Navigation Links
Putting a green cap on garbage dumps
Date:11/24/2008

Landfill sites produce the greenhouse gases, methane and carbon dioxide, as putrescible waste decays. Growing plants and trees on top of a landfill, a process known as 'Phytocapping', could reduce the production and release of these gases, according to Australian scientists writing in a forthcoming issue of International Journal of Environmental Technology and Management.

Despite legislative pressures to reduce landfill use, in certain parts of the world it remains the most economical and simplest method of waste disposal.

Biodegradation of organic matter in a landfill site occurs most rapidly when water comes into contact with the buried waste, explains Kartik Venkatraman and Nanjappa Ashwath of the Department of Molecular and Life Sciences, at Central Queensland University (CQU), Rockhampton, Australia. They point out that conventional approaches to reducing this effect involve placing compacted clay over the top of a landfill to form a cap that minimizes percolation of water into the landfill.

Some sites do not attempt to prevent water percolation and biodegradation and instead install gas collection systems to trap the methane released.

The use of clay capping has generally proved ineffective in trials in the USA, the researchers say. The problem being that in arid regions the clay cap dries out and cracks allowing water to easily percolate into the landfill. Equally problematic, methane gas collection is an inordinately expensive option for many Australian landfills that do not reach the methane production threshold to enable efficiency.

Hence, a new technique, known as phytocapping, which involves placing a layer of top soil and growing dense vegetation on top of a landfill, was successfully trailed at Rockhampton's Lakes Creek Landfill not far from Central Queensland University. This research was conducted by Kartik Venkatraman and Nanjappa Ashwath (CQU) in conjunction with the Rockhampton Regional Council and Phytolink Pty LTD.

Selected plant species are established on an unconsolidated soil placed over the waste. The soil acts both as "storage" and "sponge" and the plants as "bio-pumps" and "rainfall interceptors". For an effective site water balance, it is important that appropriate plant species are chosen and the soil depth optimized. As such, the team has investigated the effects of different ranges of species as well as soil depth.

The team's studies of the benefits of a landfill phytocap show that the approach can reduce surface methane emission four to five times more than the adjacent un-vegetated site. They found that a cap of 1400 mm thickness also reduces surface methane emissions 45% more than a cap half as thick.

The team also looked at the effects of nineteen tree species, including acacias, figs, eucalyptus, and other Australian native species, growing in the phytocap to determine which species are most effective at reducing water percolation and methane emissions. The root system acts as a good substrate to methanogens, which oxidizes methane thereby reducing methane emission into the atmosphere.

The benefits of phytocapping include, cutting in half the cost of landfill remediation and providing biodiversity corridors along which wild species can travel. The process also inverts the aesthetic qualities of landfills adjacent to urban communities, and in some cases, introduces economical benefits such as timber and fodder. "The establishment of phytocaps would offer an additional and economical way of reducing methane emission from landfills," the researchers conclude.


'/>"/>

Contact: Kartik Venkatraman
k.venkatraman@cqu.edu.au
Inderscience Publishers
Source:Eurekalert

Related biology news :

1. Department of Energy putting power in the hands of consumers through technology
2. Putting stem cell research on the fast track
3. Duke study pinpoints potential green collar job growth in US
4. MIT: Safe storage of greenhouse-gas carbon dioxide
5. MIT analysis shows how cap-and-trade plans can cut greenhouse emissions
6. Parasite-resistant peppers green alternatives to chemical pesticides
7. Expert recommends town councils to design low-allergy impact green spaces
8. A green future for scrap iron
9. What is really happening to the Greenland icecap?
10. Potent greenhouse gas more prevalent in atmosphere than previously assumed
11. Green tea may delay onset of type 1 diabetes
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/10/2016)... , March 10, 2016 ... new market research report "Identity and Access Management Market ... Audit, Compliance, and Governance), by Organization Size, by Deployment, ... 2020", published by MarketsandMarkets, The market is estimated to ... 12.78 Billion by 2020, at a Compound Annual Growth ...
(Date:3/9/2016)... March 9, 2016 This BCC Research report ... of the RNA Sequencing (RNA Seq) market for the ... instruments, tools and reagents, data analysis, and services. ... of the RNA-Sequencing market such as RNA-Sequencing tools and ... main factors affecting each segment and forecast their market ...
(Date:3/9/2016)... , March 9, 2016  Crossmatch ® , ... enrollment solutions, today announced the addition of smart ... Altus multi-factor authentication platform. New contextual and ... to step-up security where it,s needed most — ... Washington, DC . --> ...
Breaking Biology News(10 mins):
(Date:5/26/2016)... ... 2016 , ... After several promising treatments in Panama using ... of Knowledge in Panama, a 6 year-old Duchenne’s muscular dystrophy patient received his ... following FDA approval of a second application for a single patient, investigational new ...
(Date:5/26/2016)... ... May 26, 2016 , ... FireflySci has ... in leading laboratories all over the globe. Their cute firefly logo has been ... awesome cuvettes, FireflySci makes spectrophotometer calibration standards that never require recalibration. These ...
(Date:5/25/2016)... ... May 25, 2016 , ... ... delegation at BIO 2016 in San Francisco. Located at booth number 7301, representatives ... to answer questions and discuss the Thai biotechnology and life sciences sector. ...
(Date:5/25/2016)... ... May 25, 2016 , ... ... recently became double board-certified in surgery and surgery of the hand by the ... is no stranger to going above and beyond in his pursuit of providing ...
Breaking Biology Technology: