Dilute Wastewater Treatment via Stream Segmentation
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Solution Overview
Problem
Anaerobic biological systems face challenges in treating dilute wastewaters due to high energy demands, ammonia inhibition, and fugitive methane emissions, which hinder their widespread adoption for wastewater treatment, especially in domestic and municipal applications.
Innovation Solution
A wastewater treatment process divided into three stages: separation, conversion, and optional polishing, where dilute wastewater is first separated into a low-strength stream for reuse and a high-strength stream for anaerobic processing, reducing energy requirements and ammonia inhibition, and minimizing fugitive methane emissions by concentrating contaminants before anaerobic digestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If anaerobic biological systems are used to treat dilute wastewater, then energy demand is reduced and biogas is produced, but large reactors are required which increase capital investment and negate benefits
Solution Approach 1:
The patent divides the wastewater stream into two separate streams: a dilute stream that is bypassed around the anaerobic reactor and a concentrated stream that is fed to the anaerobic reactor. This segmentation allows the system to handle dilute wastewater without requiring excessively large reactor volumes, as only the concentrated portion needs anaerobic treatment.
Solution Approach 2:
The patent extracts the water portion from the dilute wastewater stream, separating it from the contaminants. This extraction concentrates the contaminants into a smaller volume that can be efficiently treated anaerobically, while the extracted water is discharged or reused without requiring large treatment capacity.
2Productivity
If source separation is implemented to prevent dilution of higher strength wastewaters, then anaerobic treatment efficiency is improved, but infrastructure costs increase and user behavior change is required
Solution Approach 1:
The patent performs preliminary concentration of contaminants from the wastewater stream before anaerobic treatment. By pre-concentrating the wastewater through evaporation or other separation methods, the system achieves high treatment efficiency without requiring complex source separation infrastructure or changes to existing wastewater collection systems.
3Loss of energy
If nitrogen-rich wastewaters are treated anaerobically, then energy recovery is possible, but ammonia inhibition occurs which decreases biogas production and causes scaling
Solution Approach 1:
The patent extracts ammonia or nitrogenous compounds from the wastewater stream before anaerobic treatment through processes like stripping, ion exchange, or chemical precipitation. This removal eliminates ammonia inhibition in the anaerobic reactor, allowing efficient biogas production from the treated wastewater while preventing scaling and equipment damage.
4Reliability
If heating is applied to accelerate pathogen inactivation and hydrolysis in anaerobic treatment, then disinfection effectiveness is improved, but energy cost increases tremendously
Solution Approach 1:
The patent performs preliminary concentration of the wastewater stream, reducing its volume before anaerobic treatment. This preliminary action means that less water requires heating for pathogen inactivation and hydrolysis, significantly reducing the energy cost while maintaining disinfection effectiveness. The concentrated stream requires proportionally less thermal energy to achieve the same treatment outcomes.
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 process enhances the efficiency and cost-effectiveness of anaerobic treatment by reducing energy needs, minimizing ammonia inhibition, and decreasing fugitive methane emissions, making anaerobic systems more viable for treating dilute wastewaters without the need for extensive infrastructure changes or user behavior modifications.
Implementation Method 1
A filtration unit divides the wastewater from the settling chamber into two streams: a permeate stream that is delivered to the polishing subsystem and a concentrate stream that is returned to the settling chamber
Implementation Method 2
The slurry is then delivered to the conversion subsystem where it is broken down into biogas and an aqueous effluent stream
Implementation Method 3
In some embodiments, a pump or other apparatus (not shown) can be used to drive the wastewater feed into the chamber 12. In addition, the wastewater can be passed through a coarse filter, such as a screen, before entering the chamber 12 to remove trash and prevent large, abrasive objects from passing through the subsystem.
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
In one embodiment, a dilute wastewater treatment system includes a separation subsystem configured to receive dilute wastewater and separate it into a product stream containing a low concentration of organic material and a reject stream containing a high concentration of organic material, and a conversion subsystem configured to receive the reject stream from the separation subsystem and anaerobically treat the reject stream to break down the organic material and separate it from water within the reject stream.