Environmental Hygiene Note |BHM and IHM Food Science and Nutrition|

Introduction

Environment literally means surroundings, and everything that has an impact on an organism throughout the course of its existence is referred to as that organism’s environment. It includes every aspect of the natural and biological environment, as well as how they interact.

Environmental hygiene refers to the practice of enhancing the environment around us through practice sanitation and cleaning practices ensuring clean and safe surrounding to prevent adverse impacts on human health. It is also commonly referred to as environmental health, which is a broad field that aims to promote and protect public health by managing our environment.

Waste, commonly referred to as garbage, is any unusual or undesirable , substance, or product that can no longer function, is no longer required, or has been determined useless by whoever is producing it. It can include a range of materials in the solid, liquid, or gaseous states and can comprise both artificial and naturally occurring substances.

Waste are of two types on the basis of degradability:

1. Biodegradable Waste: It is also known as moist waste. It contains organic components that can eventually decompose naturally as a result of the action of microbes. Kitchen waste (like fruit peels, vegetable trimmings), food leftovers, yard debris (such as leaves and twigs), and other organic materials are the main examples of this category of waste.
2. Non- biodegradable Waste: It is also known as dry waste. It can be recyclable and reusable. These sorts of wastes are significant polluters because they do not decompose or break down over time by microorganisms. Examples: plastics, metals, glass, rubber tyres, and many synthetic materials.

Also it can be categorized on the basis of composition as:

1. Solid Waste: It is distinguished by the presence of substances that are not liquid or gaseous. Plastics, paper, glass, metals, and other inorganic materials are included in this category.
2. Liquid Waste:It composed of waste materials in a liquid form. Sewage, industrial wastewater, and other liquids that need particular treatment and disposal techniques fall into this category. To avoid contaminating water sources and ecosystems, proper handling of liquid waste is essential.
3. Gaseous Waste: It is also called as ‘gas emissions or gaseous pollutants’. It refers to waste items that are gaseous in nature and are released into the earth’s atmosphere as a result of a variety of human activities and industrial operations. These waste materials have the potential to have a negative impact on the environment, human health, and the general quality of the air. The major sources can be :
   • old vehicle producing harmful gases like carbon monoxide (CO) & nitrogen oxides
   • Natural sources: Gases like carbon dioxide and methane (CH4) can be released by volcanic eruptions, wildfires, and natural processes.
   • Various gases, including sulfur dioxide (SO2), nitrogen oxides (NOx), and volatile organic compounds (VOCs), are released by factories and manufacturing facilities.
   • Use of various insecticides and pesticides sprays during agricultural activities and many more.
4. E-waste (Electronic Waste): It includes old cellphones, computers, and other electronic equipment as well as discarded electronic equipment and parts. It is an intricate combination of materials made of polymers, metals (such as copper, aluminum, and precious metals like gold and silver), glass, circuit boards, wires, batteries, etc. Additionally, dangerous substances like lead, mercury, and flame retardants with bromine are also found in many electronic equipment which are harmful for environment.

Environmental hygiene encompasses the control of biological, chemical, and physical elements that have an impact on the environment, including the air, water, soil, and surfaces. It is crucial to safeguarding public health and wellbeing as well as stopping the spread of infectious diseases. A lack of environmental hygiene is capable of resulting in the growth of microorganisms that cause harmful disease, exposure to harmful substances, and physical dangers that can cause harm or illness.

Environmental hygiene involves a variety of practices, including surface cleaning and disinfection, waste management, pest control, proper urbanization including green spaces and assuring the safety of water and air quality. It also entails putting laws and policies into place that support sustainability and environmental preservation. It also include proper design, maintenance, and management of sanitation and sewage systems along with development encouraging eco-friendly and sustainable practices, such as energy conservation, renewable energy use, sustainable agriculture, etc.

Hence, environmental hygiene emphasizes improving the welfare of both the environment and human beings by acknowledging their interdependence. It attempts to make sure that natural resources are used in a way that maintains and sustains them for future generations, without endangering the environment or endangering public health.

Significance of Environmental Hygiene

Environmental hygiene is a multidisciplinary field that recognizes how closely our environment and health are related. It highlights the fact that our well-being is significantly influenced by the environments in which we live, work, and play recognizing that our health can be improved or jeopardized on its conditions.

Environmental hygiene has crucial importance for various reasons. A complete list of the significance of environmental hygiene is provided below:

1. Disease Control or Lowering Disease Risk

By reducing sources of contamination, proper environmental hygiene lowers the risk of diseases, such as water borne illness, air-borne, food borne infections, and vector-borne diseases.

Water Borne Disease: These are diseases that are mainly spread by polluted water sources. Pathogens such as bacteria, viruses, and parasites frequently cause these disorders. Cholera, Typhoid, Dysentery, Hepatitis A, etc

Vector borne Disease: These are caused by parasites, viruses and bacteria. Mosquitoes and other disease-carrying insects thrive in particular types of environments.like malaria, dengue, zika virus, chikungunya and lyme disease.

Airborne Disease: These are diseases brought on by pathogens, typically bacteria or viruses, which can spread through the air. Respiratory illness like Tuberculosis, Influenza (flu), COVID-19, Asthma and bronchitis are its common examples.

2. Improvement of Life Span and Quality

Environmental hygiene ultimately improves general living circumstances, improves settlements, and fosters a better standard quality of life. Stress is reduced, recreational options are increased, and a sense of wellbeing is fostered by a clean and well-maintained environment, all of which contribute to a higher quality of life.

3. Promotes Habitat Protection and Biodiversity, or Preservation of Ecosystem

By increasing environmental health awareness, we can provide better protection for the  flora and fauna around us. By minimizing pollution, destruction of habitat, and chemical contamination, environmental hygiene promotes biodiversity and ecosystem health. The conservation of natural habitats and ecosystems promotes biodiversity, upholds the vital equilibrium of life on Earth.

4. Reduces global warming or strengthens fight against climate change
5. Conservation of Resources

Environmental hygiene takes into account that our natural resources are limited. It places a strong emphasis on using resources like water, land, and energy responsibly in order to reduce waste and environmental damage.

6. Food Safety

In addition to preventing foodborne illnesses and guaranteeing nutritional safety, it encourages safe food cultivation, handling, storage, and preparation.

7. Economical benefits

Long-term cost savings can be achieved through sustainable environmental practices since they lower healthcare costs and reduces the financial burden of disaster recovery like flood . Economic growth, tourism, and investments are also all attracted to healthy environments, which benefits both communities and individuals.

8. Improved mental health
9. Preservation of cultural heritage
10. Sustainable development

Garbage Disposal and It’s Methods

In order to preserve a clean and healthy environment, stop the spread of disease, and lower the risk of pollution, proper waste disposal is crucial.

The elimination, disposal, reuse and recycling, or destruction of undesired items, such as waste or garbage produced by industrial, home, or agricultural operations, is referred to as waste disposal. Simply, the act of handling and disposing of waste in an environmentally friendly and efficient manner is known as garbage disposal.

In addition to maintaining a clean and safe environment, appropriate waste disposal makes a substantial contribution to environmental sustainability and public health. The entire journey of waste is a complex and well-organized process that begins with the right away waste that emerges in our homes, businesses, and industries and ends with its collection, transportation, treatment, and final disposal.

Recycling and Reuse

Energy is saved by recycling and reusing waste, and this practice is encouraged since it protects the environment.Non-decomposable waste items, such as shattered glass, metal scraps, wires, etc., can be recovered and used throughout various processes. Some materials can be recycled again without being processed.

Materials that can be transformed into new goods can be recycled.

Advantage

Decreases the demand for raw materials extraction and manufacturing, reduces waste volume, controls pollution, minimizes carbon footprint, and protects natural resources and ecosystems along with various health benefits

Challenges

Requires appropriate sorting, processing infrastructure, and customer involvement as encouraging people to reduce, reuse, and recycle requires sustained efforts in education and outreach

METHODS

1. Open Dumps or Dumping

It is an unsustainable and hazardous approach to waste management that involves the careless or unsafe manner and frequently unhygienic disposal of garbage and other solid waste products, subject to open burning, exposed to the elements, vectors like flies, rats, cockroaches, stray dogs, birds, etc. and scavengers like vultures, crows, etc.

Despite some open dumps are removed shortly after they formed, the majority will stay in place for an extended length of time.

The possible dangers of open dumping include the release of harmful chemicals, gases and heavy metals into the air, land and water, the growth of disease-carrying rodents and insects, and unpleasant odors, and/or physically hazards from piercing or sharp objects.

• It is regarded as the most hazardous or unhygienic disposal alternative.
• It is typically unregulated, meaning there are no standards or guidelines for waste disposal at these sites.
• When garbage builds up and starts to break down, carbon dioxide and methane are produced. It is possible to extract, clean, and use these gasses to produce energy. Due to the uncontrolled nature of these sites, managing and extracting these gasses from open dumps can be difficult. Hence, rather than open dumps, this approach is more frequently useful to managed or controlled landfill sites.
• Waste is not segregated; it is left untreated and unprotected (i.e. not covered).
• Serve as the hub of a breeding site or centre for flies, rats, and other pests which might cause various diseases later
• It is less expensive technique
• It is traditional and widespread techniques of waste disposal.
• There is little or no soil applied as a cover.
• Poor or no leachate management
• There is a chance of fire when combustible items build up in open landfills. These fires could generate poisonous gasses and endanger the safety of garbage workers as well as the nearby populations.

2. Landfills

A landfill is an artificially created pit excavated or dug into the ground where waste materials are layered, squeezed out and covered in preparation for disposal.
This method involves separating and spreading waste that cannot be recycled or reused into a thin layer in low-lying areas of a city. After every layer of trash, a layer of soil is added. Nevertheless, the region is considered unsuitable for building development for the following 20 years once this process is finished. It can only be used as a park or a playground instead.

It is one of the most often used techniques for disposing of waste in large quantities.

The most popular type of trash disposal is landfilling, in which waste materials is buried in specially prepared ground. Even though it’s a reasonably inexpensive practice, landfilling may cause pollution but lesser than open dumping.

Applicability: Non-hazardous and non-recyclable garbage are dumped in landfills.

Challenges: If not correctly managed, landfills can release methane gas and leachate, which can be harmful to the environment.

• Waste that is dumped in a landfill is protected from leaking harmful chemicals into groundwater and contaminating drinking water by a protective liner mainly soil.
• There is an earthen layer covering the compacted waste. Low permeability soil is ideal for landfills as it lowers the chance of leaks.
• Usually, landfills are located in areas with low ground water levels and no risk of flooding as it may uncover waste and bring out waste into surface or contaminate ground water sources.
• To stop animals from digging up the waste and flies from breeding, the dumped waste should ideally have 0.5 m of soil covering it at the end of each day. Also, sites are supposed to be at least one kilometer away of the nearby residences and ideally fenced.
• Landfill avoids breeding site for pests and scavengers too as it used to be in open dumps.

3. Composting

Composting, sometimes referred to as biodegradation, is an aerobic biological process that involves act of transforming biodegradable organic waste or materials —such as leftover food and yard waste — into humus or a product called compost (i.e. nutrient-rich material that resembles soil). The microorganisms involved are primarily fungi and bacteria.

The first step in the composting process is to bury organic wastes in a compost pit or other soil layer and allow microorganisms to break them down over certain time period. It is an eco-friendly way of waste disposal and it also promotes sustainable agriculture using compost manure. It involves gradually breakdown of organic materials over time by microorganisms like bacteria, fungi, etc.

• Microbes usually leads to a significant drop in the volume of organic waste, and in some situations, it may reduce the volume by 50% or more.
• By supplying bacteria, fungi, and other decomposing organisms with the ideal habitat, composting primarily promotes the decomposition process.
• Substance that has broken down or decomposed and after the composting process looks like rich garden soil generally known as ‘compost’.
• Compost, sometimes referred to as “black soil,” is rich in nutrients and can be used in farming as the organic fertilizer.
• It is sometimes referred to as improving the soil’s ability to retain water.
• Compost that is properly established well has a dark appearance, no odor, and stable humus.
• Composting offers the dual advantage of generating revenue while reducing waste disposal costs. High-quality compost is in demand for various purposes, such as agriculture, landscaping, gardening, and horticulture.

Advantages of Composting

• Greenhouse gas reduction]
• Environmental and economic benefits
• Decreased necessity for chemical-based fertilizers through use of organic manure i.e. compost
• Microbial decomposition through bacteria, fungi, etc
• Production of nutrient-rich compost
• Participation in sustainable practices

4. Vermiculture (Vermicomposting)

Vermiculture is the waste disposal methods by allowing earthworms to break down the organic waste, creating rich, fertile nutrient-rich manure which is known as vermicompost. Vermiculture typically involves using specific species of earthworms, such as red wigglers (Eisenia fetida) or redworms (Lumbricus rubellus).

Mary Appelhif, a biology professor, was the one who initially introduced vermiculture in the 1970s. She came up with the concept of turning kitchen garbage into worm compost by employing red wiggler worms (Eisenia fetida) in both indoor and outdoor systems.’

Composting generally requires following materials:

• Cow dung
• Earthworms
• A suitable container
• Moisture or water supply
• Pits
• Biodegradable waste like vegetable waste, dried leaves, crop residues, etc.

Things to take care for vermiculture

• It is important to keep the compost pit shaded from the sun.
• Protect the worms from ants, birds, rats, and other pests.
• When needed, mist the pit with water to maintain the moisture content.

Waste-to-Energy (W.E.T) Conversion

W.E.T. conversion is the process of turning waste materials into energy by pyrolysis, gasification, incineration, etc. This process can reduce the amount of waste that is dumped in landfills and produce usable heat and energy. Here’s an overview of waste-to-energy conversion methods:

5. Incineration

Incineration is a high-temperature dry oxidation process that converts organic and combustible garbage to inorganic, noncombustible stuff, resulting in a significant decrease of waste in both weight and volume.

(OR) Incineration is the process of treating waste or disposing of waste which involves the burning of waste at high temperatures and produces heat, flue gas, and ash from the waste. Incineration can provide energy and minimize the amount of garbage produced, but it can also discharge dangerous toxins into the atmosphere.

Municipal solid waste as well as waste from the medical industry typically gets incinerated.

The by-products of incinerators, heavy metals, are regarded to pose a serious environmental threat because they are disposed of in landfills, contaminating the land, water, and air. Nonetheless, this method has several benefits, such as decreased waste volume, production of power and heat, pollution reduction, elimination of hazardous and chemical gases, noise and odor control, and no need for waste transportation.

The incineration of about 600 metric tons of waste per day will result in the production of 400 MWh of electrical power and 1200 MWh of thermal power on an average day.

Bad Sides: Generation of greenhouse gases such as carbon dioxide and carbon monoxide.

The main objectives are to produce energy in the form of heat or electricity and to decrease the volume of waste.

• Transforms waste into heat, flue gas, and ash.
• Electric power can be produced from the heat produced during incineration.

Characteristics of waste suitable for incineration:

Certain waste materials are not appropriate for incineration due to their high moisture content or low calorific value, which prevents them from burning completely. The most important requirement for waste suitable for incineration is that it have a minimum calorific content.

• Lower moisture content: Moisture content below 30%
• Calorific value: Depending on the technology and operating efficiency, the needed calorific value can vary, but ideally it shouldn’t be less than 6500kJ/kg.
• An additional requirement is that the waste must fit into the combustor. Before they burn, some combustible objects, like tires in specific conditions, need to be shred in order to make them smaller. In order to handle large materials, shredders are sometimes installed in the pit area of incineration operations.

Also there are various types of incinerator plant designs, each with its own characteristics and applications. Moving grate, fixed grate, rotary-kiln, and fluidized bed are a few examples of different incineration plant designs.

6. Pyrolysis

The word pyrolysis is derived from the Greek word ‘Pyro‘ meaning ‘heat‘, and ‘lysis‘ means ‘disintegration or break down‘. The process of pyrolysis is a thermochemical breakdown in which organic materials, such as polymer compounds, biomass, and some specific types of waste, are heated to extremely high temperature in the absence of oxygen or with a minimal quantity of oxygen.

• Glass metals and inert materials are mechanically processed and separated from solid wastes before the residual waste is processed in a pyrolysis reactor.
• It’s important to keep in mind that pyrolysis modifies the chemical composition of the material being pyrolyzed (the initial reactant and the final product have very different chemical compositions).
• Solid waste, agricultural residues, scrap tires, non-recyclable plastics, and other non-recyclable items can all be converted into clean energy through the pyrolysis process.
• It offers a convenient way for transforming waste from cities into products that can be utilized to produce chemicals, heat, and power.
• The temperatures at which this process occurs typically range from 500 to 600 degrees Celsius.
• It is an irreversible process that involves a change in chemical composition and physical state.

Advantages of pyrolysis

Destruction of pathogens, Reduced water volume, Limited need for fuel: One can limit the supply of external fuel by utilizing the generated gases as fuel, produces lower emissions of harmful air pollutants, etc.

Limitations

1. Complication and high cost: Pyrolysis is a technically complex process that requires specialized equipment and controls which also makes it expensive.
2. Requires for an Air Purification System: Pyrolysis can generate flue gases and emissions that may contain pollutants, odors, and potentially harmful compounds. To meet environmental regulations and ensure air quality, the installation and operation of an effective air purification system are necessary.

Important Questions from this Unit