MAP Particle Recovery from Sludge via Crystallization
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Solution Overview
Problem
Existing methods for treating organic wastewater and sludge fail to effectively recover fine MAP particles with particle diameters less than 25 µm, leading to a lower phosphorus recovery ratio, especially when the phosphorus component from these particles constitutes a significant portion of the sludge.
Innovation Solution
A method that utilizes anaerobically treated sludge as seed crystals to grow MAP particles by crystallizing and precipitating the phosphorus component in solid-liquid separation water, followed by pH adjustment to dissolve remaining MAP particles in the sludge, allowing for their separation and recovery using a physical means like a liquid cyclone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical means such as liquid cyclone are used to separate MAP particles, then large MAP particles can be separated, but fine MAP particles with particle diameter less than 25 µm cannot be separated and are discarded
Solution Approach 1:
The invention changes the particle size parameter of MAP by controlling crystallization conditions. By adjusting supersaturation degree, temperature, and crystallization time, fine MAP particles are transformed into coarser particles with diameter of 25 µm or more that can be separated by liquid cyclone, thereby resolving the contradiction between separation capability and phosphorus recovery
Solution Approach 2:
The invention performs preliminary crystallization treatment before separation. MAP particles are grown in advance under controlled crystallization conditions to reach a size suitable for physical separation, enabling subsequent efficient separation by liquid cyclone and preventing loss of phosphorus in fine particles
2Quantity of substance
If phosphorus component from fine MAP particles is present in significant amount in sludge, then phosphorus recovery ratio drops significantly when using conventional physical separation methods
Solution Approach 1:
The invention changes the physical state and size parameters of phosphorus-containing MAP particles through controlled crystallization. By adjusting crystallization parameters, phosphorus is concentrated into recoverable MAP particles rather than remaining as fine dispersed particles, thereby improving phosphorus recovery ratio even when phosphorus content in sludge is high
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 approach significantly increases the phosphorus recovery ratio by enabling the separation and recovery of fine MAP particles that were previously unaccounted for, enhancing the overall phosphorus recovery efficiency.
Implementation Method 1
by using MAP particles contained in anaerobically treated sludge as seed crystals, the MAP particles are grown by crystallizing and precipitating, as MAP, a phosphorus component dissolved in solid-liquid separation water
Implementation Method 2
separation into the grown MAP particles and MAP depleted sludge
Data Source
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AI summary
Provided is a technique which makes it possible to recover fine MAP particles which cannot be separated by a physical means such as a liquid cyclone so as to significantly improve a phosphorus recovery ratio from sludge. Proposed is a method for treating organic waste water or organic sludge including a phosphorus separation step in which by using MAP particles contained in anaerobically treated sludge obtained by anaerobically treating organic waste water or organic sludge as seed crystals, the MAP particles are grown by crystallizing and precipitating, as MAP, a phosphorus component dissolved in solid-liquid separation water returned from the subsequent sludge amount reduction step, followed by separation into the grown MAP particles and MAP depleted sludge, a pH adjustment step in which the pH of the MAP depleted sludge obtained by the separation in the phosphorus separation step is lowered to dissolve the MAP particles remaining in the MAP depleted sludge, thereby obtaining pH-adjusted sludge, and a sludge amount reduction step in which dewatered cake is obtained by concentrating and dewatering the pH-adjusted sludge and a part or the whole of solid-liquid separation water obtained by the concentration and dewatering is returned to the phosphorus separation step.