Why is leachate bad? is often asked. The answer is explained here in its potential to pollute, cause fish-kills and make water supplies undrinkable.
Leachate is produced in landfills and it is just about the worst thing landfills do to the environment.
The Bad Impacts of Leachate if it Escapes Landfills (Rubbish Dumps) Into the Environment
Solid waste landfills may cause severe environmental impacts if leachate and gas emissions are not controlled. Leachate generated in municipal landfill contains large amounts of organic and inorganic contaminants.
Leachate may also have a high concentration of metals and contain some hazardous organic chemicals. The removal of organic material based on COD, BOD and ammonium from leachate is the usual prerequisite before discharging the dump waters into natural waters.
As a general rule, it is characterized by high values of COD, pH, ammonia nitrogen and heavy metals, as well as strong color and bad odor. At the same time, the characteristics of dump water also vary with regard to its composition and volume, and biodegradable matter present in the leachate against time. All these factors make leachate treatment difficult and complicated. via sciencedirect.com
Our opinion is that leachate is bad in all the ways mentioned above if it is allowed to flow into the ground or into streams and rivers around the landfill which created it.
Why is Leachate Bad? – More Bad Effects of Polluted Dump Water
Leachate is a genotoxic agent on mammalian cells. Several possibilities were put forward to explain the mechanisms of leachate-induced MN formation during a study.
It was possible that leachate was absorbed into the cells and induced the change of pH within and outside cells, which might affect the activities of enzymes and change the structures of DNA.
A second possible mechanism for leachate-induced MN involved the formation of free radicals, either via autoxidation or by enzyme-catalyzed oxidation of organic compounds in dump water, such as chlorinated and nonchlorinated hydrocarbons, including carbon tetrachloride, chloromethane, chloroethane, chloroethylene, decanoic acid, nonanoic acid, etc.
These free radicals could react with lipids and lead to lipid peroxidation of cell membrane in tissues, causing the breakage of the DNA chain by oxidizing the base in DNA and covalent binding between the product of lipid peroxidation and DNA.
These free radicals could also react with proteins, affect the structures and functions of enzymes, and alter membrane properties. In addition, these free radicals could attack nucleic acids, especially some spots in purine and pyridine, result in base substitution and breakage of DNA, and eventually induce mutation.
Microbial populations in landfill leachate-contaminated aquifers are dominated by bacteria (eubacteria and archaea), as shown by analysis of the phospho lipid fatty acids (PLFAs) (Ludvigsen et al., 1999).
The total number of bacteria reported in landfill leachate plumes are in the range of 4×104–1.5×109 cells g−1 dry weight (dw) and the number of colony-forming units, living cells, are in the range of 60–107 CFU g−1 dw (Christensen et al., 2001).
However, the large variation caused by different analytical methods and the fact that different types of aquifers were studied mask the difference in the number of bacteria inside and outside the plume. The total number of bacteria in the aquifer down-gradient from the Grindsted Landfill (DK) was fairly constant with distance from the landfill, and the ATP content (an estimate of living cells) showed no significant trend (Ludvigsen et al., 1999).
In contrast, the number of living bacteria estimated by the PLFA concentration was higher close to the landfill than further away from the landfill. From the measurements of ATP and PLFA, the viable biomass ranged from 104 viable cell g−1 dw to 106 viable cell g−1dw (Ludvigsen et al., 1999), clearly demonstrating the presence of a significantly viable population. via sciencedirect.com
Leachate in the Bad Old Days of Waste Management
In the bad old days of waste management, it was not unknown for dump water to contaminate groundwater which was an obvious environmental and public health nightmare if ever there was one! Today, however, sites are lined with an impermeable barrier, making them rather like a giant garden pond, to ensure that the it cannot escape and pipes then take it as it collects to special treatment facilities to comply with modern pollution regulations.
Between changes in legislation and the huge upsurge in composting and recycling, the waste management in general and landfilling in particular, has undergone a major step change over recent years.
Although the legacy of previous decades will ensure that methane and the water in landfills will remain potential problems for some years to come at long-standing sites, things are definitely getting better – and that has got to be welcome news for everyone. via recyclingexpert.co.uk
What’s Bad About Leachate: It’s a Liability!
Modern landfills will take hundreds of years to decompose to the point that they are effectively inert and pose no threat to the environment from the escape of leachate.
This suggests that the liability on future generations to monitor, extract and treat, the leachate from large modern landfills for long periods, is likely to be high. This is bad. via leachate.co.uk
Leachate Treatment That Fails to Control Total Nitrogen Content is Still A Danger
Leachate is a by-product of sanitary landfills, and, due to its large concentration of pollutants, it must be properly treated before being discharged. The total amount of it generated by solid waste sanitary landfills has reached 30 million tons per year. Because the waste composition is very complex, with high organic, ammoniacal nitrogen, and salt content, landfill leachate is considered to be a special wastewater].
The amount of pollutants in one ton of landfill leachate is equivalent to the amount of pollutants found in 100 tons of urban wastewater.
Directly discharging dump water into the surrounding environment would cause irreversible harm, especially to groundwater systems.
Conventional sewage treatment leaves behind high concentrations of ammoniacal nitrogen in landfill leachate which can cause the eutrophication of water bodies. Although biochemical treatments are used to reduce the ammoniacal nitrogen concentration to agreed levels, nitrite concentration in leachate can remain high.
Nitrite is a recognized carcinogen; if attention is only given to the control of ammoniacal nitrogen and TN is neglected, the detrimental effects of leachate on the environment could be substantial. Implementing more stringent emission standards for TN in leachate is therefore imperative for countries that want to protect their local environment. via hindawi.com
The Human Health Impact of Leachate Contamination of Groundwater
In evaluating the human health impact of leachate contamination of groundwater, the pathway considered has been direct ingestion of contaminated water.
Faecal coliform contamination of the aquifer was detected as a primary impact, and coliforms were also incubated from some of the leachate samples.
In terms of risk management bacterial contamination is generally easy to deal with, either by boiling or disinfecting the groundwater.
However, the current study has demonstrated that inefficient chlorination of groundwater with a high organic loading, possibly dump water derived, can give rise to the production of trihalomethane compounds (THMs), some of which are recognised as being both toxic and carcinogenic.
Although this finding may be of only minor or no concern in a well-managed end-of-pipe treatment system, it may constitute a hazard in other situations. via semanticscholar.org
So, leachate is bad for all of us if it gets out of the landfill and spills into the environment around any landfill.
Why Leachate is Bad for Us and the Planet – Conclusion
Why is leachate bad… Well, now that you have read this article you should know just how has the potential to pollute, cause fish-kills and make water supplies undrinkable.
If the landfills are all built as Sanitary Landfills and the leachate is either treated of disposed of responsibly (say by trucking it to a large sewage Wastewater Treatment Works for treatment) the leachate can be prevented from escaping to the environment.
Unfortunately, that is expensive and it not only needs to be done properly, the treatment of that dump water may be needed for over a hundred years after the landfill closes.
The question is who will keep on treating it for so long? Where will they get the money to treat it in 50 or 100 years time?
Making leachate is bad, we are convinced of that. For this reason, all communities should seek to stop landfilling and recycle as soon as possible.