With the improvement of people’s environmental awareness, the sewage treatment industry has developed rapidly and the production of sludge has increased significantly. All know the harmful substances in sewage sludge, such as pathogenic microorganisms, parasitic eggs and many other risk factors. At this time, a sludge dryer is needed. Why use a sludge dryer? What is the significance and value of the sludge dryer?
First, introduction to sludge dryer
The sludge dryer quickly passes through the “adhesive phase region” during the drying process. At the same time, the ingenious structure makes the sludge reach the bidirectional shear state during the drying process. The dried sludge is continuously and continuously fed into the feeding port of the dryer by the screw feeder. After the sludge enters the body, the sludge is turned over and stirred by the rotation of the blade, and the heating interface is continuously updated to contact the body and the blade. It is heated sufficiently to evaporate the surface moisture contained in the sludge.
At the same time, the sludge is conveyed in the direction of the discharge port with the rotation of the blade shaft in a spiral path, and the stirring is continued during the transportation, so that the water oozing out from the sludge continues to evaporate. The uniformly dried product is then discharged from the discharge port. The jacketed shell structure is adopted, so that the sludge is uniformly heated at various interfaces inside the machine, the shaft body rotates, the sludge does not churn in the equipment, and the heated surface is continuously refurbished. Thereby, the steaming rate of the equipment is greatly improved, the purpose of sludge drying is achieved, and the low-cost operation of the whole device is realized.
Different materials are selected for different drying processes. It is very important to choose the correct drying process. The single-drum dryer does not dry for the material to make the color of the baked material poor. The sludge is a kind of material that is not easy to dry, so that the dried material is dry and uneven. The DC vortex and AC reciprocating quick dryer make the baked materials have good color and save resources and improve economic benefits.
Second, the significance of sludge dryer
Sludge is a solid precipitation material produced by water and sewage treatment processes. Its main characteristics are: high water content (up to 99% or more), high organic content, easy to rot and odor, and fine particles, small specific gravity, and a gelatinous liquid state. The main sources of sludge are: domestic sewage sludge, industrial wastewater sludge and water supply sludge. The disposal and treatment of various sludges has become a stubborn disease that restricts urban development and urban sanitation.
With the strengthening of energy conservation and emission reduction, the improvement of people’s environmental awareness and the increasing production of municipal sludge, the problem of sludge disposal and development and utilization has become an important issue in environmental protection. The development of sludge drying treatment technology has made sludge agricultural, sludge fuel and sludge incineration possible. The improvement and innovation of sludge drying technology and sludge dryer directly promoted the development of sludge disposal methods, expanded the selection of sludge disposal methods, and made them in terms of safety, reliability and sustainability. More and more reliable guarantees.
In the environmental protection industry, sludge treatment and disposal is still a relatively backward domain. It is also a domain that I urgently need to accelerate. Along with the expansion of the scale of urban sewage treatment, sludge is also produced as a by-product of sewage treatment. According to the average solid content of 0.02% of municipal sewage on a dry matter basis, it can produce 31,400 tons/day of dry sludge. According to the 80% moisture content before sludge dewatering, 157,000 tons of wet sludge is produced every day. In the year of 360 days, the annual production of wet sludge is about 56.52 million tons.
The sludge has complex composition and contains pathogenic microorganisms, parasitic eggs, toxic and harmful heavy metals and a large number of refractory substances. If improperly treated, it is easy to cause secondary pollution to the environment. However, my sludge disposal rate is very low, and the sludge has not been disposed of in a harmless manner, posing a serious threat to the ecological environment.
Third, the value of sludge drying after using sludge dryer:
1. Incineration treatment:
The dried sludge has a calorific value of about 1300 to 1500 kcal. The three tons of dried sludge can be equivalent to 4,500 kcal of coal, which can be mixed in coal to burn in the boiler. The sludge can produce tons of steam. The blending ratio of dry sludge to coal is 100 to 200 kg of sludge per ton of coal.
2. Sludge brick:
It can be added into clay to make bricks with a mass ratio of 1:10. Its strength is equivalent to that of ordinary red bricks, and it has a certain calorific value. During the process of firing bricks, it can spontaneously ignite and increase heat.
3. Biochemical fiberboard:
Under alkaline conditions, a series of physicochemical changes (globulin denaturation) occur after heating, drying and pressurization. The activated sludge resin (protein glue) is made by this denaturation, and the fibers are bonded and pressed. Plate.
4. Admixtures in cement plants.
5. Landfill compost:
Because the sanitary landfill management is not in place, it is easy to produce secondary pollution. In addition, the company has formulated relevant standards and technical policies for sanitary landfill. The water content of the mixed landfill for printing and dyeing sludge is less than 60%, and the transverse shear is greater than 25KN/ Square meters. In fact, the moisture content of the de-cemented cake is more than 80%. The direct landfill treatment has been restricted by the current regulations, and direct landfill is not allowed. The family has increased law enforcement in this regard.
Composting treatment Because organic sludge contains nitrogen, phosphorus and potassium, it is a necessary fertilizer component for crop growth. The crude protein or globulin of the organic component in the activated sludge is a good soil conditioner, and the sludge has stable properties and can be used as a fertilizer, which has agricultural utilization value. But until now, the composting treatment of printing and dyeing sludge in the society is still unacceptable and has not been promoted.
After reading the article, did you find that it is very meaningful and valuable to use the sludge dryer? After the sludge is dried, the sludge becomes waste and the danger is avoided. Waste has become a treasure that can be used.