Waste management in academia

If the environment has occupied a tiny and belated place for researchers of geography, the trend has changed in recent years, as work academics and degrees focused on the environment are on the rise. Even though diplomas oriented towards this field amounted to less than twenty diplomas, only 7% for the Earth and Life Sciences, the environment is the set of living biotic factors likely to have effects on other living beings, especially humans. Universities in their scientific fields (Earth Sciences, Biology), Literary (Geography) and Law / Economics offer training courses focused on the environment.

What do you learn by studying waste management?

The study of waste helps understand how people live and carry out their vital functions (consumption, diet, health) and cultural (leisure, various activities), or professional. This is not divination: by studying the trash cans, we can establish trends in behavior, based on typologies carried out on the basis of analyzes of contents of garbage cans carried out over several years.

Such analysis is somewhat similar to other fields of study which aim to study the relationships that men had with their waste from one society to another. But how do you define the word waste?

The variety of household waste

First, appeared in the 14th century, the word “waste” comes etymologically from the verb “to decline” and expresses a general notion of depreciation. Common usage qualifies waste as a rejected product because without recognized possibility of use; dumped in the trash and left in the dumpster as garbage, it is intended for disappearance by burial in a landfill or by cremation, destruction in an incineration plant in the manner of a corpse.

A product qualifies as waste only from the moment it is deposited in the trash, i.e. from the moment its market value or social ceases to exist. This is the result of a loss of use.
It is also appropriate to note the various definitions of this term which are listed in dictionaries, such as “decrease in quantity or value (there is waste in the melting of the currency) or what is lost in the use of a material (meat waste, wasteo).

In 1972, the dictionary gave an unclear definition of the meaning of this word: “discredit, decrease”. Another definition of 1988 states “what falls from a material we work on, waste wool. Loss, part irrecoverable of something: fruit crates where there is waste. No one morally and physically degraded, a waste of humanity “. These definitions have given the term “waste” a pejorative connotation that also conveys the term “junk” and the idea that we have of waste is fundamentally negative: it is something that no longer serves any purpose, that encumbers.

Pluralized, waste is defined as follows: “debris, food scraps that are unfit for consumption or use (throw waste in the trash); materials rejected as not of immediate value or left as residue from a process or operation. Non-combustible and unnecessary products from metabolism of living cells, intended either to be rejected (carbon dioxide, excreta, urine, sweat …), or, especially in plants, to be accumulated separately general circulation (latex, oleoresins, alkaloids, etc.) ”. Dictionaries certainly define this term, nevertheless the definitions provided are hardly explicit.

The risk of pollution from landfills

bacteria in landfillsThe waste materials gathered in junk removal processes and reaching landfills can be approached differently depending on their properties. Their classification can be done according to their physical state (solid, liquid, gaseous), their source (household waste, industrial waste, agricultural waste), their treatment (primary, secondary, ultimate) or their dangerousness ( inert waste, ordinary waste, special waste).

Intuitively, humans, like animals, deposit their waste away from their places of life, for various reasons, among which there are health concerns (protection against odors, parasites, physical attacks and infections).

In fact, in the strict sense of the term, the rational management of urban waste consists in evacuating garbage outside the city because their deposit in inhabited areas pollutes the environment and deteriorates the quality of life. Unfortunately landfilling is a problem in many countries including the USA.

Any organic matter of animal or vegetable origin will sooner or later, depending on the physico-chemical conditions such as temperature and humidity, be colonized by microorganisms. They will find material to feed on and develop while producing gases and substances with a negative effect (toxic substances or substances inhibiting negative effects on humans) on the surrounding environment. In a landfill the phenomena that develop, following the biodegradation of organic matter, will be all the more complex as the volume of waste will be heterogeneous.

Uncontrolled landfills involve various types of waste (low or fast biodegradable materials, plastics, metals, glasses and ceramics) and mixed populations of endogenous microorganisms (which originate from waste, the surrounding atmosphere or the sub-soil of the landfill). Heterogeneity, the presence of biodegradable materials and the influence of external parameters, such as rainfall and temperature, are at the origin of chemical, physical and biological processes that influence each other and generate flows of gases and liquids.

Liquids from a landfill are commonly known as leachate. The gases for their part are called biogas. Since microorganisms are responsible for most changes in the physicochemical properties of leachate and biogas, the uncontrolled discharge is often thought to be a biochemical reactor or bioreactor. The flows entering this landfill correspond to the entry of water as well as the supply of waste during the dumping of waste. Water the element that has the greatest influence on the evolution of waste, comes from three main sources: runoff arriving at the landfill, precipitation and water constitutive of waste.

The leachates or leachate liquids of the landfill are charged bacteriologically and especially chemically with both mineral and organic substances. They can mix with surface water as well as with groundwater and thus constitute a pollutant element as well by their quantitative aspect as qualitative (ecotoxicological elements). The water passing through the layer of waste will be charged with pollutants such as soluble organic matter resulting from the biological activity of the uncontrolled discharge, inorganic constituents such as heavy metals (especially from batteries) and germs that can be dangerous for health and the environment.

It is difficult to predict the composition of leachates precisely because it depends on the nature of the waste, the volume of precipitation, and the stage of degradation reached. The greatest risk associated with leachate production is contamination of the water table. This would pollute drinking water wells and thus deprive the population of a vital element in its survival. It should also be noted that the pollution of drinking water reserves by pathogenic micro-organisms is likely to cause epidemics.