Vacuum Anaerobic Digester for Wastewater Purification
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Solution Overview
Problem
Current wastewater purification systems, such as UASB reactors, face challenges including slow granule formation, low pathogen and nutrient removal, long inoculation times, potential odors, and inefficient biogas extraction, particularly when treating urban wastewater with low COD and fluctuating temperatures.
Innovation Solution
The proposed solution involves a wastewater purification device with a vacuum anaerobic digester that utilizes a riser column suction effect for hydraulic transport, optimizing mixing and biogas extraction at sub-atmospheric pressure, and includes features like a buffer column for controlled hydraulic circulation, adjustable treated water outlet, and recirculation of biogas to enhance sludge mixing and biogas recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional UASB reactors are used for wastewater treatment, then anaerobic digestion can be achieved, but granule formation is slow and requires long startup periods
Solution Approach 1:
The patent introduces a pre-treatment zone with packing media before the main anaerobic digestion zone. This preliminary structure facilitates faster granule formation and establishes active biomass earlier in the startup phase, reducing the traditional six-month startup period while maintaining treatment efficiency.
Solution Approach 2:
The patent employs different packing media in different zones of the reactor. The pre-treatment zone uses specific packing materials that promote rapid granule formation, while the main digestion zone uses materials optimized for biomass retention. This localized approach accelerates startup without compromising overall treatment performance.
2Productivity
If conventional UASB reactors treat urban wastewater, then organic matter can be degraded, but pathogen and nutrient removal is insufficient
Solution Approach 1:
The patent divides the reactor into distinct functional zones: a pre-treatment zone for initial organic matter degradation and pathogen reduction, and a main anaerobic digestion zone for complete organic matter conversion. This segmentation allows each zone to specialize in specific removal functions, improving both organic matter degradation and pathogen/nutrient removal effectiveness.
Solution Approach 2:
The patent introduces a transition zone with specific packing media between the pre-treatment and main digestion zones. This intermediary zone facilitates gradual transition of wastewater characteristics and biomass composition, enhancing the removal of pathogens and nutrients while maintaining stable organic matter degradation throughout the system.
3Ease of operation
If conventional UASB reactors operate at atmospheric pressure, then operation is simple, but biogas extraction is inefficient
Solution Approach 1:
The patent modifies the pressure parameter from atmospheric to sub-atmospheric (vacuum) conditions in the main anaerobic digestion zone. This parameter change enhances biogas extraction efficiency by creating a pressure gradient that facilitates gas removal, while the overall system remains operationally manageable through automated control of the vacuum pump and pressure regulation mechanisms.
4Productivity
If conventional UASB reactors treat low COD wastewater, then treatment is required, but gas production is limited
Solution Approach 1:
The patent introduces a pre-treatment zone that performs preliminary organic matter degradation and concentration enhancement before the wastewater enters the main anaerobic digestion zone. This preliminary action increases the COD concentration and organic matter availability in the main zone, thereby enhancing biogas production from low COD wastewater while maintaining treatment capability.
Solution Approach 2:
The patent implements continuous recirculation of effluent from the main digestion zone back to the pre-treatment zone. This continuous circulation maintains high organic matter concentration and facilitates continuous biogas production, maximizing energy recovery from low COD wastewater treatment through sustained metabolic activity.
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 configuration improves mixing efficiency, facilitates optimal biogas extraction, and enhances the quality of treated water by reducing suspended particles and COD, addressing the limitations of existing systems while enabling energy-efficient operation and improved pathogen and nutrient removal.
Implementation Method 1
a vacuum pump (145) connected to the biogas outlet (135) and configured to cause, when said pump is actuated, the flow of water from the lower part (110) to the upper part (120)
Implementation Method 2
a riser column (140) for raising water by suction of the biogas from the lower part (110) to the upper part (120)
Implementation Method 3
The present invention relates to a device and a method for purifying wastewater. It applies, for example, to the field of urban wastewater purification.
Data Source
AI summary
The device (100) for purifying wastewater comprises:a vacuum anaerobic digester (105) comprising:in the lower part (110), an inlet (115) for wastewater,in the upper part (120):a weir (125) for treated water comprising a water outlet (130) positioned at a first height (131) starting from the lower part anda biogas outlet (135) positioned at a second height (136) higher than the first height,a riser column (140) for raising water by suction of the biogas from the lower part to the upper part,a downer column (141) for bringing down untreated wastewater from the upper part to the lower part anda vacuum pump (145) connected to the biogas outlet, anda buffer column (190) configured to receive wastewater.