The county has successfully built a full closed-loop system of “source control – standardized transportation – recycling disposal” and has been selected as one of Chongqing’s first batch of cultivation counties for Beautiful City construction on the strength of its remarkable performance in this field.
As the supplier of the core process scheme and full-line equipment for this project, Jiangsu Keson Environment Technology Co., Ltd. (Keson) draws on its years of technical accumulation and project practice in C&D waste recycling. It has developed a customized dual-stream parallel processing system for both construction waste and decoration waste for the Xiushan project, addressing the challenge of treating complex feedstocks, and realizing high-value conversion from waste to high-quality recycled aggregates. With solid technical capabilities, Keson enables Xiushan green transformation and fulfills its responsibility to safeguard the ecological landscape of this mountainous county.
Anchoring Ecological Rectification Mission to Build a Demonstration Project for County-Level Solid Waste Governance
Located at the border of Chongqing and Guizhou, Xiushan County serves as a gateway city in southeast Chongqing. With the acceleration of urbanization, C&D waste disposal was once a major bottleneck restricting the improvement of local ecological and environmental quality. This project is listed as a key initiative for the rectification of the Central Ecological and Environmental Protection Inspection and serves as a core carrier for Xiushan’s “Zero-Waste City” development, bearing the important mission of upgrading urban infrastructure and enhancing ecological governance capacity.
The project consists of a C&D waste disposal service center and waste landfills, covering a total land area of 1,034.17 mu, among which the disposal center occupies 34.17 mu with a total floor area of 3,727.26 square meters. The total investment is approximately USD 43 million. With a designed annual treatment capacity of about 100,000 tons, the project is expected to reach an overall annual processing volume of over 300,000 tons upon full operation, producing around 250,000 tons of high-quality recycled aggregates per year, which can fully cover the local demand for decoration waste, construction waste and demolition waste treatment.
Innovative Dual-Stream Parallel Process to Tackle Complex Feedstock Treatment Challenges
Construction waste and decoration waste differ greatly in composition and treatment. Traditional projects mostly adopt separate independent processing lines, which lead to redundant equipment investment, a large area occupation and high operating costs. In response to the feedstock characteristics and capacity requirements of the Xiushan project, Keson innovatively adopts a parallel processing technology for construction and decoration waste: after independent pre-sorting on two separate feed lines, the materials share the subsequent crushing, screening and purification systems, and finally produce high-quality recycled aggregates of unified standards. This design truly realizes “one system, two feedstocks, multi-stage purification, homogeneous end products”.
According to the process flow chart, the core logic of the entire production line is divided into four major stages: pre-sorting and impurity removal, multi-stage crushing and volume reduction, precise classification and purification, and recycled aggregate output.
- Dual-feed pre-sorting: Decoration waste and construction waste are fed separately through dedicated apron conveyors, with a designed processing capacity of ≥40t/h per line, meeting the capacity requirement of an 8-hour single shift. The feedstock first goes through a pre-sorting process, where light impurities and irregular materials such as textiles, plastics, wood and large-size components are removed via a manual sorting platform. The effective feed particle size is controlled within 400mm to reduce the load of the subsequent crushing process.
- Two-stage crushing and metal recovery: The pre-sorted materials enter the crushing unit, first undergoing primary crushing by a jaw crusher, then secondary and fine crushing by an impact crusher, achieving step-by-step volume reduction. Multiple stages of permanent magnetic iron separators are installed before and after the crushing section. Adopting high-strength neodymium-iron-boron magnets, they can efficiently recover ferrous materials such as waste steel bars and iron wires from the feedstock, with a metal recovery rate at the leading level in the industry.
- Multi-stage screening and air classification purification: Crushed materials enter the classification and screening unit, where they are classified into different aggregate particle sizes through multi-stage screening by double-deck composite screens and circular vibrating screens. Meanwhile, a horizontal air classifier and aggregate purifiers are equipped to remove light impurities such as residue soil, plastic flakes and wood chips through positive-negative pressure air classification technology, realizing deep purification of aggregates.
- Homogeneous product output: After the full-process treatment, both construction and decoration waste are finally converted into recycled aggregates with uniform particle size and stable purity, which can be directly used in the production of building materials such as masonry mortar, road base, permeable bricks and recycled bricks, truly turning waste into recycled products.
The core advantage of this parallel design is that it retains the targeted pretreatment for the two types of waste while realizing intensive a deep end-processing. Compared with traditional separate line solutions, it can reduce equipment investment by about 30% and area occupation by 25%, while ensuring stable and uniform quality of finished aggregates, perfectly matching the capacity scale and cost control requirements of county-level projects.
Full-Process Equipment Support for Efficient and Eco-Friendly Operation
The stable operation of the Xiushan project relies on the support of Keson’s full range of self-developed equipment. From conveying, crushing to sorting, environmental protection and intelligent control, each piece of equipment is custom-designed for the working conditions of C&D waste, featuring reliability, high efficiency and environmental friendliness.
Core Processing Equipment: Hardcore Strength for Complex Working Conditions
- Crushing system: It adopts a combination of PEW80 jaw crusher and PFW-1010 impact crusher. The primary crusher has a maximum feed size of ≤400mm and a processing capacity of ≥45t/h; the fine crusher can reach a processing capacity of 50–90t/h. The equipment adopts a V-shaped cavity design and wear-resistant lining plates and is equipped with overload protection and soft start functions. It can withstand the impact of hard materials such as concrete and bricks in construction waste and features easy maintenance and stable operation.
- Screening and purification system: The upper deck of the double-deck composite screen adopts a finger screen structure, while the lower deck adopts a flip-flow screen structure, which not only ensures the screening efficiency of large-size materials, but also solves the problem of fine material blockage. The circular vibrating screen is equipped with multi-specification detachable screen meshes, which can flexibly adjust the particle size of finished aggregates. Equipped with two LDF3508 aggregate purifiers and a horizontal air classifier, it achieves efficient separation of light materials and aggregates through multi-stage air classification, ensuring the purity of the aggregates.
- Magnetic separation system: It is equipped with multiple RCYD series permanent magnetic iron separators, with a magnetic field strength of ≥70mT at 300mm distance and automatic iron discharge function. They can continuously remove ferromagnetic impurities during material conveying, and the recovered waste metal can be directly sold for recycling utilization.
Environmental and Intelligent Control System: Digital Operation for Green Low-Carbon Performance
In response to the pain point of dust control in C&D waste treatment, the project is equipped with a full-process environmental governance system. Spray dust suppression devices are installed at the feed hoppers; the entire production line is fully enclosed and connected to a centralized dust collection system, with a single unit air volume of ≥35,000m³/h, a dust removal efficiency of >99%, and an emission concentration of ≤20mg/m³, meeting national and local air pollutant emission standards. Meanwhile, fog cannons and dry fog dust suppression systems are equipped to achieve precise control of fugitive emissions.
In terms of intelligent control, the project adopts a centralized control system of “upper computer + PLC”. All equipment can be started/stopped with one click and monitored in real time in the central control room. It is equipped with 15 HD cameras and a video storage system, realizing full-scene visual operation of the production line. The equipment generally adopts variable frequency speed control, which can dynamically adjust operating power according to feed load, achieving energy saving and consumption reduction while ensuring production capacity.
This technical system is not an isolated design, but a mature solution verified by Keson in more than 80 projects worldwide. The modular production line design and full-chain system integration capabilities provide solid technical support for the Xiushan project, ensuring the solution is both advanced and reliable.
Building a Closed-Loop Governance System to Enable Zero-Waste City and Beautiful City Development
The value of the Xiushan project lies not only in end-of-pipe recycling disposal, but more importantly, in taking this project as the core to open up a complete closed loop of “source control – standardized transportation – recycling-based disposal”, providing a systematic solution for county-level “Zero-Waste City” development.
On the source control part, the local government has established a declaration and filing system for C&D waste, which estimates and registers the waste generation of new construction and decoration projects, and regulates waste flow from the generation to avoid random dumping. In the transportation link, closed and standardized transportation is implemented, with GPS positioning and route supervision to prevent spillage, leakage and illegal dumping during transportation. On the disposal part, the resource-based production line built by Keson fully utilizes all kinds of C&D waste and converts them into recyclable building materials, forming a circular economy chain of “generation – transportation – disposal – recycling – reuse”.
Operation-Driven Continuous Innovation to Fulfill Green Development Responsibility
To date, Keson has delivered more than 80 complete solid waste treatment projects in 17 countries and over 40 regions worldwide, with over 50,000 units of equipment in stable operation, and holds more than 100 patents and multiple industry qualifications. For the Xiushan project, Keson has not only completed the full-process services of design, equipment manufacturing, installation and commissioning, but will also provide continuous technical support and operation and maintenance guarantee for the subsequent operation of the project based on its own operation experience and technical service system, ensuring the long-term stable and standard-compliant operation of the production line.
From the eastern coast to the southwestern mountainous cities, from million-ton capacity urban benchmarks to county-level livelihood projects, Keson always takes “environmental protection, resource regeneration” as its mission, and brings mature C&D waste recycling technologies to county-level regions. The launch of the Chongqing Xiushan project is not only an important node for Keson to expand its presence in the southwest market, but also a vivid practice of the company fulfilling its green development responsibility and helping local Beautiful City construction.
With technology as its pen and equipment as its ink, Keson has written a green answer sheet for C&D waste recycling among the landscapes of Xiushan, Chongqing. Looking ahead, Keson will continue to deepen its dedication to the C&D waste recycling field, continuously iterate its technologies and equipment, and provide replicable and scalable full-chain solutions for more cities and counties, contributing to Beautiful City development worldwide and promoting the green and low-carbon transformation of the whole society.
