Wastewater Purification Agent for Phosphate Removal
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Solution Overview
Problem
Biological wastewater treatment plants face challenges in effectively removing phosphorus and stabilizing flocs due to repulsive particle charges and low-density bacterial flakes, requiring excessive use of calcareous products to maintain the lime-carbonic acid balance and ensure efficient separation of treated wastewater from bacterial mass.
Innovation Solution
A mixture of organic polymers, alkaline earth metal ions, and stabilizers, such as cationized starch and polyaluminum chloride, is used to enhance precipitation and coagulation, reducing the need for calcareous products and improving phosphate removal through synergetic effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional precipitation agents (aluminum or iron salts) combined with flocculants are used, then phosphate precipitation and coagulation are achieved, but excessive amounts of calcareous products (lime compounds) must be added to maintain the lime-carbonic acid balance and ensure floc stability
Solution Approach 1:
The invention combines the functions of phosphate precipitation, coagulation, and lime-carbonic acid balance maintenance into a single integrated agent. The agent contains aluminum or iron salts for phosphate precipitation, organic polymeric flocculants for coagulation, and alkaline earth metal ions (calcium and/or magnesium) to maintain the lime-carbonic acid balance, eliminating the need for separate lime compound additions.
Solution Approach 2:
The precipitation/flocculant agent is designed to perform multiple functions simultaneously: precipitating phosphates, forming stable flocs through coagulation, and maintaining the lime-carbonic acid balance. This multi-functional approach replaces the need for multiple separate chemical additions (precipitant, flocculant, and lime compounds) with a single comprehensive agent.
2Productivity
If separate tailings ponds and/or SBR reactors are used for sedimentation, then separation of treated wastewater from bacterial mass is achieved, but the process complexity and space requirements increase
Solution Approach 1:
The invention performs preliminary coagulation and flocculation actions within the aeration tank before the sedimentation step. By adding the precipitation/flocculant agent that contains organic polymeric compounds, flocs are formed and stabilized in advance, which then settle more efficiently in the existing sedimentation facilities, reducing the need for complex separate treatment systems.
3Stability of the object's composition
If large amounts of lime compounds are added to stabilize the lime-carbonic acid balance, then pH stability and floc stability are maintained, but the cost and chemical usage increase
Solution Approach 1:
The invention changes the chemical composition parameters of the precipitation agent by incorporating alkaline earth metal ions (calcium and/or magnesium) in addition to the aluminum or iron salts and organic polymeric flocculants. This compositional modification enables the agent to maintain the lime-carbonic acid balance and stabilize pH without requiring separate lime compound additions.
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
The solution achieves a stronger phosphate precipitation effect, reduces the need for lime compounds by up to 70%, and effectively stabilizes flocs, leading to significant savings in additives and a decrease in carbon dioxide generation, while maintaining efficient nitrogen elimination processes.
Implementation Method 1
Phosphate is precipitated by aluminum or iron salts
Implementation Method 2
This effect can be further intensified by combining these with a flocculant such as organic polymeric compounds
Implementation Method 3
the bound calcium includes precipitated calcium, in particular calcium carbonate
Data Source
AI summary
A biological treatment agent for municipal wastewater is proposed, comprising a mixture of at least one metal-based phosphate precipitation precipitant and flocculants. To reduce the use of lime milk during precipitation, it is proposed that the mixture include at least one organic polymer, alkaline earth ions, and preferably a stabilizer.