Related Experiment Video
Updated: Jun 7, 2026
06:55
Low-Cost, Volume-Controlled Dipstick Urinalysis for Home-Testing
Published on: May 8, 2021
Low-cost struvite production using source-separated urine in Nepal
1Eawag: Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland. bastian.etter@eawag.ch
Water Research
|October 29, 2010
Summary
Researchers developed an efficient method to recover phosphorus from human urine, creating a valuable fertilizer. This process, using struvite precipitation, offers a sustainable solution for nutrient security in agriculture, especially in regions dependent on imported fertilizers.
Area of Science:
- Environmental Science
- Agricultural Science
- Chemical Engineering
Background:
- Human urine is a rich source of phosphorus, a critical nutrient for agriculture.
- Developing countries, like Nepal, face challenges with high costs and limited availability of imported fertilizers.
- Urine-diverting dry toilets offer a practical method for source separation of human urine.
Purpose of the Study:
- To investigate the feasibility of recovering phosphorus from human urine as a fertilizer.
- To evaluate struvite precipitation as an efficient method for phosphorus recovery.
- To identify cost-effective magnesium sources and optimize the recovery process.
Main Methods:
- Struvite precipitation using bittern as a magnesium source.
- Reactor design with external filtration and sedimentation-only setups.
- Analysis of phosphorus removal efficiency, magnesium dosage, and treatment time.
- Economic analysis considering fertilizer prices and process optimization.
Main Results:
- Struvite precipitation efficiently recovered over 90% of phosphorus using a filtration system.
- A sedimentation-only reactor achieved only 50% phosphate removal.
- Bittern is a viable magnesium source, but local magnesite offers a cheaper alternative.
- Optimizing precipitation and recovering spontaneously formed struvite and calcium phosphate can increase recovery by over 40%.
Conclusions:
- Struvite precipitation is a highly effective and simple method for converting human urine into a granulated phosphorus fertilizer.
- Process optimization, including magnesium source selection and enhanced recovery techniques, is crucial for financial sustainability.
- Further research into recovering nutrients from the reactor effluent could provide additional revenue streams and improve overall resource utilization.
Related Concept Videos
01:23Formation of Concentrated Urine
There is a gradient of solutes in the interstitial fluid from the renal cortex through the medulla, known as the medullary osmotic gradient. The juxtamedullary nephrons establish and maintain this gradient using countercurrent mechanisms with loops extending deep into the medulla. These nephrons also use countercurrent mechanisms to regulate urine volume and concentration. The interaction between the descending and ascending limbs of the nephron loop creates an osmotic gradient through...
01:20Formation of Dilute Urine
The formation of dilute urine is a critical renal adaptation that maintains fluid balance, particularly during periods of high fluid intake. This process primarily involves the juxtamedullary nephrons. By adjusting the permeability of water and ions in response to physiological conditions, the kidneys can either conserve or excrete water, resulting in concentrated or dilute urine.
Filtrate Osmolarity in the PCT
Initially, as the filtrate passes through the proximal convoluted tubule (PCT), its...
Filtrate Osmolarity in the PCT
Initially, as the filtrate passes through the proximal convoluted tubule (PCT), its...
01:32Filtration and Urine Formation
The function of the kidneys is to filter, reabsorb, secrete, and excrete. Every day the kidneys filter nearly 180 liters of blood, initially removing water and solutes but ultimately returning nearly all filtrates into circulation with the help of osmoregulatory hormones. This process removes wastes and toxins but is also crucial to maintain water and electrolyte levels. Most of these functions are performed by the tiny but numerous nephrons contained within the kidneys.
01:30Urinary Tract Calculi III: Medical Management
The diagnosis of renal calculi involves several imaging techniques, including non-contrast CT scans and ultrasound. These methods help visualize kidney stones, assess their size and location, and detect possible obstructions. Additionally, Measuring urine pH is useful for diagnosing specific stone types, such as struvite (alkaline pH) and uric acid stones (acidic pH). Cystine stones are primarily linked to cystinuria, a genetic condition. A urinalysis helps detect blood in the urine (hematuria)...
01:28Acute Pyelonephritis II: Diagnostic Studies and Management
Introduction:For diagnosing acute pyelonephritis, a comprehensive patient history is collected to identify symptoms such as dysuria, frequent or urgent urination, flank pain, or costovertebral angle (CVA) tenderness that may suggest a kidney infection.Physical ExaminationDuring the physical examination, CVA tenderness is assessed. This involves gentle percussion over the costovertebral angle, where tenderness often indicates a kidney infection.Diagnostic TestsUrinalysis: Used to identify white...
01:24Physiology of Urine Formation
Urine formation is an essential function of the human body. It plays a critical role in maintaining homeostasis by regulating the volume and composition of body fluids. The kidneys, the primary organs involved in this process, filter blood to remove waste products and excess substances, ultimately producing urine.
Glomerular Filtration
The first stage in urine formation is glomerular filtration. Each kidney contains approximately 1 million nephrons, the functional units of filtration, with a...
Glomerular Filtration
The first stage in urine formation is glomerular filtration. Each kidney contains approximately 1 million nephrons, the functional units of filtration, with a...