Causes of Air Pollution

Air pollution is one of the most visible forms of pollution. Anyone who's seen the brownish-yellow sky over a city, or dark smoke belching from the tail pipe of a bus or industrial smoke stack knows what it looks like. It's effects are not always so obvious, and range from contaminated rain to ozone levels to global warming. There are also health concerns, making air pollution a serious environmental concern.

Air pollution is essentially the introduction of particles into the atmosphere that does not belong there. Particulate matter, tiny pieces of contaminants, which because they are lighter than air become airborne. They might then rise high into the air to travel on the winds, or float near ground level. This is a result of both the kind of pollutant and where it is released. Car exhaust, for example, starts much lower than industrial smoke. Air pollution does not have to be man made chemicals. The desertification of wilderness areas releases extra dust and sand into the air that also causes many of the problems associated with chemical air pollution.

Air pollution may be caused by various natural and anthropogenic processes. Below are listed some of the main air pollution causes.

NATURAL:

• Volcanic activities – volcanic eruptions emit a serious of toxic gases (including sulfur and chlorine) as well as particulate matter (ash particles) but are usually restricted to localized areas;

• Winds and air currents – can mobilize pollutants from the ground and transport them over large areas;

• Wildfires – add to the atmosphere smoke, carbon monoxide as well as particulate matter (containing organic contaminants such as PAHs) and could affect significant areas although in general are restricted and may be contained;

• Microbial decaying processes – microorganisms which are present in any environment have a major role in natural decaying processes of living organisms as well as environmental contaminants; this activity results in the natural release of gases especially methane gas;

• Radioactive decay processes – for example radon gas is emitted due to natural decay processes of Earth’s crust which as potential to accumulate in enclosed spaces such as basements;

• Increasing temperatures – contribute to an increase in the amounts of contaminants volatilizing from pollution soil and water into air.

ANTHROPOGENIC:

• Mining and smelting – emit into the air a variety of metals adsorbed on particulate matter that is suspended in the air due to crushing & processing of mineralogical deposits;

• Mine tailing disposal – due to their fine particulate nature (resulting after crushing and processing mineral ores) constitute a source of metals to ambient air which could be spread by wind over large areas;

• Foundry activities – emit into the air a variety of metals adsorbed on particulate matter that is suspended in the air due to processing of metallic raw materials (including the use of furnaces);

• Various industrial processes may emit both organic and inorganic contaminants through the following mechanisms:

1. Accidental spills and leaks of stored chemicals
2. Handling and storage of chemicals – especially of volatile inorganic chemicals

• Transportation – emits a series of air pollutants (gases – including carbon monoxide, sulfur oxides and nitrogen odides - and particulate matter) through the tailpipe gases due to internal combustion of various fuels (usually gases such as opxides of carbons, of sulfur, of nitrogen, as well as organic chemicals as PAHs)

• Construction and Demolition activities – pollute the air with various construction materials. Of special threat is the demolishion of old buildings which may contain a series of banned chemicals such as PCBs, PBDEs, asbestos.

• Coal Power Plants – by burning coal they may emit a series of gases as well as particulate matter with metals (such as As, Pb, Hg) and organic compounds (especially PAHs);

• Heating of buildings – emits a series of gases and particulate matters due to burning of fossil fuels;

• Waste Incineration – depending on waste composition, various toxic gases and particulate matter is emitted into the atmosphere;

• Landfill disposal practices – usually generate methane due to intensification of natural microbial decaying activity in the disposal area;

• Agriculture – pollute the air usually through emissions of ammonia gas and the application of pesticides/herbicdes/insecticides which contain toxic volatile organic compounds;

• Control burning in forest and agriculture management – includes controlled burning that will emit gases and particulate matter (similar to wildfires described above)

• Military activities – may introduce toxic gases through practices and training;

• Smoking – emits a series of toxic chemicals including a series of organic and inorganic chemicals, some of which are carcinogenic;

• Storage and use of household products such as paint, sprays, varnish, etc that contains organic solvents which volatilize in the air (hence the smell we all feel while using them);

• Dry cleaned clothes - may retained and emit in the atmosphere small amounts of chlorinated solvents (such as PCE) or petroleum solvents that have been used by the dry cleaners; this could eventually create a health risk if the clothes returned from the dry cleaners are stored in enclosed indoor spaces.

BaxterStorey's innovative approach to Food waste management

Adrienne Cohen describes the nationwide programme of recycling food waste into green energy set up by BaxterStorey, one of the UK’s leading catering companies.

by Adrienne Cohen

Waste is an unavoidable by-product of delivering food services. A breathtaking 3.5 million tonnes of food waste from the UK hospitality sector goes into landfill sites every year. Caterers have ‘greened’ their services in recent years with sustainable produce and recycled packaging, but the issue of waste management is becoming an increasingly hot topic. 

BaxterStorey’s view

One example of a company looking to manage its burden more effectively is BaxterStorey, one of the UK’s leading independent food service management companies. The company prepares and serves over 25 million freshly prepared meals every year in staff restaurants throughout the UK to clients including Barclays, Selfridges, ITV and Virgin Atlantic Airways.

Mike Hanson, Head of Sustainability and Environmental Management at BaxterStorey, agrees that the catering industry needs to pay greater attention to the role of food waste management in its overall approach to sustainability and vitally, profitability. ‘Sustainable practice that involves precise waste management practice in the workplace kitchen, and sound economic management is a strong proposition for caterers and their clients to consider. The current climate dictates that all businesses must be operating in all aspects in a manner sensitive to the environment, and also in a fashion that makes the most fiscal prudence for their survival. Landfill taxes have risen astronomically, and the recent budget announced that landfill tax is set to double again from the current £40 per tonne to £80 within three years. This is a cost that catering operations are going to have to get their heads around controlling quickly.’

Mike Hanson believes that the hospitality industry has a great opportunity to be seen to be doing more than simply complying with waste regulations. ‘As a significant contributor to the food waste mountain, catering providers must focus more intently on food waste management and avoid sending food waste to landfill wherever possible. The range of options for dealing with food waste is expanding all the time and innovation in this area is also showing itself to deliver practical and affordable actions which can be readily implemented.’

For BaxterStorey, waste management – and in particular food waste management – is a key tenet of its overall sustainability practice. The company has won a series of awards for its sustainable behaviour and, in 2009, became the first company in its sector to launch a nationwide programme of recycling food waste into green energy. Its launch, explains Mike Hanson, was not simple. ‘We operate from more than 700 sites across the UK and finding a local solution to manage each site’s food waste was a complex issue. In an ideal world we’d compost all of our food waste and we do have a series of partnerships with local facilities where such a solution is in use. However we have not been able to make use of composting on a broad scale simply because not every site has a local facility for this to be an achievable goal.’

BaxterStorey chose a waste to renewable energy programme as a national service over composting as it made more operational sense for them. As Mike Hanson explains, ‘We were able to partner with a specialist whose own network made it a sensible option for us to use the bio-energy route. Frankly, we’d be undoing all the good we were hoping to achieve by composting if we were having to road haul the waste across long stretches to find a suitable unit in which we could manage the process.’

Converting food waste to biofuel

Working with PDM Group, one of the UK’s largest food chain by-product recyclers, BaxterStorey began a trial in September 2008 to recycle waste food from the kitchens it operates into biofuel. The trial was so successful that within six months the project was rolled out making the service available to all clients. To date, 230 tonnes of food waste have been recycled into 57 MWh of renewable energy, enabling 50 tonnes of carbon dioxide emissions from fossil fuel use to be displaced.

The service has now been implemented at 10 % of all sites and BaxterStorey is hopeful that the pace of roll-out will increase over the coming months. The biggest issue the company faces in extending the programme’s reach is client understanding of the issue, and the ability for them to see this as not simply another cost. As Mike Hanson points out, ‘We operate the kitchens on behalf of our clients and, while we encourage all of our clients to use alternative waste management streams, ultimately the decision is theirs.’

BaxterStorey has embarked on a joint communications programme with PDM Group to help clients understand the benefits of the service. Clients’ initial reactions are positive but, when they consider the operational process, many hesitate about instituting it. ‘The fear of rotting food in bins remaining on the site and the complication of more than one waste operator collecting from their site is a real barrier for many, even though we can prove that these issues are easily surmountable.’

Where the service is used, food waste is separated at source using small kitchen caddies which are then emptied into in larger bins outside the kitchen. The PDM system enables BaxterStorey’s staff to capture all its food waste, explains PDM’s Commercial Director, Philip Simpson. ‘Our innovative process enables caterers to recycle all types of food waste with no additional work other than putting it in a separate bin. We can handle raw meats and fish, which would need to be cooked even to go to landfill, and packaged food, which can also go straight into our bins that we can separate in our de-pack unit.’

PDM offers BaxterStorey a dedicated service, collecting bins when needed – be it daily, three times a week, or just weekly. As PDM’s service is national, it takes the waste to its nearest sites where it is bulked up with other food waste from retailers, hotels and restaurants. The waste is then taken to PDM’s integrated renewable energy and recycling plant in Widnes – the first facility of its kind in the world.

Once the food arrives at the facility it passes through a de-packaging unit where it is separated from tins, cartons and plastics. It is then mulched into a puree which is used as a wet fuel for the facility’s combined heat and power (CHP) plant. ‘This carbon neutral process can recycle more than 200,000 tonnes of food waste a year into enough energy to power approximately 16,000 homes. The added environmental benefit is there is no by-product, other than electricity, so there is no risk of creating another waste stream,’ adds Philip Simpson.

Anaerobic digestion added

Over the next 12 months, some of BaxterStorey’s food waste will be turned into renewable energy by anaerobic digestion (AD) as a new digester at PDM’s Doncaster site becomes fully operational. This technology is seeing great uptake from retailers. Philip Simpson says, ‘Anaerobic digestion is probably the greenest form of food waste recycling technology currently available.’ The technology is seeing significant government support, with AD projects eligible to access millions of pounds of funding.?The PDM anaerobic digester can process around 45,000 tonnes of food waste per year, generating 2 MW of renewable energy and providing enough power for some 4000 homes. The digester will also produce 40,000 tonnes of nutrient-rich fertiliser each year for use by local farmers.

Persuading caterers to recycle food waste

As the range of alternative routes to landfill grows and become more accessible, why isn’t the catering industry responding to the need to manage the disposal of waste food in a more effective manner and help reduce the food waste mountain they contribute to? Along with the well-worn response that more education is needed, Mike Hanson says, ‘At the bottom of everything caterers are business people. You need to appeal to their financial instinct to drive change.’

While the impact of soaring landfill tax is sure to make some open their eyes, Mike Hanson believes that this alone will not galvanise the majority to make rapid change. ‘Landfill tax has been rising at an excessive rate for some years now and this still has not spurred significant action. We manage waste carefully at BaxterStorey because we believe it’s the ethical thing to do – but we’re in a minority. If a stronger commercial tag can be placed on the issue then we’ll get there faster.’

Mike Hanson cites the need for waste management partners to give their clients more financial incentive to support a shift in the mindset. ‘There is an excellent opportunity to pitch waste being turned into bio-energy as a revenue driver to the caterer. If the processor splits revenues from sale of energy to the utility houses more generously, they’ll grow demand far more quickly.’

He adds that taking a bottom line approach may certainly be what makes many listen initially, but an even more creative route that processing partners should be considering is to help the caterers grow their businesses and become partners in the truest sense to their clients. This is what he’d like to see in the longer term. ‘From provenance to food miles, Fairtrade to organic, consumer awareness of all sustainability-focused food issues is on the up. Food processing companies should seize on this. Splitting revenue from the sale of green energy from food waste so that the caterer can donate the revenue to charitable or community causes is a really strong marketing message that the end client can use, and one that encourages consumers and businesses to buy products and services.’

This is especially true for contract caterers whose blue chip clients are obliged to report on corporate social responsibility. Mike Hanson concludes, ‘The more we can assist our clients’ ability to meet their CSR goals, the better. If processing partners work more closely with caterers to help them attract greater business, the result is going to be a win for all – more catering demand, more waste and more waste management.’

Water Pollution

When toxic substances enter lakes, streams, rivers, oceans, and other water bodies, they get dissolved or lie suspended in water or get deposited on the bed. This results in the pollution of water whereby the quality of the water deteriorates, affecting aquatic ecosystems. Pollutants can also seep down and affect the groundwater deposits.

Water pollution has many sources. The most polluting of them are the city sewage and industrial waste discharged into the rivers. The facilities to treat waste water are not adequate in any city in India. Presently, only about 10% of the waste water generated is treated; the rest is discharged as it is into our water bodies. Due to this, pollutants enter groundwater, rivers, and other water bodies. Such water, which ultimately ends up in our households, is often highly contaminated and carries disease-causing microbes. Agricultural run-off, or the water from the fields that drains into rivers, is another major water pollutant as it contains fertilizers and pesticides.

Domestic sewage refers to waste water that is discarded from households. Also referred to as sanitary sewage, such water contains a wide variety of dissolved and suspended impurities. 

It amounts to a very small fraction of the sewage by weight. But it is large by volume and contains impurities such as organic materials and plant nutrients that tend to rot. The main organic materials are food and vegetable waste, plant nutrient come from chemical soaps, washing powders, etc. Domestic sewage is also very likely to contain disease-causing microbes. Thus, disposal of domestic waste water is a significant technical problem. Sewage generated from the urban areas in India has multiplied manifold since 1947.

Today, many people dump their garbage into streams, lakes, rivers, and seas, thus making water bodies the final resting place of cans, bottles, plastics, and other household products. The various substances that we use for keeping our houses clean add to water pollution as they contain harmful chemicals. In the past, people mostly used soaps made from animal and vegetable fat for all types of washing. But most of today’s cleaning products are synthetic detergents and come from the petrochemical industry. Most detergents and washing powders contain phosphates, which are used to soften the water among other things. These and other chemicals contained in washing powders affect the health of all forms of life in the water. 

Biochemical oxygen demand, or BOD 

The amount of organic material that can rot in the sewage is measured by the biochemical oxygen demand. BOD is the amount of oxygen required by micro-organisms to decompose the organic substances in sewage. Therefore, the more organic material there is in the sewage, the higher the BOD. It is among the most important parameters for the design and operation of sewage treatment plants. BOD levels of industrial sewage may be many times that of domestic sewage. Dissolved oxygen is an important factor that determines the quality of water in lakes and rivers. The higher the concentration of dissolved oxygen, the better the water quality. When sewage enters a lake or stream, micro-organisms begin to decompose the organic materials. Oxygen is consumed as micro-organisms use it in their metabolism. This can quickly deplete the available oxygen in the water. When the dissolved oxygen levels drop too low, many aquatic species perish. In fact, if the oxygen level drops to zero, the water will become septic. When organic compounds decompose without oxygen, it gives rise to the undesirable odours usually associated with septic or putrid conditions.

Agricultural Run off

The use of land for agriculture and the practices followed in cultivation greatly affect the quality of groundwater. Intensive cultivation of crops causes chemicals from fertilizers (e.g. nitrate) and pesticides to seep into the groundwater, a process commonly known as leaching. Routine applications of fertilizers and pesticides for agriculture and indiscriminate disposal of industrial and domestic wastes are increasingly being recognized as significant sources of water pollution.

The high nitrate content in groundwater is mainly from irrigation run-off from agricultural fields where chemical fertilizers have been used indiscriminately. 

Eutrophication 

 

When fresh water is artificially supplemented with nutrients, it results in an abnormal increase in the growth of water plants. This is known as eutrophication. The discharge of waste from industries, agriculture, and urban communities into water bodies generally stretches the biological capacities of aquatic systems. Chemical run-off from fields also adds nutrients to water. Excess nutrients cause the water body to become choked with organic substances and organisms. When organic matter exceeds the capacity of the micro-organisms in water that break down and recycle the organic matter, it encourages rapid growth, or blooms, of algae. When they die, the remains of the algae add to the organic wastes already in the water; eventually, the water becomes deficient in oxygen. Anaerobic organisms (those that do not require oxygen to live) then attack the organic wastes, releasing gases such as methane and hydrogen sulphide, which are harmful to the oxygen-requiring (aerobic) forms of life. The result is a foul-smelling, waste-filled body of water. This has already occurred in such places as Lake Erie and the Baltic Sea, and is a growing problem in freshwater lakes all over India. Eutrophication can produce problems such as bad tastes and odours as well as green scum algae. Also the growth of rooted plants increases, which decreases the amount of oxygen in the deepest waters of the lake. It also leads to the death of all forms of life in the water bodies.

Industrial effluents

 

Waste water from manufacturing or chemical processes in industries contributes to water pollution. Industrial waste water usually contains specific and readily identifiable chemical compounds. During the last fifty years, the number of industries in India has grown rapidly. But water pollution is concentrated within a few subsectors, mainly in the form of toxic wastes and organic pollutants. Out of this a large portion can be traced to the processing of industrial chemicals and to the food products industry. In fact, a number of large- and medium-sized industries in the region covered by the Ganga Action Plan do not have adequate effluent treatment facilities. Most of these defaulting industries are sugar mills, distilleries, leather processing industries, and thermal power stations. Most major industries have treatment facilities for industrial effluents. But this is not the case with small-scale industries, which cannot afford enormous investments in pollution control equipment as their profit margin is very slender.

Effects of water pollution 

The effects of water pollution are not only devastating to people but also to animals, fish, and birds. Polluted water is unsuitable for drinking, recreation, agriculture, and industry. It diminishes the aesthetic quality of lakes and rivers. More seriously, contaminated water destroys aquatic life and reduces its reproductive ability. Eventually, it is a hazard to human health. Nobody can escape the effects of water pollution.

The individual and the community can help minimize water pollution. By simple housekeeping and management practices the amount of waste generated can be minimized.