, Art Papers, etc.
Makati, Metro Manila website: http://asiapulppaper.yocal.ph/

RACO Trading Phils, Inc.
Products: numerous grades of pulp, paper and paperboard, packaging products and packaging equipment.
Makati, Metro Manila website: http://www.racophil.com/

Pulp Specialties Phils., Inc.
Products: Capacitor paper, Electrolytic Condenser Paper Insulation (as asbestos substitute), roofings, wallboards, speakers, speaker cones Cigarette paper, plug wrap, floral tapes, etc.
Sitio Magbangon, Barangay Tinag-an, Albuera, Province of Leyte website: http://www.pulpspecialties.com/index-2.html

Glatfelter
Products: abaca pulp
Lanao del Norte website: http://www.glatfelter.com/sustainability/environmental/production.aspx

Trust International Paper Corporation Philippines (TIPCO),
Products: newsprints and newspaper
Malabacat, Pampanga (mill site) website: http://www.tipco.com.ph/

Noah's Paper Mills Incorporated
Products: Paper / Paper Tubes
Marikina, Metro Manila website: http://www.philippinecompanies.com/search/paper-mills

Bataan Pulp And Paper Mills
Products: Pulp and Paper
Makati, Metro Manila website: http://www.philippinecompanies.com/companyprofile/37612/bataan-pulp-and-paper-mills
East Asia Paper Mills
Products: Photography, Print and Publishing
Mandaluyong, Metro Manila website: http://www.philippinecompanies.com/companyprofile/42113/east-asia-paper-mills

Aclem Paper Mills
Products: Pulp and Paper
Juan Luna, Binondo, Manila website: http://www.philippinecompanies.com/companyprofile/37716/aclem-paper-mills

Globe Paper Mills
Products: Pulp and Paper
Binondo, Manila website: http://www.philippinecompanies.com/companyprofile/37610/globe-paper-mills

Philippine Paper Mills
Products: Pulp and Paper
Tondo, Manila website: http://www.philippinecompanies.com/companyprofile/37614/philippine-paper-mills

Liberty Paper Mills, Inc.
Products: Pulp and Paper
Valenzuela, Bulacan website: http://www.philippinecompanies.com/companyprofile/37722/liberty-paper-mills-inc-

Asia Paper Industrial Corporation
Products: Pulp and Paper
Cabuco, Cavite website: http://www.philippinecompanies.com/companyprofile/37722/asia-paper-industrial-corporation

Dasmariñas Paper Mills Inc.
Products: Pulp and Paper
Dasmariñas, Cavite website: http://www.philippinecompanies.com/companyprofile/37618/dasmari-as-paper-mills-inc-

Danao Paper Mill
Products: Kraft Pulp
Danao City, Cebu website: not available

Details of the Manufacturing Process

I. General Overview
Pulp Production
Worldwide, 90% of pulp is produced from wood as the principal raw material while the remaining 10% comes from other plant sources such as abaca (Pulp Specialties Philippines Inc., 2007). Mainly, the steps in manufacturing from wood to paper are: raw material preparation and handling, pulp manufacturing, pulp washing and screening, bleaching, stock preparation and paper making. Chemical recovery and recycling is a crucial feature of this industry, employed rather efficiently and in quite many steps along the manufacturing line. Water is a key material for the manufacture of pulp and paper; in addition to its several uses as steam during the actual processing lines (in the digester, press driers, etc.), it is also used to generate power for the mill (Bajpai, 2012; ÅF-Engineering AB, 2011; Tran and Vakkilainnen, 2008).
Pulp may be produced at the same site where paper is being manufactured (integrated mill). Wood is debarked and chipped prior to the pulping process. It has long since been generally agreed that a uniform chip size is best and desirable. The bark and excessively fine chips are sent as fuel for the recovery system to be discussed later in the text (American Pulpwood Association Inc., 2008; Fuller, 1987).
Where the main purpose is to remove non-cellulosic material, primarily lignin, pulping may be done mechanically (which includes augmented variations termed thermomechanical, chemimechanical or chemithermomechanical pulping) for low grade papers such as newsprint. Kraft pulping is a full chemical pulping process that offers superior pulp strength and is the most dominating chemical pulping process worldwide (Bajpai, 2012).
White liquor, essentially a sodium hydroxide – sodium sulfide mixture, is used in a digester to dissolve lignin in the wood material. It is generated from a mixture various causticizing agents, virgin or recycled/regenerated, including calcium oxide, sodium carbonate, water, etc.; the main active components, however, are sodium sulfide and sodium hydroxide. Kappa number after digesting may range from 30 – 100 (ÅF-Engineering AB, 2011; “Purpose of Pulping,” 2007). After cooking, effluent streams of black liquor and non-condensable gases are obtained. These waste streams are bound for chemical recovery and materials recycling systems which will be discussed later in this text. Cooked wood chips, now roughly pulp yet unbleached, are deknotted before proceeding further; knots are sent back to the digester so that their fibers are not wasted.
An oxygen delignification stage, employing alkali (expressed as NaOH) and molecular oxygen, is utilized before the main bleaching stage. Implemented at around the 1980’s and 1990’s, it serves the purpose of effecting a net decrease of the chemicals to be used in the chlorine-using bleaching stage – the step that utilizes and releases highly toxic and corrosive chemicals (Patrick, 2005; van Heiningen and Genco, n.d.). Effluent from this stage is merely termed COD (chemical oxygen demand), implying a wastewater stream that has high levels of oxidizable organic matter; it may be carried over to the bleaching station, be discarded through a wastewater effluent of its own, or sent to recycling systems.
Bleaching is a multi-stage process which gives pulp material ready for paper production. It is in this stage that the final adjustment of kappa number may be made (i.e., a final delignification is being done), but most importantly, it is the stage where the base brightness of the paper is decided (“base” brightness is the term used because further alterations to improve such parameter may be done during the paper-making stage). Mills generally employ 3 to 5 bleaching stages that wash the dissolved lignin and spent chemical along a waste effluent stream. Figure 1 is an example from ÅForsk-Engineering. Because the waste substances (chlorinated phenols, dioxins, etc.) from this stage are highly toxic and corrosive, recovery of said substances are highly impractical (Bajpai, 2012). Figure 1. Direction of pulp is represented by the ochre arrow, while the blue arrows represent flow of bleaching chemicals (towards treatment). D stands for chlorine dioxide, E for sodium hydroxide, P of hydrogen peroxide, and O for oxygen. “Clean condensate” comes from the chemical recovery and recycling systems. “HD” in “HD O2” stands for high-density.

Diagrams from ÅForsk-Engineering are from a proposed model mill published on late 2010 and use elemental chlorine-free bleaching while Sappi, through a video released on their official YouTube channel, claims that their bleaching method is total chlorine-free.
After bleaching, the pulp (now called “raw stock”) is refined to become ready for paper making.

Chemical Recovery (Tran and Vakkilainnen, 2008; New Zealand Institute of Chemistry, n. d.) Black liquor from the digester plant is yet much too dilute for the organic compounds dispersed to be used as fuel for a recovery boiler. It is subject for concentration in an evaporation plant to give non-condensable gases (NCG’s), steam, and a 60% – 70% of sludge (basis is Dry Solids).
The recovery boiler is fueled by reject biomass and non-condensable gases from the first steps of the pulping process (debarking, chipping, digestion). Feeding the concentrated black liquor into the oxygen-deficient environment of the boiler gives back the spent Na2S. The inorganic smelt of sodium compounds is recovered as a molten smelt consisting of sodium sulfide and sodium carbonate. This is dissolved in water or dilute alkali (recycled from the recausticizing plant) to give green liquor. Green liquor is recausticized back to white liquor to be used again for digestion. Losses are compensated for by introducing virgin sodium carbonate and sodium sulfate into the black liquor before evaporation. Recausticizing involves the use of calcium oxide from the burning of calcium carbonate in a lime kiln. The reaction takes place in a slaker and then through a series of agitated tanks respectively:
CaO + H2O → Ca(OH)2(aq)
Ca(OH)2(aq) + Na2CO3(aq) → CaCO3(s) + 2NaOH(aq)
Calcium carbonate is neither soluble in water nor in dilute acid/base solutions and thereby gives a sludge. Mills employ gravity settling devices (clarifiers) for such reactions so that the sludge is in the underflow and the recently-reformed white liquor is on top and readily separable from the insoluble calcium carbonate.
The sludge or “mud” is then subject to a weak wash. The washing is used to dissolve the recovery boiler smelt, while the recovered calcium carbonate is fed to a lime kiln to generate calcium oxide which will again be used for recausticizing.

Paper-making (Bajpai, 2012; Sappi, 2012)
Raw stock is converted into finished stock for the paper machine. Refining may be a single or multi-stage process wherein the pulp is subjected to forces (tensile, compressive, shear, etc.) to develop the properties of the fiber; in addition to improving/manipulating the degree of fiber fibrillation, various subtle changes actually happen to give a fiber the capability of more flatness and flexibility. While fiber-to-fiber bonding might probably be the most basic force that holds a sheet of paper together, wood fibers alone would give rough-textured and unevenly dense paper; hence, additives such as alum and starch (Northern Port Realty Corporation, 2014) are added inter alia. Slurry composition is adjusted after refining prior to feeding into the headbox where the fibers start to exhibit its foremost sheet properties.
As the slurry exits the headbox onto the wire mesh (of the Fourdrinier machine or modified versions of it), the fibers align in the direction of the wire and interlaces to finally form a sheet out of the pulp that is still basically a wet web of fibers. The water exits through the mesh usually with the aid of vacuum boxes located under the Fourdrinier table. After web formation, the paper will go through an extensive series of pressing and drying sections; heat being employed at the later part of the process. It should be noted that final moisture content is not zero; too dry paper will probably become too brittle.
Modifications have been made to the initial design of the Fourdrinier machine. Because water exits only through one side at this stage, one side of the final product might have different properties from the other side. Manufacturers, over the years, have developed twin wire mesh systems to address this issue.
Before reeling the paper into a roll, a calender is employed to give the paper an initial level of smoothness.
The incoming web is reeled until a predetermined diameter is obtained. A new reel is placed immediately after the preceding one is removed from the receiving end of the paper machine.
For materials used for paperboard or corrugated paper boxes, usually no further processing is required; the rolls are cut and sold to customers for production of folders, brown envelopes and the like. For other products, off-the-line process operations are conducted such as coating, calendaring, or super calendaring and winding.

II. Danao Paper Mill
The Paper Mill project of Cebu Northern Port Realty Corporation was most recently upgraded starting the year 2002 and operations resumed in 2005. The plant operates continuously for 24 hours a day and 300 days per year. The main product is corrugating medium (kraft paper) and is produced at a rate of 40 tons per day.
Fresh water for the mill comes from a dam located at the mountains and three deep wells as alternate sources of fresh water. Total water required is 2200m3 per day. The water is used as dilution to the pulpers, cooling water, shower water at high pressure and for the production of steam. There is no dedicated power-plant on site; the water is neither returned to the sources. Water is recycled as much as possible, with total wastewater surmounting only to 1% to 2% per day. Pulp-fiber waste also surmounts to about 1% per day. The effluent first passes through a clarifier tank and only the clear wastewater from the overflow is discharged to the existing lagoon. The underflow sludge mainly consists of carbonate and waste pulp fibers; after separation from the clarifier tank it is puddled nearby where it dries under the sun. The “soil-like” matter is then shoveled elsewhere, purportedly, to be used as appropriate for gardening and landscaping purposes around the mill site.

Stock Preparation Old corrugated cartons (OCC’s) are the primary raw materials in addition to yellow pad paper and used envelopes. These materials are stocked in bales at around 450 – 900 kg per bale. The pile is four to six meters high and is housed in such a way that inventory taking is easy.

Repulping Process
(Re)Pulping
OCC’s are conveyed into the pulper along with diluting water for 5 to 10 minutes. Here, disintegrator blades operate at high speeds and the output is a stock whose consistency is roughly 4% (4kg fiber per 100L mixture).

Primary Cleaning The stock is pump into a settling chamber called a Riffler where the heavier particles settle down the flow path of the lean pulp and water mixture. The lighter mix flows to the inclined screen for dewatering and to the pulper stock storage chest. The water drained through the wire is recovered and reused.

Secondary Cleaning The pulp and water mixture at a regulated consistency of 3.5% – 4% is pumped into a High Density Cleaner to “loosen” the heavier solid particles from the pulp fibers by centrifugal action. A counter pressure water flow at a given pressure is made to flow against the downward moving pulp mixture to aid in the task, as well as to result in less denser material to float. The upward counter-current is collected with filtering; the filtrate is reused and the residue – plastics, polystyrene foam particles – are collected in a sack. “High density” refers to the pulp mixture, whose relative density is greater than that of the separated plastics. Combi-sorter Accepted fibers from the high density cleaner go to a double screening set-up using a hole-screen and slotted screens. This further separates the larger fibers from the acceptable sized fibers with a deflaking action for fiber agglomerates to reduce the flake size. This happens as the paper is not completely disintegrated in the pulper. The mixture of larger flakes and plastics are reprocessed using a vibrating screen so that fiber material is recovered and plastics are discarded. The main pulp mixture, now at 0.9% consistency, continues to the low density cleaner.

Low Density Cleaning It is in this stage that a final rough cleaning is commenced. “Low density” refers, again, to the pulp mixture having a density less than that of the sands, grits and metallic dirt that will be separated.

Final cleaning by Hole Screens The accepted pulp from the low density cleaner is passed through a hole screen for final particle size and particle density separation operating at 0.8% – 1% consistency. Accepts from this stage goes into the thickener.

Pulp Refining The thickened pulp stocked at the refiner stock chest is ready for refining. The consistency regulator controller is set at 3.8% to 4.2%. The refining equipment is a double disk refiner with a 355 kW motor. The refining blades are 24 inches in diameter, rotating at 900 revolutions per minute. Automatic safety back-off device is installed. The refiner can handle up to 80 tons of pulp per day. The refining process control is dictated by the drainage rate and fiber length index of the pulp.

Pulp Blending After the refinery operations, the refined stock is stored at the Refined Stock Chest, and then transferred to a pulp mixing tank where metered chemical additives are added. The mix needs retention time for full incorporation of the additives; hence, the mixed stock is transferred to a blending tank for 30 minutes. After blending, the stock is transferred to the machine chest where a pump feeds the stock to the Jordan refiner for final correction of the drainage ability of the pulp. The drainability is controlled by a fibrillating/cutting treatment. Frome here, the stock is fed to the constant level box (or stuff box) then to the suction pipe of the fan pump which pumps the pulp suspension at low consistency to the vertical screen for the last cleaning step and provides a stable flow to the headbox distributor pipe. On these lines, the coagulants, drainage agents, retention aids, defoamers and pH adjusters are introduced. The stock flow, consistency variations, pH variations and variations in retention-aids affect the operation of the headbox and the subsequent operations at the Fourdrinier table.

The Paper Machine Proper
Headbox
The paper machine is the heart of the paper mill; the headbox is its key factor. It is explicitly a must that the suspension leaving the headbox be uniform. The headbox deals with fiber suspensions in the range of 0.6% to 1% consistency. Basically, a sheet of paper is just a determined shape of fiber networks, and the properties of the fiber network are greatly determined by the consistency of the incoming pulp/fiber suspension. As the suspension leaves the headbox through a slit of predetermined width, assisted by a pressure pump designed to purge the mixture in a completely uniform fashion to the wire mesh of the Fourdrinier table, the sheet fiber-to-fiber bonding structures immediately begin to form; on a macroscopic level, one will see a wet sheet of paper being formed from a suspension containing 99% water. Water drains from the wire mesh and onto the couch pit, where it is drained to a collecting vessel for reuse.

Wet Presses The wet sheet at 80% water content leaves the Fourdrinier table through a couch roll, transferred to a travelling felt, and is pressed between a pair of press rolls (cylinders). An area of sheet leaving a pair of pressers is accepted immediately by a felt that helps drain the water from the sheet by absorption. Note that this segment is part of the Fourdrinier Table in the process flow diagram.

Dry Presses The dryers consist of 24 cylinders grouped into 3; each group contains 4 internally steam-heated pressing pairs of cylinders. The air in the area to which moisture is released by the sheet is removed by a blower for each dryer pair.

Boiler Steam for the dryer section is produced by the Bio-mass boiler at a rate of 10 kg/cm2 saturated steam pressure and 8 tons steam per hour production. This is passed through a pressure regulated valve; outlet pressure is set at 4 to 5 kg/cm2. The steam distribution is in three sections and the steam pressure is controlled at different entering pressures to provide cascading effect for the flash steam to be used in the next stage of drying process.

Reel and Winder The dry sheet coming out of the dryers is wound at a reel to a diameter of 1.5m on a spool. The spool is rubber layered for friction, hence to enable tension as the spool is rotating and the paper is tightly wound. As the maximum spool diameter is reached, the sheet is merely sheared off and immediately transferred on to a new spool. The finished spool is removed using a reel crane and moved to the winder for cutting to the ordered size. Wastes from the process are sent back to the pulper as raw material.

Mass Balance 2.2 Tons/hr of paper; start at headbox as fibre suspension to calender/reel as dry paper.

Input | Tons | | Output | Tons | Fiber | 2.09 | | Paper | 2.2 | Water | 258.91 | | Water from Fourdrinier table | 249 | | | Effluent water from 1st press | 6.38 | | | Effluent water from 2nd press | 0.58 | | | Water vapor from dryer | 2.44 | | | | Total | ~261 | | Total | ~261 |
Table [ 1 ]Mass Balance. Basis: 1 hour of operation. Note: composition after 2nd pressing is the same after 3rd pressing (see PFD at fig. 3)
Figure 2. example PFD from ÅForsk-Engineering.
Figure 2. example PFD from ÅForsk-Engineering.

Figure 3. PFD from Danao Paper Mill
Figure 3. PFD from Danao Paper Mill

Waste Management

I. Overview There are a vast number of principles and methods with which to treat wastewater effluents from the pulp and paper industry (Johnson Screens®, 2010; Gunderson, 2014; Veolia, 2010). Included are: microfiltration methods, contact clarifiers, pressure and gravity type filters, dissolved air flotation, electro deionization, reverse osmosis, and biological treatment methods. When wastewater is treated and its polluting constituents are reduced below accepted environmental levels, it may be discharged into water bodies or reused.
Modern integrated mills have four major liquid effluent wastes: those that contain high amount suspended solids (mainly fibrous), high COD, toxicity (including adsorbable organic halides, chlorinated organic compounds), and color (Gunderson, 2014; New Zealand Institute of Chemistry, n.d.). Solid wastes to be considered are the burnt biomass discharge batches from the boilers, sludge from clarification of turbid waters. Turbid effluents that can no longer be re-circulated along the production lines (mainly in the pulpers) can be pooled in a conventional clarifier tank; the sludge may be discharged to landfills and burnt or incinerated. High COD/BOD waters (usually from O2 delignification methods) are treated using biological or chemical means; and extensive commercial technological products have been produced ever since. Treatment would be best done on- or off-site; basic considerations would include treatment and transportation costs. When a mill uses bleaching, effluents would usually contain dioxins, furans and other persistent organic pollutants such as polychlorinated biphenyls among other chlorinated hydrocarbons; in Germany, AOX is used as a representative parameter of biotoxicity and potential hazard arising from the aforementioned chemical classes (Noma, Yamane, and Kida, 2001). Ozone has remained a choice for the obliteration of acute toxicity of the waste and the treatment of chlorinated hydrocarbons. Such treatment is expensive, but combining such a method with biological treatment is still an attractive option.

II. Danao Paper Mill Wastewater effluent from the mill purportedly has no impact to the environment. All wastewater effluents (except water vapor as steam) are collected into a conventional clarifier tank. The sludge is purportedly stacked at an area near the site, dried under the sun, and is used by the mill workers as gardening material. The sludge is supposedly alum, starch, organic material coming from the pulp and mainly carbonate – hence, the sludge is purportedly and basically soil. The overflow clear water is discharged into an existing lagoon adjacent to the sea. Workers are even reported to have done fishing activities whenever the tides are high. Personnel from the environmental agencies rarely visit the mill (about once or twice every two years); no flags were raised even during the times that they did visit. The mill is said to have negligible environmental impact.

Future Trends and Direction

I. Pulp and Paper industry in the Philippines
Philippine pulp and paper industry was one among 17 Philippine industries that need upgrading; the criteria being (1st) potential strength to generate employment, (2nd) address missing gaps, linkages and spill-over effects, (3rd) level of product sophistication, and (4th) competitive market environment. Philippine Institute for Development Studies (PIDS) acting vice president Dr. Rafaelita M. Aldaba said as quoted by Sun Star (2013) that “for paper there is a need to expand fiber raw material base, develop massive tree plantations and commercial agro forestry integrated with virgin wood pulp production.”

II. Danao Paper Mill Finance and capital has been a problem for the mill. An aid to further income of the company would be to install hot stock disperging and size press machinery. Many buyers prefer not to buy kraft paper with colored spots, and hot stock dispergers serve to eliminate said spots in addition to adding fiber strength. Size presses aid the retention of chemical additives hence less amount would then be needed should this equipment be available; also, it will help achieve more flatness for the paper. In a matter of 3 – 5 years, a marine-life-habitable pond will be in place adjacent to the lagoon behind the mill. Overflow from the clarifiers will first pass through the pond before overflowing into the lagoon. Total budget for the said plans was estimated to be 3 million pesos last 2012.
Conclusion
As with probably any industry, Pulp and Paper has long since been subject to development. In particular, development towards greener manufacturing is underway and is making progress. Delignification processes are now purportedly being carried out using total-chlorine-free (TCF) methods – a decent strategy to avoid chlorine-based compounds that are harmful to the atmosphere. The rising problem is now with fiber supply. Because complete and statistically reliable reports are hard to obtain due to negligence of countries that should respond when asked for information by Food and Agriculture Organization of the United Nations (2011), one can only hope that our forests, worldwide, are capable of sustaining the ever-increasing production of paper (“The Paper Life Cycle,” n.d.). Danao Paper Mill has received no urgent recommendations from DENR. Its recycling methods are efficient and have negligible environmental impact; nonetheless, there is always room for development.

Recommendation This goes to the consumers. Recycling paper is a must. Explicitly separate trash bins for paper need to be implemented strictly. This could substantially reduce the need for harvesting virgin raw material for paper production. For Danao Paper Mill, any upgrade that could serve to reduce the usage of even the minute chemicals being currently used might be best installed. It also could be worthwhile, in the long term, to consider the PMIR criteria for development and upgrade.

References
(In order of appearance)

Andritz Pulp & Paper (2014). Research and Development. [ONLINE] Available at: http://www.andritz.com/pulp-and-paper/pp-research-development.htm. [Last Accessed March 4, 2014].

Confederation of European Paper Industries (2011). Pulp & Paper Industry Main economic developments. [ONLINE] Available at: http://ec.europa.eu/enterprise/sectors/wood-paper-printing/files/advisory-committee/3-cepi-101129_ec_fbi_advisory_committee_cepi_presentation-pat_en.pdf. [Last Accessed March 4, 2014].

Custom Content (2013). The Paper Chase. [ONLINE] Available at: The Paper Chase 2013 http://customcontentonline.com/sections/130114_Paper.pdf. [Last Accessed March 4, 2014].

Food and Agriculture Organization of the United Nations (2009). State of the World's Forests. [ONLINE] Available at: http://www.fao.org/docrep/011/i0350e/i0350e00.htm. [Last Accessed March 4, 2014] in Green Blue joint environment programme (2009). Supply and Demand. [ONLINE] Available at: http://thepaperlifecycle.org/use/in-depth/supply-and-demand/. [Last Accessed March 4, 2014].

Reuel John F. Lumawag (2013). 17 Philippine industries need upgrade. [ONLINE] Available at: http://www.sunstar.com.ph/davao/business/2013/11/28/17-philippine-industries-need-upgrade-316162. [Last Accessed March 4, 2014].

American Pulpwood Association (2008). CHIP QUALITY WHAT DOES IT MEAN TO YOU AND YOUR CUSTOMER?. [ONLINE] Available at: http://flash.lakeheadu.ca/~repulkki/for3234/Chip_Quality.pdf. [Last Accessed March 4, 2014].

William S. Fuller (1987). Kraft Pulping New Developments in an Old Technology. [ONLINE] Available at: http://frmconsulting.net/articles/kraft_pulping.pdf. [Last Accessed March 4, 2014].

Bajpai, P., (2012). 'A Brief Description of the Pulp and Paper Making Process'. In: (ed), Biotechnology for Pulp and Paper Processing. 1st ed. : Springer. pp.7 - 13.

Honghi Tran and Esa Vakkilainnen (2008). The Kraft Chemical Recovery Process. [ONLINE] Available at: http://www.tappi.org/content/events/08kros/manuscripts/1-1.pdf. [Last Accessed March 4, 2014].

Ångpanneföreningens Forskningsstiftelse (2010). Energy consumption in the pulp and paper industry - Model mills 2010 Integrated fine paper mill. [ONLINE] Available at: http://www.aforsk.se/images/pdf/09-163fine-paper-final-jan-2011.pdf. [Last Accessed March 4, 2014].

KnowPulp (2007). Chemical Pulping. [ONLINE] Available at: http://www.knowpulp.com/english/demo/english/pulping/cooking/1_process/1_principle/frame.htm. [Last Accessed March 4, 2014].

Ken Patrick (2005). Mills Boost Production, Cut Fiber Cost By Cooking to Optimum Kappa Levels. [ONLINE] Available at: http://www.paperage.com/issues/march_april2005/03_2005kappa.pdf. [Last Accessed March 4, 2014].

Adriaan van Heiningen and Joseph M. Genco. Oxygen Delignification Principles and Practice. [ONLINE] Available at: http://www.epa.gov/projctxl/inter2/1001.pdf. [Last Accessed March 4, 2014].

Jeff Gunderson (2014). Water Treatment in the Pulp and Paper Industry. [ONLINE] Available at: http://www.waterworld.com/articles/iww/print/volume-12/issue-3/feature-editorial/water-treatment-in-the-pulp-and-paper-industry.html. [Last Accessed March 5, 2014].
Johnson Screens (2010). Johnson Screens Solutions for Pulp and Paper. [ONLINE] Available at: http://www.johnsonscreens.com/sites/default/files/5/741/Pulp%20&%20Paper%20Capabilities.pdf. [Last Accessed March 5, 2014].
Veolia Water (2010). Creating Water Solutions for the Pulp and Paper Industry. [ONLINE] Available at: http://www.veoliawaterst.com.au/vwst-australia/ressources/files/1/16912,VWS-Australia-Creating-Water-Solut.pdf. [Last Accessed March 7, 2014].
Noma, Y.; Yamane, S.; Kida, A.;, (2001). Adsorbable organic halides (AOX), AOX formation potential, and PCDDs/DFs in landfill leachate and their removal in water treatment processes. J Mater Cycles Waste Manag. 3 (1), pp.8
Rein Munter (n.d.). Industrial Wastewater Treatment. [ONLINE] Available at: http://www.balticuniv.uu.se/index.php/component/docman/doc_download/286-water-use-and-management-19-industrial-wastewater-treatment. [Last Accessed March 8, 2014].