This invention discloses a method for conditioning and dewatering sludge in a water purification plant. Firstly, ultrasonication is used to break up the sludge in the purification plant; then, chemicals are added to re-flocculate the disintegrated sludge; and finally, the treated sludge is treated. Mechanical dehydration. The method for regulating the sludge of the water purification plant in the invention can significantly improve the dewaterability and sedimentation of the sludge, convert the difficult-to-remove internal water into free water that can be easily removed, realize sludge reduction, and reduce subsequent pollution. The cost of mud transportation and processing is simple and easy to implement.
Claims
A method for conditioning dewatering sludge in a water purification plant, comprising the steps of:
Step 1: Use ultrasound to break up the sludge in the water purification plant;
Step 2: Add chemicals and re-flocculate the broken sludge;
Step 3: Mechanically dehydrate the conditioned sludge.
The method for conditioning and dewatering sludge of a water purification plant according to claim 1, wherein the ultrasonic reactor used in step 1 is a slot type ultrasonic reactor, a probe type ultrasonic reactor or a parallel plate near field. Ultrasonic reactor, ultrasonic breaking time is 10~30min.
The method for conditioning and dewatering sludge of a water purification plant according to claim 2, characterized in that: the tank type ultrasonic reactor, the transducer of the reactor are arranged around the reaction tank, and the frequency is a1kHz, a2kHz. , a3kHz and a4kHz, where the values ​​of a1, a2, a3, and a4 are all 25, 40, 68, 80, 100, 125, or 160, with a total of 98 frequency combinations; the input power of the reactor is 0~450W, continuous Adjustable, sound energy density is 23.3~30.0W/L.
The method for conditioning and dewatering sludge of a water purification plant according to claim 2, characterized in that: the probe type ultrasonic reactor has a reactor frequency of bkHz, a value of b is 25 or 40, and acoustic energy. The density is 300~500W/L; the probe is 2.0~2.5cm away from the sludge interface during ultrasonication.
The method for conditioning dewatering sludge of a water purification plant according to claim 4, characterized in that: the magnetic stirring speed of the probe-type ultrasonic reactor is 250-310 rpm.
The method for conditioning and dewatering sludge of a water purification plant according to claim 2, characterized in that the parallel plate near-field ultrasonic reactor has a frequency of c1kHz and c1 in the parallel plate side of the reactor. The value is 25, 40, 68, or 100; the frequency of the lower side of the parallel plate is c2kHz, the value of c2 is 68, 100, 125, or 160; the upper and lower sides constitute 225 kinds of frequency forms of the ultrasonic reverberation field; the sound energy density is 0 ~500W/L.
The method for conditioning and dewatering sludge of a water purification plant according to claim 1, characterized in that the chemical agent in step 2 is a coagulant, a coagulant and a coagulant aid composition or a coagulant Composition with oxidants.
The method according to claim 7, wherein the coagulant is aluminum sulfate, aluminum chloride, ferric chloride, polyaluminum chloride or polyferric sulfate. The coagulant aid is quicklime, dilute hydrochloric acid, activated silicic acid or polyacrylamide; the oxidant is potassium permanganate, permanganate complex agent, ozone or calcium peroxide.
The method for conditioning and dewatering sludge of a water purification plant according to any one of claims 1 to 8, characterized in that the reflocculation and conditioning in step 2 is performed, firstly, rapidly stirring and mixing for 0.5 to 1 min at 200 to 300 rpm. , Then add chemicals, and then 50 to 80rpm stirring and re-flocculation 15~20min, and finally left to settle for 25~30min.
The method for conditioning and dewatering sludge of a water purification plant according to any one of claims 1-8, wherein the dosage of the chemical agent is determined according to the mass of the sludge TSS, and the added chemical agent is used. The mass concentration ratio of TSS to sludge is 0.5% to 1%.
Instructions
Method for conditioning and dehydrating sludge in water purification plant
Technical field
The invention belongs to the technical field of environmental protection, and in particular relates to an ultrasonic pre-shredding and re-flocculation combined dewatering method for sludge conditioning of a water purification plant.
Background technique
In China, more than 95% of water purification plants still use the conventional "coagulation-precipitation-filtration-disinfection" process, and most of the produced sludge is directly discharged into the water body, resulting in secondary pollution of the water body. Water purification plant sludge moisture content is about 95%
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