Carson Ph., Mumford C. Hazardous Chemicals Handbook (Справочник по опасным химическим веществам)

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Table 16.4 Major solid wastes: origin, quantities and destination

Type Origin Method of disposal Present uses

Colliery spoil Mining Mainly tipping on land, As fill and in manufacture

some in sea of bricks, cement and

Some used lightweight aggregate

China clay waste, Quarrying Mainly tipping and in As fine aggregate in

overburden sand, lagoons concrete, in

micaceous residue Some used manufacture of bricks

and blocks and as fill

Household refuse Household Mainly landfill Some resource and energy

Some incineration recovery

Pulverized fuel ash and Waste from power stations Some used As fill and in manufacture

furnace bottom ash burning pulverized coal Remainder in old workings of cement, concrete

or artificial lagoons blocks, light-weight

aggregate, bricks etc.

Blastfurnace slag Iron smelting Nearly all used As roadstone, railway

ballast, filter medium,

aggregate for concrete,

fertilizer and in

manufacture of cement

Trade waste Industry Mainly landfill Unknown

Some incineration

Steel-making slag Steel making Some returned to blast- As roadstone

furnaces, remainder

dumped or used as fill

near steel works, or sold

Furnace clinker Waste from chain grate All used Concrete block making

power stations

Incinerator ash Residue from direct Most dumped As fill and for covering

incineration Minor usage refuse tips

Byproduct calcium Manufacture of Mainly in sea. Some In manufacture of floor

sulphate phosphoric acid and of dumped on land screeds

hydrofluoric acid Some used

Waste glass Waste glass within No utilization in If segregated, recycled

household refuse household refuse

Slate waste Mining and quarrying slate Mainly tipping, some Inert filler, granules,

backfilling of old expanded slate

workings aggregate and filter

Minor usage medium, road building

Tin mine tailings Tin mining Minor utilization. Tailing Aggregate for concrete

lagoons and discharge

into sea

Fluorspar mine tailings Fluorspar mining Minor utilization Aggregate for roadmaking

Tailing lagoons and concrete

Red mud Production of alumina Minor utilization, rest in Pigment in paints and

lagoons plastics

Copper slag Smelting Complete utilization Grit blasting

Tin slag Smelting Major utilization Grit blasting and road

Some in tips building

Zinc-lead slags Smelting of zinc and lead Stockpiled and used Bulk fill and some in

locally pavement asphalt

Quarry wastes Quarrying Some utilization Roadmaking, brickmaking

Remainder tipped

CHEMICALS AND THE ENVIRONMENT: SOURCES AND IMPACT 499

500 CHEMICALS AND THE ENVIRONMENT: SOURCES AND IMPACT

The common practice in waste management is either to recycle waste or to treat and dispose

of it at the end of a process. However, many ‘end-of-pipe’ treatment processes simply transfer a

waste, albeit sometimes in a different chemical form, from one environmental medium (i.e. air,

land or water) to another often at high dilution.

It would obviously be desirable to eliminate the generation of waste. Practical alternatives are to

minimize it by reduction at source or to recycle it. Table 16.7 illustrates the hierarchy of waste

minimization practices. Source reduction includes increased process efficiency; economies in

the use of energy are also relevant, e.g. it may result in a decrease in the consumption of fossil fuels:

• so reducing the air pollutants generated; or

• reducing boiler operation, with a consequent decrease in the discharge of cooling water and

boiler-blowdown discharges.

‘Accidental’ pollution incidents arise from spillages, gas emissions, and liquid discharges sometimes

in transportation. The main considerations are prevention, containment, and effective mitigatory

and emergency action according to the principles outlined in earlier chapters. Effective clean-up

and decontamination are then needed.

The more common requirement to control routine disposal and dispersion of solid, liquid or

gaseous pollutants is based upon different criteria, e.g. their persistence in the environment (as

with the effects attributed to ozone-depleting gases, or the problem of heavy metal contamination

Table 16.5 Examples of hazardous gases generation from waste pretreatment processes

Process Associated problems Hazardous airborne contaminants

liberated (in addition to the

principal reagents)

Neutralization of strong Fierce reaction Chlorine

mineral acids from metal Possibility of mixing with Nitrogen dioxide

finishing trades (sulphide water or organic materials Sulphur dioxide

and hypochlorite Hydrogen sulphide

contamination common)

Chlorination/oxidation of Mixing cyanide with acids Hydrogen cyanide

cyanide wastes from heat liberates hydrogen cyanide

treatment plant

Separation of oil and Emulsion splitting may Hydrogen

water mixtures from involve generation of Hydrogen sulphide

engineering and heat heat, hydrogen and Phosphine

raising plant hydrogen sulphide

Detoxification of chromic Use of sulphite Sulphur dioxide

acid and chromium salts

from the plating industry

Detoxification of by- Water and weak acids Arsine

products from smelting liberate attack gas Phosphine

Treatment of ammonia- Liberation of gaseous Ammonium chloride

bearing waste from ammonia Nitric acid

chemical industry

Removal of sulphides Generation of sulphide Hydrogen sulphide

from leather industry waste gas

of land), synergistic effects (as with the enhanced toxicological effects of smoke in the presence

of sulphur dioxide) or long-term cumulative effects. Thus the different considerations relating to

occupational compared with environmental exposures to air pollutants are exemplified in Table 16.8.

Atmospheric emissions

Sources

Important atmospheric pollutants comprise smoke, dust, grit, fumes and gases. Types of emission

are shown in Table 16.9.

Table 16.6 Effects of major pollutants on materials

Pollutant Primary materials attacked Typical effect

Carbon dioxide Building stone e.g. limestone Deterioration

Sulphur oxides Metals

Ferrous metals Corrosion

Copper Corrosion to copper sulphate (green)

Aluminium Corrosion to aluminium sulphate (white)

Building materials

(limestone, marble, slate, Leaching, weakening

mortar)

Leather Embrittlement, disintegration

Paper Embrittlement

Textiles (natural/synthetic) Reduced tensile strength, deterioration

Hydrogen sulphide Metals

Silver Tarnish

Copper Tarnish

Paint Leaded paint blackened by formation

of lead sulphide

Ozone Rubber and elastomers Cracking, weakening

Plastics Degradation, weakening

Textiles (natural/synthetic) Weakening

Dyes Fading

Nitrogen oxides Dyes Fading

Hydrogen fluoride Glass Etching, becoming opaque

Solid particulates Building materials Soiling

(soot, tars) Painted surfaces Soiling

Textiles Soiling

Acid water (pH <6.5) Cement and concrete Slow disintegration

Ammonium salts Slow to rapid disintegration

If cement is porous, corrosion of steel

reinforcement may occur

Fats, animal or May cause slow disintegration

vegetable oils

Calcium chloride May cause steel corrosion if concrete is

porous/cracked

Calcium sulphate (and Disintegrates concrete of inadequate sulphate

other sulphates) resistance

Solvents Plastics, rubber May cause changes due to penetration

Oxalic acid Beneficial: reduces effects of CO

, salt water,

dilute acetic acid

Paraffin Slow penetration, not harmful

Phenol (5% solution) Slow disintegration

Caustic alkali Not harmful <10–15% concentration

ATMOSPHERIC EMISSIONS 501

502 CHEMICALS AND THE ENVIRONMENT: SOURCES AND IMPACT

Combustion processes are the most important source of air pollutants. Normal products of

complete combustion of fossil fuel, e.g. coal, oil or natural gas, are carbon dioxide, water vapour

and nitrogen. However, traces of sulphur and incomplete combustion result in emissions of

carbon monoxide, sulphur oxides, oxides of nitrogen, unburned hydrocarbons and particulates.

These are ‘primary pollutants’. Some may take part in reactions in the atmosphere producing

‘secondary pollutants’, e.g. photochemical smogs and acid mists. Escaping gas, or vapour, may

Table 16.7 Waste minimization in the hierarchy of waste management practices

Elimination Complete elimination of waste

Source reduction Avoidance, reduction or elimination

of waste, generally within the confines

of the production unit, through changes Waste

in industrial processes or procedures minimization

Recycling Use, reuse and recycling of wastes for

the original or some other purpose, e.g.

input material, materials recovery or

energy production

Treatment Destruction, detoxification,

neutralization, etc. of wastes into less Treatment and

harmful substances safe disposal

Disposal Discharge of wastes to air, water or land

in properly controlled, or safe, ways such

that compliance is achieved. Secure land

disposal may involve volume reduction,

encapsulation, leachate containment and

monitoring techniques

Higher priority

Lower priority

Table 16.8 Factors in exposure and effects of air pollutants

Exposure Occupational Environmental

Population Adults (16–65) All population including infants,

Fit for work; possibly monitored aged, infirm hypersensitive subjects

Period Basic working week, e.g. <40 hr/wk, Continual unless area vacated;

48 wk/yr plus overtime; therefore therefore elimination and recovery

intermittent elimination and depend on irregular periods of low/

recovery times. Holidays excepted zero concentrations

Levels Possibly measurable fractions of Normally very low: at limits of

OESs (mg/m

) analytical/instrumental sensitivity

(µg/m

)

Dust, fume, gas, Generally single pollutants Mixture of primary pollutants, from

vapour, mist Known origin different sources and secondary

Hazards probably known pollutants. Possible additive or

Recognized problem synergistic effects

Personal protection and possibly health Origins may be difficult to prove

surveillance provided Hazards not quantified

Probably freshly formed/released Exposure largely unheeded

Concern Specific effects, therefore increased Decreased well-being

costs, accident rate; reduced Non-specific respiratory troubles

productivity Irritation of eyes, nose and throat

Damage to property and vegetation

Injury to animals

Decrease in ‘amenity’

Long-term ecological effects

Table 16.9 Continuous/intermittent emissions to atmosphere

High level

Routine Vents General ventilation (factory atmosphere)

Local extraction (dust, fumes, odour)

Flare stacks Normal flaring

Chimney

Irregular Plant maloperation Process plant

Dust and fume extraction plant

Flare stack Emergency/occasional flaring

Plant failure Process plant – emergency venting

Extraction/collection plant (cyclones,

precipitators, filters, scrubbers)

Low level

Routine Process equipment cleaning

Materials handling (discharge, conveying, bagging)

Waste handling/deposition

Irregular Plant maloperation (e.g. unauthorized ‘venting’)

Plant failure – spillages, pipe joint failures

Start-up/shutdown

Dismantling/demolition

Unauthorized waste incineration (rubbish burning)

Fires

also be associated with the storage or processing of volatile materials or ‘accidents’ which occur

in handling and transportation.

Dust can be emitted wherever solids are mined (e.g. in quarries), processed (e.g. flour mills,

woodworking factories, metal smelting and foundries), or handled/transported in particulate form.

Construction and demolition operations also generate dust.

In Table 16.9 emissions are classified as ‘persistent’ or ‘irregular’, and as to the level (i.e. the

height above ground) at which they are likely to be generated.

Effects

The effects of atmospheric pollution are chemical, and concentration, specific. However, additive,

and sometimes synergistic, effects arising from mixtures are important. A summary of the potential

effects of common air pollutants is given in Table 16.10.

As noted above (Table 16.8), in considering a limit on concentration at ground level to ensure

that there is no significant risk to health of local residents it is essential to recognize the important

difference from occupational exposure. Thus the Occupational Exposure Limits quoted in Chapter

5 cannot readily be extrapolated to assess or control non-occupational exposure. Damage to

animals, vegetation and growing crops (which can occur at extremely low levels with some

pollutants) and to buildings, etc. must also be considered.

Liquid effluents

Sources

The manner by which aqueous-based waste streams may arise in a factory from process uses of

LIQUID EFFLUENTS 503

504 CHEMICALS AND THE ENVIRONMENT: SOURCES AND IMPACT

water, cooling water, wash-rooms and canteens, and steam-raising is exemplified in Figure 16.1.

Within the UK the majority are treated prior to discharge to sewers operated by a sewage undertaker.

Following further treatment they are then discharged to natural waters or the open sea. Some

effluents are subjected to treatment by the producer before similar final discharge.

Strict control is necessary over pollutant levels, acidity, temperature, turbidity, etc. because of

their impact upon aquatic environments. Common pollutants in aqueous effluents are identified

in Table 16.11.

Effects

The pH of rainwater is normally about 6 but can be reduced significantly by absorption of acidic

exhaust gases from power stations, industrial combustion or other processes, and vehicles. Acids

may also enter the waterways as a component of industrial effluent. In addition to the direct

adverse effects on aquatic systems (Table 16.12) low pH can result in the leaching of toxic metals

from land, etc.

The salts of the heavy metals beryllium, cadmium, chromium, copper, lead, mercury, nickel

and zinc are all of high eco-toxicity. For example, the toxicity of some heavy metals to rainbow

trout is demonstrated in Table 16.13; coarse fish are somewhat more resistant.

Table 16.10 Major atmospheric pollutants and their effects

Contaminant Manmade source Effects

Sulphur dioxide Combustion of coal, oil and other Vegetation damage

sulphur-containing fuels Sensory and respiratory irritation

Petroleum refining, metal smelting, Corrosion

paper-making Discoloration of buildings

Hydrogen sulphide Various chemical processes Odours, toxic

Oil wells, refineries Crop damage/reduced yields

Sewage treatment

Carbon monoxide Vehicle exhaust and other combustion processes Adverse health effects

Carbon dioxide Combustion processes ‘Greenhouse’ effects

Nitrogen oxides High-temperature reaction between Adverse health effects

atmospheric nitrogen and oxygen, e.g. Sensory irritants

during combustion Reduced visibility

Byproduct from manufacture of fertilizer Crop damage

Ammonia Waste treatment Odour

Irritant

Fluorides Aluminium smelting Crop damage

Manufacture of ceramics, fertilizer HF has adverse health effects on

cattle fed on contaminated food

Lead Combustion of leaded petrol Adverse health effects

Solder, lead-containing paint

Lead smelting

Mercury Manufacture of certain chemicals, paper, paint Adverse health effects

Pesticides

Fungicides

Volatile hydrocarbons Motor vehicles Vegetation damage (especially

Solvent processes unsaturated hydrocarbons)

Chemical industry Some are irritants

Adverse health effects

Particulates Chemical processes Nuisance

Fuel combustion Adverse health effects

Construction Reduced visibility

Incineration processes Deposition on buildings

Motor vehicles

Source of

water

Treatment Usage Effluent

treatment

Discharge/

recycle

Inland/

coastal

waters

Foul water

drains

Segregate

Settle

Process

Chemical

biological

treatment

To reuse

RecycleRecycleRecycle

Soften

Deionize

Process

Mains

supply

Washing

Toilets

Canteen

Borehole

Flocculate

Settle

Filter

Sterilize

Steam

raising

Recycle

Process

cooling

Evaporative

cooling

Surface

water drains

Rivers, etc.

Fish are generally more susceptible to poisoning than microscopic plants or other animals; as

such they are a good indicator species. A summary of the concentrations of selected substances

at which toxic effects have been detected in bacteria, algae, crustacia and protozoa is given in

Table 16.14.

Heavy metals may also be concentrated in passage up the food chain. Other pollutants, e.g.

fungicides, pesticides, biocides, polychlorinated biphenyls or organic mercury compounds, are

persistent and can therefore also bioaccumulate.

Cyanides can be fatal to fish at <1 ppm. Because of concern over the possible in vivo conversion

of nitrate into carcinogenic nitrosamines, the nitrate content of drinking water must be strictly

controlled. Nitrate and phosphate pollution can also cause eutrophication in still, or slow-moving,

warm waters by stimulation of algae growth in the presence of strong sunshine. This chokes the

water and results in depletion of light and oxygen content.

Trace contaminants such as sodium chloride, iron and phenols (especially if chlorinated) may

also impart a characteristic taste if water is subsequently used for drinking purposes.

As discussed in Chapter 17, legislative controls including stringent consent conditions are

applied in the UK to all discharges to specified sewers. (Discharge of effluent to surface water

drains is prohibited.) Limits, or even total prohibitions, are placed upon certain chemicals to avoid

Figure 16.1

Factory water supply: usage and disposal

LIQUID EFFLUENTS 505

506 CHEMICALS AND THE ENVIRONMENT: SOURCES AND IMPACT

Table 16.11 Common pollutants of aqueous effluents

Pollutant Example

Alkali Sodium hydroxide (caustic soda)

Potassium hydroxide (caustic potash)

Calcium oxide (lime)

Calcium hydroxide

Sodium, potassium and calcium carbonates

Ammonia (q.v.)

Ammonia

Biocides

Biodegradable waste Sewage

Food waste

Organic chemicals

Boron, borates, fluoroborates –

Bromine –

Chloride Sodium chloride

Chlorine Hypochlorites

Chromic acid (hexavalent chromium) Potassium dichromate

Cyanide Copper cyanide

Nickel cyanide

Potassium cyanide

Silver cyanide

Sodium cyanide

Zinc cyanide

Emulsified oil Suds

Fluoride –

Fluorine –

Metal salts in alkaline solution Cuprammonium complex

Nickel and cobalt ammonia complex

Cyanides (q.v.)

Copper pyrophosphates

Plumbites

Zincates

Metal salts in acid solution Most metals as acid salts, e.g.

chloride

nitrate

sulphate

Mineral acid Hydrobromic acid

Hydrochloric acid

Hydrofluoric acid

Nitric acid

Sulphuric acid

Miscible/soluble organic materials Acetone

Alcohol

Acetic acid

Non-metallic inorganic dissolved compounds Arsenic

Selenium

Oil, grease, wax and immiscible organics Lubricating oil

Animal fat

Chlorinated solvents

Organometallic compounds –

pH Acids

Alkalis

Pharmaceuticals –

Phenols and related compounds Phenol

Cresol

Phosphate Detergents

Sewage –

Sulphate Calcium sulphate

risks to sewermen, e.g. from the generation of toxic gases such as hydrogen sulphide, to avoid

obstruction of flow, e.g. from suspended solids, to eliminate any risk of explosion or fire from

volatile flammable liquids, and to ensure there is no subsequent interference with waste treatment

processes.

The type of consent conditions imposed, where the effluent represents only a small proportion

of the flow in a sewer, are exemplified in Table 16.15.

More stringent limits are imposed upon discharges to natural waters as exemplified in Table

16.16. In both cases the BOD, the biological oxygen demand, represents the demand for oxygen

in order to decompose the organics in the effluent.

Solid wastes

Land pollution has arisen from the direct dumping of domestic and industrial solid waste, but this

Sulphite liquor Sodium sulphite

Suspended particles –

Total dissolved solids Carbonate

Chloride

Nitrate

Phosphate

Sulphate

Table 16.11 Cont’d

Pollutant Example

Table 16.12 Sensitivity of aquatic organisms to lowered pH

pH Effect

6.0 Crustaceans, molluscs etc. disappear

White moss increases

5.8 Salmon, char, trout and roach die

Salamander eggs fail to hatch

Sensitive insects, phytoplankton and zooplankton die

5.5 Whitefish and grayling die

5.0 Perch and pike die

4.5 Eels and brook trout die

4.0 Crickets, frogs and northern spring peepers die

Table 16.13 Toxic concentrations of heavy metals to rainbow trout

Concentration (mg/l) which kills half the number of exposed fish

in 48 hours (LC

)

Metal Soft water Hard water

Copper 0.04 0.5

Cadmium 0.05 5.5

Zinc 0.5 3

Lead 1 –

Nickel 15 100

SOLID WASTES 507

508 CHEMICALS AND THE ENVIRONMENT: SOURCES AND IMPACT

is not the sole cause. It may arise from excessive application of agrochemicals, and indirect

contamination resulting from leaks or from leaching of hazardous components from liquid waste

disposal sites, or from atmospheric fallout. Land may also become contaminated by chemicals

processed, stored or dumped at the site, perhaps in the distant past. Such contamination may pose

a health risk to workers on the site, those subsequently involved in building, construction or

engineering works, or the public (e.g. arising from trespass), and to animals.

Soil surveys relating to construction work require samples from at least the depth of excavation;

water seepage may cause cross-contamination of land. Some guidelines for the classification of

contaminated soils are summarized in Table 16.17.

Table 16.14 Concentrations, in ppm, of substances which show toxic effects in various organisms

(in river water, pH 7.5)

Bacteria– Green algae–

Escherichia Scenedesmus Daphnia Protozoa

coli quadricauda magna microregma

Copper 0.08 0.15 0.1 0.05

Zinc 1.4 to 2.3 1 to 1.4 1.8 0.33

Chromium III 4 to 6 42 37

Cyanide 0.4 to 0.8 0.16 0.8 0.04

Cyanate 10 520 23 21

Sulphide 93 40 26

Phenol 40 16 30

Toluene 200 120 60

-Xylene 500 40 16 10

-Xylene 40 24 70

-Xylene 40 10 50

Amyl alcohol 280 440 20

Formic acid 100 120

Butyric acid 200 60

Butyl acetate 320 44 20

Amyl acetate 180 120 40

Table 16.15 Type of consent conditions for discharge to sewers. (Other factors, e.g. the specific sewer, flowrate, total

volume discharged, are also defined)

Parameter/substance Maximum allowed

pH range 6–10 (permitted range)

Sulphate (as SO

) 500–1000 mg/l

Free ammonia (as NH

) 500 mg/l

Suspended solids 500–1000 mg/l

Tarry and fatty matter 500 mg/l

Sulphide (as S) 10 mg/1

Cyanide (as CN) 10 mg/l

Immiscible organic solvents nil

Calcium carbide nil

Temperature 45°C

Petroleum and petroleum spirit nil

Total non-ferrous metals 30 mg/l

Soluble non-ferrous metals 10 mg/l

Separable oil and/or grease 300–400 mg/l