Why is overuse of phosphorus problematic, and how can recycling wastewater help address the problem?
The world is rapidly approaching a phosphorus crisis, which would have drastic implications for the global food supply because farmers rely heavily on it to enhance agricultural production. The use of phosphate fertilizers, which allows us to produce twice as much food as we could without it, has quadrupled over the past 50 years and will continue to grow as long as the global population continues to increase.
Phosphate is a naturally occurring mineral essential for plants and animals. It is applied to agricultural crops in huge quantities worldwide to encourage rapid plant growth. Yet while countries the world over depend on phosphate to maintain food security, rock phosphate is mined in just a few countries and stocks are running out.
Scientists fear that if the overuse of phosphorus continues, it could outstrip supply, leading to fertilizer shortages that could cripple global food production. If this happens, the few countries with rock phosphate reserves could hold sway over the rest of the world.
Environmental Impact of Phosphate Fertilizer
While phosphate is good for crops, it’s not so good for the environment. In fact, researchers consider phosphate pollution to be one of the biggest problems the planet is facing, after climate change.
Once applied to crops, nutrient-rich phosphate and nitrogen-based fertilizers can wash off soils and enter waterways, or leach into groundwater supplies. This, along with other nutrient inputs from animal waste and sewage discharge, is fueling harmful algal blooms in both freshwater and coastal ecosystems, including ones that are sources of drinking water.
Overuse of phosphate fertilizers is not only causing dead zones in aquatic systems, but it is also causing an increase in global methane emissions, which contribute heavily to climate warming. Once all the nutrients in water are depleted, algal blooms die off, stripping oxygen from water and releasing methane as the algae decays. Oxygen depletion can lead to mass die-offs of aquatic life and ocean dead zones that are devoid of oxygen that supports life.
Finding Alternatives to Phosphate
Some scientists are optimistic that with some creative thinking, this trend can be reversed. In a recent report, “Our Phosphorus Future,” researchers outline measures to prevent the impending crisis, including ways we can recycle phosphorus.
One of the greatest potential solutions is recycling phosphate from slaughterhouse waste, animal manure, and sewage effluent. Slaughterhouse waste consists of blood, bones, and horns, which are used to make products such as bonemeal and are added to soil as fertilizers. Studies have shown that fertilizer made from slaughterhouse waste can be an effective or better substitute for conventional phosphate fertilizer.
While many consider human and animal wastewater to be just that, a waste, it’s rich in phosphates that could be recycled and applied to crops as a nutrient-rich fertilizer. However, treated wastewater must meet strict regulatory standards to ensure that it can be safely applied to crops produced for human consumption.
Recycling wastewater for reuse is very promising and could help address several phosphate-related challenges. It could reduce demand for rock phosphate and irrigation water, thereby preserving sources of fresh water. It could also help limit nutrient runoff and minimize the environmental impact of nutrient-rich wastewater discharges.
Wastewater Reuse Solutions
Fluence has advanced wastewater treatment technologies for water reuse that ensure recycled water complies with regulatory requirements. Fluence’s innovative energy-efficient membrane aerated biofilm reactor (MABR) solutions produce treated wastewater that can be reused for the surface irrigation of food crops, as well as landscaping.
MABR is an energy-efficient treatment solution with exceptional nutrient removal. It uses passive aeration and biofilm-based nitrification-denitrification during primary and secondary treatment, cutting energy consumption used during the aeration process by 90% compared to conventional wastewater treatment technologies.
Contact Fluence to learn more about our water and wastewater reuse solutions.