World-wide, paper is mostly produced from cellulose fibres. Less than two-thirds comes from wood, one-third comes from recycled paper and about 5% comes from non-wood sources. Recycling is principally developed in western countries (40% of the production in western Germany for example) and non-wood fibres (such as bagasse, cereal straws, bamboo) in developing countries.
The leading pulp producers are in North America (USA 71.4 Mt., Canada 16.5 Mt.), whilst the European Community (39.6 Mt.), Japan (28 Mt.), China (16 Mt.) and the ex-USSR (10.3 Mt.) are also important producers.
Paper and paperboard production for each continent is:
|Central and North America:||91.2 Mt.||38.3%|
|Europe and ex-USSR||77.4 Mt.||32.5%|
|South America||7.7 Mt.||3.2%|
|Africa and Oceania||5.5 Mt.||2.3%|
Source: FAO 1991
The purpose of this section is not to report statistics, but to highlight worldwide disparities in paper consumption which correlates significantly with the economic level of the country. For example, the 1988 consumption per capita was: USA: 310 kg; Sweden: 246 kg; France: 142 kg; China: 6 kg. This data shows that western countries are consumer leaders. The consumption of a Chinese citizen is less than 2% of that of a US citizen.
It is also interesting to take into account the evolution of the production/consumption rate. The last 30 years show an evolution in the total production/consumption of paper (in million tons):
The main steps for papermaking are:
which can be split into 3 groups of activity to be studied during the EIA or the EA.
Figure 1: Main kinds of activities to be studied during the EIA or the EA of a pulp and paper project.
About 30% of paper production is based on recovered paper, and the balance uses virgin raw materials. Wood is the main fibrous raw material used to produce pulp, and accounts for more than 90% of the production. Non-wood fibres are an important source of raw materials, especially in developing countries. They can be by-products of agriculture such as bagasse and cereal straws, or industrial crops like bamboo, esparto, sisal, flax, and sorghum.
Whatever the sources of the material, it generally needs to be cultivated (even if the management is coppice or natural regeneration) and it always has to be harvested.
These two operations have to be addressed in the EIA, principally in the case of the exploitation of non-renewable resources (such as primary forests) or the replacement of such forests by plantations of industrial wood such as eucalyptus or pine.
After transport to the plant, the raw materials are processed to transform them into paper. These operations involve inputs and outputs to the process. They require space and consequently can compete with other uses for the site. In addition, manpower requirements and the safety of workers and populations must be an issue of concern for investors.
Generally, pulp and paper plants have large capacity, and need important stocks of raw material in the plant or in the production area. These stocks can be sources of pollution or diseases (particularly in forest areas). The EIA study must take into account these particular points.
Preparation of the raw material is necessary before it enters the papermaking process. Wood, for instance, first needs to be debarked usually by mechanical or hydraulic processes, and is then disintegrated, generally by chipping into particles of the adequate size.
All raw materials used in papermaking, except chemicals, fuels and additives, contain fibres, but cellulose fibres constitute approximately only 50% of the dry-weight of raw materials. The goal of pulping is to separate the fibres from the material. The remaining components (hemicellulose and lignin) must be treated and constitute the major potential sources of pollution in chemical pulping.
Basically, there are 3 different groups of pulping methods,
This method consists in grinding raw material against an abrasive surface to defibre the raw material (more generally softwood) without any lignin dissolution. A high yield is obtained by this method, generally more than 95% of the dry-weight of the wood. Some methods use high temperature and pressure to increase the efficiency of the process. Mechanical pulping generates very low polluting effects but is an energy intensive process, as the non-cellulosic wood components are not available (as in chemical pulping) for energy recovery. World-wide 1989 production : 33 Mt.
This method separates the fibres from the raw material by making soluble all the non-cellulosic components in a cooking liquor at high temperature and pressure. Chemical pulping gives better paper quality, but is potentially the cause of greater environmental pollution. Capital and operating costs are higher than those of mechanical pulping. The yield of chemical pulping is about 50% of the dry-weight of raw material. World-wide 1989 production : 122 Mt. (90% sulphate or kraft, 10% bisulphite).
A wide range of processes combining mechanical and chemical methods are available but they represent a small part of the world-wide paper production. They generally involve a chemical pre-treatment of the raw material, before a mechanical treatment to liberate the fibres. The yields of these processes are situated between those for mechanical and chemical pulping. World-wide 1989 production : 7.5 Mt.
Pulp for packaging material can generally be used without bleaching. For other purposes, it has to be bleached. In mechanical pulping the most common agents are sodium or hydrogen peroxide and sodium hydrosulphite used alone or in combination. For chemical pulping, chlorine, sodium or calcium hypochlorite and chlorine dioxide are used. Oxygen pre-bleaching becomes more important in order to reduce chlorine use.
Paper mills can be integrated with a pulp mill or be independent. In the latter case, the pulp is generally dried before processing.
Pulp preparation includes slushing, mechanical pre-treatments, blending of pulps of different qualities and addition of fillers and other additives to make paper. The type of process differs for each paper quality required.
The five main paper grades listed in decreasing order of production volume are: (French statistics)
|- Cultural paper: newspaper, books, writing paper…||46%|
|- Packaging paper: kraft for packaging, corrugated paper…||37%|
|- Industrial paper: cigarette, sensitized paper, dielectric, checks, filters..||3%|
|- Tissues: toilet paper, handkerchiefs, napkins…||5%|
Raw material, end products, by-products and wastes, need to be transported inside or outside the plant. As the facilities generally have quite a sizeable production capacity (more than 500 t/day), transportation after the establishment of a paper mill always increases significantly around the plant. The change between the previous situation and the new one is something which must be assessed in the EIA.