Water Pollution Treatment: Methods And Techniques

Water pollution is the contamination of water bodies, which negatively impacts their uses. It is usually a result of human activities, with sources including sewage discharges, industrial activities, agricultural activities, and urban runoff. Water pollution can lead to the degradation of aquatic ecosystems, the spread of water-borne diseases, and a reduction in ecosystem services such as drinking water. To address water pollution, it is necessary to identify the source of pollution (point source or non-point source) and the type of water body affected (groundwater, surface water, or ocean water). Treatment methods include improving sanitation, sewage treatment, industrial and agricultural wastewater treatment, erosion control, sediment control, and stormwater management.

Improving sanitation and sewage treatment

Infrastructure Upgrades:

• Invest in centralized sewer systems: Many areas, especially in developing countries, rely on decentralized septic systems. Transitioning to centralized sewer systems can improve wastewater management by collecting sewage in a network of pipes and pump stations, transporting it to municipal treatment plants.
• Upgrade onsite sanitation systems: In areas where centralized systems are not feasible, advanced onsite sanitation systems can be implemented. These include vermicomposting systems, onsite sewage systems (OSS), and aerobic treatment or filtration systems to reduce nutrients, pathogens, and suspended solids.
• Repair and maintain existing systems: It is crucial to regularly repair and maintain sewage system components, fixing leaks and defects to prevent untreated sewage from contaminating surface and groundwater.

Treatment Processes:

• Biological treatment processes: Most sewage treatment technologies use biological processes. When selecting a treatment technology, engineers and decision-makers consider various factors, including desired effluent quality, construction and operating costs, land availability, energy requirements, and sustainability.
• Disinfection and advanced treatment: Advanced sewage treatment plants may include tertiary treatment with disinfection to remove harmful microorganisms. Some plants even have a fourth treatment stage to eliminate micropollutants like heavy metals, pharmaceutical products, and personal care product residues.
• Resource recovery: Instead of focusing solely on waste removal, the Global Wastewater Initiative promotes resource recovery. This approach aims to extract value from wastewater by recovering energy, nutrients, and other valuable materials.

Stormwater Management:

• Separate stormwater and sewage: In many cities, stormwater and sewage are combined in a single sewer system, which can overwhelm treatment plants during high precipitation periods. Separating these systems can reduce the risk of combined sewer overflows, preventing untreated sewage from flowing into water bodies.
• Implement stormwater best management practices (BMPs): BMPs for stormwater include constructing retention ponds, implementing green infrastructure (e.g., permeable pavements, green roofs), and utilizing stormwater for irrigation or groundwater recharge after proper treatment.

Public Education and Behaviour:

• Promote proper waste disposal: Educate the public about the importance of proper waste disposal. Encourage individuals to dispose of chemicals, oils, and non-biodegradable items appropriately to prevent them from entering the drainage systems and water bodies.
• Reduce plastic consumption: Encourage the reduction, reuse, and recycling of plastics. Plastic pollution is a significant issue in oceans, with fishing boats, tankers, and cargo shipping contributing greatly to this problem.
• Encourage water-conscious landscaping: Suggest that homeowners consider landscaping that reduces runoff and minimizes the use of pesticides and herbicides, which can contaminate waterways.

Controlling industrial wastewater

Industrial wastewater is one of the leading causes of water pollution, and it is essential to implement effective strategies to control and treat it. Here are several approaches to address this issue:

Regulations and Policies

Municipal authorities have implemented various schemes and policies to govern water quality and set permissible limits for toxic elements in industrial effluents. These policies also aim to raise awareness among people and restore water bodies affected by industrial activities. For instance, the US Environmental Protection Agency (EPA) has established the National Pretreatment Program to regulate the discharge of industrial and commercial wastewater into municipal sewer systems.

Technological Solutions

The advancement of technology offers innovative solutions for controlling industrial wastewater. One notable example is the development of an Industrial Cloud-Based IoT (Internet of Things) System for real-time monitoring and controlling of wastewater. This system employs sensors to collect data on parameters such as temperature and pH levels from wastewater inlets. By analyzing this data, administrators can make informed decisions and take prompt action against illegal or impermissible discharges.

Rhizo-filtration

Rhizo-filtration is a biological technique proposed as a sustainable and eco-friendly approach to controlling industrial wastewater quality. This method utilizes plant species to eliminate toxins from the water. The process is capable of removing heavy metals and other toxic elements, and the treated plants can be harvested and used as biofuel briquettes, replacing traditional fuels. Additionally, the remaining ashes can be utilized as fertilizers to maintain soil fertility.

Centralized Waste Treatment

Centralized waste treatment facilities play a crucial role in managing industrial wastewater. These facilities are designed to handle and treat large volumes of wastewater generated by various industries, including oil and gas extraction and shale gas extraction wastewater. The EPA provides guidance and regulations for these treatment works, ensuring that wastewater is properly managed and treated before discharge.

Mining Operations

Mining activities can significantly impact water quality, and it is essential to implement controls to minimize their environmental footprint. The EPA has established requirements for mining operations, including the management of wastewater discharges. By adhering to these requirements, mining companies can help protect surface and groundwater quality, preserve drinking water supplies, and maintain the surrounding aquatic and terrestrial habitats.

Reducing agricultural runoff

Conservation Practices

Conservation practices, often referred to as Best Management Practices (BMPs), are tools that farmers can employ to minimise soil and fertiliser runoff, effectively manage animal waste, and enhance water and air quality on their farms. One such practice is the utilisation of no-till and cover crop methods, which help curb the volume of polluted runoff reaching nearby streams and bodies of water. The adoption of these practices has the potential to significantly decrease nitrogen pollution, improving both environmental and economic outcomes.

Efficient Irrigation Systems

The Environmental Protection Agency (EPA) recommends transitioning to high-efficiency irrigation systems to mitigate agricultural runoff. By investing in innovative technologies, such as Boom Technology and Dry Wheel Track Technology, farmers can achieve more uniform water distribution, reducing soil erosion and compaction while lowering overall water usage.

Landscaping Techniques

Landscaping techniques can be employed to minimise runoff and reduce the use of pesticides and herbicides. Implementing buffer zones, such as strips of vegetation or natural filters, can help capture and filter pollutants before they reach water bodies.

Proper Waste Management

Implementing proper waste management practices is crucial. This includes the responsible disposal of chemical cleaners, oils, and non-biodegradable items to prevent them from contaminating water sources. Additionally, maintaining vehicles to prevent leaks of oil, antifreeze, or coolant is essential to avoid oil pollution, a significant contributor to water contamination.

Education and Awareness

Educating farmers, landowners, and the general public about the sources and impacts of water pollution is vital. Understanding the unique characteristics of local water sources, the treatment of wastewater, and the flow of stormwater can empower individuals to take targeted actions to reduce their contribution to water pollution.

By implementing these strategies and adopting a holistic approach to reducing agricultural runoff, we can help protect our precious water resources and ensure their sustainability for future generations.

Preventing plastic pollution

Policy and Regulatory Actions:

• Governments should enact and enforce stringent regulations to limit plastic production and use. This includes supporting and implementing treaties like the Global Plastics Treaty, which aims to address the entire lifecycle of plastics and reduce plastic pollution globally.
• The US EPA's National Strategy to Prevent Plastic Pollution outlines six critical objectives: reducing pollution from plastic production, innovating material and product design, decreasing waste generation, improving waste management, enhancing capture and removal of plastic pollution, and minimizing loadings and impacts on waterways and the ocean.
• Legislation and policies should focus on reducing single-use plastics, promoting reusable alternatives, and holding plastic-producing corporations accountable for their environmental impact.

Industrial and Corporate Actions:

• Industries must reduce their reliance on plastic packaging and products, especially single-use plastics. They should invest in reusable, recyclable, or compostable alternatives and innovative product designs that are environmentally friendly.
• Corporations, especially those contributing significantly to plastic pollution, should take responsibility for their plastic waste and actively work towards reducing, recycling, and properly disposing of their plastic products.
• Industries can also collaborate with environmental organizations and communities to develop sustainable practices and support initiatives that address plastic pollution.

Individual Actions:

• Individuals can play a crucial role in preventing plastic pollution by reducing their plastic consumption, reusing plastic items whenever possible, and recycling plastic waste responsibly.
• Properly disposing of chemical cleaners, oils, and non-biodegradable items is essential to prevent them from contaminating water sources.
• Educating oneself about the water sources and wastewater treatment practices in one's community can help identify areas where individual actions can have the most impact. Joining local initiatives or encouraging neighbors to reduce plastic consumption and improve recycling practices can also make a collective difference.

International Cooperation:

• Preventing plastic pollution requires a global effort, with high-income countries taking the lead in reducing plastic usage, boosting recycling rates, and providing assistance to lower-income nations.
• Middle- and low-income countries should focus on expanding plastic waste collection, improving recycling infrastructure, and reducing leakage from waste sites.
• International collaboration is vital to address the complex nature of plastic pollution, ensuring that actions are tailored to the specific needs and capabilities of each country while collectively working towards a cleaner and safer planet.

Managing stormwater

Stormwater management is the process of reducing the runoff of rainwater or melted snow into streets, lawns, and other sites, as well as improving water quality. When stormwater is absorbed into the soil, it is filtered and eventually replenishes aquifers or flows into streams and rivers. However, heavy rainfall can cause excess moisture to run across the surface and into storm sewers, carrying debris, chemicals, bacteria, eroded soil, and other pollutants with it.

In urban and developed areas, impervious surfaces such as pavement and roofs prevent precipitation from naturally soaking into the ground. Instead, water runs rapidly into storm drains, sewer systems, and drainage ditches, causing flooding, erosion, turbidity, and sewer system overflow. To address these issues, stormwater management employs a combination of pervious surfaces, grey infrastructure, and blue/green infrastructure.

Pervious surfaces, also known as permeable surfaces, are porous and allow water to infiltrate through them into the soil and groundwater. Examples include pervious concrete, porous asphalt, and interlocking concrete pavers. These surfaces help to reduce the amount of runoff and can be used in parking lots, driveways, and sidewalks.

Grey infrastructure, such as culverts, gutters, and storm sewers, collects and transports runoff quickly. By eliminating curbs or adding curb cuts, runoff can be directed into pervious areas and filtered through low-impact development (LID) features. Vegetated filter strips, for example, can be used to treat runoff from roads, roofs, and small parking lots.

Blue/green infrastructure protects, restores, or mimics the natural water cycle. Constructed wetlands, for example, capture and filter stormwater while creating diverse wildlife habitats. "Green" roofs are covered with vegetation to enable rainfall infiltration and evapotranspiration, reducing the effects of atmospheric pollution and decreasing the "heat island" effect.

Overall, stormwater management aims to reduce the negative impacts of stormwater runoff on the environment and infrastructure by employing a combination of strategies that promote infiltration, filtration, and the restoration of natural water cycles.

Frequently asked questions