Vertical Percolation Filter Active Aeration Nitrogen Removal
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Solution Overview
Problem
Current wastewater treatment systems, particularly those using planted filters with vertical percolation, face limitations in treating heavily loaded effluents with high nitrogen and phosphorus removal efficiency, often requiring multiple stages and significant land area, while also facing issues with clogging and incomplete nitrification.
Innovation Solution
A wastewater treatment device with a purification basin featuring a lower saturated layer with active aeration and an upper unsaturated layer with passive aeration, utilizing an intermittent active aeration system and water retention mechanisms to maintain a water seal, allowing for efficient treatment of particulate matter and dissolved pollutants without pre-treatment, and promoting aerobic conditions for enhanced nitrification and denitrification reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple stages of vertical filters are used to improve nitrogen removal efficiency, then the purification performance is improved, but the land footprint and device complexity increase
Solution Approach 1:
The patent combines nitrification and denitrification processes into a single vertical filter stage by creating distinct aerobic (upper layer) and anoxic (lower layer) zones within the same filter body. This merging of multiple treatment functions into one unit achieves high nitrogen removal efficiency without requiring multiple separate filter stages, thereby reducing land footprint and system complexity
Solution Approach 2:
The filter is segmented into at least two distinct layers with different oxygen conditions: an upper aerobic layer for nitrification and a lower anoxic layer for denitrification. This internal segmentation allows both nitrification and denitrification to occur simultaneously in different zones within the same filter, achieving complete nitrogen removal in a single stage rather than requiring multiple sequential filters
2Area of stationary object
If compact filters with superimposed material layers are used to reduce land use, then the area is reduced, but clogging risk and incomplete nitrification occur
Solution Approach 1:
The patent applies local quality by creating different environmental conditions in different parts of the filter: the upper layer maintains aerobic conditions with adequate oxygen supply for complete nitrification, while the lower layer creates anoxic conditions favorable for denitrification. This localized optimization of environmental conditions ensures both nitrification completeness and denitrification efficiency within the compact filter structure
Solution Approach 2:
The patent introduces dynamic aeration control where the aeration rate is adjusted based on operational conditions to prevent clogging while maintaining nitrification efficiency. The system dynamically balances oxygen supply to ensure complete nitrification in the upper layer while preventing excessive oxygen penetration that would inhibit denitrification in the lower layer, thus maintaining reliability in the compact design
3Area of stationary object
If heavily loaded effluents are treated with single-tank compact filters, then the land footprint is reduced, but the overall nitrogen yield is limited to 70%
Solution Approach 1:
The patent optimizes key parameters including the height ratio between aerobic and anoxic layers, aeration rates, and hydraulic loading rates to achieve high nitrogen removal from heavily loaded effluents in a single tank. By carefully controlling the oxygen transfer rate and layer thickness, the system achieves complete nitrification followed by effective denitrification, reaching overall nitrogen yields exceeding 90% despite the compact single-tank configuration
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 system achieves high yields in treating domestic and industrial effluents with reduced land footprint, low sludge production, and lower energy consumption, effectively handling heavily loaded effluents with improved nitrogen and phosphorus removal without the need for pre-treatment, while maintaining landscape integration and easy maintenance.
Implementation Method 1
diffusion, both from the surface and from the bottom thanks to the network of drains connected to aeration chimneys (it allows the renewal of the gaseous phase of the inter-granular spaces in an unsaturated medium)
Implementation Method 2
water retention means capable of maintaining, in the basin in operation, a water seal of a height predetermined which corresponds to the entire height of the lower layer
Implementation Method 3
nitrification by nitrifying bacteria under aerobic conditions (leading to the oxidation of ammoniacal nitrogen into nitrites and then into nitrates)
Implementation Method 4
denitrification reactions carried out by denitrifying bacteria (leading to the reduction of nitrates into gaseous compounds)
Implementation Method 5
wastewater is sent to the surface, percolates vertically through the filter bed and is collected at the bottom by a drainage network
Data Source
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AI summary
The invention relates to a sewage treatment device (1) such as a planted filter in which the circulation of the sewage follows a vertical flow, the device comprising a purification tank (10) intended for receiving sewage, the tank including at least two vertically adjacent layers of filtering materials: a lower layer (100) saturated with water located at the bottom of the tank and comprising draining means, and an upper layer (101) not saturated with water located above the lower layer, the upper layer including passive aeration means, the passive aeration means including a network of aeration drains (4) located at the bottom of the upper layer, characterised in that the device includes a system (3) for active aeration of the saturated lower layer, the active aeration system (3) being located at the bottom of the lower layer and being distributed essentially over the entire surface covered by the lower layer of the purification tank, the active aeration system being intended for homogeneously aerating the entire lower layer, also characterised in that the device comprises water-retaining means (2) capable of maintaining, in the operational tank, a trap seal with a predetermined height that corresponds to the entire height of the lower layer, and in that the upper layer has a height H2 of at least 30 cm.