Sewage sludge solutions

SEWAGE SLUDGE INTRODUCTION

Sewage sludge, or named municipal sludge, is a by-product of the municipal drainage system. It is mainly derived from urban drainage systems, including sludge from drainage pipes, pumping stations and sewage treatment plants. Its characteristics are high water content, perishable, and strong. It has a large amount of pathogenic bacteria, parasitic eggs, heavy metals such as chromium and mercury, and toxic and harmful carcinogens that are difficult to degrade, such as polychlorinated biphenyls. If these sludges are not removed from the sewage treatment system in time, the effect of sewage treatment will be affected. In severe cases, the sewage treatment plant will be shut down; and the random disposal and stacking of sludge will cause secondary pollution to the surrounding environment. At present, how to properly handle the sludge problem has become an urgent problem for most local governments in China.

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CURRENT SITUATION

The problem of sludge treatment is to solve the problem of continuously decreasing water content. The current common treatment methods include deep dewatering, composting, digestion, etc. The final disposal includes land use, incineration, and landfill. Landfill is the simplest method, and the technical difficulty is low. However, sludge containing water perecntage of 60% and 80% can not be landfilled, and soil mechanics risks such as landslide and settlement may occur. Therefore, it is necessary to carry out sludge dewatering treatment for landfill sludge. Incineration is a common practice at home and abroad. Sludge can be burned alone or in combination with domestic garbage, coal-fired power plants and cement kilns. However, inadequate disposal, secondary pollution transfer, high cost, etc. are the drawbacks of various methods.

Analysis of sewage sludge disposal technology

Sludge rotary kiln co-processing

The solid waste that meets or meets the requirements for entering the kiln after pretreatment is put into the cement kiln, and the clinker production is carried out while the solid waste is disposed of harmlessly. The high temperature of the existing cement production line kiln is used.

(1) Attention should be paid to safety issues during processing.

(2) Large investment.

(3) High operating costs.

(4) There are high requirements for the composition and processing capacity of garbage.

Anaerobic sludge

Hydrolysis (conversion of particulate matter into soluble compounds), fermentation, methanogenesis.

(1) Large investment and high cost.

(2) There are security issues.

(3) A large amount of biogas residue is generated and needs to be processed again.

(4) Methane gas is difficult to incorporate into the municipal pipeline network.

Aerobic composting of sludge

Use straw and other auxiliary materials to reduce the sludge hydration rate to 60%, increase the gap to reach the required CN ratio, and continue to supplement oxygen, and 25 to 80 days of alcoholic humification.

(1) The composting process generates a lot of odors and pollutes the surrounding environment.

(2) High operating costs.

(3) The sludge quality is unstable, and the heavy metals are difficult to stabilize.

Sludge incineration

The main equipment is in the shape of a tower, with a perforated plate at the bottom. The heating medium sand is placed on the plate as a combustion bed. The tower is lined with refractory materials.

(1) Large investment and severe corrosion to the boiler.

(2) High maintenance costs.

(3) Exhaust gas emissions have a great impact and are prone to produce harmful gases such as Erniying.

Sludge sanitary landfill

Mixed with landfill.

(1) Easy to pollute water and atmosphere.

(2) The floor space is large and there are hidden safety hazards.

Rotary kiln drying

Use coal or natural gas to dry sludge.

(1) High operating costs.

(2) High-temperature drying is easy to produce odor.

(3) There are hidden dangers.

 Stabilizing agent

Add lime and other solidifying agents to the original sludge, and produce a chemical reaction with the sludge to release a lot of heat and reduce the moisture content.

(1) The sludge cannot be reused, only landfill.

(2) High operating costs.

Plate and frame secondary filter press

Dilute the sludge by about 90%. After adding the agent, perform secondary pressure filtration.

Add a lot of chemicals to increase the dry weight of the sludge.

What can we do for you？

LCDRI is seeing various problems encountered in sludge treatment. After years of research, it has formed a patented product, sludge carbonization and retorting furnace. The sludge carbonization dry distillation furnace equipment always follows the design concept of “advanced application, safe and reliable, economical and reasonable, low consumption and energy saving” in the process of equipment development. The designed treatment capacity is 48t/d (the sludge moisture content is 20%), and the sludge carbon is produced. Granular or sludge ceramsite, can adapt to 0.5~2 times design yield change to achieve “a set of equipment, two kinds of processes”, complete the first set of equipment development and standard demonstration in China.

The core innovation of the equipment is to produce both sludge ceramsite and charcoal activation treatment. The equipment is adapted to different processing requirements by computer to produce two qualified products: sludge ceramsite and activated carbon. Adopt advanced computer control system, fully realize unmanned production, adopt advanced thermal flow field analysis, develop high-efficiency gas-solid heat exchange equipment, greatly improve heat exchange efficiency, reduce heat consumption, reduce power consumption, and apply to pollution In the mud resource comprehensive treatment device; research and development of efficient and safe sludge carbonization and calcination special combustion device; research and development of safe sludge carbonization sealing device; research on exhaust gas mechanism and performance after sludge carbonization and calcination, and develop efficient and safe exhaust gas Processing equipment to achieve clean and environmentally friendly production; study different states and requirements of the same processing equipment in sludge carbonization and calcination of ceramsite, adaptability, achieve non-stop switching, fully realize computer automatic adjustment; sludge input can be realized The change is 0.5~3 times; the investment is equivalent to 15%-20% of the two production lines of sludge ceramsite and sludge activated carbon; using the calorific value of the sludge itself, no external fuel is consumed in the production process.

At present, the system has obtained 2 invention patents and 5 utility model patents. The successful application of the system equipment has filled and broken the technical gap in China’s sludge pyrolysis and carbonization utilization. Compared with the current international advanced sludge pyrolysis carbonization equipment, the system is more energy-efficient, more efficient and safer. More automated. The successful application of this system equipment has enabled China to upgrade its sludge utilization and harmless treatment to a new level!