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Construction and Demolition Waste Washing System with Increased Mobility through Rapid Coagulation of Turbid Water

Final Report Summary - TURBOWASH (Construction and Demolition Waste Washing System with Increased Mobility through Rapid Coagulation of Turbid Water)

Many industries from construction and mining to shipping and automotive use recycled water. The most widely used methods to treat water enabling it to be recycled involve the use of chemical coagulants. Despite the use of numerous separation stages the chemicals remain in the water and as such lead to inefficiency and safety hazards. Furthermore the cost of chemical coagulants is increasing. Current separation techniques involve the use of large settlement tanks or clarifiers and further processing of solid materials is required to remove excess water. This has proved challenging as hydrophilic chemicals are used in the coagulation stage.

A consortium of European small- and medium-sized enterprises (SMEs) with a rare combination of skills have participated in a project to develop a compact water turbidity removal system with faster water usage through the use of innovative electrocoagulation techniques coupled with novel coalescer and separation technology. The project has investigated problems associated with the use of chemical coagulants in the C&DW water recycling industry by employing combined electrochemical and separation technologies. The novel solution can increase the rate of cleaning and water treatment, removing the requirement for coagulation chemicals and for large volumes of water, significantly enhancing contaminant removal from the construction waste and thus promoting the reduction of harmful chemicals. This offers significant improvements in the performance of construction and demolition waste techniques and will overcome the barriers for their application.

In TURBOWASH, the SMEs and researchers have proposed a combined electrocoagulation and separation system with continuous in situ monitoring and feedback to increase efficiency and quality of water recycling in the EU industry. The overall objective of the TURBOWASH project was to develop and validate an innovative compact water turbidity removal system for effluent from C&DW and primary aggregate processing. The system will provide faster water usage (a 10-15 minute turbidity removal cycle) permitting more efficient and reliable water treatment. The prescribed technology involves the use of electrocoagulation techniques coupled with novel coalescer technology. This will negate the requirement of chemical additions, thereby achieving a purer clay phase suitable for reuse, and lower contamination in the aqueous phase through the inherent chemical oxidation effect of the electrocoagulation process. Furthermore, developing a modular transportable water treatment system, of no more than 15 000 litres, will enable the addition of further treatment applications and wider use by SME's at construction sites, significantly reducing vehicle movements. Scientific and technical objectives include an increased knowledge of the characteristics and performance of construction waste processing technology. The focus is on mixed waste streams contaminated with various materials, where reduced water usage and a fast and efficient water treatment system are of paramount importance.

The project aimed to develop an innovative mobile washing system of 15 000 litre capacity to reduce the waste and safety hazards associated with chemical treatment of water in the European construction and demolition waste (C&DW) industry. The TURBOWASH product is intended to replace conventional wash water treatment processes which involve the use of chemical coagulants and large settlement tanks or ponds. The TURBOWASH system will provide an environmentally-friendly and cost-effective method of treating waste wash water negating the need for chemical additions. The system will be modular in nature, compatible with existing washing technology and easily assembled with the added flexibility of being suitable for variety of waste streams.

The C&DW wash water and electrocoagulation technology has been validated on a pilot basis using two case studies with conditions representing the processing of building rubble, soil extraction deposits and roadway demolition residues. The proposed research and development is therefore pre-competitive. Further development will be necessary to produce an integrated product to gain market acceptance. It is planned that the commercial product will be developed for production within an 18-month period following the project end.

During this time, the group will further undertake targeted marketing surveys and capability analysis to ensure that the manufactured products meet customer needs across the various EU countries. Designs will be standardised as far as possible and made compatible with the manufacturing capabilities of the producing partners in the supply chain. Funding will be obtained as necessary through venture or other sources, having prepared our Investment Readiness case as early as possible using the dissemination and market awareness information gathered during the later months of the project itself.

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