Sludge resource recovery method based on hydrothermal treatment of digested sludge

A technology for hydrothermal treatment and sludge digestion, which is applied in water/sludge/sewage treatment, sludge treatment, biological sludge treatment, etc. It can solve the problem of digestive system inhibition, energy and volume waste, and insufficient nitrogen and phosphorus resources. Recycling and other problems to achieve the effect of improving the system degradation rate and methane yield, improving dehydration performance, and reducing the amount of dosing

Inactive Publication Date: 2017-05-31
TONGJI UNIV
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Problems solved by technology

However, the existing thermal hydrolysis pretreatment + high-solids sludge anaerobic digestion process also has the following problems: (1) part of the energy and volume of the thermal hydrolysis system is wasted in hydrolyzing easily degradable organic matter, (2) sludge Thermal hydrolysis can be used to dehydrate directly without adding chemicals, but the dehydration performance of biogas residues will be relatively poor after thermal hydrolysis sludge is digested. (3) The stability and quality of anaerobic digested sludge will be improved with the development (4) A large amount of nitrogen and phosphorus resources in sludge have not been effectively recovered
This method mainly adopts the post-thermal hydrolysis process, which greatly improves the energy utilization efficiency, but does not consider the dehydration of biogas residues and the recovery of nitrogen and phosphorus resources, does not make full use of the hydrothermal effect of thermal hydrolysis, and contains high ammonia nitrogen. B

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  • Sludge resource recovery method based on hydrothermal treatment of digested sludge

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Effect test

Embodiment 1

[0039] The solid content of the dewatered sludge in the urban sewage treatment plant is 20%, and the VS / TS is about 55%. The dewatered sludge and the digested sludge are mixed and tempered by the dewatered liquid filtered by the plate and frame. In theory, the thermal hydrolysis reflux pressure The filtrate reflux can dilute the solid content of the feed to about 15%, and the hot water pressurized steam can heat the feed sludge to about 60 °C. Below 10, the pulped sludge is pumped into the medium temperature digestion system for efficient methane production, the digestion temperature is 35±1℃, and the residence time is 15-20d. The solid content of the digested sludge is about 12%, which can be directly treated by thermal hydrolysis. The hydrothermal temperature is 120 °C and the time is 60 minutes. Because the sludge has undergone anaerobic digestion, the easily degradable substances have been degraded, reducing thermal hydrolysis. System volume and energy consumption. After t...

Embodiment 2

[0041] The solid content of the dewatered sludge in the urban sewage treatment plant is 15%, and the VS / TS is about 60%. The slurry sludge enters the high temperature acidification section at 55°C. Since the sludge contains a large amount of reflux dissolved organic matter, the residence time can be shortened to 2d, and the acid can be produced efficiently in a short time. Then it enters the medium temperature methane production reactor at 35°C, and the residence time is 14d. The methane production process is basically completed. Compared with traditional anaerobic digestion, the residence time can be greatly shortened and the reactor volume can be reduced. The digested sludge is treated by thermal hydrolysis, the solid content is about 10%, the hydrothermal temperature is 175 °C, and the hydrothermal time is 30 minutes. After treatment, the sludge viscosity can be reduced to less than 1 / 10 of the original sludge. After the partial cooling of the thermally hydrolyzed sludge, ...

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Abstract

The invention discloses a sludge resource recovery method based on hydrothermal treatment of digested sludge. The method comprises the following steps: performing dehydration treatment on sludge so as to obtain dehydrated sludge with the solid content of 15-20%; mixing the dehydrated sludge and a press filtrate in which nitrogen and phosphorus are removed in a slurrying and tempering reactor, preheating, slurrying and tempering; pumping the sludge subjected to slurrying and tempering into an anaerobic digestion system so as to produce biogas; introducing the sludge subjected to anaerobic digestion into a pyrohydrolysis reactor for performing hydrothermal treatment, relieving pressure and cooling after pyrohydrolysis so as to obtain a mixed solution, and performing plate-frame pressure filtration dehydration so as to form high-dryness biogas residues; regulating the pH value of the press filtrate to 9-11, adding a magnesium salt to produce struvite so as to realize phosphorus recovery; regulating the pH value to 11-13, and performing ammonia stripping, thereby realizing nitrogen recovery; and refluxing the press filtrate in which nitrogen and phosphorus are removed back to the slurrying and tempering reactor, mixing with the dehydrated sludge, and performing cycle treatment. The method disclosed by the invention has the advantages that the sludge degradation rate and methane yield are effectively improved, and nitrogen and phosphorus resources are recovered.

Description

technical field [0001] The invention relates to the technical field of solid waste recycling, in particular to a sludge resource recovery method based on hydrothermal treatment of digested sludge. Background technique [0002] With the development of urbanization and sewage treatment in our country, a large amount of surplus sludge is produced and needs to be safely treated and disposed of. As of March 2016, my country has built more than 3,910 urban sewage treatment plants, with a sewage treatment capacity of 167 million cubic meters per day, and an annual output of 30 million to 40 million tons of municipal sludge (with a moisture content of 80%). However, due to my country's lagging sludge treatment and disposal technology, imperfect management and laws and regulations, there has always been the status quo of "heavy water and light sludge". 80% of sludge is dumped and disposed of irregularly. Promote sludge treatment and disposal. [0003] According to research, about 60...

Claims

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Application Information

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IPC IPC(8): C02F11/12C02F11/00C02F11/04C02F11/10
CPCC02F11/00C02F11/04C02F11/10C02F11/12Y02E50/30
Inventor 董滨杨东海胡崇亮王有晴戴翎翎戴晓虎
Owner TONGJI UNIV
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