The European Union's Water Framework Directive states that its “ultimate aim is to achieve the elimination of priority hazardous substances and contribute to achieving concentrations in the environment near background values for naturally occurring substances”. Some of these substances are synthetic organic chemicals that come from industrial activities. A large amount of wastewater containing tetramethylammonium hydroxide (TMAH) is generated each year in Europe by electronics and semiconductor manufacturers. Because of the toxic properties of TMAH, the current limit of 7 milligrams per litre established in the Italian reqion where the Coordinating Beneficiary operates is considered too high for adequate protection of aquatic ecosystems. Industrial streams containing TMAH require further treatment before they can be discharged into drainage systems. Current approaches to treatment of wastewater containing TMAH entail high costs for companies and negative environmental impacts.
The objective of the LIFE BITMAPS project was to establish a pilot plant to demonstrate a new and innovative process for the treatment of effluents from electronics and semiconductor manufacturing. The project aimed to contribute to the implementation of the Water Framework Directive by introducing more efficient treatment technologies that will help reduce TMAH pollution at source. By recycling wastewater, it will also demonstrate the application in practice of the circular economy priority of water reuse and savings in industrial processes. Moreover, in proposing a more efficient, effective and innovative solution for industrial wastewater treatment, the project will contribute to one of the priority areas of the European Innovation Partnership on Water. Specifically, the project aimed to: 1. Design, construct, and validate a pilot plant for treatment of effluent from electronics and semiconductor manufacturing that contains photoresist/TMAH (PR/TMAH), ammonium fluoride solution, and nitric, acetic and hydrofluoric mixed solutions; 2. Demonstrate the use of microorganisms to facilitate TMAH biodegradation; 3. Demonstrate the financial viability of the process using a life-cycle costing method; 4. Demonstrate more-efficient water management and evaluate the reuse of treated wastewater in the industrial plant; and 5. Increase awareness of environmental issues among electronics and semiconductor manufacturers, influencing industrial investments in innovative and safer technologies.
The LIFE BITMAPS project developed an innovative and efficient process for the treatment of effluents from electronics and semiconductor manufacturing, in particular, spent tetramethylammonium hydroxide (TMAH) photoresist solution. This technology is completely new in the industry. The project team demonstrated the feasibility of this aerobic process for wastewater treatment at industrial scale, in the premises of the coordinating beneficiary LFoundry. They successfully validated the prototype. Monitoring has proven the environmental and economic benefits of the process, in terms of efficiency of the biodegradation of TMAH, reduction of the TMAH level in wastewater, reduction of in-site water consumption, and savings in TMAH disposal costs.
The improved treatment of wastewater coming from electronics industry facilities brings a range of environmental benefits. The project team achieved: a biodegradation of TMAH with an overall efficiency target of 99%, in terms of TMAH concentration for the output stream compared to the input concentration; and a reduction of the TMAH level in wastewater by a factor of almost 20 (from 7 mg/L to 0.4 mg/L). By furthermore implementing the upscaling, the project achieved a potential reduction of on-site water consumption by 53% and operational savings from a 100% reduction in TMAH waste disposal costs, halving of the cost of reagents.
The project team proved the replicability of the results in the electronics and semiconductor manufacturing sector, and the economic feasibility of the process. Several technical reports were elaborated to this aim, including a technology overview, investment analysis, variable costs analysis, working capital analysis, overheads analysis, projected revenue analysis, and structure of commercialisation activities.
A White Paper on BAT (Best Available Technologies) for the treatment of spent TMAH photoresist solution in semiconductor industries was elaborated, in line with regulation in force and the requirements of the Joint Research Centre (JRC). More generally, work on the policy front has been stepped up, and legal barriers have been overcome in order to review the concentration limits for TMAH with Abruzzo Region and the Italian Ministry of Environment.
The project results are likely to last after the project end, as the beneficiaries have confirmed to have direct interest to continue the activities implemented. Indeed, an Italian patent related to the process developed has been licensed by three associated beneficiaries. Their intention is to operate under a new spin-off company. The path to commercialization includes provision of research services and design, construction and operation of pilot and/or industrial plants.
Contacts established with the European Semiconductor Industry Association (ESIA), and its other members (coordinating beneficiary LFoundry is a member), and the Italian Association of Chemical Engineering (AIDIC) could favour the uptake of the project’s process. At European level, the project team identified about 40 sites belonging to semiconductor companies who would be interested in the developed technology to treat wastewater.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).