Selenium Recovery from Wastewater Using Pseudomonas stutzeri
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Solution Overview
Problem
Current methods for wastewater treatment, such as coagulation precipitation and chelate treatment, are costly and inefficient for recovering selenium from wastewater due to low selenium content in chemical sludge, and existing biological treatments face challenges in optimizing conditions for effective selenium recovery.
Innovation Solution
A method using Pseudomonas stutzeri NT-I microorganisms to reduce water-soluble selenium compounds into elemental or gaseous selenium, involving specific temperature, pH, and aeration conditions in a jar fermenter system, allowing for efficient recovery of selenium from wastewater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coagulation precipitation or chelate treatment is used to clean wastewater, then wastewater can be treated, but treatment cost increases and selenium cannot be recovered as a resource
Solution Approach 1:
The patent converts the harmful toxic selenium compounds in wastewater into beneficial elemental selenium through biological reduction. The microorganism Pseudomonas stutzeri NT-I reduces selenate and selenite into elemental selenium, which is non-toxic and can be recovered as a resource, thus transforming a waste treatment problem into a resource recovery opportunity
Solution Approach 2:
The patent replaces conventional chemical treatment methods (coagulation precipitation, chelate treatment) with a biological treatment system using microorganisms. This substitution eliminates the need for chemical reagents and sludge disposal, reducing treatment costs while enabling selenium recovery
2Reliability
If conventional chemical treatment methods are used, then wastewater can be cleaned, but selenium content in chemical sludge is low and selenium cannot be recovered
Solution Approach 1:
The microorganism transforms dissolved selenium compounds into solid elemental selenium through biological reduction, concentrating selenium into a recoverable form rather than dispersing it in chemical sludge. This enables selenium recovery as a resource while maintaining wastewater cleaning effectiveness
Solution Approach 2:
The patent utilizes phase transition from dissolved selenium compounds (selenate/selenite in aqueous phase) to solid elemental selenium (precipitated phase) through biological reduction. This phase change concentrates selenium into a form that can be easily separated and recovered from the treated wastewater
3Loss of substance
If biological treatment method using Pseudomonas stutzeri NT-I is used, then selenium can be recovered, but treatment conditions must be optimized for efficient recovery
Solution Approach 1:
The patent optimizes treatment parameters including pH (maintained at alkaline conditions), temperature, and aeration to maximize selenium recovery efficiency. By controlling these parameters, the system achieves efficient conversion of selenate and selenite into elemental selenium while simplifying the overall treatment process
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 enables the efficient recovery of selenium by converting toxic water-soluble selenium compounds into non-toxic, water-insoluble elemental or gaseous forms, facilitating recycling and reducing treatment costs.
Implementation Method 1
Pseudomonas stutzeri NT-I is capable of efficiently reducing selenate into selenite and further reducing selenite into elemental selenium
Implementation Method 2
converting toxic water-soluble selenium compounds into non-toxic, water-insoluble elemental or gaseous forms
Data Source
AI summary
An object of the present invention is to provide a method for efficiently recovering solid selenium or gaseous selenium from wastewater/waste using a microorganism. The present invention provides a method for recovering selenium, comprising reducing a water-soluble selenium compound so as to produce elemental selenium or gaseous selenium by allowing a sample containing a water-soluble selenium compound to come into contact at a temperature which is more than 35° C. and is 40° C. or less at pH 7.0 to 9.4 with a microorganism capable of producing elemental selenium or gaseous selenium through reduction of a water-soluble selenium compound.