The bidders for the estimated $60 million-70 million contract are Austria's VA Tech, Generale des Eauxand Degremont, both of France, and Germany's Walter Bau.

TSC is now reviewing the bids before submitting its recommendations to the World Bank, which is part-financing the scheme. A contract award is expected to be announced within three months.

At least six groups of local and international companies in May prequalified and were approved by the World Bank to bid for the design-build-operate project.

In the first phase, the plant will have a capacity of 450,000 cubic metres a day and will serve a population of 2.1 million. During phase 2 of the five-phase development, which will be implemented between 2006 and 2011, capacity will be doubled to cover 4.2 million people. Phases 3-5 of the wastewater scheme will see the expansion of the network and the construction of an additional plant in southwestern Tehran to serve a population of 10.5 million by 2029.

A team of Austria's ILF Consulting Engineers, Kuwait-based KEO International Consultantsand the local Parsconsultwas appointed in 2001 to provide consultancy services and technical assistance to TSC.

A team of ILF and Parsconsult is part of a group of at least five companies bidding for another contract to provide supervision services on the construction of the estimated $44 million eastern trunk main. TSC and the World Bank, which is expected to announce a final decision on the winning proposal in September, are in the process of evaluating the bids.

The award of the contract will be followed by a tender for the construction of the eastern trunk line.

The local Loshan Companylast July was awarded the $22 million contract to install the western trunk line, which stretches over a distance of 23 kilometres. Other local companies have been awarded, and are awaiting the award of, contracts worth a total of more than $200 million for laterals and interceptors. Among the larger contracts yet to be awarded is the construction of an 18-kilometre tunnel with a diameter in the range of 2,000-3,000 millimetres.

Implementation costs of phase 1 of the wastewater scheme are estimated at about $340 million, $145 million of which will be provided by the World Bank. The bank in May 2000 agreed to resume lending to Iran after a gap of seven years and despite US pressure. TSC is providing parallel financing of $195 million.