Understanding Sewage Pollution: Causes And Human Impact

Sewage pollution is a critical issue that poses a significant threat to aquatic ecosystems and human health. It is caused by a combination of factors, including outdated sewer systems, improper waste disposal, blockages, and insufficient treatment facilities. Over 80% of global sewage is discharged into seas without adequate treatment, leading to the contamination of water sources and the spread of harmful bacteria, viruses, and chemicals. This pollution has severe ecological and health consequences, damaging natural habitats, reducing biodiversity, and causing illnesses in humans and aquatic life. With increasing urbanisation, climate change, and overpopulation, the problem of sewage pollution is becoming more acute, requiring urgent attention and investments to mitigate its detrimental effects.

Antiquated sewer systems

The situation is similar in the United States, where aging sewer systems, some nearing 100 years old, are overwhelmed and failing. Years of neglect, growing populations, and climate change have resulted in frequent line breaks, pump failures, and overflows. In Florida, for example, there were nearly 14,000 sewage spills in the last five years, releasing over 1.6 billion gallons of sewage into communities and waterways. Many communities are not connected to central sewers and rely on antiquated cesspools and septic systems that do not adequately treat sewage, allowing household waste to contaminate ground and surface waters.

The consequences of these antiquated systems are dire. Sewage pollution poses risks to human health, with water users susceptible to contracting harmful illnesses, including viruses and antimicrobial-resistant bacteria. It also affects biodiversity, amenity value, and can kill fish and other aquatic life. The pollution further damages natural ocean ecosystems and habitats, such as kelp beds and seagrasses, reducing biodiversity and the ocean's ability to store carbon.

To address these issues, significant investments are required to upgrade and modernise sewer systems. In the US, it is estimated that it would cost over $25 billion per year to fix leaking pipes. While this would likely result in higher water rates for residents, it is essential to prevent further environmental degradation and protect public health.

Poor sanitation and treatment facilities

Inadequate sanitation infrastructure, such as outdated and poorly maintained sewer systems, further exacerbates the problem. Most drainage networks worldwide are old and obsolete, built when populations were lower and storms were less frequent. These systems cannot cope with increasing populations, urbanization, and climate change, often resulting in overflows and the discharge of untreated wastewater into rivers and oceans.

Sewer treatment plants face significant challenges due to blockages caused by foreign materials in wastewater, such as fats, oils, grease, and solid waste. These blockages reduce pipe diameters and can lead to complete clogs, requiring costly replacements and contributing to flooding and pollution.

Additionally, treatment plants may malfunction or become overwhelmed during heavy rainfall, generating more wastewater than they can handle. In such cases, the excess water is often released into nearby streams, bays, and rivers, ultimately flowing into seas and oceans, further spreading sewage pollution.

The lack of proper sanitation and treatment facilities has severe environmental and health consequences. Sewage pollution harms aquatic ecosystems, destroys coastal habitats, and spreads diseases. It introduces harmful toxins, bacteria, viruses, and chemicals, which can contaminate water sources and affect both wildlife and human populations.

Blockages from waste materials

Sewage pollution is a pressing issue that poses a significant threat to both the environment and human health. One of the primary causes of this pollution is blockages from waste materials. These blockages occur when people carelessly flush items down the toilet that should be disposed of correctly, such as papers, sanitary products, wipes, nappies, cotton buds, and even plastics. These items accumulate in sewer pipes, leading to clogs and hindering the normal flow of wastewater.

The consequences of these blockages are dire. They cause toilets and sewer systems to overflow, resulting in the release of untreated sewage into rivers and the ocean. This pollution has a detrimental impact on aquatic life, killing fish and other species. It also reduces biodiversity and the ocean's ability to store carbon, affecting ecosystems such as kelp beds and seagrasses.

Another significant contributor to blockages is the improper disposal of fats, oils, and grease. When poured down the sink, these substances solidify as they cool, sticking to the insides of drains and sewers, leading to complete clogging. This issue is exacerbated during the rainy season, when flooding can generate more wastewater than sewage treatment plants can handle, leading to the release of untreated water into natural water bodies.

Furthermore, sewage infrastructure itself plays a role in blockages. Many drainage networks are old and obsolete, designed when populations were lower and storms were less frequent. Inadequate planning and lack of investment in modernizing these systems result in their inability to cope with increasing urbanization and climate change. This is particularly evident in the UK, where water companies routinely discharge raw sewage into natural water bodies due to the antiquated sewerage system.

The impact of sewage pollution extends beyond the environmental realm. It poses risks to human health, with water users susceptible to contracting various illnesses, including viral, bacterial, and parasitic infections. The presence of pathogens, viruses, bacteria, and worms in sewage can lead to acute diseases in both humans and animals, highlighting the urgent need to address the issue of blockages from waste materials.

Flooding and overflow

Flooding and sewage overflow are closely linked. Firstly, rising sea levels and increased storm surges caused by climate change lead to more frequent and severe flooding. When flooding occurs, stormwater can be polluted and easily transport environmental toxins to the sea. This polluted stormwater can then penetrate wastewater treatment plants, causing them to become overloaded and potentially resulting in the dumping of toxic water into the sea.

Additionally, flooding can cause sewage overflows by damaging plumbing and sewerage systems or through backflow. This can lead to the release of untreated sewage into rivers and the ocean, which can have significant negative impacts on the environment and human health. For example, in the UK, water users are as likely to become ill from seawater as they were in the 1990s, with conditions ranging from sore throats and upset stomachs to serious illnesses like gastroenteritis, hepatitis, and E. coli.

Furthermore, the combination of flooding and sewage overflow can result in the contamination of drinking water sources, leading to waterborne illnesses. A 1998 study published in the International Journal of Epidemiology attributed one-third of all reported gastroenteritis cases and two-thirds of all ear infection cases to water pollution. The impact of flooding on sewage systems can be mitigated through the use of modern check valves, which help to minimize the problems caused by flooding and protect people and properties from its effects.

The problem of flooding and sewage overflow is exacerbated by outdated and inadequate sewerage systems, particularly in urban areas. Urban sprawl increases the amount of stormwater surging into sewers, overwhelming their capacity and leading to overflows. Poor infrastructure maintenance and weak enforcement of regulations further contribute to the issue.

Human health impacts

Sewage pollution has a significant impact on human health, with water users at risk of contracting harmful illnesses. The impact of water pollution on human health varies depending on factors such as country, region, age, and gender. However, in general, water pollution can cause various diseases and adverse health outcomes. Here are some specific ways in which sewage pollution affects human health:

Waterborne Diseases and Infections

Water pollution can lead to the transmission of waterborne diseases, with diarrhoea being the most commonly caused disease due to the presence of enteroviruses in contaminated water sources. Other illnesses include sore throats, upset stomachs, gastroenteritis, hepatitis, and E. coli. Sewage can also contain harmful viruses and antimicrobial-resistant bacteria, which can be contracted by individuals coming into contact with polluted water.

Skin Diseases

Exposure to or use of heavily polluted water has been associated with an increased risk of developing skin diseases. The specific pollutants in the water can irritate the skin and cause various dermatological issues.

Cancer

Water pollution has been linked to an increased incidence of cancer. Contaminants such as industrial chemicals, heavy metals, and algal toxins can accumulate in the body over time, potentially leading to the development of cancerous cells.

Childhood Diseases

Water pollution can also impact the health of children, making them more susceptible to various childhood diseases. This can include respiratory issues, developmental problems, and other health complications.

Environmental Degradation

Sewage pollution contributes to the degradation of natural ecosystems, reducing biodiversity and harming aquatic life. This, in turn, can have indirect impacts on human health. For example, the contamination of fish populations in rivers and oceans can lead to the consumption of contaminated seafood, posing risks to human health.

Economic Impact

The economic impact of sewage pollution cannot be overlooked, as it affects livelihoods and access to resources. For example, pollution in coastal areas can impact fishing industries and reduce tourism, thereby affecting the economic stability and health of communities dependent on these sectors.

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