Scope
Nantycaws landfill site located near Carmarthen, has been developed
as a disposal facility for domestic, industrial and commercial wastes
arising within Carmarthenshire and neighbouring counties. The site has
been developed in a series of phases. Phase 1 was completed by the former
Carmarthen District Council. Phase 2 and the currently active Phase
3 are run by CWM Environmental Limited, a company wholly owned by Carmarthenshire
County Council. The site is licensed to receive solid waste only, which
can include special or difficult wastes.
Problem
During the summer of 1997, the site started to receive a calcium sulphate
based waste from an industrial site in South East Wales. This waste was
subsequently believed to have been responsible for, or was making a significant
contribution to odour problems at other landfill sites where it had been
deposited in South Wales.
The Environment Agency received the first complaints from
local residents relating to odours in the vicinity of the site in July
1998, some time after the first inputs of sulphate waste. Potential sources
of odours identified by the Agency included (i) hydrogen sulphide gas
emissions due to the breakdown of the sulphate waste, (ii) odours from
accelerated waste degradation due to elevated rainfall and leachate re-circulation
(iii) landfill gas emissions from cells (iv) odours due to leachate storage.
The number of complaints increased during November and December 1998,
and the Agency instructed CWM Environmental Limited to take immediate
action.
Since December 1998 CWM Environmental Limited has implemented
a series of measures to reduce the potential for odours. These have included
reduced re-circulation and increased off-site disposal of leachate, reduced
working faces, extra cover materials for wastes, wells for landfill gas
extraction and the installation of a landfill gas flare. However, even
with these measures, odours could still arise from the leachate and working
faces, and CWM Environmental Limited needed a liquid product that could
be applied directly to the source of the odour.
Solution
In the autumn of 1999, following consultation with Eco Technology Limited,
and laboratory based trials, CWM Environmental Limited took delivery of
200 litres of Super F SFA PLus LCH.
Application Method
The SFA Plus LCH is applied directly to the large 640,000 litre leachate
lagoon in 5 litre doses. (Which represents almost a 1:130,000 dilution
ratio). Dispersion is encouraged through use of a bowser and pumping equipment
to agitate and blow air through the lagoon. A volume of treated leachate
is then taken by bowser to the working face of the landfill and sprayed
directly on to the waste and the surrounding perimeter. In hot weather
conditions the internal working roads are also treated to counter any
malodours.
The SFA Plus LCH has three successful applications; neutralisation
of odours in landfill leachate, on the working face, and internal site
use. The product reacts on a molecular level to bind and neutralise odours
in both liquid and air.
Outcome
The product is applied only when required, and produces immediate results.
If malodours are particularly bad, the product is added to the lagoon
until neutralised and a pleasant odour of Super F remains.
As quoted in a report by Simone Astins of the Environment
Agency published in October 1999 ".... the company (CWM) has conducted
trials with the use of a chemical (Super F) to reduce odours from the
leachate. These trials have proved successful and the product is now being
utilised for larger scale leachate treatment on site". The Agency have
not pursued CWM Environmental Limited again since these measures were
taken, and there has been no further action or complaints regarding malodours
from site.
Mr Mike Lewis (Landfill Manger and COTC holder) has been
very impressed by the product and describes it as "excellent......highly
effective......we will certainly purchase Super F again in the future".
For a selection of case studies
on odour solutions provided by Eco Technology Limited please contact
our team.
