Pro Assist filed two complaints against the tender, on October 18 and 28, which will be examined by the Commission for Protection of Competition, the regulator said in two separate announcements concerning the launch of proceedings regarding the two complaints.
The 1.64 million levs ($929,000/839,000 euro) tender, benefiting from EU funding under Operational Programme Environment 2014-2020, was launched in September.
In July, a tie-up of local companies GBS-Plovdiv, Glavbolgarstroy and EKO-proekt 2000 won the tender for the reconstruction of the WWTP with a 58.7 million levs offer.
The EU-backed tender for the WWTP's reconstruction was launched in March 2018 but took over a year to complete as it was suspended on several occasions due to complaints filed with the competition regulator.
(1 euro = 1.95583 levs)