25 Waste Disposal

R. Radha

1. OBJECTIVES

After this session, the learners should able to

1.     Describe waste management

2.     Describe the ways to dispose the waste and how to recycle the generated waste in the proper way

2.    INTRODUCTION

Waste is any unwanted, undesirable, discarded or intended to be discarded material left over after the completion of certain process. Waste can also be denoted as rubbish, garbage or junk. The types of waste are municipal or metropolitan solid waste, commercial marketing waste, harmful waste and food processing waste. Vast quantities of waste are generated in the hospitality industry posing a major concern and worry for its safe disposal. Improper waste pollutes the environment to a great extent. Waste management programme can help to save the cost involved in waste disposal and conserving the resources. Waste management program considers two aspects that are waste minimization and waste disposal.

3. DEFINITION

The food that is thrown away or cannot be used for consumption in large quantities in food sectors is called as food waste or food loss. Food wastage occurs during the processing, production or preparation, trading or during ingesting. Management of food waste should begin at every stage of food operation right from the process of purchasing till the end of selling the finished goods.

The difference between the food loss and food waste is

i) Food loss is defined as the decrease in edible part of food during the processing, production and in the post harvest stage.

ii) Food waste on the other hand is defined as the loss of food that occurs during several stages right from marketing to final consumption of the finished good due to the behavior of consumers or retailers.

4. CLASSIFICATION OF WASTE MANAGEMENT

In the food industry, wastes must be disposed of regularly and efficiently to prevent contamination of any food product. Wastes arising from catering establishment are broadly classified into three groups:

1.   Solid waste (garbage and refuse),

2.   Liquid wastes (sewage) and

3.   Gaseous wastes (smoke and fumes).

Solid wastes in the form of refuse and garbage are the major waste which arises from the catering industry. They pose a big problem in disposal to the caterer. Liquid wastes are normally disposed through sewers provided by the municipality in towns and cities whereas gaseous waste are expelled into the atmosphere where they get diluted by diffusion and air currents.

4.1. Solid Waste

Solid waste includes solid portions of the discarded material such as glass bottles, crockeries, plastic containers, metals and other wastes. Solid wastes should preferably be sorted into biodegradable and non-biodegradable wastes and stored separately. The bio-degradable solid wastes are agricultural wastes, food wastes, paper, byproducts of food processing, manure, yard wastes etc. They may be compacted or concentrated before disposal. Agricultural wastes can be used as feed or as fertilizers after appropriate treatment.

Garbage or swill is the waste matter resulting from the preparation, cooking and consumption of food. It includes all inedible useless scraps of food, which need to be disposed off. Waste matter from preparation process will include vegetable and fruit peels, trimmings, rotten food stuffs and split food. Sometimes leftover food after serving is considered as waste. Refuse refers to any waste material, either non-food or swill. Non-food waste from the kitchen includes all cans, bottles, paperbags, polythene bags, lids, cardboard; cartons and waste from service units such as paper napkins and straws also contribute significantly to the overall solid waste matter. Some of these non-food items are non-biodegradable.

The hygienic disposal of waste materials is extremely important in the control of pests.

The accumulation of food waste and greasy or sticky paper may attract rats and mice and be the breeding place for many insects.

The waste should be kept in tightly covered bins or plastic sacks during its immediate accumulation at places inside the building, e.g. service rooms.

The bins and sacks should be removed by the house keeping staff to the main waste collection area outside the building from where they will be removed by the local authorities.

Rats and mice make nests in stored papers, boxes, old linen and similar articles. Any accumulation of these should be removed from time to time to ensure that rodents are not making nest. The contents of the waste paper bins should be collected in paper or plastic sacks, while those of the ash trays should be collected separately in bins because of the fire risk. Later both types of waste will be taken to the main waste collection area outside the building

4.2. Liquid Waste

From sinks, baths, and lavatory basins that are taken by a system of pipes into the house drain and from there to the sewer. After emptying a sink full of dirty water, sufficient clean water should be run so that the trap below the sink contains clean water.

Kitchen waste consists of various materials and in large establishments bones, fat, articles made of glass etc, are often kept separate from ordinary food waste and are sometimes sold. Food waste may also be sold as pig food.

After the garbage is collected, it should be discarded in a proper way without creating any trouble to the society. Nowadays, due to increase in population and standard of living of people, there is also increase in the accumulation of waste products.

Waste from the food establishment is of biodegradable and should be disposed in the proper manner because it is highly perishable and paves the way for growth of microorganism with foul odours. Before selecting the method for waste disposal, it is compulsory to understand the value of waste matter and problems arising due to it if not disposed in the correct manner.

5. METHODS OF WASTE DISPOSAL

Landfilling, burial, composting, burning, disposing, setting up biogas plants, recycling and vermin-culture.

5.1. Landfilling

Land filling is also known as dumping. It is a site for the disposal of waste materials by burial and is the oldest form of waste treatment. Historically, landfills have been the most common method of organized waste disposal and remain so in many places around the world.

Some landfills are also used for waste management purposes, such as the temporary storage, consolidation and transfer, or processing of waste material (sorting, treatment, or recycling).

5.2. Dumping

The easiest method of disposing waste which is commonly in practice is disposing the garbage in the low lying area or dumping it in the pit. This makes the bacteria to decompose the waste and reduce its actual volume. However, there are some demerits of this method of waste disposal like

1.  Wind disperses the thin debris

2.  Flies and rodents feed on the garbage and pave the way for infection.

3.   Looks unpleasant and final product is bad odor.

4.   Dumping in the low lying area may prone to pollution of underground water

5.3. Burial

Like dumping, burial is another method of disposing waste, where dumping is used for disposing large volume of waste, burial is used for disposing small volumes of garbage.

The time taken for the complete decomposition of buried organic matter to harmless mass is about six month. Food service establishment that set up on temporary basis could dispose the garbage using this method.

5.4.Composting

Composting is another way of disposing waste where the garbage is collected in the sewage tank and solid particles settle at the bottom of the tank. Nitrogen and phosphorus are highly concentrated in the animal and plant waste which should be returned back to the soil by this method.Waste is decomposed by fungi and bacteria enabling the nutrient rich compost to be formed which can be utilized as fertilizers to the soil. This process of composting occurs for several days at 60○C with the formation of carbon di oxide, water and heat. The disease causing larvae and eggs of the files are completely destroyed by this process.

5.5. Incineration

Incineration is process of converting the large volumes of garbage into ashes by burning. This method is practiced when the rate of landfilling is very high. The burning of trash is done in the specially built incinerator which is tall enough with sufficient supply of air for efficient burning. The incinerator should be checked for proper working condition before the start of process to avoid accidents. Compared to other method of waste disposal, incineration is safe and hygienic method.

Disadvantages of incineration

1. If refuse does not burn properly, too much offensive smoke is produced which in turns pollutes the air.

2. Organic nitrogen which could have been returned to the soil is converted into inorganic nitrogen and is returned to the atmosphere.

3. This method cannot be used during the rainy season or if the garbage is wet.

4. Although incineration is ideal from the sanitary point of view, it is costly compared to other method. Moreover the cost of fuel and fertilizer value of the waste is lost.

Any presence of fine ash makes burning difficult and therefore dust or ash should be stored separately. In this method no manure is formed. The volume of garbage is reduced to one-fourth its original weight. The residue is a mass of hard material called clinkers and is used for road making. The cost of transporting refuse is minimized. This is one of the best methods of garbage disposal.

5.6. Mechanical disposers

Mechanical disposers include pulpers or disintegrator and mechanical compactors.

These can be installed in catering establishment and are useful because they help in reducing the volume of garbage and the number of garbage bins required. These methods require an access to a drain, water for cleaning and a power source.

5.7. Pulpers or disintegrators

The pulper or disintegrator grinds food waste into tiny particles then it is flushed with water. When the machine is switched on, the waste from the sink drops into the pulper and gets finely cut, it is flushed into the kitchen drain and disposed off along with sewage. The ordinary drainage system can dispose soft refuse like fruit and vegetables trimmings, peels, soft bones and meat trimming. If any solid waste remains, they have to be pulled out and discarded along with refuse.

Advantages

This machine is useful because it helps in preventing accumulation of solid, wet garbage which would otherwise decay very quickly and helps to prevent contamination of the prepared foods in the kitchen.

Garbage disposal machine

The latest way of disposing kitchen waste as soon as it is produced is through an automatic garbage disposal machine. This is also the quickest and most hygienic way of garbage disposal. These machines are fitted under the existing sink or may be purchased as a self-contained unit.

5.9. Biogas technology

The organic matter present in solid waste is decomposed by bacteria in absence of air (anaerobic condition) by passing biogas in a biogas digester. The approximate composition of biogas is 60% methane and 40% carbon di oxide. For better yield of biogas, the organic solid waste may be mixed with poultry waste, grass, leaves, straw, kitchen waste, etc.

6.  IMPACTS OF IMPROPER WASTE MANAGEMENT ON HEALTH

• Air, water and soil pollution
•  Solid waste creates the ideal atmosphere for insects to breed and spread infection during the rainy seasons
• Generation of green house gases from the organic waste in the landfills
•  Spread of deadly diseases like cholera and dengue by rodents and insects from the waste.
•  Health issues such as infections to lungs, nose and throat due to inhalation of the air from the disposed waste.
• Immune system gets altered causing allergy and asthma
•  Pollution load will be higher due to improper disposal of solid waste.

7.  CONCLUSION

Improper waste disposal is the biggest concern for the urban Indians. For efficient waste management in our country, there should be some changes brought to national policy.

Instead of bringing the policy changes after the damage to the public, it should be thought at the beginning to save the country from serious health effects.