Patented plant for treatment and recovery of road-cleaning residue (EWC 200303) and similar.
WASTE AND TECHNOLOGY
Road-cleaning residue (identified by EWC 200303) is derived from road-cleaning activities carried out with the use of sweeping machines. Generally speaking, this residue is a complex and variable mix of road waste such as dust, soil, mud and the like resulting from the continuous action of weather and traffic, and seasonal waste such as foliage, branches, sand and the like, produced by weather (or consequential human actions) and limited to particular periods of the year.
This waste is by nature differentiated, as it is collected separately from other municipal solid waste (MSW).
The quantities of such waste are included in the calculation for the percentage of sorted waste, as specified by Italian Legislative Decree 152/2006 as amended and Italian Ministerial Decree of 26 May 2016 “Guidelines for calculating the percentage of sorted urban waste collected”, when such waste, collected separately, is sent for recovery.
The potential average annual production per inhabitant is estimated at 17-22 kg/inhabitant; considering a population of approximately 60 million inhabitants, the potential production of road-cleaning residue is estimated at approximately 1.02-1.32 Mt per year.
Italian Legislative Decree no. 121 of 3/09/2020, Annex 8, point 1, paragraph 2, specifies that “In order to exclude the need to treat road-cleaning residue (EWC 200303), which must be primarily sent for material recovery, it is necessary for product analysis to demonstrate that the percentage content of putrescible organic material does not exceed 15% (including the amount present in screened waste (<20 mm.)”.
Therefore, road-cleaning residue cannot be disposed of in landfills as is, because it is waste for which a tangible and advantageous alternative for recovery and re-use exists, in addition to being subject to criteria, guidelines and the aforementioned legislative decree that prohibit it from being sent to landfill as is, due to its putrescible organic matter content.
THE PRINCIPLES OF THE WASHING PROCESS
Ecocentro Tecnologie Ambientali’s patented road-cleaning residue washing technology is based on the following fundamental principles:
- transfer of pollutants in dissolved, emulsified or suspended form from the treated waste to the processing water.
- separation of solid contaminant particles through sorting processes.
- removal of contaminants transferred from the waste to the water by the physical-chemical processes of precipitation, disemulsification, coagulation, flocculation, molecular breakdown and sedimentation.
- concentration of organic contaminants in silt and separation of silt from recovered materials.
- purification by chemical-physical-biological treatment, filtration, etc. of sludge containing silt and pollutants to maximise recirculation and reuse of purified water.
Systems for the treatment and recovery of road-cleaning residue are available in two standard versions, according to the required capacity:
- Th6 system, guaranteed average annual hourly capacity of 6 tons/h.
- Th11 system, guaranteed average annual hourly capacity of 11 tons/h.
Both system versions are based on the same design principle, differing in the size of the machines installed; the two system sizes cover the majority of requests from public and private customers, as they have been designed on the basis of a cost/benefit assessment based on the optimal catchment areas and the sustainability of the relative works.
We also design and build versions with specific capabilities according to customer requirements.
MATERIALS OBTAINED FROM TREATMENT
Ecocentro Tecnologie Ambientali’s patented systems enable up to 90% of incoming waste to be recovered, resulting in EC-certified quality products and other recoverable categories:
SAND, GRAVEL, SHINGLE
The solid treatment section plays a fundamental role in the process; it is in this section that the washing and separation (and therefore recovery) of the product categories making up the incoming waste take place. The heart of the solid treatment section is the COUNTER-CURRENT WASHING UNIT, a machine registered with a specific patent; the washing mechanisms are based not only on the passage of the contaminant through a solution, but above all on a series of physical mechanical actions, such as friction, abrasion between particles, impact, etc., which are fundamental for obtaining optimal recovery yield and high quality materials. The counter-current water flow inside the machine allows lighter product categories, mainly leaves, fine sand and silt, to be carried away, with the separation of heavier materials, consisting of inert materials of various grain sizes. Organic materials are then sent for further washing and dewatering through vibro-drying and compaction; heavy inert materials are graded, and finer materials are subjected to further cyclone washing and passed through spiral graders. Turbid wash water containing silts, clays and the majority of contaminants is sent to the liquid treatment section.
The purpose of the liquid treatment section is to:
- remove pollutants and silt from turbid processing water.
- purify water through chemical-physical and biological treatments involving activated sludge, filtration, etc. to maximise its reuse in the washing cycle, thus reducing the consumption of industrial water.
In its most complete form, the liquid treatment section consists of the following units:
- chemical and physical water treatment.
- storage and recirculation of treated water.
- biological treatment using activated sludge and secondary sedimentation.
- final purification treatments.
- storage, preparation and dosing of chemical reagents.
The purification efficiency of the liquid treatment section is of fundamental importance both to guarantee effective washing, in order to obtain quality products, and to reduce water consumption, favouring the recirculation of purified water (generally more than 80%).
The sludge treatment section consists of a pre-thickening unit and a mechanical dewatering unit for pumpable liquid sludge from the liquid treatment section.
Ecocentro Tecnologie Ambientali has developed various mechanical dewatering methods, taking into account the constituent characteristics of sludge from road cleaning, which differ significantly from those of common sludge from biological and chemical-physical purification. Due to their specific nature, the treatment section allows for pre-conditioning of the liquid sludge, with highly flexible management in terms of flow rate and dosage, and treatment by filter press and/or centrifuge, specifically designed to maximise dewatering efficiency.
ELECTRICAL SYSTEM AND AUTOMATION
The system sections are interconnected and operate in a fully automatic manner.
The system is equipped with a main electrical panel and sub panels for specific functional units, and all power and signal distribution lines.
The on-board instrumentation, consisting of load cell flow meters monitoring material flow, pH meters, dissolved oxygen meters, liquid and sludge treatment line flow rate meters, pressure and temperatures meters, etc., collects all the operating data required for efficient regulation and management. The main control panel is equipped with a large HMI touch screen panel that is easy and intuitive to use, and which shows the status of all the system units, any alarms, dedicated pages for settings, start and stop sequences, maintenance schedules, etc., which can be remotely mirrored on any device connected to the internet. The plant’s automation system (PLC and operator panel) is set up for interconnection and bidirectional data exchange with any factory management systems customers may use (Industry 4.0 ready).
CERTIFICATION, FUNCTIONAL TESTING AND COMMISSIONING
Once the system has been constructed, functional verification and commissioning takes place; our specialised personnel, all with experience of systems, provide support to the Client during commissioning, adjustment and verification of all performance parameters. This phase is supervised and coordinated by the Ecocentro Tecnologie Ambientali technical department and also includes staff training, with theoretical lessons and operational support.
Once checks have been successfully completed, Ecocentro issues both CE certification of the entire system and all technical documentation necessary for correct operation, and in particular the user and maintenance manual, in accordance with the provisions of the Machinery Directive.
The continuous monitoring of data from the Group’s systems and recovery performance achieved with systems built for third-party Clients allow us to offer contractually regulated and tested performance. We can guarantee:
- average annual hourly waste treatment capacity.
- average annual hourly capacity for turbid water purification for recirculation.
- quality and quantity of wastewater.
- quality of the products obtained (CE certification, compliance with UNI-EN standards for the specific sector of use, performance certification pursuant to EU regulation 305/2011 in accordance with system 2+, compliance with the release test according to Italian Ministerial Decree 05/02/1998 as amended by Italian Decree no. 186 of 05/04/2006)