Treating Landfill Leachate: A Case Study
Leachate

In the water/wastewater business, leachate refers to the water that passes through a landfill, accumulating many pollutants from the waste. Leachate collects in the bottom of the landfill, where it’s pumped out and then treated. Leachate can be a tough waste to treat, as a client of ours recently found out.

The client in question is a landfill in Kentucky. The landfill recently had a wastewater plant constructed to treat its leachate. After construction, the treated effluent water from the treatment plant met most of the permit limits, including BOD, TSS, pH and ammonia, but the Whole Effluent Toxicity (WET) test is where it failed. This test entails putting treated wastewater into a container, and (here’s where things get really wild) adding fish and water fleas to the water. If too many die, the water is considered toxic and fails the WET test.

Because the treated leachate is not meeting all of the permit limits, it can’t be discharged to the receiving stream, forcing the client to spend tens of thousands of dollars each month to haul its treated leachate to a municipal wastewater treatment plant for further treatment.

LDG was recommended to the client by a wastewater microbiologist that was helping them with operation of their treatment plant. After considering several options, we recommended an ultrafiltration and reverse osmosis process to solve the problem. To test our recommendation, we conducted a bench scale test. We sent a sample of the landfill’s treated leachate to Dynatec, a manufacturer of wastewater membrane treatment systems. Dynatec treated the sample using ultrafiltration and reverse osmosis, then sent the treated sample to be WET tested. The sample passed.

The next step is to do an on-site pilot test. This involves Dynatec setting up a small version of the ultrafiltration and reverse osmosis system at the client’s landfill, treating the leachate on-site, and WET testing it before installing any permanent equipment. We anticipate that the project will be complete by the end of this year, and that our client will finally be able to discharge their treated leachate.

As we mentioned before, treating leachate is difficult, and our client’s dilemma is all too common. If you’re a landfill with a leachate treatment problem, visit our water/wastewater page to find out how we can help. http://www.larsondesigngroup.com/services/waterwastewater-engineering/

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