Landfill is the most common way to eliminate municipal solid wastes. In general, landfills contain a mixture of materials which are highly inhomogeneous, in¬cluding a very high organic component as well as soluble mineral substances. This generates heavily polluted leachates, which arise primarily due to rainwater seeping through the landfill, and from the moisture of the waste itself. Also it can occur from groundwater ingress due to inadequately sealed landfill liners.
This presents significant variations in volumetric flow and chemical composition. Untreated leachate is hazardous to the environment if allowed to enter water systems, forcing government authorities to implement increasingly stringent regulations for pollution control and landfill wastewater treatment.
Normally it is sufficient to treat the landfill leachate to a quality that meets the standards so that it can be discharged to the nearest municipal wastewa¬ter treatment plant for fur¬ther processing. Should this not be possible, it can be necessary to treat the leachate to meet the requirements for direct dis¬charge into a river, stream or lake.
The wastewater has high and variable concentration of dissolved solids, dissolved and colloidal organics, heavy metals and xenobiotic organics.
The leachate is usually of a higher temperature than the groundwater in the area due to exothermal processes inside the landfill and is usually turbid, brown in colour, with a very strong odour.
Over the past 20 years, the Clearfox Team has successfully designed many plants all over Europe.
Drone flight over a FBBR at a landfill site in Germany:
Leachate from landfill
is wastewater which is accumulated on the bottom of a compartment or a landfill. The composition and the hydraulic flow of this water depends on the type of waste which was stored, the annual precipitation and the age of the landfill. Older landfills drain less biodegradable organic matter (BOD/COD relation of zero). Typically pollution can be high in nitrogen concentrations (NH4, N02, N03, various hydrocarbons – often organ halogens, chlorides, sulphates, different heavy metals (i.e. Zn, Cu, Ni, Cr, Cd, Hg, Pb and more)
The wastewater usually shows less turbidly, it has a less brown color and a penetrating smell can be detected. So in short: it is highly polluted, it has fluctuating hydraulics and it requires various process technologies to meet the effluent requirements, according to the local regulations.
AVE – Alte Schanze, Germany is a landfill with production residues (i.e. electroplating, fuel ashes), urban, oily and construction waste. It also has an older landfill section with different harmful residues, dating back to the year 1979.
Out of the landfill there is approximately 200.000 m3 of leachate per year, which is collected and then needs to be treated. The existing landfill leachate wastewater system onsite was not capable of reaching the effluent requirement. A new system required and was put to tender. After a selection period PPU was submitted for engineering, procurement and construction of the main part of the new waste water system.
Why PPU was selected? What are the advantages for the client:
We could offer our standard ClearFox containerized treatment modules. So the complete solution was available from one company. Also we have more than 25 years experience with complex industrial wastewater. The process technology suggested from PPU was validated by external consulting offices. All wastewater treatment modules have been approved externally. Also – our cost/price ration was unmatched in comparison to our competitors all over Europe.
Requirements for the industrial wastewater treatment plant
The selected process technology:
Precipitation, Flocculation, Dissolved Air Flotation, Ozone Treatment, Denitrification, Nitrification, Fuzzy Filtration, Activated Carbon Adsorption. The sludge goes to an existing gravity thickener and it is pressed.
Pictures of the installed system and processes
Precipitation, flocculation lines, saturation lines Chemical treatment for split table matter,pH adjustment, buffering and nutrients adjustment
Ozone treatment Cracking into degradable organics, reducing COD, providing carbon source for denitrification of nitrate, control of nitrite hyperboloid mixer system optional methanol dosing, recirculation BOD from Ozon Circle
Twin Dissolved Air Flotation – DAF Floating of oil, floatable matter, Fine separation of TSS and split flocculated material Sludge discharge into a sludge funnel and pumped to thickening
Control cabinet for connected power 100 kilowatt, touch panels, SCADA System to main unit, Frequency controllers, flow controls, etc
Lamella clarifiers, sludge return and side channel blower battery with splitter
Nitrification reactors, cascades FBR-reactors, the Sea container are outside the building, they are weather protected and insulated
5 independent reactors, flow splitting, manual change between gravity flow for nitrification- denitrifcation as per demand
Fuzzy filtration and activated carbon filters for adsorption trace substances, pesticides and finally polishing effluent as police function
The wastewater can be led through several process steps. These can be like in the pictures above. The process is fully automatic and the daily flowrate, which is depending on the rainfall can be adjusted manually. All steps can be bypassed, and the flow can be reversed by manually switching valves (i.e. if more nitrate in raw water, then first denitrification, then nitrification) The following effluents between the treatment steps are achieved.