Landfill leachate treatment strategies can vary quite considerably subject to the individual challenges on each site as well as relative strengths, composition and volumes of leachate. Cornelsen can assist you in the specification, design, build, installation & commissioning of the most appropriate solution for your site. Naturally, we can thereafter provide operation and maintenance services.
Process Design and Implementation – Based on a minimum of information we will work with our clients to provide a practical and economical process design which will then form the foundation of the project. Each project engagement can range from providing feasibility studies, design layouts and process flows, project management, specification, HAZOP’s, P&ID’s, landfill products and plant support.
Depending upon leachate strengths and ground water volumes, smaller SBR plants or Reed Beds can be installed, only treating a percentage of the gathered leachate and by utilising the collected ground water the discharge can be blended (diluted) before final discharge.
Typical Application – Sequencing Batch Reactor (SBR)
The most common way of treatment is with a Sequencing Batch Reactor (SBR) which acts to eliminate ammonia through biological nitrification and BOD from the raw leachate, plus considerably reduce any COD.
Treatment plants normally consist of three concrete tanks, Feed (raw), Treatment (SBR) and Discharge (treated). As a rule the SBR is normally between 10-14 times larger than the required daily discharge.
The raw leachate is dosed into the SBR (containing activated sludge) for a period while the SBR is mixed and aerated. At the end of the feed period (typically 17 hours) the SBR is aerated and mixed for a further hour to ensure all the raw leachate is treated.
The mixed liquor is then allowed to settle, with the activated sludge (live treating media), settling to the bottom of the tank leaving a layer of clearer treated leachate at the top.
At the end of the settlement period (typically 2 hours) the treated leachate is pumped to the treated tank for controlled discharge to sewer.
A by-product of the biological activity associated with treatment of the leachate is an increase in acidity within the SBR. Caustic soda is dosed periodically to control the Ph level within the tank. Temperature is a key factor in the treatment of leachate, therefore concrete tanks with roofs are recommended.