Navigation Links
Putting a green cap on garbage dumps

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
Inderscience Publishers

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:
(Date:5/16/2016)... , May 16, 2016   EyeLock LLC ... today announced the opening of an IoT Center of ... strengthen and expand the development of embedded iris biometric ... unprecedented level of convenience and security with unmatched biometric ... one,s identity aside from DNA. EyeLock,s platform uses video ...
(Date:4/28/2016)... BANGALORE, India , April 28, 2016 /PRNewswire/ ... product subsidiary of Infosys (NYSE: INFY ), and ... global partnership that will provide end customers with ... banking and payment services.      (Logo: ... area for financial services, but it also plays a fundamental ...
(Date:4/19/2016)... DUBAI , UAE, April 20, 2016 ... can be implemented as a compact web-based "all-in-one" system ... in the biometric fingerprint reader or the door interface ... requirements of modern access control systems. The minimal dimensions ... the ID readers into the building installations offer considerable ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... ... 2016 , ... In a new case report published today in STEM CELLS ... developed lymphedema after being treated for breast cancer benefitted from an injection of stem ... with this debilitating, frequent side effect of cancer treatment. , Lymphedema refers ...
(Date:6/23/2016)... Andrew D Zelenetz ... Published recently in Oncology ... touchONCOLOGY, Andrew D Zelenetz , discusses the ... is placing an increasing burden on healthcare systems ... With the patents on many biologics expiring, interest ...
(Date:6/23/2016)... Pleasant Prairie, WI (PRWEB) , ... June 23, ... ... sciences consultancy focused on quality, regulatory and technical consulting, provides a free ... webinar is presented on July 13, 2016 at 12pm CT at no charge. ...
(Date:6/23/2016)... 2016 adds 2016 ... its pharmaceuticals section with historic and forecast data ... more. Complete report on the Cell ... 15 companies and supported with 261 tables and ... . The Global Cell Culture Media ...
Breaking Biology Technology: