HYDERABAD: After trying bio-remediation methods, Hyderabad Metropolitan Development Authority (HMDA) has decided to try “remediation” to eradicate the foul smell, stop the growth of algae and improve water quality at the Hussainsagar.
HMDA officials have floated global tenders of Rs 10 crore for the job. The bio-remediation attempted so far is a process that treats contaminants by altering environmental conditions and stimulating growth of microorganisms that degrade pollutants. In remediation, water will be tested and external chemicals used for neutralisation, which could arrest bad odour and improve water quality.
Last year, the HMDA had entrusted bio-remediation to Matrix Environment Inc. for a period of six months after floating global tenders. Matrix reportedly started work in Mar-ch 2020 and continued till August, as the agreement period was for six months. Authorities contended that they terminated the work of Matrix as rainwater expected into the lake in the monsoon would wash away contaminants.
Prior to that, the HMDA floated global tenders and accorded the project to city-based Ezox Environment LLP. Expressing satisfaction over the pilot project, the Ezox, in collaboration with Matrix Environment, a Ca-nada-based firm with exp-ertise in controlling water pollution and removing sediments in water bodies, was given the project.
However, HMDA expressed displeasure with the work and terminated the project. The reason was not disclosed but official sources said that the firm was registered in a mechanic shed at Mir Alam Tank Road opposite the Nehru Zoological Park at Bahadurpura in the city. When asked about this, Param Jyothi, executive engineer, said the HMDA had never agreed to engage Ezox Environment LLP to take up the Hussainsagar cleaning project. The official refused to answer further queries.
In 2018, the Hussainsagar cleaning project was handed over to NACOF, a Bengaluru-based company. It treated the lake water using effective microorganisms (EM) technology, sprayed EM solution and introduced Bokashi balls (EM mud balls) in the lake. The outcome was satisfactory for a while, as the water quality improved. The foul smell reduced while dissolved oxygen (DO) ranged from 3.6 to 6.4 mg/l and biochemical oxygen demand (BOD) ranged between 30 and 36 mg/l. The agreement was signed with the company for 12 months and Rs 3 crore was spent.
However, a heavy downpour brought the condition of the lake back to square one.
HMDA is now going in for “remediation” of Hussainsagar. It invited requests for proposal (RFPs) on March 22 from proven technology companies, which provide in-situ treatment using bio-remediation or equivalent technology to remove algal blooms and minimise odour generated from the water body. The main objective of the project is to reinstate the natural ecosystem and improve water quality by increasing the dissolved oxygen (DO) level.
