What Is Leachate?

So you want to understand what leachate is? You would be surprised how many people ask that question by seeking the answer from the world wide web. This is why we've created this article to clarify what family or friends might feel you ignorant of, and even stupid for wondering about what they might think was obviously a foolish issue.

An advantage of the world wide web is that you can ask these questions on virtually any topic, and on every occasion without worrying that your buddies think about what you ought to know already about what you are discovering.

So, I want to now get on with giving an answer to your issue about what leachate really is.

First, leachate can be defined as: the liquid (mostly water) which having passed through a mostly solid substance or mixture of substances picks up on its way substances which can be both liquid and solid particles, and runs out at the bottom.

To make that more clear, here is a listing of where leachate may appear, as follows:

- landfill leachate (also known as tip leachate and dump water)
- compost leachate (sometimes called compost tea)
- manure heap leachate.

This really is a bad smelling list, so let's make an effort to de-stress he issues. It may be labeled into the following kinds of leachate,as follows:

- Fresh and smelly leachate is "acetogenic" leachate
- Older leachate from landfills which are a number of years old and is call "methanogenic" leachate, as it comes from methane gas producing landfills which produce landfill gas

The key of such are:

- in the age and the degree of odour which is much worse in the new leachates.

The unique attribute is the fact that leachate is a highly organically contaminated liquid which even in small quantities can harm streams and rivers and make groundwater undrinkable if leachate contaminated water is present in a well.

The important matter, is to recollect about leachate is that it is best to take measures to make sure that making it is avoided, because once a lot of it has been produced it is expensive to dispose of without damaging the environment.

Since you have checked this article out, and have read it to the end, you clearly needed to understand a lot more about leachate, which we hope we will, have aided, you with. As a result of this research you may quite prudently have applied the services of the world wide web wisely to answer a very specific query that it is vital that you at this time resolve. Now, it is possible for you to compliment yourself for what you have learned. By training ourselves, every one of us can obtain greater results in life, and now we undoubtedly desire that you'll do well, as well.

Realize easy methods to minimise, and then if necessary treat, landfill leachate by going to our landfill leachate web site at leachate.co.uk/main.

Can Landfill Leachate be Treated by Anaerobic Digestion?

Every now and again the question of whether landfill leachate can be effectively treated by Anaerobic Digestion is raised.

My reply is yes, and in fact, it has already happened in the landfill before you usually see most leachate. After an initial aerobic (acetogenic) stage, modern landfills in effect become anaerobic digesters themselves. Once this has occurred the leachate produced has already been subjected to a form of anaerobic digestion, so there is little additional treatment which an AD Plant can provide to these mature leachates once leachate is removed from the landfill.

In a modern Municipal Solid Waste (MSW) landfill. as it is filled, each cell or area within it, will within 6 months to one year, or, at the most eighteen months, not only become airless, but methanogenic (methane producing). Once this happens, the decomposition process taking place in the landfill is broadly similar to, but slower than, that which occurs in an anaerobic digester.

So, modern lined and well regulated landfills these days do, almost without exception, produce a mature methanogenic leachate.

As a result the use of Anaerobic Digestion to treat landfill leachate is not normally a good choice and the use of the Anaerobic Digestion process to treat landfill leachate is not very effective. This can be readily deduced just by thinking about the processes which leachate undergoes within a landfill. The big problem with using AD on a mature leachate would be the lack of significant reduction of ammoniacal nitrogen in the discharge, and ammoniacal nitrogen is one of the most important contaminants to remove, for reduced toxity to water life.

However, the opposite does work. Now think of using aerobic reactors to treat Anaerobic Digestion concentrates, if these concentrates cannot for any reason be disposed as a fertiliser product and thus have to be treated as a waste material.

So, leachate treatment plant aerobic biological reactors can be used very effectively to treat AD liquid digestate, if that "product" ends up proving to be unsaleable locally. Indeed, on site aerobic digestate treatment might be essential in these circumstances if no sewage treatment works was available to accept tanker loads of liquid from an AD Plant.

New UK Environment Agency Statement on Leachate Irrigation

There has been a gap in the information provided by the UK environment Agency since last year when the BAT Guidance for leachate treatment was publised on the web site www.environment-agency.gov.uk .

The whole area of leachate treatment by irrigation, which is still practised in the UK at a few landfill sites, and which is used to a much greater extent in Europe generally, was until now without any guidance.

To a certain extent that gap has been closed by the position statement published in February, which can be read here.

The regulatory position statement covers the application of treated landfill leachate to short rotation coppice (SRC), but the principles described would presumably also apply to other forms of irrigation (eg grass plot).

In other EU countries, including Scandinavia (which is normally seen as exemplary in their application of environmental controls), the rules are much more relaxed as follows:-

- They allow untreated leachate to be irrigated to short rotation coppice (SRC)

- They allow irrigation not only during soil-moisture deficit periods, but also in many cases when there is not a soil-moisture deficit, so in Europe such schemes entail run-off during irrigation from the irrigated area during wet weather.

- They do not require the base of the irrigated area of treated landfill leachate to short rotation coppice (SRC) to be engineered and to have a barrier to prevent any loss to groundwater, as this is prohibitively expensive for such an otherwise inherently low cost process.

The question has to be asked that if the UK Environment Agency (EA) consider that the EU regulations such as the EU Groundwater Directive, and the EU Landfill and Waste Management Directives require them to take this position, why are not the other EU states applying equal stringency?

Finally, the position statement makes no reference to the dilute leachate which emerges from many old landfill sites in large volumes, where often a lack of original engineering design allows the leachate to become extensively diluted by groundwater.

These old leachates are often very dilute in nature, yet still environmentally damaging, and the techniques which would be applicable under BAT to these would hardly be those which would be applicable for a strong leachate from a WM Licensed or Permitted site. Yet there is still no UK EA guidance on BAT for these examples of leachate.

In my view the effect of this interpretation of the EU regulations will be that the potential opportunity for the nutrients from leachate, which could otherwise be used to water and fertilise extensive use of willow coppicing, much of which in turn could be used for biomass energy production, will be lost.

If it can be done elsewhere, as it is being done, with proper scientific monitoring and control, it should be possible to do this within the UK.

We would be pleased to receive your views - comment on the leachate blog or email me steve.last[at]virgin.net with your views, which if suitable and with your permission, we would like to publish. See also www.leachate-irrigation.com .