Magnesium Ammonium Phosphate Recovery via Loosening and Flushing
Solution Overview
Problem
Existing methods for recovering magnesium ammonium phosphate (MAP) from sludge are inefficient in separating microcrystals, which are difficult to separate using standard techniques, limiting the overall phosphorus recovery rate.
Innovation Solution
A method involving a two-stage process with an aerobic reaction tank for initial MAP crystal formation and an anaerobic tank for microcrystal growth, combined with a loosening and flushing process in the extraction device to grade crystals, allowing smaller crystals to return and grow, and a closure-free extraction device design for efficient separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard separation methods are used to separate MAP crystals from sludge, then macrocrystals can be separated effectively, but microcrystals cannot be separated due to their small size
Solution Approach 1:
The patent applies preliminary action by providing a guide structure in advance that directs macrocrystals to the extraction device while allowing microcrystals to remain in the reaction tank for further growth. This pre-positioned guidance system ensures that only appropriately sized crystals are extracted in the first stage, preventing the loss of microcrystals that would otherwise be difficult to separate later.
Solution Approach 2:
The patent segments the crystal separation process into multiple stages: first extracting macrocrystals through the guide structure, then allowing microcrystals to grow in subsequent batches. This segmentation of the separation process by crystal size enables efficient recovery of both macrocrystals and microcrystals through iterative extraction cycles.
2Productivity
If a closure device is provided in the extraction device for separating MAP crystals, then extraction efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the closure function from a separate device component and integrates it into the guide structure itself. The guide structure serves dual purposes: directing macrocrystals to the extraction device and providing the closure function when positioned in the extraction device opening. This eliminates the need for a separate closure device while maintaining extraction efficiency.
Solution Approach 2:
The guide structure is designed with multi-functionality, serving both as a directional guide for macrocrystals and as a closure device when placed in the extraction device opening. This universal design reduces the total number of components needed in the system while maintaining both guidance and extraction functions.
3Device complexity
If microcrystals are separated immediately after precipitation, then separation process is simplified, but phosphorus recovery rate decreases due to inability to separate microcrystals effectively
Solution Approach 1:
The patent applies preliminary action by allowing microcrystals to remain in the reaction tank and grow into macrocrystals through additional precipitation cycles before extraction. This pre-growth period enables microcrystals to reach a size where they can be effectively separated using the same guide structure and extraction device, eliminating the need for complex microcrystal-specific separation equipment.
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 rate by enabling the growth of microcrystals to a size that can be easily separated, improving the efficiency of MAP crystal extraction and recovery.
Implementation Method 1
digested sludge is aerated to increase its pH value by CO2 stripping
Implementation Method 2
a reaction tank is used in which sludge is guided in a cycle. Precipitated MAP crystals collect in a floor area of funnel-shaped design
Implementation Method 3
magnesium chloride being added to the sludge and magnesium ammonium phosphate crystals (MAP crystals) precipitated from the sludge
Implementation Method 4
The heavy MAP particles are passed into a lower funnel of the device and extracted from there via a pipe
Implementation Method 5
The heavy MAP particles are passed into a lower funnel of the device
Data Source
AI summary
The invention relates to a method and an assembly for recovering magnesium ammonium phosphate from slurry that is supplied to a reaction container (10) in which an aerobic milieu is present and in which the slurry is guided in a circuit with the aid of ventilation. Cationic magnesium, such as magnesium chloride, is added to the slurry, and magnesium ammonium phosphate crystals which are precipitated from the slurry are removed via a removal device (30) provided in the base region of the reaction container. Substances which contain magnesium ammonium phosphate crystals collected in the removal device (30) are loosened and/or rinsed.