Reducing Sewage Pollution: Strategies For Cleaner Waterways

Sewage pollution is a pressing issue that poses a significant threat to both human health and the environment. Improper management of sewage treatment and disposal can have detrimental effects, with over 2.3 billion people worldwide suffering from diseases linked to water. This problem is exacerbated by ageing infrastructure, with sewage pipes in some cities being over a century old and prone to cracks and leaks.

To reduce sewage pollution, it is crucial to address the root causes and implement effective solutions. This includes proper maintenance and repair of sewage systems, preventing overflows and spills, and ensuring that wastewater is adequately treated before discharge. Additionally, public awareness and behavioural changes are vital to reducing sewage pollution.

Fix ageing infrastructure

Ageing infrastructure is a critical issue in the fight to reduce sewage pollution. From mains water pipes to reservoirs, pump stations, sewage pipes, and treatment plants, the network that delivers and treats water is in a state of disrepair in many parts of the world. In the US, there are over 2 million miles of water pipes underground, with an average age of 45 years, and some pipes are even over a century old. This ageing network is reaching the end of its lifespan and is in dire need of repair or replacement.

One of the main challenges with ageing infrastructure is water loss due to leaks. As pipes deteriorate, they become more prone to breaking, leading to significant water loss. In the UK, for example, leaky pipes result in a staggering 3 billion litres of water loss each day. The situation is even more concerning in the US, where over 148,000 municipal water systems distribute 39 billion gallons of water daily, with a pipe break occurring every 2 minutes on average.

To address this issue, effective asset management is crucial. Water utilities need to implement strategic asset management plans that prioritize capital spending and investment in maintenance. This includes conducting thorough evaluations of existing infrastructure to determine whether refurbishment or replacement is the best course of action. Factors such as the condition of the infrastructure, capital costs, availability of space, impact on ongoing plant operations, and the required operational life of a rehabilitated or new structure should be considered.

In addition to repairs and replacements, upgrading treatment equipment and increasing design flow can help future-proof water resource recovery facilities against increasing extreme rainfall events caused by climate change. Upgrading to modern technologies that utilize membranes to increase surface area can also be a solution, as these systems have a smaller footprint and can be retrofitted into existing infrastructure.

Furthermore, population growth will put even more strain on ageing infrastructure. By 2050, when the world's population is expected to reach 10 billion, the pressure on water systems will be immense. To prepare for this, water companies must reduce leakage and per capita consumption, and additional asset replacement may be necessary to avoid supply interruptions.

In conclusion, fixing ageing infrastructure is crucial to reducing sewage pollution. By implementing strategic asset management plans, evaluating and upgrading infrastructure, and preparing for population growth, water utilities can help ensure that communities have access to clean and safe water for generations to come.

Improve wastewater treatment plants

Wastewater treatment plants are a major element of water pollution control. The construction of centralized sewage treatment plants began in the late 19th and early 20th centuries, with the aim of removing impurities from wastewater before it reaches natural bodies of water. Today, these plants have become large, complex facilities that require a lot of energy for their operation.

• Upgrade outdated infrastructure: Many wastewater treatment plants are outdated and nearing the end of their effective lives. Upgrading these plants with modern technology can improve their efficiency and effectiveness in removing impurities.
• Separate stormwater and sewage systems: Combined sewer systems that mix stormwater and sewage can become overwhelmed during periods of wet weather, leading to overflows of untreated sewage into water bodies. Separating these systems can reduce the risk of overflows and improve the treatment process.
• Improve maintenance and repair: Regular maintenance and timely repair of cracks, blockages, and other issues in the sewage collection system can help prevent overflows and spills. This includes fixing broken pipes, clearing blockages caused by tree roots, grease, or debris, and ensuring proper fitting of inspection holes.
• Increase treatment capacity: During heavy rainfall, the volume of wastewater can exceed the capacity of treatment plants, leading to overflows. Increasing the treatment capacity, such as by constructing additional tanks or expanding existing facilities, can help manage this issue.
• Implement advanced treatment processes: Advanced wastewater treatment processes, such as tertiary treatment, can remove more than 99% of impurities from sewage. While this can be expensive, it may be necessary to meet stringent environmental and governmental standards.
• Explore decentralized systems: Decentralized wastewater treatment systems, where waste is treated at the source rather than at a centralized plant, can be more flexible and adaptable to changing urban growth patterns. On-site septic tanks and leaching fields, for example, provide effective and low-cost solutions for suburban or rural areas.
• Adopt nature-based solutions: Nature-based solutions, such as constructed wetlands, green roofs, and permeable pavements, can complement conventional treatment infrastructure. These solutions can effectively remove pollutants, mitigate flooding, create habitats, and provide recreational spaces.
• Improve sludge treatment and disposal: Sewage sludge, the residue that accumulates in treatment plants, requires proper treatment and disposal. Anaerobic digestion, for example, is a biological process that decomposes organic solids and stabilizes sludge, making it easier to dewater and dispose of.
• Recover resources: Wastewater contains valuable resources such as nitrogen and phosphorus, which can be recovered and reused. Technologies such as the Revolving Algal Biofilm system can remove these nutrients and enable wastewater reuse, creating a sustainable circular economy.
• Invest in research and development: Continuous investment in research and development can lead to innovative solutions for wastewater treatment. This includes exploring new technologies, such as membrane bioreactor processes and ballasted floc reactors, as well as improving existing processes to enhance their efficiency and effectiveness.

Reduce stormwater runoff

Stormwater runoff is a major contributor to sewage pollution. This is because stormwater can infiltrate old pipes, overwhelming the entire system and causing overflows of under-treated sewage into local waterways and the ocean. This is particularly true in older communities where storm and sanitary sewers are combined.

To reduce stormwater runoff, it is important to implement strategies that prevent stormwater from entering the sewer system in the first place. Here are some ways to do this:

Reduce Impervious Surfaces

Concrete and asphalt roads, driveways, and walkways prevent rainwater from soaking into the ground. Instead, rainwater flows across these surfaces and picks up pollutants before entering storm drains. By reducing the number of impervious surfaces, you can minimize the amount of stormwater runoff and the pollutants that enter the sewer system. Consider using gravel, wood chips, or permeable pavement for walkways and patios.

Disconnect/Redirect Downspouts

Downspouts from roof gutters can contribute to stormwater runoff if they empty onto paved surfaces. Redirect downspouts to discharge rainwater onto grassy areas or landscaped areas with shrubs and flowers. This will allow rainwater to soak into the ground and reduce the amount of stormwater entering the sewer system.

Use Rain Barrels or Cisterns

Capturing rainwater from your roof in rain barrels or cisterns can help reduce stormwater runoff. This collected rainwater can then be reused for watering lawns and gardens during dry weather.

Proper Roof Drainage

Ensure that your roof gutters and downspouts are properly maintained and directed away from paved surfaces and towards grassy or landscaped areas. This will help to slow down the flow of stormwater and give it a chance to soak into the ground.

Landscaping and Site Management

Implementing landscaping techniques such as terracing slopes, creating buffer strips of thick vegetation, or naturalizing areas with prairie, woodland, or wetland plants can help slow down and filter stormwater runoff. These practices can increase the absorption of rainwater into the ground and reduce the amount of stormwater entering the sewer system.

By implementing these strategies, you can help reduce stormwater runoff and minimize the impact of sewage pollution on the environment and public health.

Avoid using cesspools and septic systems

Sewage pollution is a pressing issue, with billions of gallons of untreated sewage being released into surface waters every year. This has a detrimental impact on human health, with an estimated 3.5 million Americans falling ill annually from contact with contaminated water.

To reduce sewage pollution, it is important to avoid using cesspools and septic systems, which are outdated and can lead to groundwater contamination. Here are some reasons why you should avoid these systems:

Health and Environmental Risks

Cesspools and septic systems are designed to collect and store sewage, but they do not treat it effectively. This means that harmful bacteria, viruses, and chemicals can leach into the surrounding soil and groundwater, causing pollution and posing a risk to human health.

Inadequate Wastewater Treatment

Unlike modern sewage treatment systems, cesspools and septic systems lack proper filtration processes. They simply store wastewater, allowing sludge to pile up and effluent to drain directly into the soil. This can lead to the spread of diseases and contamination of water sources.

Vulnerability to Overloading and Flooding

Cesspools and septic systems are often vulnerable to overloading or flooding due to heavy rains or snowmelt. They are not sealed like conventional septic tank systems, so they can easily become overwhelmed, leading to overflows and further pollution.

High Maintenance and Costly

Cesspools, in particular, require frequent pumping and maintenance to keep them functioning. The cost of maintaining a cesspit can be high, and failure to do so properly can result in fines in some places.

Phasing Out and Restrictions

Due to the health and environmental risks associated with cesspools and septic systems, many places have restricted or banned their use. Modern environmental regulations encourage or require connections to municipal sewage systems or the use of more eco-friendly alternatives.

Alternative Options

Instead of relying on cesspools or septic systems, it is advisable to explore other options such as connecting to a centralized municipal sewer service or installing a modern septic system with proper filtration and treatment processes. Other alternatives include package plants, holding tanks, or sanitary sewer hookups.

Embrace decentralised systems

Decentralised wastewater treatment systems are an effective way to protect water quality and reduce sewage pollution. These systems are a combination of different natural wastewater treatment techniques, such as settler/biogas settler, anaerobic baffled reactor, planted gravel filter (horizontal/vertical) and polishing ponds. Decentralised systems can be designed to treat wastewater flows from 1m³ to 1000m³ and can be integrated into the landscape.

Benefits of Decentralised Systems

Decentralised systems are a valuable component of watershed management plans and sustainable development programs. They can benefit both urban and rural areas by providing affordable solutions and reducing environmental risks. These systems can be applied to homes, businesses and industrial centres, and their recycling capabilities can support water resource management goals in arid regions.

Green Technology

Onsite wastewater management systems are considered 'green technology' as treated effluent recharges local aquifers. Innovations in this area include the reuse or recycling of treated effluent, which can be used for irrigation, toilet and urinal flushing, or make-up water for commercial boilers. These applications reduce the demand for potable water and aid in the preservation of water sources.

Cluster Systems

Decentralised systems can serve a cluster of homes, a subdivision or small community, as well as commercial and industrial complexes. If serving multiple sources, a collection system conveys the wastewater to a combined treatment and dispersal component. These systems utilise the capacity of soil to remove or transform pollutants in the effluent, avoiding discharges into surface waters and maintaining groundwater quality and quantity.

Cost-Effectiveness

Decentralised wastewater treatment systems are cost-effective, with low operation and maintenance costs. They can be constructed using locally available materials and can be designed to treat wastewater with high grease content, suspended solids and organic matter.

Frequently asked questions