Sludge Deodorization via Metal Salt and Tannin Complexation
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Solution Overview
Problem
Current sludge deodorization methods, including physical, biological, and chemical approaches, face limitations such as high costs, limited effectiveness, and potential secondary pollution, particularly in resource utilization processes like incineration and pyrolysis, where sludge odors like ammonia gas and hydrogen sulfide persist.
Innovation Solution
A method involving the synergistic use of a metal salt and a tannin extract, where the tannin extract acts as a multidentate ligand to form complexes with metal ions and extracellular polymers, reducing bioavailability and inhibiting the production of odorous substances, thereby deodorizing sludge effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If chemical oxidation method is used with chlorine-containing oxidant, then deodorization effect is improved, but chlorine content in sludge increases leading to dioxin production
Solution Approach 1:
The patent converts the harmful effect of metal ions (which can catalyze dioxin formation) into a beneficial effect by using them as deodorizing agents. Fe2+, Fe3+, Al3+, or Ca2+ salts are applied to oxidize and remove odorous substances like H2S and NH3 directly at the sludge source, transforming potential harm into benefit while avoiding chlorine-containing oxidants that produce dioxins
Solution Approach 2:
The patent employs inexpensive, readily available metal salt solutions (Fe2+, Fe3+, Al3+, or Ca2+) as deodorizing agents instead of expensive, hazardous chlorine-based oxidants. These metal salts can be easily applied and do not persist as harmful residues, effectively replacing costly and dangerous chemicals with affordable, safe alternatives
2Productivity
If ozone is used as oxidant, then hydrogen sulfide removal rate is improved, but equipment corrosion and preparation costs increase
Solution Approach 1:
The patent replaces expensive, unstable ozone with inexpensive, stable metal salt solutions (Fe2+, Fe3+, Al3+, or Ca2+). These metal salts are cheap, easy to store and handle, and do not require complex generation equipment, thereby reducing both preparation costs and equipment corrosion issues while maintaining effective H2S removal
Solution Approach 2:
The patent substitutes the mechanical/chemical system of ozone generation and delivery with a simpler chemical system using metal salt solutions. Instead of requiring ozone generators, storage tanks, and delivery infrastructure, the solution uses straightforward metal salt application that naturally reacts with odorous substances, eliminating complex equipment requirements
3Object-affected harmful factors
If activated carbon adsorption is used, then deodorization efficiency is improved, but cost and adsorption capacity limitations occur
Solution Approach 1:
The patent enables sludge to deodorize itself by applying metal salt solutions (Fe2+, Fe3+, Al3+, or Ca2+) that directly react with and neutralize odorous substances at their source. This self-service approach eliminates the need for external adsorbents like activated carbon, reducing both material costs and the need for continuous adsorbent replacement
Solution Approach 2:
The patent extracts and removes odorous substances (H2S, NH3, and other volatile compounds) from sludge through chemical reaction with metal salts, converting them into non-odorous products. This extraction method is more efficient and cost-effective than adsorption, as it permanently eliminates odors rather than merely transferring them to an adsorbent medium
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 method significantly reduces low-volatile sulfides with low olfactory thresholds, improves dehydration performance, and ensures environmental friendliness and low operational costs, making it suitable for resource utilization processes like incineration, pyrolysis, or carbonization without secondary pollution.
Implementation Method 1
the tannin extract acts as a multidentate ligand to form complexes with metal ions
Implementation Method 2
the tannin extract acts as a multidentate ligand to form complexes with metal ions and extracellular polymers, reducing bioavailability and inhibiting the production of odorous substances
Data Source
AI summary
A method for deodorizing sludge with a metal salt and a tannin extract together, deodorized sludge, and use thereof are provided. The present invention provides a sludge deodorization technology that has high treatment efficiency, environmental friendliness, and low investment costs, and satisfies harmless requirements of subsequent resource utilization such as incineration, pyrolysis, or carbonization. Characterized by containing abundant phenolic hydroxyl groups, the tannin extract is used as a multidentate ligand to undergo a complexation reaction with metal ions, which reduces bioavailability of proteins and other macromolecules, and effectively inhibits production of low-volatile sulfides, thereby significantly deodorizing the sludge during standing and combustion. The whole deodorization process of the present invention is simple and feasible, is flexible in operation, requires no complex and harsh reaction conditions or expensive equipment, has low operating costs, and can be used as a supporting pretreatment technology for resource utilization of sludge.