Recovery of recycled aggregates from C&D waste
Construction and Demolition
Management of light fractions
Closed-loop plants with wash-water recovery
Water and sludge treatment plants for the recovery of demolition aggregates
From light-fraction removal to sludge dewatering, Tecnoidea designs and builds complete water and sludge treatment plants for demolition-aggregate recycling, with 45 years of experience in Italy and abroad.
Washing demolition aggregates
Construction and demolition material is not a natural aggregate. It is a heterogeneous mix of concrete, bricks, plaster and mixed aggregates, containing light contaminants such as polystyrene, plastics, wood, paper and plasterboard. These light fractions are not effectively removed by flocculation: they float to the surface, interfere with clarification and can clog the lift pumps.
C&D water-treatment systems require specific process adaptations: a dedicated physical pre-treatment stage, clarifier sizing based on the actual feed characteristics and, in hybrid plants that also treat contaminated soils, the option to integrate chemical and tertiary treatments.
The Tecnoidea solution
The water and sludge treatment process in C&D aggregate-recovery plants
Pre-treatment: removing floating fractions with a static curved screen
The turbid water generated by washing C&D material is laden with light fractions (polystyrene flakes, plastic, wood fragments) that do not settle during clarification because they remain buoyant.
Installing a static curved screen upstream of the water-treatment section addresses this issue: the water passes through the screen, while the light materials slide off to be collected separately. Without this unit, the floating fractions would build up on the surface of the clarifier, interfering with clarification and sludge settling, and potentially clogging the lift pumps.
Clariflocculation: adapted sizing
Once screening is complete, the clariflocculation cycle (reagent dosing and static settling) follows the established scheme used in quarrying plants. The operational difference lies in the sizing: demolition sludge settles more slowly than natural silt, so the clarifier is sized with a larger settling volume to reduce the upflow velocity of the water and provide sufficient residence time. The LEM (sludge-level monitoring) and SADF (automatic flocculant dosing) systems support sludge-discharge control and flocculant dosing.
Sludge dewatering and water recovery
The sludge extracted from the clarifier is stored in the sludge tank, where mechanical agitators keep it continuously mixed and homogeneous, before being pumped to the filter press. Mechanical pressure produces spadeable solid cakes, sent for disposal. The filtrate and the clarified water are returned to the closed-loop washing plant, reducing the water demand. Where the feed material is particularly clay-rich, chemical conditioning with milk of lime may be needed to improve the filterability of the sludge.
Hybrid plants: provision for tertiary processes
Many plants treat not only demolition material but also excavated soil, which may also contain chemical contaminants. In these cases, the plant may require additional units: agitated reaction tanks, milk-of-lime dosing stations and tertiary polishing sections (neutralisation, sand filters and activated carbon filters). Tecnoidea designs the plant from the outset with provision for these expansions, reducing the need for major modifications if the operating scope of the plant is expanded.
Products, plants and technologies for the C&D sector
From aggregate-recovery plants to hybrid systems designed for contaminated feed materials.
Disidratazione fanghi
La disidratazione meccanica rappresenta la fase più importante nella gestione dei fanghi di processo. Attraverso una filtrazione ad alta pressione,...
Discover the technology
Agitatore fanghi
L’agitatore fanghi è l’unità installata all’interno delle vasche dell’impianto con la funzione di omogeneizzare i fanghi. La sua azione previene...
Discover the product
Centralina pallettizzata dosaggio chimici (Serie CPDC)
La centralina pallettizzata Tecnoidea automatizza la preparazione e l’iniezione di reagenti chimici liquidi, come coagulanti, prodotti antischiuma, prodotti ossidanti e...
Discover the product
Chiarificatore dinamico
Il chiarificatore dinamico è la soluzione di chiarifica progettata da Tecnoidea per la gestione di flussi d’acqua superiori agli 800-1000...
Discover the product
Filtropressa a trave laterale
Progettata per la disidratazione meccanica dei fanghi nelle produzioni standard e medie, (con capacità di produzione fino a circa 3.3...
Discover the product
Water & Sludge Pumping
The pumping system transfers turbid water and high-density sludge between the different sections of the plant. Designed to withstand wear...
Discover the technology
Overhead-beam filter press
The Tecnoidea overhead-beam filter press is designed for mechanical sludge dewatering in high-output applications. It separates the water from the...
Discover the productSludge agitator
The sludge agitator is installed inside process tanks to keep the sludge homogeneous. It prevents the sludge from settling naturally,...
Discover the productSludge tank
Tecnoidea’s sludge tank is a dynamic process unit designed to receive thickened sludge from the clarifier and prepare it for...
Discover the product
Single-chamber flocculant unit
A compact solution for low-flow-rate applications. The single-chamber unit is Tecnoidea’s solution for preparing and dosing flocculant in plants with...
Discover the productWould you like to know more about Tecnoidea’s solutions?
Contact usWhy choose Tecnoidea for the C&D sector
Specialist expertise
Since 1981 we have treated aggregate wash water and sludge, adapting clariflocculation and dewatering processes to the specific challenges of C&D materials. Our support begins with testing in our in-house analysis laboratory, followed by a complete range of products for scalable plant solutions that can be expanded as process requirements change.
Advanced process engineering
Our engineering team designs water and sludge treatment plants for the C&D sector as integrated systems. From removing floating fractions to clarifier sizing, from sludge management to process automation: every component is engineered to operate as part of the overall system under actual plant conditions.
Service and operational continuity
We know that an aggregate-recycling plant operates with variable flow rates and demanding production cycles. Our service is structured to support operational continuity through spare parts, scheduled maintenance and remote support.
45
Years of experience in aggregate wash-water and sludge treatment
21
Water treatment systemsfor C&D aggregate-recovery plants designed and installed
References
Tecnoidea Impianti's solutions for Gruppo Gatti S.p.A.
ItalySector Construction and Demolition
Material treated Natural aggregates
Gruppo Gatti S.p.A.
Closed-loop water management and digitalisation in quarry operations
Read the case study
France
Sector Construction and Demolition
Material treated Demolition waste
Sas y care – Mymat
Compact water and sludge treatment plant for aggregate washing
Read the case study
Swiss
Sector Construction and Demolition
Material treated Demolition waste
H2M
Water and sludge treatment plant for washing natural and recycled materials.
Read the case study
Germany
Sector Construction and Demolition
Material treated Demolition waste
Durmin Entsorgung und Logistik GmbH
Semi-mobile, containerised water and sludge treatment plant with closed-loop water recovery.
Read the case study
Our partners
