Trickling Biofilter for Simultaneous Nitrification and Denitrification
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Solution Overview
Problem
Current biofiltration processes for treating liquid pig manure struggle to achieve very low nitrogen concentrations due to limited nitrification in the primary biofilter and subsequent denitrification in the polishing biofilter, leading to elevated nitrate levels and incomplete nitrogen transformation.
Innovation Solution
A method utilizing a trickling biofilter with a filtering medium supporting microorganisms that promotes simultaneous nitrification and denitrification by adjusting nitrogen and carbon loads and adding oxygen at varying flow rates to achieve substantial nitrogen removal, potentially eliminating the need for a polishing biofilter stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If nitrification is maximized in the primary biofilter to meet low ammoniacal nitrogen release constraints, then ammoniacal nitrogen removal is improved, but nitrate concentration at the outlet becomes elevated
Solution Approach 1:
The patent merges nitrification and denitrification processes into a single biofilter unit. The filtering medium contains both nitrifying bacteria (which convert ammonium to nitrate) and denitrifying bacteria (which convert nitrate to nitrogen gas), allowing both processes to occur simultaneously within the same reactor, thus eliminating the need for separate primary and polishing biofilters
Solution Approach 2:
The patent creates different local conditions within the biofilter to support both nitrification and denitrification. The filtering medium provides aerobic zones (for nitrification) and anoxic zones (for denitrification) through its structure and oxygen distribution, allowing each bacterial population to thrive in its optimal environment within the same system
2Object-generated harmful factors
If denitrification is promoted in the polishing biofilter to reduce nitrate levels, then nitrate removal is improved, but the low load of residual organic matter limits denitrification efficiency
Solution Approach 1:
The patent adds a carbon source (such as methanol, acetate, or glucose) to the effluent before it enters the biofilter. This preliminary addition of easily assimilable carbon provides the necessary electron donor for denitrifying bacteria, enabling them to effectively reduce nitrates to nitrogen gas even though the manure itself has low organic matter content at this stage
Solution Approach 2:
The patent introduces an external carbon source as an intermediary substance to facilitate the denitrification process. This added carbon acts as a mediator that bridges the gap between the low organic matter available in the treated effluent and the high carbon demand of denitrifying bacteria, enabling efficient nitrate removal
3Object-affected harmful factors
If a two-stage biofiltration system is used to treat liquid pig manure, then nitrogen transformation is achieved, but the system complexity increases and complete nitrogen removal is difficult to achieve
Solution Approach 1:
The patent combines two separate biofilter stages into a single integrated unit. By incorporating both nitrifying and denitrifying bacteria in one reactor with appropriate zonation, the system achieves the same nitrogen removal function with reduced complexity, eliminating the need for multiple treatment stages while maintaining or improving removal efficiency
Solution Approach 2:
The single biofilter is designed to perform multiple functions simultaneously: it conducts both nitrification (ammonium to nitrate conversion) and denitrification (nitrate to nitrogen gas conversion), as well as organic matter degradation. This multi-functional design replaces the specialized functions of separate primary and polishing biofilters
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 achieves an average removal of 90-100% of total nitrogen, with effluent nitrogen levels below 100 mg/L, ensuring compliance with stringent environmental standards by optimizing nitrification and denitrification conditions within a single biofilter.
Implementation Method 1
the mechanisms of nitrification (NH4→NO3) and denitrification (NO3→N2) take place simultaneously
Implementation Method 2
the mechanisms of nitrification (NH4→NO3) and denitrification (NO3→N2) take place simultaneously
Implementation Method 3
adding oxygen with a flow rate varying from 0.1 to 0.66 m/hour to the trickling biofilter
Data Source
AI summary
A method of biofiltration of a liquid effluent by simultaneous nitrification and denitrification uses the adding of an oxygen source at a predetermined rate and optionally the adding of a carbon source (such as whey) thus enabling the complete transformation of the nitrates (NO3) present in the effluent at the time of treatment through a biofilter. The specific operating conditions favoring the simultaneous nitrification and denitrification include the controlled injection of a slight quantity of air, adjustment of the level of nitrogen load (TKN+NO3) and the level of carbon load thereby making possible elimination for the most part of the release of unwanted nitrogen in the form of NO3 or NO2.