Treating Leachates from Landfills with Biofilm Processes

A large cause of pollution is from landfills leaching into the soil, groundwater, and surface water. Many landfills that are not managed properly and even ones that are can produce leachate which is polluted wastewater. This wastewater is toxic and can contain hazardous components such as heavy metals. The leachate from landfills causes surface water, groundwater and soil pollution. A study performed by A. Gálvez, L. Giusti, et al. in association with the University of Granada, Spain and the University of the West of England, UK, demonstrated some new ways to control this toxic leachate in order to make landfills cleaner and safer on the environment. The study is called “Stability and efficiency of biofilms for landfill leachate treatment” and it was published in the journal “Bioresource Technology” in 2009.

The purpose of this study was to determine how efficient biological aeration filtrate is for the treatment of leachate. The study concentrated on leachate produced at the Harnfill landfill site in the UK. The study looked at how the leachate from landfills can be treated by a biofilm process. A biofilm is a thin resistant layer of organisms (bacteria) that stick together and form on surfaces. The biofilms are supposed to have a higher resistance to toxic agents and a lower sensitivity to low temperatures, and the study was trying to prove whether this was true or not.

Leachate samples were collected from the Harnfill landfill site and they were brought back to a laboratory for analysis. The leachate samples were put in four identical biological aerated filters and they were tested for biofilm that was forming on them. Some tests were done on the columns to determine what the biofilms could withstand. Some of these tests included testing for the pH, conductivity and heavy metal levels. The columns were also tested under several different temperatures and these included 20⁰C, 30⁰C, 40⁰C, and 45⁰C. The results of the study showed that the biofilm had a high resistance to antibiotic and other toxic agents and it was very adaptable to a wide range of conditions.

The biological aerated filters were found to produce biofilms which reduce the toxins of the leachate. This therefore makes the landfills less harmful for the environment and safer for the people that live near the landfills. Because of the tests done with different temperatures, the biological aerated filters are now known to operate efficiently in temperatures between 20 ⁰C and 45⁰C without showing toxic effects. The study performed by A. Gálvez, L. Giusti, et al proved that using biological aerated filters to remove biodegradable parts of organic matter contained in leachate was a very feasible, cost efficient and environmentally friendly process. As said in the study, “This demonstrates the flexibility of the biofilm process as it is able to treat leachates of different origin and composition.” (Gálvez et al. 2009). This discovery is very important because it will mean that landfills can continue to function without being harmful to the environment and to the society.

Resources
Gálvez, A., Giusti L. et al. Stability and efficiency of biofilms for landfill leachate treatment (2009). Bioresource Technology. 3 June 2009. http://journals1.scholarsportal.info/tmp/2868637342054989626.pdf. Accessed 13 October 2009.