it’s the organic that causes problems in the landfills.
Leachate is the contaminated liquid formed when waste degrades and liquid separates from solids (hydrolyse), but also when rainwater percolates through waste in a landfill or disposal site.
When the leachate trickles through the landfill, it extracts soluble or suspended solid organic and non-organic matter; none by itself is toxic in the beginning. However, inside the landfill, the oxygen is consumed quickly creating an anoxic environment. As the pH value drops the acids can dissolve almost everythingthing resulting in a highly polluted effluent containing organic matter, nutrients, heavy metals, salts, and other contaminants. Due to its significant pollution potential, leachate must be carefully collected, managed, and treated to prevent soil and groundwater contamination. Effective leachate management is therefore a fundamental requirement for sustainable landfill operation and environmental protection.
In Morocco, leachate management represents a major challenge. In 2022, the total leachate stock was estimated at between 2 and 3 million m³, largely due to the high proportion of wet organic matter in household waste (around 70%) and its high moisture content (50–75%). These waste characteristics result in substantial leachate generation, estimated at 200 to 250 liters per tonne of landfilled waste. Leachate is typically a dark, acidic liquid with very high pollution loads, including elevated BOD₅ and COD values (up to 60,000 mg/L and 80,000 mg/L respectively), as well as high electrical conductivity (20–40 mS/cm).
The limited implementation of adequate landfill infrastructure—such as drainage systems and stormwater management—further aggravates the situation. Currently, only a small fraction of leachate is properly treated, and the risk of groundwater infiltration remains significant, particularly at older landfill sites. In addition, retention basins are increasingly reaching saturation, creating a growing operational and environmental challenge to the operator of controlled landfills across the country.
avoiding leachate – an integrated organic waste treatment approach.
generizon proposes a structured solution to eliminate the generation of new leachate at its source.
The strategy relies on a fully integrated organic waste management model, that was developed by generizon, where each waste stream is directed to the most suitable biological treatment process rather than being disposed of in landfill conditions that promote uncontrolled liquid formation. The concept is clear. Coherent. Efficient.
Landfill diversion and treatment pathways:
- Organic Fraction of Municipal Solid Waste (OFMSW) → Plug-flow anaerobic digestion, optimized for high-solids content and minimal liquid effluent generation.
- Source Separated Organic Waste (SSOW) → CSTR technology, ensuring homogeneous mixing, process stability, and efficient biogas recovery.
- Green waste → Aerobic composting, producing a stable soil amendment while preventing excess leachate formation.
generizon has dedicated extensive research and technical development to addressing the risks associated with this hazardous liquid. The philosophy is simple: design systems that avoid leachate generation from the beginning, rather than managing environmental consequences afterward.
leachate treatment.
As the landfill expands, the accumulated volume of leachate increases proportionally. Over time, storage ponds reach their maximum capacity, making intervention unavoidable. At this stage, costly and technically complex treatment solutions must be implemented, often requiring a combination of advanced engineering processes such as:
- Biological treatment systems.
- Physico-chemical treatment processes.
- Membrane technologies such as Reverse Osmosis (RO).
- Ammonia stripping.
- Forced evaporation.
- Thermal treatment (heating or boiling).
These solutions are capital-intensive and operationally demanding, highlighting the importance of preventing leachate generation at the source rather than relying solely on downstream treatment.
generizon provides reverse osmosis containerized systems.
evacuation of leachate from landfill gas wells.
Due to its high organic fraction and significant moisture content, Municipal Solid Waste (MSW) generates substantial quantities of leachate, often representing a large portion of the landfilled mass. Within compacted waste bodies, this leachate can accumulate as “perched” liquids, migrating toward LFG extraction wells, obstructing gas flow, and potentially affecting slope stability.
To address these challenges, robust pumping systems capable of operating under harsh conditions—such as corrosive liquids, high suspended solids, and elevated temperatures—are required to efficiently evacuate liquids from wells. Proper liquid management is essential to convert the landfill into a controlled bioreactor, thereby optimizing LFG production and overall system performance.
generizon provides electrical landfill gas well leachate pumps and complete systems.
injecting some leachate in the landfill.
After many years of evacuating leachate and continuous biogas production the landfill réacteur will start drying out.
Leachate recycling consists of reinjecting a controlled portion of leachate back into the landfill body to keep it moist. The practice is commonly used in bioreactor landfills to enhance moisture distribution, accelerate waste stabilization, and stimulate anaerobic microbial activity, thereby increasing biogas/methane production. While leachate recirculation can reduce external storage volumes and improve degradation rates, it does not eliminate the overall liquid load; it must be carefully managed to avoid slope instability, excess pore pressure, or uncontrolled seepage. As such, leachate recycling is a management strategy — not a definitive solution — and requires proper design, monitoring, and operational control.
injecting some leachate in the AD processes.
In high-solids anaerobic digestion of the OFMSW using a plug-flow reactor, the input material is often contaminated, and the resulting digestate certainly not suitable for agricultural application. In this context, the controlled reinjection of a portion of leachate previously stored from old landfills can be considered a feasible technical option.
This approach treats the leachate biologically within a controlled anaerobic environment while simultaneously enhancing moisture balance and microbial activity in the reactor. As a result, the plug-flow digestion process can achieve higher and more stable biogas yields than conventional landfill gas (LFG) extraction systems, while also contributing to the progressive reduction of accumulated legacy leachate.
leachate in Moroccan landfills.
