2 Waste sources and generation rates

Dr. J. Rajesh Banu

Objectives:

After completing this module, you should be able

To impart knowledge about the kind of solid waste generated at various location.
To develop the skill of segregate the solid waste according to type and composition.
To create awareness among the people to minimize the solid waste generation through the following activities reduce, reuse and recycle.
To provide knowledge associated to the techniques used to estimate quantity of waste generation
To understand the factor influencing solid waste generation rate.

Description

Solid Waste

The term solid waste refers to useless or unwanted and non-liquid material that has no longer value to the owner who is liable for it. Solid wastes are generated due to human activity, when the material consider as useless, unwanted or has no longer value. In connection with that, solid waste generation rates may differ from community to country which depends on the human life style, financial status, industrial structure and techniques used to minimize the waste.

Source of solid waste

The purpose of this portion to discuss about frequent source of solid waste was shown in the Figure 1 and the reader to aware knowledge about different kind of solid waste generated with corresponding source was exposed in Table 1.

Residential waste

Residential wastes include four kinds of solid waste: household waste, garden waste, bulky waste and household hazardous waste generated from single-family and multi-family housing. It consists of organic waste and inorganic waste as listed in the Table1. Tenant and owner are answerable for proper disposal of solid waste.

Commercial waste

Commercial wastes originate from various locations such as shopping mall, marriage hall, complex, cinema threats, restaurant, hotel and motel etc. It consists of combustible waste and non-combustible waste as listed in the table1. Customer, Site manager and owner are responsible for proper disposal of solid waste.

Institutional waste

Institutional wastes come from numerous public and government organization such as schools, college, hospital, office and research & development etc. It consists of combustible waste and non-combustible waste as listed in the table1. But medicinal waste should be processed and handled separately from the other solid waste generated. Students, Staff, Doctor, Patient and Head of the institute are in authority for proper disposal of solid waste.

Industrial waste

Institutional wastes generated from two different locations such as small scale and large scale industry. Solid waste consists of heavy metal, oil, paints and lubricant etc.as listed in the table1. The waste that generated contains organic, inorganic and hazardous waste it should be handled carefully which toxic to the human life. Similarly, large scale industrial waste sometimes used as raw material for small scale industries. Employee and employers are in charge for proper disposal of solid waste.

Agricultural waste

The waste that are derived from crop and plants harvesting, waste accumulated in orchards and vine yard, the production of animals for slaughter are collectively known as agricultural waste. In several location public facing problem in disposal of animal manure in particularly from diaries and feedlot, sometime the animal manure consists of hazardous substance. On the other hand, the renter and proprietor answerable for proper disposal of solid waste.

Municipal Services

The term municipal solid waste refers to solid waste from dry leaf from road side and public garden collected during sweeping, road side waste collection container, landscape, dead animals and automobile parts removed automatically from vehicles during travel etc., Municipality Labour, Municipality staff and government official responsible for proper disposal of solid waste. It may consist of organic and non-organic substance such as food waste, paper, plastic and glass etc are found near public places like bus station and railway station etc.

Table 1. Solid waste – Sources, composition and waste generator

Treatment Plant Site

Solid and semisolid waste from wastewater, common effluent and industrial treatment plant are collectively known as treatment plant facility. It mainly consists of organic matter such as sludge, which biodegradable and also energy can be derived from the waste sludge in the form of biogas through wet fermentation (anaerobic digestion). The main principle components of biogas are methane which is alternative source of energy. Solid waste generated should be disposed with proper care and Plant technician, Plant Manager and site supervisor are in charge for disposal.

Construction and Demolition waste

Construction waste comes from construction of new buildings, repair and remodelling works. Likewise, demolition waste comes from bridges, razed building, sidewalks and broken out streets. The waste consists of steel, concrete and electrical tool, wiring materials etc., as listed in Table 1. Workers, site supervisor and Project manager are answerable for proper disposal of solid waste.

Both construction and demolition waste are similarly at particular material such as broken plastics, glass and reinforced steel etc.,

Waste Generation Rate

The rate of change of quantity of solid waste generation with respect to stipulated time is termed as waste generation. The waste generation rate is governed by various factors (i.e) it depends mainly upon the geographical location, customs, climate, living conditions and economic standard of the area. The characteristics, quantities, volume and composition of solid waste generated may differ from one country to another and between urban and rural areas. The per capita waste generation in Indian cities is summarized in Table 2. The average per capita waste generation depends on population. A population of 0.1 to 0.5 million generates 210 g/capita/day waste. The quantity of Municipal solid waste generation in metro Cities / State Capitals is tabulated from the reports of Central pollution control broad (CBCP 2011) in Table 3.

Table 3. Municipal Solid Waste Generation in Metro Cities / State Capitals

Techniques to estimation waste generation rate

Quantity of solid waste generated are typically estimated on the basis of data collected by a survey conducted on characterization of solid waste, otherwise using earlier statistical report of solid waste or several amalgamations of the two analyzing methods.

Load count analysis

In this method, the number of individual loads and the corresponding waste characteristics (types of waste, estimate volume) are noted over a specified time period.

Weight volume analysis

In this method, measuring the volume solid waste in the truck and weight of each load will give sample data. Similarly, No. of load and time period not a constrain.

Material mass balance analysis

In this method, the mass solid waste is analyzed in a system boundary or controlled volume.
To analysis the rate of generation and movement of waste with any grade of consistency.
To execute a complete material mass balance analysis for individual kind of solid waste generated at different source.
Mass of solid waste entering into the system should be equal to mass of solid waste leaving from system as shown in the figure 2.

From the above figure we formulated the equation for material mass balance analysis as follows:

The rate of generation may be positive or negative, if rate of generation within the system boundary is higher than rate of decay then it possesses positive sign. Similarly, if rate of decay within the system boundary is higher than rate of generation then it possesses negative sign.

Problem

Using following data evaluation the quantity of solid waste generated rate per week for a city residential area consists of 5000 homes. Given data are collected from local transfer station and observation period was one week.

Factors that affect waste generation rates

Waste reduction at source

Reduction can be done at the point of source through the person who is disposed the material as no value or useless and reuse before it discard.
Reduce avoidable or unnecessary packing.
Use material with higher durability and easy repairable.

Reduce

Disposable goods: paper plate, paper bowl, Styrofoam cup, plastic spoon, roll of paper towels, paper napkin; Durable goods: ceramic/plastic plate, metal spoon, glass/plastic drinking cup, dish towel, cloth napkin).
For example, recovery of one tonne paper can save 17 trees.

Reuse

Instead of buying new containers from the market, use the ones that are in the house.
Cleaning and using the material over and over again
Increasing the lifespan of the product
For example don’t through away the soft drink can or bottle covers them with homemade paper or paints on them and uses them as pencil stands or small vases.

Recycling

Materials that can be broken down and reprocessed to manufacture new items.
Separated waste material can be used again as a useful material by processing it. (Glass , Paper and Plastic)
Use shopping bags made of cloth or jute which can be used over and over.

Degree of recycling

Extending the life period or usage of material or product for further processing.
For example rechargeable batteries are used and it can be charged for next use.

Socio economic background

Quantity of waste generation may be depends on person to person with corresponding to their economic feasibility.
In case huge quantity of waste can be generated by high class community when compared to mild and low class community.
For example high class community use more electronic device to express their economic status like mobile phone, tablet, laptop computers etc.

Climatic condition

Temperature plays a major role in solid waste disintegration faster at higher than cooler climate.
For example solid waste such as sludge available from wastewater treatment plant must require feasible temperature to produce biogas through anaerobic digestion

Summary

In this lecture we educated about:

Various sources of solid waste generation.
Rate of solid waste generation
Techniques used to estimate of solid waste generation.
Factors influencing the waste generation rate.

you can view video on Waste sources and generation rates

References:

Tchobanoglous George, Hilary Theisen, and Samuel Vigil. Integrated Solid Waste Management. Engi-neering Principles and Management Issues. New York: McGraw-Hill, 1993.
Kreith, Frank, ed. Handbook of Solid Waste Management. New York: McGraw-Hill, 1994