Synergetic treatment method of energy-saving dehydration and efficient heavy metal removal of sewage and sludge

A sewage sludge and synergistic treatment technology, applied in dewatering/drying/concentrating sludge treatment, etc., can solve the problems of difficult disposal of sewage, high acidity and alkalinity of wastewater, improve dehydration performance, reduce heavy metal concentration, and reduce organic harmful substances Effect

Active Publication Date: 2014-05-07
ZHEJIANG UNIV OF TECH
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  • Abstract
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Problems solved by technology

The use of various inorganic strong acids and strong alkalis will cause the acidity and alkalinity in the wastewater to be too high, and the final sewage is difficult to dispose of. It is necessary to develop and use new environmentally friendly chemicals

Method used

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  • Synergetic treatment method of energy-saving dehydration and efficient heavy metal removal of sewage and sludge
  • Synergetic treatment method of energy-saving dehydration and efficient heavy metal removal of sewage and sludge

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Embodiment 1

[0021] Primary sludge with a moisture content of 98.7% was mechanically dehydrated by a belt filter press in Hangzhou Qige Sewage Treatment Plant to obtain primary dewatered sludge with a moisture content of 82%. Collect 10kg of primary dewatered sludge and bring it back to the laboratory for refrigeration; 100.0g of dewatered sludge once, add 2.0g of composite additives (HEDTA, oxalic acid and NH 4 NO 3 Mixture with a mass ratio of 17:2:1) is fully stirred and mixed evenly, and the sludge is transferred into the hydrothermal reactor; the stirring motor is turned on at a speed of 100r / min, and then the electric heating is turned on (the actual project can directly pass saturated steam) to make The temperature of the hydrothermal reactor is raised to 160°C, the pressure is at 450kPa, and maintained for 60 minutes. After the time is met, stop the electric heating and cool the reactor; after the reactor cools down, stop the stirring motor and take out the sludge, and use the plat...

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Abstract

The invention provides a synergetic treatment method of energy-saving dehydration and efficient heavy metal removal of sewage and sludge. The method comprises the following steps: mechanical dehydrating crude sludge, adding composite additive which is 1-3 percent by mass of the dehydrated sludge into the sludge; uniformly mixing the sludge and the composite additive, and transferring the mixture into a hydrothermal reactor, reacting for 30-60 min at 150-180 DEG C under the pressure of 400-1,000kPa; cooling after the reaction is completed, filter-pressing and dehydrating by using a plate-and-frame filter press; regulating the pH value of the filter-pressed sludge to 5.5-10 by quicklime and discharging to the outside to serve as soil, or regulating the Ca/S molar ratio to 1.0-1.2 by adding quicklime and carrying out incineration treatment. According to urban domestic sewage and sludge treated by the method, the solid content can be increased, the concentration of heavy metal can be reduced, organic noxious substances can be reduced, applicability of sludge soil utilization can be improved, and emission of incineration treatment pollutants can be reduced.

Description

(1) Technical field [0001] The invention relates to a coordinated treatment method for energy-saving dehydration of sewage sludge and high-efficiency removal of heavy metals. (2) Background technology [0002] Sludge is a solid sediment produced during sewage treatment, accounting for about 0.3% to 0.5% of the treated water (based on a water content of 95%). The wet sludge (85% moisture content) produced by urban sewage treatment in my country can reach more than 30 million tons. Sludge contains a large amount of harmful substances, such as heavy metals, organic pollutants (polycyclic aromatic hydrocarbons and dioxins, etc.), a large number of pathogenic microorganisms, etc., and it is easy to form "secondary pollution". Solid waste that has great harm to human body and environment. Sludge production in the process of urban sewage treatment is increasing, how to safely and economically dispose and utilize sludge has become an urgent problem. Sludge land utilization is a m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/12C02F11/14
Inventor 严密徐璋任建莉胡艳军平传娟钟英杰
Owner ZHEJIANG UNIV OF TECH
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