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Lesson 4: Water Pollution
Learning Objectives
- Explain the relationship between solid waste management and water pollution.
- Identify different water filtration methods and their role in preventing water pollution.
Introduction: The Vital Connection Between Solid Waste Management and Water
Water is not just a resource; it is the essence of life, deeply embedded in the fabric of cultures, especially within Indigenous communities. It serves as a mirror reflecting the interplay between environmental stewardship and cultural health. Indigenous teachings emphasize water’s multifaceted roles: a source of beauty, a symbol of purity, a habitat for life, a tool for cleansing, and a thread connecting all aspects of existence. This profound understanding underscores the principle that water is sacred, powerful, and inherently medicinal, linking every element of the natural world.
Yet, the vitality of water extends beyond spiritual and cultural dimensions; it directly influences our ecosystem’s health and our own well-being. As Elders articulate, water’s significance permeates every aspect of life, intertwining with health, education, governance, and environmental integrity. This intrinsic value of water highlights the urgency of safeguarding our water sources from pollution, particularly that stemming from improper solid waste management.
In this context, understanding the relationship between solid waste management and water pollution becomes crucial. Our journey begins with examining how waste disposal practices impact water quality and the broader implications for ecosystems and communities. Furthermore, we will explore various water filtration methods as vital tools in preventing water pollution, ensuring the purity and safety of this essential life source. Through this exploration, we aim to embrace a holistic approach to waste management, one that honors the teachings of Elders and the indispensable nature of water in sustaining life and cultural vitality.
Elders stress that, “Water cannot be separated into one realm. In the same way, water is important to life, health, education, the laws that govern our lives, and the environment.” (Sanderson, 2004, p. 113)
Solid Waste Management and Water Pollution
Before we delve into the connection between solid waste management and water pollution, it’s crucial to understand the significance of this relationship. Improper disposal of waste, particularly hazardous materials, poses a significant threat to our environmental health, particularly to soil and water resources. When waste isn’t disposed of correctly, harmful chemicals can leach into the ground, compromising soil quality and potentially contaminating groundwater. This contamination poses risks not only to human health but also to aquatic ecosystems and biodiversity.
A notable case highlighting the long-term environmental impact of industrial operations is the history of the Imperial Oil refinery in Regina, which operated from 1916 to 1975. The legacy of contamination from this refinery underscores the importance of effective waste management in preventing soil and water pollution. It’s a stark reminder of the lasting environmental challenges posed by past industrial activities and the need for vigilant waste management practices.
This context sets the foundation for a more detailed exploration of how solid waste management practices directly impact water pollution. We’ll also discuss strategies to mitigate these effects, focusing on the importance of responsible waste disposal and innovative water filtration methods.
Soil and Water Pollution
Improper disposal of hazardous waste or the lack of proper treatment can lead to the contamination of soil and water resources. Toxic chemicals from waste can seep into the ground, affecting soil fertility and potentially entering the groundwater, posing risks to human health and ecosystems.
The following article details an issue of controversy caused by an Imperial Oil refinery operating in Regina from 1916 to 1975.
Leachate
Leachate is caused by rainwater or snow melt that goes into the landfill, filters through the waste, and becomes contaminated. Discharge of landfill leachate directly into surface water is not an acceptable practice.
There are several components of a modern landfill that address the problem of leachate running into the environment water system:
- Landfill base and base liner- the base ground below a landfill needs to be geologically stable and impermeable to underground aquifers. A base liner of clay or some other engineered material needs to be used to ensure leachate can be collected, tested, and managed.
- A leachate management system provides an approach to preventing, collecting, sampling, pumping out, and treating leachate.
- Landfill cover on a daily, intermediate, and final basis causes precipitation to roll off the landfill rather than seep in. Engineering the landfill with an appropriate slope also prevents moisture from seeping. Other stormwater management systems such as berms and ditches are used to divert and control water flow off and away from the landfill.
Filtration and Preventing Water Pollution
Municipal water management involves the management and treatment of water at the local level to ensure a safe and reliable water supply for communities. One crucial aspect of municipal water management is water filtration. Water filtration is the process of removing impurities and contaminants from water to make it safe for consumption and various other uses.
Here are some common methods of water filtration used in municipal water management:
Coagulation, Flocculation and Sedimentation
- Coagulation
Coagulation involves the addition of chemicals known as coagulants to the water. Common coagulants used in municipal water treatment include aluminum sulfate (alum) and ferric chloride.The coagulants destabilize the suspended particles in the water, causing them to clump together and form larger particles called floc.
The coagulation process works through several mechanisms:- Neutralization: Coagulants neutralize the electrical charges on suspended particles, allowing them to come closer together and form floc.
- Enmeshment: The coagulant molecules form bridges between particles, helping to aggregate them.
- Sweeping: The coagulant floc captures smaller particles as it grows in size, aiding in their removal.
- Flocculation
Flocculation is the next step following coagulation. During flocculation, gentle mixing or stirring is applied to the water to promote the collision and contact between the floc particles formed during coagulation. The slow and controlled mixing helps the floc particles to aggregate and form larger, heavier particles.
Flocculation aims to enhance the formation of well-settling floc that can be easily separated from the water during sedimentation. The flocculation process allows the floc particles to grow in size and become more readily settleable.
The duration of the flocculation process can vary depending on the characteristics of the water being treated. Typically, it ranges from 15 minutes to an hour or more. - Sedimentation
After the coagulation and flocculation processes, the water is left undisturbed in a sedimentation basin or clarifier. During this stage, gravity causes the floc particles to settle down to the bottom of the basin. This settling process is known as sedimentation.
The settled floc, along with other larger suspended particles, forms a layer of sludge at the bottom of the basin, while the clearer water remains above. The sludge is periodically removed and treated separately.
It’s worth noting that the dosage and type of coagulant used, as well as the design of the coagulation and flocculation units, can vary depending on the specific water characteristics and treatment facility. Regular monitoring and adjustment of coagulant dosages are performed to optimize the efficiency of the coagulation and flocculation processes.
Filtration
Following sedimentation, the water undergoes filtration to further remove smaller particles and impurities that may still be present. The filtration process can involve passing the water through beds of sand, anthracite coal, or other granular media, which help trap and remove fine particles.
Municipal water treatment involves employing various filtration methods to remove impurities and contaminants from water. Here are some common water filtration methods used in municipal water treatment:
- Rapid Sand Filtration: Rapid sand filtration involves passing water through a bed of granular media, typically sand or a combination of sand and anthracite coal. The media bed traps and removes suspended particles, turbidity, and some microorganisms. Periodically, the sand bed is cleaned through backwashing to remove accumulated particles.
- Direct Filtration: Direct filtration is a modified version of rapid sand filtration that skips the coagulation and flocculation steps. Instead, coagulants are added directly to the water before it enters the filter. This method is effective for treating water with low turbidity and a relatively low concentration of suspended particles.
- Diatomaceous Earth Filtration: Diatomaceous earth (DE) filtration involves using a porous filter medium made from fossilized remains of diatoms (microscopic algae). The DE filter can effectively remove small particles, bacteria, and other microorganisms. The filter medium requires periodic cleaning and replacement.
- Membrane Filtration: Membrane filtration methods use semi-permeable membranes to physically block and separate impurities based on their size. There are different types of membrane filtration used in municipal water treatment:
- Microfiltration (MF): MF uses membranes with larger pore sizes (0.1 to 10 microns) to remove suspended solids, bacteria, and some larger viruses.
- Ultrafiltration (UF): UF utilizes membranes with smaller pore sizes (0.001 to 0.1 microns) and can remove suspended solids, bacteria, viruses, and some macromolecules.
- Nanofiltration (NF): NF employs membranes with even smaller pores (around 0.001 microns) to remove divalent ions, organic matter, and some smaller particles.
- Reverse Osmosis (RO): RO employs a dense membrane with very small pores (around 0.0001 microns) to remove dissolved solids, salts, and other contaminants. It is effective for desalination and producing highly purified water.Membrane filtration methods require regular maintenance and cleaning to prevent fouling and ensure optimal performance.
- Activated Carbon Filtration: Activated carbon filters use a bed of activated carbon to adsorb organic compounds, chlorine, and some other chemicals that affect taste, odor, and color. The activated carbon has a large surface area with adsorptive properties, effectively trapping impurities. Periodic replacement of the carbon bed is necessary to maintain its effectiveness.
- Slow Sand Filtration: Slow sand filtration involves passing water through a thick bed of fine sand at a slow rate. The sand bed provides both physical filtration and biological purification. The sand grains trap suspended particles, while microorganisms attached to the sand’s surface consume and break down organic matter. Slow sand filtration is a natural and effective method but requires large surface areas and longer filtration times
- Biological Filtration: Biological filtration utilizes biological processes to remove impurities. This method typically involves passing water through a filter bed with a high density of microorganisms, such as activated sludge or biofilm filters. The microorganisms metabolize organic matter and nutrients, reducing their concentrations in the water.
These filtration methods are often used in combination or as part of a multi-stage treatment process in municipal water treatment plants. The specific filtration techniques employed depend on the water quality, treatment goals, and regulatory requirements of the specific region or municipality.
Disinfection
After filtration, disinfection is carried out to eliminate any remaining bacteria, viruses, and other pathogens. Common disinfection methods include chlorination (adding chlorine), ultraviolet (UV) disinfection, and ozonation.
Disinfection is a crucial step in municipal water treatment to ensure that the water is free from harmful microorganisms, such as bacteria, viruses, and parasites. Here’s an elaboration on three common disinfection methods used in municipal water treatment:
- Chlorination: Chlorination is one of the most widely used disinfection methods in municipal water treatment. It involves the addition of chlorine-based compounds, typically chlorine gas, sodium hypochlorite, or calcium hypochlorite, to the water. Chlorine is highly effective in killing or inactivating a wide range of microorganisms.
The chlorination process works by introducing a sufficient chlorine dosage into the water to achieve a desired disinfection level. The chlorine reacts with microorganisms, disrupting their cell structures and metabolic processes. It can also react with organic matter, reducing taste and odor compounds.
Chlorination is known for its residual effect, meaning that a small amount of chlorine is intentionally left in the treated water to provide ongoing disinfection as it flows through the distribution system. This residual chlorine helps prevent the regrowth of microorganisms and ensures the water remains safe during distribution.
Chlorine is a deadly chemical and must be used very carefully. Improper use of chlorine is detrimental according to an interview conducted on reserve land in Saskatchewan: “Our water was being treated for a while at [location]. We had a little treatment plant going on there and we started having problems with it. You know, it was just the colour of, it was like [brown]. Even worse than that…There’s three houses there. Well, we didn’t even dare, it was being treated so bad that there was so much chlorine in it, it was wrecking our clothes. Our black clothes were brown, purple. The elasticity in socks, your underwear, your bras, was cracking. It was eating away at it…All we were doing in it was showering and even that, our skin was getting so dry. Our eyes were burning, your nose would burn when you were showering because there was so much chlorine in it. The [chlorine] levels were just unreal
Bharadwaj, L., & Bradford, L. (n.d.). Chapter 4: INDIGENOUS WATER POVERTY: IMPACTS BEYOND PHYSICAL HEALTH. In Northern and Indigenous Health and Healthcare. essay, University of Saskatchewan. Retrieved from https://openpress.usask.ca/northernhealthcare/chapter/chapter-4-indigenous-water-poverty-impacts-beyond-physical-health/ on June 10, 2023
- Ultraviolet (UV) Disinfection: UV disinfection utilizes ultraviolet light to inactivate microorganisms in water. It involves the use of UV lamps that emit UV-C light with a specific wavelength (usually 254 nanometers) known for its germicidal properties.
In UV disinfection, water passes through a chamber where UV lamps are positioned. The UV light penetrates the cell walls of microorganisms, damaging their DNA or RNA, thereby rendering them unable to reproduce or cause infection. UV disinfection primarily targets bacteria, viruses, and some parasites.
UV disinfection is a chemical-free method that does not produce harmful disinfection byproducts. However, it does not provide a residual effect, meaning it only treats the water at the point of disinfection and does not offer ongoing protection during distribution. Therefore, proper monitoring and control of the system are essential to ensure effective disinfection.
- Ozonation: Ozonation involves the use of ozone, a highly reactive form of oxygen (O3), to disinfect water. Ozone is generated on-site using specialized ozone generators and is a powerful oxidizing agent.
Ozone disinfection works by introducing ozone into the water, where it reacts with microorganisms and other organic compounds. The ozone molecules break down the cell walls of microorganisms, disrupting their structure and metabolic processes. It is highly effective in killing bacteria, viruses, and other pathogens.
Ozonation offers several advantages as a disinfection method. It is highly efficient and fast-acting, capable of providing effective disinfection in a relatively short contact time. Ozone also helps remove taste and odor compounds, organic contaminants, and certain inorganic substances from the water.
However, ozone does not provide a residual effect like chlorination, so additional disinfection or other treatment methods may be needed to maintain water safety during distribution.
It’s important to note that the choice of disinfection method or combination of methods depends on various factors, including water quality, treatment goals, regulatory requirements, and the specific needs of the municipal water treatment facility. Often, multiple disinfection barriers are employed to ensure comprehensive and reliable disinfection throughout the treatment process.
pH Adjustment and Chemical Addition: Sometimes, pH adjustment is necessary to ensure the water’s acidity or alkalinity is within the desired range. Additionally, chemicals like fluoride may be added for dental health benefits or other substances to enhance water quality.
Distribution:
Once the water has been treated and filtered, it is distributed through a network of pipes to homes, businesses, and other water users in the community.
It’s important to note that the specific filtration methods and processes employed can vary depending on the quality of the source water, local regulations, and the level of treatment required to meet safety standards. Municipal water treatment facilities are designed to ensure that the water supplied to communities meets or exceeds regulatory requirements for safe drinking water.
Journal Question:
Using the forum labelled “Course 9: Chapter 2” make a journal entry responding to the prompt below. Ensure that you title the entry “Lesson 4”. After writing a journal entry, go and make a comment on two other posts from your classmates. It can be about anything you noticed, liked, agreed with etc. The idea is to continue the dialogue about the topic.
Prompt: Reflect on your daily water usage and consider the journey that water takes to reach your tap. How does understanding the efforts involved in water filtration and treatment change your perspective on water conservation? Write a short reflection on one action you can take to reduce your impact on water pollution and contribute to the sustainability of this essential resource.
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Criteria |
Exemplary |
Accomplished |
Developing |
Beginning |
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Purpose |
Strong voice and tone that clearly addresses the purpose for writing. |
Appropriate voice and tone. The purpose is largely clear. |
Attempts to use personal voice and tone. Somewhat addresses the intended purpose. |
Demonstrates limited awareness of use of voice and tone. Limited evidence of intended purpose. |
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Understanding |
Many interesting, specific facts and ideas are included. |
Many facts and ideas are included. |
Some facts and ideas are included. |
Few facts and ideas are included. |
|
Conventions |
All grammar and spelling is correct. |
Only one or two grammar and spelling errors. |
A few grammar and spelling errors. |
Many grammar and spelling errors. |
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Reply |
Made two significant contributions to the online forum. Highly supportive of others. |
Made one contribution to the online forum. Supported group members. |
Attempted to contribute to online forum but was vague and unclear in the writing. |
Minimally involved. Offered limited support to online group members. |
Works Cited:
Bharadwaj, L., & Bradford, L. (n.d.). Chapter 4: INDIGENOUS WATER POVERTY: IMPACTS BEYOND PHYSICAL HEALTH. In Northern and Indigenous Health and Healthcare. essay, University of Saskatchewan. Retrieved from https://openpress.usask.ca/northernhealthcare/chapter/chapter-4-indigenous-water-poverty-impacts-beyond-physical-health/ on June 10, 2023
Sanderson, C. D. (2004). Nipiy Wasekimew / Clear Water: The meaning of water from the words of the Elders – The interconnections of health, education, law and the environment Doctoral dissertation, Faculty of Education, Simon Fraser University, Burnaby, BC. Retrieved from http://www.collectionscanada.gc.ca/obj/thesescanada/vol2/002/NR58519.PDF