Phosphorus Removal in Acidic Chemical Pulping Effluent
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Solution Overview
Problem
Current methods for reducing phosphorus in effluents from chemical pulping processes, especially those involving acidic stages, are costly and operationally complex, such as tertiary treatment and the use of phosphorus-concentrating microorganisms, which are not effective in acidic conditions.
Innovation Solution
A method involving obtaining two portions of effluent or filtrate from acidic stages, adjusting the pH of one portion to alkaline using an alkaline agent, precipitating phosphorus as a phosphate salt, separating the precipitate, and combining it with the second portion to produce a purified effluent or filtrate, which can be further treated or discharged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional tertiary treatment or phosphorus-concentrating microorganisms are used to reduce phosphorus in effluent, then phosphorus removal effectiveness is improved, but investment cost and operating cost increase significantly
Solution Approach 1:
The invention changes the pH parameter of the effluent from acidic to alkaline by adding alkaline material, which transforms the chemical environment to enable phosphorus precipitation. This parameter change allows phosphorus to be removed through simple chemical precipitation rather than requiring complex tertiary treatment systems or specialized microorganisms, thereby reducing both investment and operating costs while maintaining effective phosphorus removal
Solution Approach 2:
The invention replaces complex mechanical and biological treatment systems (tertiary treatment plants, anaerobic digesters for phosphorus-concentrating microorganisms) with a simple chemical precipitation process. By substituting the mechanical/biological system with a chemical reaction-based system, the complexity and cost of the treatment facility are significantly reduced while achieving the same phosphorus removal objective
2Reliability
If phosphorus-concentrating microorganisms are used in anaerobic media to reduce phosphorus, then phosphorus removal is achieved, but operational complexity increases and specific treatments are required
Solution Approach 1:
The invention changes the pH parameter from neutral/anaerobic conditions to alkaline conditions, which fundamentally alters the treatment mechanism from biological to chemical. This parameter change simplifies the operational requirements by eliminating the need for anaerobic environment control, mixing systems for microorganisms, and specialized operational procedures, while achieving effective phosphorus removal through straightforward chemical precipitation and filtration
3Ease of operation
If effluent from acidic stages is discharged directly to the environment, then operational simplicity is maintained, but environmental pollution from phosphorus occurs
Solution Approach 1:
The invention changes the pH parameter of the effluent from acidic to alkaline by adding alkaline material, which triggers phosphorus precipitation. This simple parameter change, combined with filtration, effectively removes phosphorus pollution while maintaining operational simplicity. The process can be integrated into existing facilities without requiring complex additional equipment, thus achieving both environmental protection and operational ease
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 effluents, is cost-effective with minimal equipment investment, and can be performed at the chemical pulping mill, allowing for efficient phosphorus removal even with small volumes of treated effluent, suitable for subsequent bacterial waste water treatment processes.
Implementation Method 1
adjusting pH of the first portion of the effluent or filtrate to alkaline with an alkaline agent
Implementation Method 2
allowing phosphorus to be precipitated in form of a phosphate salt
Data Source
Figure 1a~1g
Figure 2
AI summary
The invention relates to a method for reducing phosphorus in effluent or filtrate from a process which comprises at least one stage in which conditions are acidic, wherein the method comprises the steps of: a) obtaining a first portion of an effluent or filtrate from a stage in which conditions are acidic; b) obtaining a second portion of an effluent or filtrate from the same or different stage in which conditions are acidic; c) adjusting pH of the first portion of the effluent or filtrate to alkaline with an alkaline agent; d) allowing phosphorus to be precipitated in form of a phosphate salt; e) separating the precipitate to produce purified effluent or filtrate; and f) combining the purified effluent or filtrate with the second portion of the effluent or filtrate. The process may be a chemical pulping process in which pulp is cooked in a digestion apparatus (1), washed in a washing apparatus (2), bleached in a bleaching apparatus (3) in which an acidic bleaching stage (3') takes place, after which the pulp is separated in a separation apparatus (4) from an acidic effluent or filtrate which is divided into the first and second portions of effluent or filtrate. The invention also relates to the corresponding chemical pulping and purification apparatus.