Sludge Dewatering via Kitchen Waste Acidification and Low-Temp Hydrolysis
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Solution Overview
Problem
Current sludge dewatering methods face challenges with high energy consumption, generation of refractory chemical oxygen demand (COD), and secondary pollution due to the use of chemical reagents, especially in high-temperature thermal hydrolysis processes, which limits efficiency and complicates the treatment of filtrate and sludge cake.
Innovation Solution
A method combining anaerobic biological acidification of excess sludge with low-temperature thermal hydrolysis using kitchen waste, where the sludge and kitchen waste are mixed, centrifuged, and then subjected to thermal hydrolysis at 100-140°C to enhance dewatering performance without adding chemical reagents, utilizing waste heat for energy recovery and returning volatile fatty acids as a carbon source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-temperature thermal hydrolysis (190-320°C) is used to improve sludge dewatering performance, then dewatering efficiency is improved, but energy consumption increases and refractory COD is generated
Solution Approach 1:
The patent changes the temperature parameter from high-temperature (190-320°C) to low-temperature (100-140°C) thermal hydrolysis, combined with pH adjustment to 2-4, achieving effective dewatering without the high energy consumption and refractory COD generation associated with high-temperature processes
Solution Approach 2:
The patent combines chemical treatment (acidification using kitchen waste) with physical treatment (low-temperature thermal hydrolysis) to create a composite treatment system that achieves synergistic effects, improving dewatering efficiency while avoiding the drawbacks of either method alone
2Productivity
If chemical reagents (coagulants, flocculants, acid/alkali) are used to improve sludge dewatering performance, then dewatering performance is improved, but secondary pollution and high reagent dosage are caused
Solution Approach 1:
The patent uses kitchen waste to generate organic acids in situ through fermentation, which then serve as the acidifying agent for sludge treatment. This self-service approach eliminates the need to import external chemical reagents, reducing secondary pollution while maintaining effective dewatering performance
Solution Approach 2:
The patent converts kitchen waste, which would otherwise be discarded, into a valuable acidifying reagent through controlled fermentation. This recovery process transforms waste into a resource that improves dewatering without introducing harmful chemical substances
3Productivity
If physical methods (ultrasonic, electric field, freeze-thaw, high-temperature thermal hydrolysis) are used to improve sludge dewatering performance, then dewatering performance is improved, but energy consumption increases
Solution Approach 1:
The patent dramatically reduces the temperature parameter from conventional high-temperature thermal hydrolysis (190-320°C) to low-temperature range (100-140°C), while compensating with pH adjustment to achieve the same dewatering effect with much lower energy input
4Productivity
If high-temperature thermal hydrolysis is used to improve sludge dewatering, then dewatering efficiency is improved, but refractory COD is generated making subsequent treatment difficult
Solution Approach 1:
The patent changes the temperature parameter to a lower range (100-140°C) and combines it with acidic pH conditions (2-4), which effectively breaks down sludge structure and releases bound water without generating the refractory COD that results from high-temperature carbonization
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 high-efficiency sludge dewatering with a solid content of 35-40% in the sludge cake, effective COD degradation, and innocuous utilization of dewatered materials, reducing energy consumption and avoiding refractory COD formation, while using kitchen waste to promote acidification and hydrolysis, thus improving dewatering performance and enabling resource utilization.
Implementation Method 1
anaerobic biological acidification
Implementation Method 2
hydrolysis acidification
Implementation Method 3
low-temperature thermal hydrolysis
Implementation Method 4
centrifugation
Data Source
AI summary
A method for sludge dewatering using kitchen waste to synergistically enhance a coupling of an anaerobic biological acidification and a low-temperature hydrothermal of excess sludge is disclosed. The method includes the following steps: first, uniformly mixing the excess sludge from a sewage treatment plant and the kitchen waste for an anaerobic biological acidification reaction at 36.5-37.5° C. for 2-4 days; then, concentrating the acidified mixture by centrifugation at a speed of 3000-5000 rpm for 5-10 min; performing a low-temperature thermal hydrolysis treatment on a residue obtained after removing a supernatant for 15-30 min at 100-140° C.; and after the thermal hydrolysis treatment is finished, cooling and dewatering to obtain a dewatered sludge cake and a dewatered filtrate. The new method realizes high-efficiency sludge dewatering and innocuous utilization of dewatered filtrate and sludge cake without adding chemical reagents and effectively avoids generating hardly-degradable chemical oxygen demand.