Conventional septic systems are effective at removing pathogens from wastewater, but they don’t remove nitrogen. Nitrogen contributes to the formation of harmful algae blooms and reduces dissolved oxygen levels in coastal waterways. Nutrient pollution from farm waste, chemical pesticides, and fertilizers is widespread. Fortunately, there are solutions. They include buffering your property with native vegetation and choosing organic phosphate-free fertilizers.
Alternatives to Pesticides & Fertilizers
The nutrient-rich wastewater discharged by conventional septic systems and cesspools contributes significantly to coastal marine ecosystem degradation. It includes eutrophication (too many nutrients in a water body), harmful algal blooms, beach closures, shellfish restrictions, and fish kills. A primary solution to this issue is installing an advanced nitrogen-reducing septic system that reduces nitrogen (ENR-OSTDS). These include nitrogen sensors, which monitor nitrate, nitrite, and ammonium in septic effluent.
These advanced sensors help control nitrogen’s fate and protect the environment and human health. Because nitrogen, like other elements, cycles throughout the entire natural environment in organic and inorganic forms, prevention is the best way to keep it from polluting our waters. It includes the site selection of leaching fields and the design and regulation of septic tank inputs, discharge, and flow rates to avoid overloading and contaminating the soil. It also involves adequate capacity and the design of the leaching field to ensure that nitrogen is decomposed through a process known as nitrification.
The Role of Nitrogen-Reducing Septic Systems
Many coastal communities use traditional septic systems and cesspools to treat waste. Unfortunately, these systems are not designed to remove nitrogen from wastewater to concentrations protective of water quality and the coastal environment. The excessive amount of nutrients in a body of water, known as eutrophication, is caused by this nitrogen and can result in harmful algal blooms, fish kills, and beach closures. TNC is working to address this problem by promoting Innovative/Alternative On-site Wastewater Treatment Systems (I/A OWTS) that reduce the amount of nitrogen in wastewater. Generally, a septic system or sewage treatment facility must be installed by commercial septic system engineering in cases where the main public sewer is unavailable for development. Sewage and wastewater generated on-site can only be treated with a commercial septic system in such situations.
How Septic Systems Pollute Water
Many homeowners rely on a septic system rather than a public sewer for water at home. The wastewater that is processed by the septic system contains harmful bacteria, viruses, and nutrients that can pollute your drinking water well. It is essential to keep your septic tank pumped out (de-sludged) regularly (2-5 years) and to locate your water well at the appropriate distance from the septic system. Wastewater from your household drains and toilets enters the septic tank and settles into different layers – solid waste on the bottom, liquid in the middle, and scum on top. The liquid effluent then seeps into the soil in the drain field. As it soaks into the soil, the helpful bacteria in the ground break down pathogens and other pollutants. However, septic systems fail to remove the organic nitrogen found in sewage. This nitrogen eventually forms nitrate in the leaching field, which can enter waterways and cause problems with nearby water supply sources. This excess nitrate can also contribute to eutrophication, habitat loss, and land conversion.
The Clean Water Act
Any pollution discharge into navigable waters without a permit is prohibited by the Clean Water Act (CWA). These discharges are governed by the EPA’s National Pollutant Discharge Elimination System (NPDES) permit program. The CWA also empowers States and federally recognized tribes to establish more protective standards and limits than the federal CWA provides. Nitrogen, an essential element of all living things, can be toxic in its nitrate form if too much is deposited in our waterways. High nitrate levels have been linked to drinking water contamination, the eutrophication of freshwater lakes, and the degradation of coastal areas.
Some states now require advanced nitrogen-reducing systems on new construction in “impacted” areas. In these areas, septic systems are being replaced with innovative and alternative on-site wastewater treatment and disposal systems that reduce the nitrogen content of effluent to protect water quality in local communities and well water sources such as springs and coastal waters.
