Municipal Sludge Recovery Using Ozone Oxidation and Ferrite Separation
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Solution Overview
Problem
Current sludge disposal methods in municipal wastewater treatment plants face challenges in achieving complete stabilization, resource recovery, and cost-effectiveness due to low organic matter content, high sulfide content, and the presence of heavy metals, which pose risks and incur high treatment costs.
Innovation Solution
A treatment method involving ozone oxidation, pupa shell powder slurry, and polydimethyl diallyl ammonium chloride is used to degrade organic matter and remove heavy metals, followed by centrifugation and calcination to produce soil fertilizer and ferrite, with the liquid phase used as a carbon source in wastewater treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional anaerobic digestion is used to treat sludge, then the treatment process is simple, but the sludge cannot reach stabilization standard due to low organic matter content and high sulfide content
Solution Approach 1:
The patent applies ozone oxidation as a strong oxidant to treat sludge with low organic matter content and high sulfide content. Ozone oxidizes sulfides to sulfates and degrades organic matter, enabling the sludge to meet stabilization standards that conventional anaerobic digestion cannot achieve. This resolves the contradiction by using advanced oxidation technology to improve stabilization reliability without requiring overly complex process integration.
Solution Approach 2:
The patent changes the treatment parameters by adjusting pH to 6.1-6.8 using pupa shell powder slurry and polydimethyl diallyl ammonium chloride before centrifugation. This parameter adjustment optimizes the separation efficiency and stabilizes the sludge, enabling meeting of stabilization standards while maintaining process feasibility.
2Loss of substance
If conventional stabilization methods are used, then the treatment cost is high, but resource recovery is insufficient
Solution Approach 1:
The patent extracts and recovers valuable resources from sludge through centrifugation and calcination. The solid phase is dried to produce organic soil fertilizer with water retention function, while the liquid phase is used as carbon source for wastewater treatment. Heavy metals are recovered as ferrite through calcination at 850°C. This extraction approach transforms waste sludge into useful products, reducing treatment costs and improving resource recovery simultaneously.
Solution Approach 2:
The patent converts harmful heavy metals in sludge into beneficial ferrite product through oxidation and calcination. The harmful sulfides and organic matter are oxidized and degraded, while heavy metals are precipitated and calcined to form marketable ferrite. This transforms the harmful characteristics of sludge into valuable resources, reducing treatment costs and creating revenue streams.
3Object-affected harmful factors
If sludge is treated to ensure harmlessness, then safety is improved, but volume reduction is insufficient
Solution Approach 1:
Ozone oxidation rapidly degrades organic matter and oxidizes sulfides, reducing sludge volume while ensuring harmlessness. The strong oxidation capability destroys pathogenic organisms and stabilizes the sludge matrix, achieving both safety and volume reduction in a single treatment step rather than requiring multiple sequential processes.
Solution Approach 2:
The patent employs phase transitions through centrifugation (solid-liquid separation) and calcination (thermal decomposition). Centrifugation separates the sludge into solid and liquid phases for different processing paths, while calcination at 850°C transforms the solid phase into stabilized organic soil fertilizer and ferrite. These phase transitions enable efficient volume reduction while maintaining harmlessness.
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 efficiently reduces organic matter and heavy metals, enhances water retention performance of solid phase sediment, and recycles resources by producing marketable ferrite and a high-carbon liquid phase for wastewater treatment, thereby reducing treatment costs and improving resource utilization.
Implementation Method 1
adding ferrous sulfate into concentrated sludge of the municipal wastewater treatment plants and performing ozone oxidation treatment
Implementation Method 2
ozone oxidation treatment to obtain sludge after ozone treatment
Implementation Method 3
adding pupa shell powder slurry and polydimethyl diallyl ammonium chloride into the sludge after the ozone treatment to make a pH of the sludge be 6.1-6.8
Implementation Method 4
enhances water retention performance of solid phase sediment
Implementation Method 5
centrifuging the conditioned sludge, and drying solid phase obtained by centrifugation
Implementation Method 6
adjusting a pH of liquid phase obtained by the centrifugation to 8-9 by lime water
Implementation Method 7
adding the ferrous sulfate and hydrogen peroxide, and centrifugally separating after reaction to obtain sediment
Implementation Method 8
adding the ferrous sulfate and hydrogen peroxide, and centrifugally separating after reaction to obtain sediment and supernatant
Implementation Method 9
drying and calcining the sediment to obtain ferrite
Implementation Method 10
the supernatant is taken as a carbon source and refluxed to the wastewater treatment plants
Data Source
AI summary
A treatment method for full resource recovery from sludge in municipal wastewater treatment plants is provided. Ozone is used to oxidize the cell contents of sludge, and the hermetia illucens pupa shell powder slurry, polydimethyl diallyl ammonium chloride and the like are used as conditioning materials and materials for improving the water retention performance of residues. The dehydrated products are prepared into soil water retention materials, the heavy metals separated from the sludge are recovered in a ferrite way, and the organic carbon in the liquid phase is utilized as a carbon source of a wastewater treatment plant.