|Industry and Energy - Initial Environmental Assessment Series No. 9 (NORAD, 1994)|
|Part I: General account|
|3 Possible environ mental impacts|
Table 1 contains a rough classification of the environmental impacts of various types of industrial production. Table 2 contains a similar overview of the environmental impacts of energy production based on combustion.
The environmental impacts are tabled in the following categories:
soil and ground-water
For every category the environmental impacts are given the following indication: Little, Moderate, Strong. It is emphasised that the classification is very rough, and should be used with care.
Generally the larger a project is the larger the probability of environmental impacts. The size can here be estimated in terms of funds investment, area requirements, number of employed, raw material consumption, annual production and energy requirements. Industry using obsolete technology, old production equipment or new and untested technologies merits special concern.
Several substances or chemicals are notably hazardous for human beings or the surroundings. Most chemicals will be dangerous to the work environments, if they aren't treated responsibly. Many substances can also contaminate the soil and the ground-water, preventing utilisation for a long time. Large amounts of inflammable materials or gases under pressure represent a risk. And preventive measures as well as appropriate safety routines in case of accidents are necessary. Some examples of materials and chemicals which should be considered critically are:
· environmental toxins,
· compounds that are extremely toxic to human beings,
· carcinogenic substances,
· ozone depleting substances (chlorofluorocarbons (CFCs), haloes),
· explosive or inflammable materials,
· radioactive substances, and
· illegal raw materials (ivory substances which break down ozone).
Table 3 gives examples of important environmental toxins, i.e. substances that are potentially harmful to animals, plants and other organisms, with examples of industries and products where these may be present. Important environmental toxins are heavy metals (lead, mercury, cadmium etc.) and chlorinated compounds (DDT, PCB, dioxins etc.).
The use of environmental toxins and other hazardous substances should be restricted as far as possible. Where possible alternative substances should be used.
There are several international environmental agreements which regulate amongst other discharges, use of specific substances, and transport of hazardous waste across borders. A well known example is the Vienna convention for the protection of the stratospheric ozone layer. The connected Montreal protocol requires the phasing out of specific chlorofluorocarbons (CFCs) and carbon tetrachloride within the year 2000. Many developing countries have agreed to comply with this agreement.
It is recommended to investigate if the country where the project will be implemented has adopted any international environmental agreement(s) which are relevant to the project. It may also be prudent to find out if there are environmental agreements outside the respective country with implications for the import of raw materials and export of products. A reference book on agreements as of 1992 is included in the list of relevant literature.
The environmental impacts from an industrial facility are not solely decided by technology and production equipment. It is clearly evident that the involvement and environmental responsibility of the management is just as important. When implementing an environmental impact assessment of a planned facility it is important to ascertain the environmental attitudes of the owners and management. It is also important to ascertain whether or not the environmental responsibility in the project organisation is clearly defined, and how it is being followed up.
When doing an environmental impact assessment of an existing facility it is in addition important to ascertain whether:
· discharges and other environmental conditions are
registered and documented,
· local environmental regulations are known and complied with,
· keeping and maintenance are satisfactory,
· the employees have received the necessary information and training with regard
to environmental aspects.
3.2.1 Pollution of the atmosphere
Air-pollutants appear mostly in the form of dust (solid particles) and gases. In special instances the substances may appear as liquid particles (fog) and steam.
Dust is, regardless of chemical composition, a nuisance and harmful when it appears in high concentration in air and fallout. The environmental impacts of the dust increase if it contains environmental toxins, for instance heavy metals, or if it is corrosive, e.g. quicklime and cement.
Chlorinated organic compounds and tar substances may exist bound to particles. These are health hazards in high concentrations.
Sulphur dioxide (SO2) and nitrogen oxides (NOx) are the most common air-pollutants resulting from industry and energy production. These gases are damaging to both health and vegetation. They are in addition the most important causes of acidification of the environment (acid rain).
Fluorides (especially hydrogen fluoride, HF) may damage vegetation through direct intake from the air, and animals through the ingestion of plants containing fluorides.
Volatile organic compounds (VOC) is a collective term for volatile hydrocarbons (excluding methane), alcohols and other organic substances. Most of these are individually not very damaging in the concentrations prevalent in outdoor environments. However, they may be hazardous to people and plants in combination with nitrogen oxides under influence of sunlight by forming tropospheric ozone.
The causes of unpleasant odours are usually gases or vapours. One of the most important causes of odours is hydrogen sulphide (H2S), which on the one hand is extremely toxic, but which on the other hand smells unpleasantly of rotten eggs also in low concentrations which are not damaging to health. Water with oxygen deficiency will often smell of hydrogen sulphide. Other substances causing smell will usually not have any impacts beyond the odour. But this in itself may cause considerable discomfort and should be taken seriously.
Carbon dioxide (CO2), methane, VOC and nitrous oxides (NOx) belong to the green house gases which may contribute to global heating.
Several carbon fluor compounds (CFCs, haloes) contribute to the breakdown of stratospheric ozone.
Table 4 gives an overview of important air-pollutants and their impacts. It must be stressed that the list is not comprehensive.
Table 5 gives an overview of important air-pollutants and examples of main sources in the industry.
Discharge of air-pollutants can be prevented through various measures:
· Choice of process. Use of baked anodes instead of the Soderberg anode in the aluminium industry virtually eliminates the discharge of PAH from these facilities. The discharge of mercury from production of chlorine is eliminated by using the diaphragm process which does not include mercury. Use of ammonia (NH3) instead of CFCs in refrigeration units.
· Choice of raw materials. Raw phosphate containing little cadmium for use in the fertiliser industry. Energy production from natural gas containing no sulphur instead of producing energy from coal.
· Choice of technology. Containment of processes to avoid fugitive discharges. Containment of crushing, sifting and transport of dusty materials. Containment of furnaces, tapping and refining operations in foundries and other metal industries. Containment of the stockpiles of raw materials and products within the cement industry.
The possibilities for choosing the most environmentally sound measure might in reality be restricted by available competence and resources. One such restriction might for instance be that local raw materials must be utilised.
It is possible to reduce discharge of most types of air-pollutants from industry through purification. The most important exceptions are carbon dioxide, CFCs and haloes. In practice the costs will decide the efficiency of the discharge reductions through purification.
The most important purification methods are:
· Dust (particles): Cyclones (efficient only for the large particles). Textile filters. Electrostatic precipitators. Scrubbers.
· Gases: Absorption. Adsorption. Condensation. Incineration. Catalytic oxidation. Sufficiently tall chimneys are important in order to reduce environmental impacts.
Tall chimneys are especially important in cases of substantial discharge, and when there is a short distance to houses or other sensitive areas. In cases of transient increased discharges, for instance in case of failure of purification units, it is important that the height of the chimney is dimensioned for increased discharges. It must be emphasised that tall chimneys are not a replacement for purification of discharges.
Disturbance of sleep can be the most serious impact of noise in the vicinity of industrial facilities. The regulations pertaining to noise are therefore more strict at night than during daytime. Hearing impairment for people in the vicinity will only occur in extreme cases. People are less disturbed by monotonous noise, for instance low frequency noise from fans, than from sporadic noise, e.g. sirens or expulsion of compressed air. In addition to noise from the industrial facility itself the noise from internal and external transport (trucks, loading and unloading of ships etc.) will have an impact.
The most important mitigative measures are:
· Source reduction. Choice of equipment with low noise levels e.g. electric engines, pumps, fans, ventilators, crushers. In addition choice of technical solutions implying low levels of noise.
· Containment. Noise muffling constructions surrounding crushers or other noisy equipment. Mantling of noisy machines with noise absorbing materials covered by heavy plates.
· Screening. Location of noise sources behind elevated terrain and buildings. Screens between source of noise and the recipient.
· Muffling. Elastic suspension to prevent transfer of vibrations. Mufflers in pipes for gas and air.
· Distance. Noise is muffled with increase of distance.
3.2.3 Pollution of surface water
Water is an important prerequisite for many industrial activities. Water can be a raw material (production of food and beverages), a solvent (chemical and metallurgical processes), transport medium (paper production), cleansing material (washing of vegetables and fish) and coolant (thermal power plants).
The water sources for an industrial activity can be surface sources (streams, rivers and lakes), ground-water, and in some cases rainwater. The most important factor regarding the amount of available water in an area is the climate. Physical and chemical processes, and the conversion of biological matter, will be different in the various hydrological ecosystems.
Many surface water sources are used as recipients of waste water which may cause pollution impacts. Where possible discharge sources should always be located downstream of a drinking water source. The industry discharges must be reduced so that the water quality in the recipient body is maintained.
Purification units require efficient operations in order to function as intended. Many purification facilities in developing countries are not run satisfactorily, something which considerably increases the pollution. This highlights the importance of assessing projects within industry in conjunction with water supply projects.
The ground-water is largely well protected against contamination. However, groundwater may be threatened by uncontrolled leakage of pollutants. One should therefore assess the potential threats to the groundwater in the relevant industrial area. Because of the long retention time for groundwater, contamination may ruin the possibility of usage of the ground-water for the foreseeable future.
An elaboration of the environmental impacts related to the use of water is given in a separate booklet:
No. 7 - Water supply, wastewater, irrigation.
The introduction of contaminants to water sources may cause various environmental impacts. Particles in the waste water can in sufficient concentrations cause siltage and sedimentation of the recipient. Nitrogen and phosphorous are especially important nutrients. The introduction of these nutrients can cause increased algal bloom (eutrophication). If the water source lacks nutrients, the introduction of nutrient salts within certain limits may be beneficial. In freshwater the phosphates are most important for the growth of algae, while in saltwater with high saline content nitrates are decisive. The introduction of waste water with high saline content to cultivated land may cause a salinization of the soil. Excessive introduction of organic matter to water sources may alter the oxygen balance and cause anaerobic conditions (lack of oxygen) which in turn may cause death of fish and alter the composition of species. In addition smell will occur and the water will taste bad due to the development of gas in the water. Garbage such as paper, textiles, plastic etc. in the water is unpleasant, and may disturb activities such as fishing or bathing. Heavy metals may harm human beings, and are acutely toxic to aquatic organisms. Some heavy metals are big-accumulative. Chlorinated organic compounds take a long time to break down. These may accumulate in the food chain and may be toxic or make the drinking water taste bad (chlorinated phenols). Many of the substances are also harmful to the aquatic organisms. Tar substances (including PAH) are primarily highlighted because they may be carcinogenic to human beings. One assumes that PAH may also be harmful to aquatic organisms. Mineral oil may in large quantities be lethal to aquatic birds and eggs, larvae, spawn and rooted aquatic organisms. The introduction of heated or cooled waste water may cause undesirable changes to the composition of species in the recipient.
Table 6 gives an overview of important water pollutants and their impact areas, and table 7 (page 34) gives their main sources in the industries. It must be emphasised that the lists are not comprehensive.
Pollution impacts from discharges of waste water will vary with the type of recipient:
· Lakes. The sensitivity is dependent on the size, water flow rate and other conditions. Eutrophication is a common problem.
· Rivers have some self-purifying capacity, especially with regard to organic material and nutrient salts. The self-purification capacity depends on the water flow rate and the length of the river.
· Estuaries (shallow coastal areas and bays, for instance in connection with river mouths) are basically vulnerable ecosystems due to the variation of the saline content. The pollution impacts will depend on the rate of pollution introduction, fresh water flow rate and tidal activity. The layering of the water can reduce the dissemination of the pollutants. One should be extra careful with regard to the discharge of waste water in estuaries.
· Ocean recipients with open seas and good water rates have an extensive capacity for assimilation, dissolution and decomposition of many pollutants. Controlled discharges of waste water to marine environments through well planned localisation of discharge points and technically sound discharge pipes may represent a good solution to waste problems in coastal areas. However, one must warn against establishing considerable discharges of heavy metals and compounds that are not easily decomposed.
The discharge of waste water should not take place directly at the edge of the water, but should be submerged at the deepest point in the river itself or be led out to deep water in lakes or oceans.
Discharges of water pollutants can be prevented through various alternative measures:
· Choice of process. Transition from using chlorine gas for bleaching in the cellulose industry to use of oxygen and peroxide plus chlorine dioxide. Production of tita nium dioxide pigment with the chloride process instead of the sulphate process, in order to avoid the creation of residual of diluted sulphuric acid.
· Choice of raw material. Avoid cadmium and chrome for chemical treatment of metal surfaces.
· Choice of technology. Purification of dust content in waste gases with dry filters instead of washing with water. Use of vacuum cleaners/sweeping machines for cleaning instead of hosing. Cooling of processing equipment with air instead of water. Measures to reduce the consumption of water. Closed circuits including recycling of water.
It is possible to purify all types of waste water from the industry. In practice the costs will define the purification limits.
The most important purification methods are:
· Mechanical purification:
- Sedimentation of particles heavier than water.
- Flotation of oil and other droplets and particles lighter than water.
- Filtration. Membrane filtration.
· Biological purification:
- Anaerobic (without air).
- Aerobic (with air).
· Chemical purification:
- Precipitation of dissolved and finely dispersed undissolved materials by treatment with chemicals (flocculation agents, acids, bases, calcium, iron, aluminium).
- Desinfection through treatment with chlorine (Cl2) or ozone(O3).
· Other purification methods:
- Adsorption on activated carbon.
- Ion exchange.
3.2.4 Pollution of soil and ground-water
Soil and ground-water can be polluted through direct introduction of polluted (acid) rain, gases and particles from the atmosphere. Such phenomena cause extensive soil washout and other damages to densely populated and industrialised parts of the world, like Europe and North America. Further the introduction of radioactivity and heavy metals such as lead and cadmium may adversely impact the soil and plant growth. Pollution of soil often has a slow stealthy development and may have major consequences for the soil as a productive resource. Those developing countries who have little energy consumption and low industrial production compared to the available land area are less vulnerable to this type of regional pollution.
Pollution of soil and ground-water in the vicinity of industries as a consequence of discharges to air may occur in special circumstances. However, this is not common.
Industrial pollution of soil and groundwater occurs primarily in connection to:
· Infiltration of waste water which is not led to a recipient body of water.
· Leakages directly to the ground. . Burial and deposition of waste.
Purification of contaminated soil and groundwater is difficult and very costly. The emphasis should therefore be put on preventive measures.
Production waste from industry can simply be defined as substances the industry desires to get rid of. Some types of waste can be utilised, and are therefore valuable. The delineation between waste and bi-product is not always clear, and changes with time and place. Waste which is extra toxic or environmentally damaging, and which therefore must be treated with special care, is defined as hazardous waste. In practice it is not always easy to distinguish between hazardous waste and other waste.
Important types of production waste from industry are:
· Mineral waste. Ash from combustion of solid fuels. Dust from purification units for waste gases. Slag from metallurgical processes.
· Animal and vegetable waste. Waste from food industry, butcheries, dairies and fish processing industry.
· Waste containing fibre. Paper from printing presses and packaging. Sawdust. Bark. Waste fibres from factories producing paper.
· Other waste. Waste from construction and demolition. Used packaging. Residue of raw materials. Faulty products.
· Hazardous waste (oil, solvents, PCB, asbestos, dust and sludge containing heavy metals).
Table 8 shows examples of types of production waste occuring in various industries. The creation of waste can be prevented or reduced through a series of alternative measures:
· Choice of raw materials. Production of cement using raw materials with a low alkaline content (Na, K) and chloride. Recirculation of packaging.
· Choice of process and technology. Containment of processing equipment to prevent leakages. Process control to prevent faulty products which become waste.
The most important principles for the disposal of waste are:
· Recycling. Recycling of packaging, e.g. bottles and barrels.
· internal recirculation. Recirculation of fluorides from waste gases to the electrolytic cells at aluminium smelters. Recovery of metal from slag in metallurgical industries. Recovery of cooking chemicals in the cellulose industry.
· External recirculation. Dust containing silica from ferro-silicone production utilised in production of concrete. Waste from the food industry used as animal fodder. Paper waste utilised as raw material for paper and cardboard industry. Waste used as fuel.
Several industries utilise product waste as raw materials for new production. Metals, paper, textiles and glass are well-known examples of this. The collection, transport and sorting of waste prior to recirculation is labour intensive and may therefore be well suited for developing countries. In many developing countries recirculation is widely practiced.
The most important technical principles for the treatment of waste are:
· Deposition: Uncontrolled deposition of waste may be contagious and pollute air (fires) and water (seepage). Waste deposits which contain "edible" waste are attractive for undesired animals (carrion, rodents, birds and insects). The problems are reduced considerably through controlled deposits with covering of the waste and location such that the seepage does not contaminate valuable water resources.
· Composting: A denotation for various processes entailing the biological breakdown of organic waste. Compost can be utilised in agriculture and forestry.
· Incineration: Incineration of waste on open fires results in excessive fumes and incomplete combustion. This is therefore not recommended. The use of special furnaces is more efficient, and gives a possibility for the recovery of energy. Purification of the waste gases will usually be necessary.
· Other methods: Chemical treatment, for instance oxidation of cyanides to harmless compounds. Treatment of dust or sludge with cement in order to adapt it for deposition .
More information on environmental impacts of waste management is given in a separate booklet:
No. 11 Waste management.
3.2.6 Major accidents and accidental discharges
Accidents with impacts beyond the vicinity of the workplace are termed major accidents. The most important categories of major accidents in industry are explosions, fires, poisoning and environmental damages related to uncontrolled discharges. Internationally catastrophic discharges within the chemical industry, e.g. Bhopal in India or Seveso in Italy, are few but especially well-known. Less devastating accidents are numerous, and will especially be prevalent where there is a combination of dangerous processes and substances with a weak administration, competence and maintenance. Generally one assumes that roughly 20% of the accidents are attributable to the technology, while 80% are due to human error.
The risk for major accidents is present in connection with:
· Extremely toxic substances (e.g. methylisocyanate, several pesticides, mercury).
· Explosives and other reactive substances (e.g. hydrogen, ammonium nitrate).
· Inflammable substances in large quantities (e.g. gasoline, natural gas).
· Gas under pressure (e.g. chlorine, oxygen).
· Dangerous equipment (e.g. furnaces, chemical reactors, high pressure processes including steam facilities!.
A risk analysis may be relevant to identify possible accident scenarios and to develop preventive measures.
Contingency plans may be required. If contingency plans shall be meaningful, the primary requirement is that the personnel is organised and that regular training is given. In addition equipment, such as fire extinguishers, is needed.
3.2.7 Physical and chemical working environment
In the industry there are frequently close connections between the chemical and the physical environment at the work places and the discharges of pollution in the environment. This is one of the reasons why the industry frequently regards HES (health, environment, safety) as an integrated responsibility of management. In government the responsibility is usually divided, different ministeries have responsibility for the workplace and external environments.
The physical and chemical work environment is recommended included in the initial assessment.
The employees may be harmed through exposure to the impacts
· Mechanical energy (falls, blows, contact with rotating or moving machinery).
· High temperatures (flames, steam, contact with hot objects).
· Electric energy (shock).
· Chemical substances (inhalation, skin contact).
Some substances that are especially critical in relation to work environments are:
· Carcinogenic substances. Benzene, PAH, asbestos, quartz-dust, sawdust from several tropical hard woods.
· Heavy metals. Cadmium, lead, mercury.
· Solvents. Alcohols, hydrocarbons, chlorinated compounds.
Table 9 contains a list of workplace air contaminants. The list is not comprehensive.
The physical and chemical work environment can be cared for through:
· Appropriate choice of process, raw materials and auxiliary substances.
· Design and maintenance of facilities.
· Systematic efforts to replace dangerous substances, equipment and methods with less dangerous ones.
· Use of personal protection equipment.
· A system for the management of dangerous substances. This includes proper marking and use of product data sheets which give information on prevention and treatment of injuries.
· Systematic monitoring. Periodic health controls, inspections and measurements.
One should also take special consideration of certain cultural conditions that may be of importance with regard to the work place security. An example may be that the employee desires to wear specific clothing which may be dangerous or unsuitable in the vicinity of moving machinery. Another example may be that religious rituals like fasting periods may cause exhaustion and the employee may consequentially be less observant than usual. How the conditions are adapted to allow for such culturally motivated actions will vary. But the solutions can be found in cooperation with those this applies for.
3.2.8 Impacts caused by products
Pollution is not only due to discharges during production. The environmental focus is increasingly being directed at the products, how they are being used and how the waste is being treated subsequent to use.
In an initial assessment the emphasis should be on whether the industry is producing products that are environmentally damaging. Examples are products that contain toxic, carcinogenic or environmentally harmful substances.
The consumers are increasingly demanding that the products which they buy are being produced in an environmentally responsible manner. As an example large consumer groups are currently avoiding the purchase of cellulose bleached with chlorine. An industry with substantial discharges is therefore running a market risk.
The waste amounts should be minimised when implementing measures at product development or production level. An example is to avoid superfluous packaging, and to use packaging that can be re-utilised (return bottles of glass or PET) or recirculated in another manner (used cartons as raw materials for new products).
Polyvinyl chloride (PVC) is a well-known example of products that are environmentally controversial. The arguments against PVC are the work environment problems at the production stage (the raw material VCM is carcinogenic), discharges and waste from the production process, some environmentally harmful additives and discharge to air when incinerating waste. Arguments for the use of PVC is that it is cheap, is durable and is advantageous with regard to energy requirement compared to many competitive products. Use of good technology for production and possible waste incineration can assist to prevent pollution problems at the work place and in the environment.
A comparison of for instance PVC and alternative materials can be done by a life cycle analysis. A life cycle analysis includes a systematic assessment and evaluation of all environmental impacts from "cradle to grave" for a product, from extraction of raw materials to the deposition of waste. A life cycle analysis is labour consuming, and lies outside the frame of an initial assessment.
3.2.9 Impacts on the community affecting the natural environment
Population movement and demographic changes as a consequence of an industrial establishment may cause increased exploitation of the natural resources in the places where new settlements emerge. But the pressure is eased on the natural resources in the vacated areas. In the new settlement areas the pressure will increase on drinking water resources, recipients for waste water, and forests as sources of fuel and building materials. Increased settlement also creates pressure on agricultural areas.
An industry project normally generates employment in other sectors, for instance transport, maintenance, service functions and public administration. Depending on the conditions each industrial employment can generate 2-3 employment opportunities in other sectors. The establishment of the respective infrastructure and buildings will in turn cause an impact on the natural environment.
Changes in the settlement patterns and the demographic composition as a consequence of individual industrial projects will often be moderate. Few projects comprise more than a few hundred employees, and in such cases a full impact analysis should normally be implemented. For small industries with for instance less than 50 employees, there will usually in most cases be minor environmental impacts for the community.
Extensive migration to an area may easily create slums.
For more information refer to the booklet:
No. 12 "Development of densely populated or urban areas".
3.2.10 Impacts on landscape and the visual environment
Impacts on the surrounding natural and cultural environment may be related to the industrial facility itself. But in many instances related elements like raw material extraction, roads, ports, power lines and waste deposits may be just as prominent.
All buildings relate to the landscape and the visual environment.
The extremes are to conceal a facility as far as possible (through appropriate
location, architecture and choice of colours) or to highlight it (through
location, and choice of lines and colours which break with the natural
surroundings). Safety concerns may set limits for landscaping; for instance in
the case of oil refineries and tank facilities it is necessary to prevent the
growth of inflammable vegetation.
Impacts on landscape and the visual environment are not subject to exact norms. But the general requirement that industrial establishment should contribute to development means that one should not be indifferent to the impacts on natural and cultural environments.
Industrial establishment is often implemented without the assistance from architects and landscape specialists. An important preventive measure is to ensure that this type of competence is included at the planning stage. During the construction it is important to restrict unnecessary cutting of trees, excessive excavation and unfortunate deposition of superfluous excavated mass. In the operations phase important aspects are maintenance, order and responsible deposition of waste.
3.2.11 Existing environmental impacts
One should investigate if the relevant areas are affected by pollution from existing activity. Relevant examples are buried waste and grounds contaminated by oil spills, and existing pollution of air, water and soil. The establishment of new polluting industry or energy production may exacerbate the pollution situation. And the result may exceed the tolerance level of the local natural environment.
In the construction or operations phase one should consider establishing a monitoring of the area, so that damage may be discovered at an early stage and corrective measures may be implemented. In cases where there are no substantial impacts, the monitoring will be useful to document this. The monitoring should be planned at an early stage, so that one has the opportunity to establish some baseline data for comparison with the previous environmental conditions.
The extent and content of the environmental assessments must be adapted to the local conditions e.g. the characteristics of the local natural environment, the extent of expected environmental impacts, available professional competence and economy.