Treasure in excreta: Fast-depleting phosphorus can be extracted from faecal sludge

Treasure in excreta: Fast-depleting phosphorus can be extracted from faecal sludge

Subject :Environment

Section: Pollution

Context: India needs more nitrogen, phosphorus and potassium for its agriculture.

More on the News:

• Presence of phosphorus is essential in soil for crop growth and its shortfall can result in reduction of crop yield. But the reserves of phosphate rock, the main source of the element is fast depleting.
• With an annual increase of 2.3 per cent in its demand, phosphorus reserves will most likely get exhausted in another 50 to 100 years, states a 2015 study by professors of the West Bengal State University, Kolkata.
• An important phosphorus resource from where a huge reserve can be generated has been largely ignored. Human excreta is indiscriminately disposed into drains every day.
• About 11 per cent of phosphorus entering Earth systems is lost in human urine and excreta, but phosphorus and nitrogen in it can be recovered by up to about 90 per cent. If recovered, this could supply 22 per cent of the current global demand for phosphorus.

Case Study:

• In Tamil Nadu’s Nilgiri district, a project was started in 2018 to use recycled water for agriculture. It also helped treat and reuse faecal sludge as co-compost for farming. Started by Rural Development Organisation Trust, along with FINISH and WASTE, it now sells compost at Rs 8 per kg to replace chemical fertilisers, which costs Rs 15 per kg.
• The project found 15 per cent increase in crop yield and 20 per cent increase in farmers’ annual income. Some farmers who used the compost to grow garlic, beetroot and carrot reported that the size of garlic increased and beetroot and carrots were more shiny and rich in colour.

Phosphorus

• Phosphorus is a chemical element with the symbol P and atomic number 15
• Phosphorus exists in several forms, including white, red, and black phosphorus. White phosphorus is the most reactive and is used in the production of chemicals and munitions. Red phosphorus is used in the production of flame retardants and other materials, while black phosphorus has potential applications in electronics and other fields.
• Phosphorus is an abundant element in the Earth’s crust, but is typically found in nature in the form of phosphates, which are compounds that contain phosphorus and oxygen.
  • Phosphate is naturally found in rocks, soil, and water, and is a key component of many biological processes. It is also present in several food sources, including dairy products, meat, fish, and nuts.
• Phosphorus has many important uses in industry and agriculture. It is used to make fertilizers, detergents, and other chemicals. It is also used in the production of steel and other metals.
• Phosphorus is generally safe for consumption in small amounts, but excessive intake of phosphorus can have negative health effects, including kidney damage, osteoporosis, and cardiovascular disease.
• Phosphorus can have both positive and negative environmental impacts. It is essential for plant growth and is a key component of many ecosystems.
  • However, excessive use of phosphorus fertilizers can lead to runoff into waterways, causing eutrophication, algal blooms, and other environmental problems.
• Phosphorus is primarily mined from phosphate rock deposits, which are found in several countries, including Morocco, China, and the United States.
• The global demand for phosphorus is expected to increase in the coming years, driven by population growth and increasing demand for food. However, the supply of phosphate rock is limited, and there are concerns about future shortages and price volatility.

Phosphorus cycle

• The phosphorus cycle is a biogeochemical cycle that describes the movement of phosphorus through the Earth’s ecosystems.
• Phosphorus sources: The primary source of phosphorus is rock, which contains phosphorus-rich minerals. Weathering and erosion of rock releases phosphorus into the soil, where it becomes available to plants.
• Uptake by plants: Plants take up phosphorus from the soil through their roots, and use it to build DNA, RNA, and other important molecules.
• Transfer to animals: Animals obtain phosphorus by eating plants or other animals that have consumed plants.
• Decomposition and mineralization: When plants and animals die, their bodies are decomposed by bacteria and fungi, which release phosphorus back into the soil in the form of inorganic phosphate ions.
• Runoff and erosion: In some cases, phosphorus can be carried away from the soil by runoff or erosion, and can accumulate in bodies of water. This can lead to eutrophication, or the overgrowth of algae and other aquatic plants, which can have negative impacts on water quality and aquatic ecosystems.
• Geological processes: Over long periods of time, some phosphorus may be buried and eventually incorporated into rock, where it can remain for millions of years.
• Human impact: Human activities such as agriculture, mining, and wastewater treatment can greatly alter the phosphorus cycle. For example, excessive use of phosphorus fertilizers can lead to runoff and eutrophication, while mining of phosphorus-rich rock can deplete this nonrenewable resource.