Background The region of Tilburg in the south of the Netherlands is facing several problems in relation to its water chain. The western parts of the region are drying up, which has negative implications for nature and agriculture. This is further complicated by a large groundwater withdrawal and it is expected that restrictions on the withdrawal of groundwater will be inevitable in the near future. At the same time, the north is experiencing a disturbance in the water balance, while the eastern part has too much water. This over-capacity overflows nature areas such as De Brand where the survival of the vegetation is under threat. The various stakeholders involved in managing the water chain in Tilburg have a common interest in finding solutions to these problems. The ALTWA project was an attempt to organize better cooperation among the stakeholders (water supply company, water board and the municipality). Objectives The ALTWA project was to demonstrate that municipal wastewater could be re-used as process water in two industrial estates (Kraaiven and Vossenberg). The measures planned included: o Building a purification installation for upgrading municipal wastewater. o Setting up a transport and distribution network to the industrial facilities that will make use of the upgraded wastewater. o Monitoring and evaluation of the use of the process water. The expected results included an annual saving of groundwater of at least 1,700,000m3 (expected to eventually expand to 8,000,000 m3). The project was to allow for the supply of cheaper alternative water, intended to be used in various ways: process water, cooling water, firewater, irrigation and infiltration. Benefits were also expected for the environment (for example, prevent the drying up of the landscape), society and the economy as a whole. The results of the project were to be disseminated throughout Europe. Results The ALTWA project has successfully demonstrated the use of pre-treated effluent of a wastewater treatment plant as industrial process water. Demonstrations were foreseen on two locations, however due to organizational difficulties (delay of a permit, replacement of the director of the beneficiary, blocking of investment decisions further to a takeover process), only one of the demonstrations took place (Kraaiven location). As a result of the postponed second demonstration (at the Vossenberg industrial estate) and the delays, the direct savings in groundwater use are much less than expected: 60,000 m3/year instead of 1,700,000 m3 originally foreseen. However, the beneficiary expects that this amount will rapidly increase in the coming years: 160,000 m3 in 2006, 400,000 m3 in 2007. At the end of the project, the beneficiary had four launching customers and negotiations with a fifth customer were ongoing. The effluent purification technique has been implemented successfully and the method of combining filtration techniques to purify wastewater is unique. The purification is done using capillary membranes: effluent is drawn through the membrane fibres in an outside-in flow path under a slight vacuum. The membrane fibres are installed directly in the tank with the water to be purified. The capacity of the system is calculated for 100 m3/hour (two hours per day) and a capacity of maximum 50 m3/hour for the remaining hours. The beneficiary indicated that it would be possible to expand the system in the future to a maximum of 150 m3/hour. The process has a good transferability potential as the resulting process water can be used for many applications (process and cooling water for industrial companies, firewater for the fire-brigade, irrigation water for golf courses and, hydrological purposes to restore water balance and prevent groundwater exhaustion). The only restriction is that a second piping infrastructure has to be installed which requires a considerable investment and may be technically challenging in some situations. The project has been successful in organizing better cooperation among all the parties involved in water management. The water supply company, municipality and the water board decided to form ‘Samen Stromen’, a joint water-chain company.