Asbestos removal project under way
Adcon is to construct reinforced concrete bunded areas at a municipal landfill site.
15 April 2019 | Environment
The Walvis Bay municipal council accepted a proposal by Adcon CC to rehabilitate the hazardous waste site and create more space at the municipal landfill for the disposal of asbestos.
The company will do so at its own cost.
Adcon was approached by Rössing Uranium Ltd and Namibia Environmental Health Consultants to assist in the planning, design and execution of an industrial scale asbestos removal and disposal project at Arandis in 2015. This project included residential and public dwellings.
Extensive surveys indicated a total of 15% of roofs had to be replaced. The rest (85%) needed to be painted with special asbestos binding compounds. Based on the information and rationale, Rössing budgeted an amount to be made available.
Lilo Niilenge, chairperson of the management committee, said a follow-up in depth survey conducted towards the end of 2017 indicated a new ratio of 80% roofs that had to be removed and 20% that could be repainted.
“As a result, the estimated space requirement for disposal of asbestos roof sheeting at the Walvis Bay Hazmat site increased from the original 500 m³ to a new estimate of 2 000 m³.”
It was proposed that Adcon gives a presentation to council on the full details of the project they did in Arandis late last year.
Niilenge said there is currently more than ample space for the Arandis asbestos roof sheeting. The methodology previously used to construct the asbestos cassettes was severely inadequate.
“The existing 220mm brick construction method regularly fails. The walls tend to crack and split open, eventually fall over and previously contained asbestos hazardous materials are then re-exposed.
“The existing bunded area (currently used for both solid and liquid hazardous waste) is the only structure incorporating and containing an impermeable lining at the bottom, which prevents hazardous liquids from seeping downwards and possibly contaminating ground water sources.
“Ideally, large and solid hazardous waste of asbestos sheeting type would be disposed of and contained in structurally sound, reinforced, solid concrete bunded areas. These areas should be located outside the existing lined bunded area, but still within the designated Hazmat boundary fencing. This will allow more space and volume for disposal of liquid type hazardous materials, and extend the serviceability and lifespan of this lined bunded area. It will also create new sound and maintenance free concrete structures for solid waste.”
She said space constraints are one of five major issues identified.
Lack of space
“The projected volume of space required for disposal of the Arandis asbestos roof sheeting exceeds the current available space within the lined bunded area. The historical construction methods used to build asbestos cassettes within above lined bunded area, has failed completely and is therefore not sufficient for that purpose. There are concerns that the current lined bunded areas' life-span will be drastically shortened, should it be used to dispose the Arandis roof sheeting and any other asbestos or solid materials in future.”
It was then proposed that Adcon constructs reinforced concrete bunded of similar type used by major bulk fuel storage sites. Adcon is one of three fully registered and government approved asbestos handling and disposal contractors in Namibia.
The projected disposal cost for the Arandis Project will be approximately N$3 million, to be funded by Rössing as Adcon's client for this project. Proposed remediation works will cost N$3 218 574.80 excluding 15% VAT.
The department compared the quantities and rates of another registered company that specialises in rehabilitation work as set out in the proposal for comparison purposes. Their total cost for the same work was N$4 420 854 excluding 15% VAT.