Following principles and guidelines have been accepted for the control of different types of pollution-
A. Prevention of entry into the environment: According to this principle, pollutants are checked at the point of their origin and are not allowed to enter into the environment by the application of specific devices.
B. Isolation: By isolation, we mean putting out or segregating pollutants at the point of their release or production. Such isolated pollutants should then be dumped at specific locations as per scientific guidelines adopted by pollution control agencies. Some of these pollutants can be recycled and reused for example reuse of fly-ash for making bricks.
C. Conversion from highly toxic to lesser harmful product: We cannot stop industrial processes simply because they cause pollutions. However we can reduce the toxicity or harmfulness of pollutants by applying bio- chemical technologies. A number of catalysts are introduced to reduce the toxicity of chemical pollutants produced during industrial processes.
D. Alternatives: These are safer substances used on the place of substances that cause hazards. For example bio- pesticides like oil of Neem and extract of garlic, are better alternatives to synthetic chemical pesticides.
E. Destruction: The chemical pollutants that are proved to be toxic, and are difficult to be substituted by safer ones- need to be blocked from further release and then destroyed in a safe and prescribed scientific manner. Advanced and Environment Friendly Incineration Technology is a good option for reduction of pollution through destruction.
F. Awareness: Matters pertaining to good citizenship, environmental consciousness and preventive methods must be explained to the common man, so that he may try to perform his duties with a high degree of civic sense. These awareness programmes can be conducted through different media like radios, TVs. seminars, demonstrations, documentary films, pamphlets, display of hoardings, banners and plays like street theatres or nukkar nataks etc.
G. Public Participation: The word ‘public participation’ means ‘sharing in common’ or ‘doing together’. In environmental context, it means, the involvement of the local public in solving their local environmental problems. It does not mean, people working under the planning and decisions of government agencies- it is rather bottom-up approach. With joint efforts, people identify their problems, make plans to resolve them and then to implement them.
H. Environmental Education: Environmental Education has been made a compulsory subject for studies at schools, colleges and other institutions. This is the most effective tool for the control of pollution and conservation of environment on grass- root level.
I. Self-Restraint – A Habit: The greed for luxury and comfort initiates the production of newer and newer products. More and more products carry more and more wastes in different forms like wrapping materials, plastic carry bags, chemical preservatives (in cases of food materials) etc. When these products are used up, their wrappings and other associated and useless materials coming to the homes of consumers are thrown out carelessly. These thrown out materials create the problem of pollution. Overuse of materials that are not important for our health and development impose burden on the family budget. These are the reasons why our thinkers and philosophers preached on self-restraint. Thus, it is important now that conservation should be made a habit.
J. Support to Professional Conservation Groups: The state and central governments should provide subsidies for conservation of environment and pollution control works being carried out by professional groups.
K. Legislative and Tax Measures: The existing laws for pollution control should be enforced properly so as to abate pollution. Industries doing eco-friendly works like recycling of wastes, regeneration of forest and production of pollution free technologies should receive tax –concession from the government.
Any big problem cannot be solved without planning and strong efforts. The pollution of environment is certainly a big problem. So, planning for its control is very necessary.
Waste Management Technologies
Land is polluted through dumping of wastes, application of chemical fertilizers and synthetic pesticides and Salinization through water logging. Following efforts must be made to abate soil pollution –
1. Solid wastes should be properly disposed by composting, land filling, and thermal processes; and by re- cycling and re- use.
2. Composts, green manure, wormy compost or natural manure should be added to soil so as to improve its fertility. The application of chemical fertilizers should be restricted for unavoidable conditions through proper assessment of the loss of nutrients in the soil.
3. The application of synthetic chemical pesticides should be substituted by the application of bio- pesticides.
4. Proper drainage of water from crop fields should be ensured to protect fields from water logging. This condition increases salt content in soil and makes it saline.
Soil Pollution principally occurs through solid wastes that originate from different sources. These are disposed through a number of methods depending on their nature and the area available for their disposal. Some popularly known methods of solid waste disposal are-
(i) Land Filling,
(ii) Incineration,
(iii) Composting,
(iv) Resource Recovery, and
(v) Recycling.
(i). Land-filling is the process of disposing solid waste in low lands or into trenches through proper sanitary methods. It involves- collection, transport, compaction, etc. processes along with proper management for gas-outlet etc. For land filling, the important thing to be taken into account is the distance of waste collection site to the waste dumping site, because it involves cost of transportation.
(ii) Incineration is the process of burning of solid waste under scientifically controlled and safe conditions. The Mechanical structure meant for incineration is called as incinerator. In this process, waste is burnt in moving grates in refractory lined chambers. The combustible gases and solids they carry are burned in Secondary Chambers. The emission from incineration is usually controlled by Wet Scrubbers, Electrostatic Precipitators, or by Fabric Filters. The heat so generated, can be used for producing steam to convert it into mechanical or electrical energy.
(iii). Composting is the process through which biodegradable waste is subjected to biological degradation in a pit called compost pit. The biodegradable waste can also be deposited in mechanical systems where it is degraded biologically to humus with a total nitrogen, phosphorus, and potassium content of 1 to 3 percent. The compost usually becomes ready for bagging and marketing within three weeks, through commercial process of composting.
(iv). Combustion and Pyrolysis are important steps of Resource Recovery. The heat generated through combustion is used to heat water to produce steam which can further be transformed into mechanical or other forms of energy. Pyrolysis is the process of destructive distillation. It involves chemical decomposition of solid waste by heat in the absence of oxygen. This results in the production of warm gases like hydrogen sulphide, hydrogen, methane, Carbon dioxide, carbon monoxide, etc. and the inert ash.
- Recycling is the process of recovery of used matter for further use through different methods like shredding, Magnetic Separation of metals, air classification, Screening, washing etc. Bottles, cans, newspapers, card boards, and other items are recycled today to minimize waste. This process lessens the load at incinerators and landfills.
