We have put together this brief and simple article to give you a basic outline of Nitrogen in wastewater and why it is important.
Nitrogen reduction is becoming a more and more common requirement in the wastewater industry, with some councils requiring proven nitrogen reduction in onsite wastewater systems. This is especially so in areas near large water bodies, such as the Rotorua lakes. The Econotreat systems have certified Nitrogen reduction and meet the requirements for these sensitive areas.
So where does the nitrogen come from and why does it matter?
Nitrogen is a major component in the proteins found in our food. Recommended protein consumption varies depending on the source of information, but it will be somewhere around 50 grams per day; average consumption is more like 65-70 grams and excess of at least 30%. Due to overconsumption of protein, our excretions contain excess nitrogen and also phosphorous. This is then processed in your onsite wastewater system, producing ammonium and phosphate ions.
These by-products are a source of nutrient for algae. Other important factors are sunlight, temperature and water movement; flowing streams aren't subject to algae blooms like still water is, due to the dilution and oxygen available to further breakdown the nutrients, therefore lakes and ponds are much more sensitive. The light and temperature factors mean water bodies are much more likely to have algae problems during summer months, dependent on the local climate.
Algae blooms are the sudden and excessive growth of algae in water bodies, caused by the additional nitrogen and phosphorous available in wastewater runoff (fertilizers and animal excretions also provide these nutrients). An algae bloom causes the water body to be covered in algae, blocking sunlight and reducing oxygen levels. Excess algae will begin to die and decompose, further reducing oxygen levels in the water and negatively impacting the ecosystem, killing fish and other life in the water, as well as smelling awful.
Away from waterways, this isn't such a concern. Nitrogen and Phosphorous are commonly found in fertilizers to promote plant growth, which is why treated effluent is great for your landscaping. The soil will take up nutrients and further purify the water before it reaches a ground water source. This is also the reasoning behind required setback distances between wastewater discharge and waterways, though there is no science behind the exact distance; the requirement varies between councils, but is typically about 20m.
How can my treatment system help protect waterbodies?
The Econotreat systems have certified nitrogen reduction. This means they reduce the nitrogen to an acceptable level before it is discharged to the environment; this is Total Nitrogen of less than 15 grams and Ammonia Nitrogen of less than 5 grams per cube. To certify the treatment levels in the Econotreat systems, they were put through the National testing facility in Rotorua. Here the systems are subjected to measured flows of wastewater, where they are able to measure the effluent and rate the systems.
The reduction of nitrogen is a complex biological process that first requires the nitrification. Nitrification produces nitrates, which are more easily denitrified. The final denitrification stage involves converting the nitrate to nitrogen gas and returning it to the atmosphere. There is much more detail that can be explored around these processes and the ensuing products and by-products.
