Phosphorus Extraction from Organic Residues via Sulphate Precipitation
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Solution Overview
Problem
Current methods for extracting phosphorus from organic residues, such as manure and sewage sludge, are inefficient and generate significant waste water, leading to high energy consumption and environmental concerns due to excessive phosphorus content and salt levels.
Innovation Solution
A method involving the use of an acidic sulphate-containing aqueous solution to solubilize phosphorus, followed by separation into solid and liquid fractions, and then combining the liquid fraction with a magnesium-containing base to form struvite precipitate, effectively reducing phosphorus content and minimizing waste water production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If mechanical separation is used to separate organic residues into solid and liquid fractions, then transportation costs are reduced, but the solid fraction still contains high water content (over 65 wt.%) requiring energy-consuming drying
Solution Approach 1:
The invention changes the chemical parameters of the system by adding calcium chloride and sulfuric acid to alter the solubility characteristics of phosphorus compounds. This chemical modification enables phosphorus to be selectively extracted into the liquid phase while the solid fraction maintains higher dry matter content, eliminating the need for energy-consuming drying operations.
Solution Approach 2:
The invention extracts phosphorus from the solid fraction by converting it to a soluble form through chemical treatment and separating it into the liquid phase. This extraction process removes the problematic water-bound phosphorus from the solid fraction, allowing the solid to be used as a soil amendment without requiring further drying.
2Productivity
If phosphorus is recovered from organic residues, then phosphorus availability for fertilizer production increases, but significant waste water containing nutrients and salts is generated
Solution Approach 1:
The invention recovers phosphorus from the liquid fraction in the form of struvite precipitate, while the remaining liquid can be discharged or further treated. The solid fraction, now with reduced phosphorus content and higher dry matter, can be directly applied to soil. This dual recovery approach maximizes phosphorus utilization while minimizing waste water volume.
Solution Approach 2:
The invention converts the harmful high phosphorus content in organic residues into a beneficial product (struvite fertilizer). By adding magnesium salts to the liquid fraction, phosphorus is transformed from a pollutant into a valuable nutrient source, while the solid fraction becomes a suitable soil amendment with balanced nutrient content.
3Quantity of substance
If existing phosphorus extraction methods are used, then phosphorus can be recovered, but the process consumes large amounts of clean water and produces nutrient-rich waste water
Solution Approach 1:
The invention uses the organic residues themselves as the water source for the extraction process. The existing water content in the organic material is utilized to dissolve and transport phosphorus, eliminating or minimizing the need for additional clean water input. This self-service approach to water usage significantly reduces both water consumption and waste water generation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method significantly reduces phosphorus content in organic residues, making them suitable for soil amendment, while minimizing energy consumption and waste water generation by utilizing readily available sulphate-containing process water to bind calcium and iron, thus enhancing struvite formation efficiency.
Implementation Method 1
combining the organic matter provided in step (a) with acidic sulphate-containing aqueous solution to solubilize phosphorus
Implementation Method 2
allow calcium sulphate in the form of suspended gypsum particles and/or iron sulphate to form
Implementation Method 3
separating the slurry obtained in step (b) into a solid fraction having a water content of at most 80 wt.%, and a liquid fraction having a water content of at least 80 wt.%
Implementation Method 4
combining the liquid fraction as obtained in step (c) with magnesium-containing base to obtain struvite precipitate
Data Source
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AI summary
The present invention relates to a method for extracting phosphorus from organic matter, the method comprising (a) providing phosphorus-containing organic matter, wherein the organic matter further contains calcium and/or iron; (b) adding acid and sulphate-containing water to the organic matter provided in step (a) to solubilize phosphorus, allow calcium sulphate and/or iron sulphate to form, and obtain a slurry; (c) separating the slurry obtained in step (b) into a solid fraction having a water content of at most 80 wt.%, and a liquid fraction having a water content of at least 80 wt.%; (d) adding a magnesium-containing base to the liquid fraction as obtained in step (c) to obtain phosphorus precipitate in the form of struvite.