Processing of the liquid fraction
Calcium phosphate precipitation
Objective
Recovery of phosphorus compounds with lime grout (CaO) or calcium hydroxide Ca(OH)2 by precipitation in the form of calcium phosphate (apatites)
Inlets
Liquid streams rich in P and N, products of other processes
Efficiency
High efficiency. The concentration of phosphorus in the clarified liquid can be found below 2 ppm
Weaknesses
Risk of ammonium volatilization in highly aerated reactors or with CO₂ stripping;
The rate of formation of apatite is lower than that of struvite (in fact, it is considered a by-product of the formation of struvite in the presence of calcium ions);
The rate of formation of apatite is lower than that of struvite (in fact, it is considered a by-product of the formation of struvite in the presence of calcium ions);
Products
Apatites (calcium phosphate)
Other outlets
Treated liquid effluent
Consumption
Energy: Low
Water: Not applicable
Reagents: Low
Investment
Not available
Operation
Not available
Observations
Depending on the dose of calcium hydroxide, three calcium phosphates can be obtained: calcium monophosphate highly soluble in water (MCP), calcium diphosphate soluble in citric acid (DCP) and almost insoluble calcium triphosphate (TCP);
Energy consumption comes solely from agitation;
A previous degradation of the organic matter could increase the purity of the apatite;
Energy consumption comes solely from agitation;
A previous degradation of the organic matter could increase the purity of the apatite;
Combination with other technologies
1. Separation -> Acidification -> Precipitation of calcium phosphate;
2. Separation -> nitrification-denitrification -> calcium phosphate precipitation;
2. Separation -> nitrification-denitrification -> calcium phosphate precipitation;
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TRL - 9
Status Consolidated
Complexity Medium
Information made by:
BETA Tech Center