How does leachate form

The kind of thing you might not have even heard about until just now. Well, unfortunately, we're going to have to burst your bubble a bit. This article is going to go over exactly what leachate is, what it does to the surrounding environment, how it's related to food waste and why municipalities are struggling to control it. Leachate is the liquid which leaches from landfills, either through rain run-off, or the organic components of landfill heaps themselves creating leakage.

Landfill sites are supposed to have leachate collection systems, which are often lagoons or closed tanks filled with the grossest possible stink-water you could ever imagine, and an underground system of pipes to collect any liquid generated over the lifetime of the landfill.

However, these collection systems do not always do what they're supposed to. According to the US Geological Survey USGS : " Landfills are often not the final repository for leachate which can be discharged to surface waters following onsite or offsite wastewater treatment.

You know that wonderful Jeff Goldblum quote, from Jurassic Park? Well, this is especially true of human-made systems, such as landfills and leachate collection systems. Leaks happen: the direction of how groundwater naturally flows, as well as the permeability of the nearby soil structure may not always be accounted for, or properly mitigated by leachate collection systems.

Leachate spills and spreading is compounded by irregular weather patterns:. As weather patterns continue to become more and more unpredictable with the complex climate change matrix, these leaks may very well increase in both severity and regularity.

Time alone will tell. Research has shown that 0. Scientific Reports, Leachate, as the name might imply, can leach - or leak - into the surrounding environment. Of particular concern, leachate can enter local water tables and bodies of water. Naveen, J. You might be wondering "what the big deal is". Well, here are some considerations:. When organic materials decompose with proper aeration, such as in composting systems, nitrogen is produced and, in reasonable quantities, can be highly beneficial to your micro-environment.

However, this is not the case with anaerobic environments, where high concentrations or organic waste and lack of air produce toxic levels of ammonia. While most water is treated with chlorine in bustling urban and suburban settings, making it technically safe to drink, chlorine can actually react with some of the compounds found in leachate - ammonia among them. Ammonia is toxic to humans and animals, causing pulmonary irritation and damage to the sinus system and eyes.

If ingested in high enough concentrations, ammonia can be lethal. Leachate contains fecal matter:. That's right. Landfilling will continue for many years yet, and thus leachate generation and its safe disposal without causing pollution, is a problem which is here to stay. Even if all the landfills could be closed, and the creation of new leachate from rainfall falling on open operational landfill phase surfaces, could be stopped today, we would still have to manage the leachate from both the present operational sites,and all the old closed landfills.

There are many thousands of existing operational and closed landfill sites, which will continue to produce leachate for generations. For that reason following good practice in leachate minimisation, collection, treatment and disposal, is a very important part of the job of any landfill operator. Navbar btm of header Home About What is Leachate? Leachate Contamination eBook News New!

Thankfully, we are reducing our reliance on landfills, partly by recycling as much as we can and focusing more on the sustainable use of anaerobic digestion plants that are converting our waste to energy. We are also reducing the number of non-biodegradable products that we use.

However, even if all landfills met these requirements, leachate from old landfills still needs addressing as the problem lingers for many years.

And it is not only landfills that generate leachate. There are many other problems associated with contaminated land in general. There are numerous sites throughout Australia where developers need to overcome leachate problems caused by historical industrial activity.

There are many infamous cases in Sydney alone, where over the last few decades we have had to deal with far more severe pollutants than those found in conventional landfill operations, and there will certainly be a lot more cases in future.

The options available include off-site disposal, discharge to sewers with or, possibly, without pre-treatment, or treatment on-site for environmental disposal or re-use. Off-site disposal is very uncommon due to prohibitive costs unless the landfill is very small. Discharge to sewers may be possible, depending on the site location and infrastructure availability and capacity. The degree to which leachate has to be treated depends on local trade waste legislation.

Leachate from landfill sites contains a variety of different substances, although by far the most significant contaminant is ammonia. Ammonia and other forms of nitrogen occur naturally in the environment, but concentration levels in leachate are alarming. Decomposition of plant, animal and human waste produces ammonia and many household and industrial cleaning products, including disinfectants, also contain ammonia.

Ammonia levels for discharge to sewers vary across Australia. Naturally, discharging into the environment has far more stringent requirements. In fact, 0.