HYDERABAD: The Hyderabad Metropolitan Development Authority (HMDA) has yet again invited global tenders to clean Hussainsagar Lake. The shortlisted agency was asked to use proven Bioremediation technologies and arrest the odour within 15 days after commencement of the work. Unlike earlier, authorities said that the conditions for onset of the reversing eutrophication process as well as odour minimisation must be specified for the proposed treatment or method.
Accordingly, the window period required for reduction of the algal blooms and odour must be specified. HMDA is particular on the characterisation and quantitative assessment of the bottom sludge in the lake as a result of the bioremediation process during the contract period should be documented by the bidder and reported to the concerned authority.
Despite not providing a permanent solution, the HMDA has been spending about Rs three crore annually. Previously, HMDA entrusted bioremediation of the lake to Matrix Environment Inc for a period of six months by calling global tenders. A Mumbai-based firm started the work in March, 2020 and continued till August. Since the agreement period was only for six months, bioremediation of the lake was stopped.
HMDA has again prepared a new RFP (Request for Proposals) for remediation of the lake and global tenders were invited and duly shortlisted several times in the last three years. The agencies which had taken up the remediation process could not yield the desired result.
However, HMDA authorities claimed that as a part of the Hussainsagar cleaning project, the nodal agency has completed a number of activities like diversion of sewage inflows, STP’s to discharge high quality of treated effluent in the lake, nala improvements in the catchment after completion of the Hussainsagar lake and catchment improvement project (HCIP) in 2013. The lake water’s quality is consistently improving and shows a significant change in the improvement of dissolved oxygen (DO). The biochemical oxygen demand (BOD) values have shown considerable improvement after the interventions.
In this regard, the intervention was carried out to arrest algal blooms, foul smell and improvement of DO for the last three years through various agencies on bioremedial basis. Therefore, in continuation of the ongoing remediation the request for proposal is aimed at identification and implementation of bioremediation techniques for minimising algal bloom formation and odour in the lake.
A senior HMDA official said that unlike previous years, the shortlisted agency should commence the work immediately after the issue of acceptance letter and the process of treatment must be completed within 15 days. The odour nuisance has to be arrested from day 16 during the period of intervention, which is up to six to 12 months