Reducing Aquatic Nitrogen Pollution: Strategies For A Healthier Ecosystem

Nitrogen is an essential element for life on Earth, but human activities have disrupted the natural nitrogen cycle, leading to serious environmental and health issues. Excess nitrogen, often from synthetic fertilizers, wastewater discharge, and fossil fuel combustion, pollutes water, air, and soil, causing toxic algal blooms, eutrophication, and dead zones in aquatic ecosystems. Addressing this crisis requires urgent action, including improving nutrient management practices, reducing synthetic fertilizer use, and doubling nitrogen efficiency in agriculture.

Reduce synthetic fertiliser use

Reducing the use of synthetic fertilisers is a key strategy in mitigating aquatic nitrogen pollution. Synthetic nitrogen fertilisers are a major contributor to the excessive nitrogen compounds in water, soil, and air, causing severe ecological damage.

Firstly, it is important to understand the impact of synthetic fertilisers on the environment. When synthetic fertilisers are overused, the excess nitrogen can be washed away from farm fields, especially during rain or snowmelt events, and end up in nearby waterways. This excess nitrogen causes eutrophication of water bodies, leading to hypoxic "dead zones" where fish and other aquatic life cannot survive. It also contributes to harmful algal blooms, which not only disrupt ecosystems but can also produce toxins harmful to humans.

Additionally, nitrogen from synthetic fertilisers can escape into the air as nitrous oxide, a greenhouse gas with a significantly higher global warming potential than carbon dioxide. This contributes to climate change and the depletion of the protective ozone layer.

To address these issues, several actions can be taken to reduce synthetic fertiliser use:

• Adopting alternative farming methods: Farmers can transition to nature-friendly farming methods that do not rely heavily on synthetic fertilisers. This includes adopting crop rotation with nitrogen-fixing crops like peas, beans, and legumes, which can improve soil fertility and reduce the need for synthetic nitrogen inputs.
• Improving fertiliser application practices: Proper fertiliser application can significantly reduce nitrogen pollution in waterways. Farmers can ensure they are applying the right amount of fertiliser at the appropriate time of year and using suitable application methods.
• Implementing conservation practices: Conservation drainage practices, such as modifying drainage system designs and using woodchip bioreactors, can help manage water movement and reduce nutrient loads while maintaining adequate drainage for crop production.
• Ensuring year-round ground cover: By planting cover crops or perennial species, farmers can prevent soil erosion and nutrient loss, especially during periods of bare ground when the soil is more susceptible to erosion and nutrient runoff.
• Planting field buffers: Establishing buffers of trees, shrubs, and grasses along field edges, particularly those bordering water bodies, can help absorb or filter out excess nutrients before they reach aquatic ecosystems.
• Reducing tillage intensity: Conservation tillage practices, such as no-till farming, can improve soil health, reduce erosion, and decrease the likelihood of nutrients reaching waterways through runoff.
• Engaging in watershed efforts: Collaboration between farmers, government agencies, conservation groups, and community organisations is vital. Working together across entire watersheds can help reduce nutrient pollution and promote sustainable farming practices.

Improve nutrient management practices

Farmers can improve nutrient management practices by adopting a few techniques. Firstly, they can apply nutrients (fertilizer and manure) in the correct amount, at the right time of year, with the right method, and in the right place. This can significantly reduce the amount of fertilizer that reaches water bodies. For instance, using nitrification inhibitors can help to prevent the conversion of nitrogen into its mobile nitrate form, reducing the risk of leaching.

Secondly, implementing conservation drainage practices is important. Subsurface tile drainage is commonly used to manage water movement in the Midwest. However, drainage water often carries soluble forms of nitrogen and phosphorus, so it is crucial to adopt strategies that reduce nutrient loads while maintaining adequate drainage for crop production. Conservation drainage techniques include modifying drainage system designs and operations, utilizing woodchip bioreactors, saturated buffers, and making changes to the drainage ditch system.

Thirdly, ensuring year-round ground cover is vital. Farmers can plant cover crops or perennial species to prevent bare ground on fields, reducing the vulnerability of the soil and nutrients to erosion and loss into waterways.

Additionally, planting field buffers is a recommended practice. By planting trees, shrubs, and grasses along field edges, especially those bordering water bodies, farmers can create a natural barrier that absorbs or filters out excess nutrients before they reach water bodies.

Lastly, implementing conservation tillage practices can help. Reducing the frequency and intensity of tilling improves soil health, decreases erosion, runoff, and soil compaction, and minimizes the likelihood of nutrients reaching waterways through runoff.

Reduce livestock waste

Livestock waste is a significant contributor to nitrogen pollution. The livestock sector emits 65 teragrams of nitrogen per year, equivalent to one-third of current human-induced nitrogen emissions. To reduce aquatic nitrogen pollution from livestock waste, several measures can be implemented:

• Adopting nutrient management techniques: Farmers can improve their nutrient management practices by applying the right amount of nutrients (fertilizer and manure) at the appropriate time of year, using the correct method, and placing them in the right location.
• Managing livestock access to streams: By installing fences along streams, rivers, and lakes, farmers and ranchers can prevent livestock from accessing water bodies, helping to restore stream banks and prevent excess nutrients from entering the water.
• Using conservation drainage practices: Implementing strategies such as modifying drainage system design and operation, woodchip bioreactors, saturated buffers, and changes to the drainage ditch system can help reduce nutrient loads while maintaining adequate drainage for crop production.
• Proper disposal of animal waste: Ensuring proper disposal and treatment of animal waste is crucial. For example, recovering ammonium nitrogen from manure in the form of ammonia water can be beneficial.
• Improving nutrient management in the livestock sector: The agricultural industry should focus on enhancing nutrient management in the livestock sector to minimize nitrogen waste.
• Adapting protein in livestock diets: Adjusting the protein content in livestock diets can help reduce nitrogen losses through waste.
• Relocating livestock operations: In certain cases, relocating livestock operations away from water bodies or to areas with better crop-livestock integration can reduce nitrogen emissions and exposure to nearby human populations.

Improve wastewater treatment

Upgrading wastewater treatment plants can significantly reduce a municipality's nitrogen footprint. While this can be expensive, it can also dramatically restore bodies of water to health.

Advanced Treatment Systems

Advanced treatment systems enable some wastewater plants to produce discharges that contain less nitrogen than plants using conventional treatment methods. Upgrading wastewater treatment systems is often expensive for municipalities and ratepayers, but upgrades can pay for themselves or end up saving a plant money.

Optimisation

Optimisation involves adjusting operations and repurposing existing equipment to remove additional nutrients. This approach is usually much less expensive than upgrades and can result in cost savings by reducing energy demand and treatment chemicals.

Combination of Optimisation and Upgrades

In some cases, optimisation along with further technology upgrades may be necessary to achieve the nutrient reduction goals of the plant.

Septic Systems

Septic systems can easily become a source of nutrient pollution if not properly maintained. An estimated 10 to 20 percent of septic systems fail at some point in their operational lifetimes. Common causes of septic system failure include aging infrastructure, inappropriate design, overloading with too much wastewater in too short a period of time, and poor maintenance.

Strategies to Reduce Nitrogen and Phosphorus Loads

Various strategies to reduce nitrogen and phosphorus loads from wastewater treatment plants are being pursued across the country.

Reduce fossil fuel burning

Burning fossil fuels is a major contributor to aquatic nitrogen pollution. Fossil fuels include oil, natural gas, and coal, which are burned to generate energy for electricity, transportation, and industrial processes. Here are some ways to reduce nitrogen pollution by decreasing the burning of fossil fuels:

Transition to Renewable Energy Sources

One of the most effective ways to reduce fossil fuel burning is to transition to renewable energy sources. This involves investing in and utilizing energy sources such as solar, wind, hydroelectric, and geothermal power. By increasing the share of clean energy sources in the energy grid, we can decrease our reliance on fossil fuels and reduce nitrogen emissions. Governments and businesses can play a crucial role in this transition by providing incentives, subsidies, and investments in renewable energy infrastructure.

Improve Energy Efficiency

Improving energy efficiency can help reduce the overall demand for energy, thereby decreasing the burning of fossil fuels. This can be achieved through various measures such as implementing energy-efficient technologies, improving building insulation, using energy-efficient appliances, and promoting energy conservation practices. Businesses can also improve their energy efficiency by optimizing their industrial processes and adopting more sustainable manufacturing techniques.

Promote Sustainable Transportation

The transportation sector is a significant contributor to fossil fuel burning. To reduce this, individuals can be encouraged to use public transportation, carpool, or opt for more sustainable options like walking or biking. Governments can invest in improving public transportation infrastructure and incentivize the adoption of electric vehicles by offering tax breaks or subsidies. Additionally, promoting remote work and virtual meetings can help reduce commuting and business travel, thereby lowering fossil fuel consumption.

Support Green Building Design

The construction and operation of buildings contribute significantly to energy consumption and fossil fuel burning. By embracing green building design principles, we can reduce the environmental impact of the built environment. This includes using energy-efficient materials, optimizing natural lighting and ventilation, incorporating renewable energy sources, and implementing water-efficient fixtures. Green building certifications, such as LEED (Leadership in Energy and Environmental Design), can be promoted to ensure that new constructions meet sustainability standards.

Raise Awareness and Education

Educating the public about the impacts of fossil fuel burning on aquatic nitrogen pollution is essential. By raising awareness, individuals can make informed choices to reduce their carbon footprint. This includes simple actions such as turning off appliances when not in use, limiting air conditioning usage, and choosing energy-efficient products. Community initiatives, school programs, and public information campaigns can play a vital role in empowering people to take collective action against nitrogen pollution.

By implementing these measures to reduce fossil fuel burning, we can significantly contribute to lowering nitrogen emissions and mitigating their harmful effects on aquatic ecosystems. It is important to note that a combination of individual, community, corporate, and governmental efforts is necessary to drive systemic change and create a more sustainable future.

Frequently asked questions