Treatment of Landfill Leachate by Irrigation and Interaction with Landfill Gas

Abstract

The treatment efficiency of landfill leachate irrigation and the effect of landfill gas addition were investigated in a vegetated compost/gravel substrate by monitoring soil moisture content, drainage water volume and quality in a two years lysimeter experiment. Landfill leachate irrigation exceeding 350 mm increased soil moisture and drainage volumes owing to the deterioration of the vegetation resulting from high sodium chloride inputs. Even so sodium chloride was lost in between the irrigation periods, the total reduction of the landfill leachate volume by irrigation decreased from 71% in the first year to 38% in the second year. Landfill gas addition also increased drainage volumes, but was less pronounced. Twenty-two percent of magnesium was retained under landfill leachate irrigation, while decreasing pH values, redox potential and high initial concentrations in the substrate released calcium, iron and potassium. Ninety-eight percent of ammonium was removed by irrigation, but 44% of the applied ammonium was leached as nitrate after oxidation took place due to a decreased uptake after the vegetation deteriorated. Landfill gas fumigation influenced landfill leachate treatment by decreasing the redox potential and the pH and increasing the drainage water content, which improved the retention of total nitrogen and sulfate, but increased the release of iron, calcium and magnesium. To conclude, landfill leachate irrigation is a valuable treatment option to minimize leachate quantities and remove ammonium independent from the presence of landfill gas if salt accumulation is avoided.

Landfill leachate treatment with willows and poplars – Efficiency and plant response

“…Therefore, irrigation regimes closer to IRR1 than IRR3 would be preferable in clay soils grown with willow, considering the high nutrient concentrations, particularly of organic N, in the leachate. On the other hand, the absolute concentrations of NH 4 -N and total P in the drainage water for treatment IRR3 for willow were not high compared with reported values Jonsson et al, 2004;Watzinger et al, 2006), whereas TOC and Cl concentrations were relatively high compared with previous findings. All the above suggest that the quality of landfill leachate is highly important in minimising environmental risks.…”

“…Scientific studies on the treatment efficiency of such systems show promising results but variable efficiency (Alker, 2002;Dimitriou et al, 2006;Watzinger et al, 2006). Studies from the UK have reported toxicity symptoms in willow plants irrigated by landfill leachate, probably due to its high ionic strength (Stephens et al, 2000).…”

Landfill Cover Soil, Soil Solution, and Vegetation Responses to Municipal Landfill Leachate Applications

“…Estimated total leaching losses of NO 3 –N (Table 7) amounted to approximately 53% of the NH 4 –N + NO 3 –N applied during the 4 yr of this study. Watzinger et al (2006) also found that 44% of the nitrogen applied in landfill leachate, as measured by drainage from zero‐tension lysimeters, was leached as NO 3 –N. In contrast, Bowman et al (2002) reported much lower NO 3 –N leaching from spray‐irrigated leachate (7–11% of N applied), largely as a result of management of their system to encourage denitrification.…”

“…In our study, increased biomass on leachate‐treated areas served as an effective erosion control measure and helped to maintain the integrity of the landfill cover. Excessive applications of high‐conductivity leachate, however, can cause the vegetative cover to deteriorate (Hernandez et al, 1999; Bowman et al, 2002; Jones et al, 2006, Watzinger et al, 2006), reducing its effectiveness as part of the treatment system.…”

Treatment of landfill leachate by irrigation of willow coppice – Plant response and treatment efficiency

“…Similar systems have been tested in the UK, USA, Poland and elsewhere (Bialowiec et al, 2007;Godley et al, 2004;Jones et al, 2006;Zalesny and Bauer, 2007). Some scientific studies on the treatment efficiency of such systems show promising results but variable efficiency (Alker, 1999;Dimitriou et al, 2006;Watzinger et al, 2006). Studies from the UK have reported toxicity symptoms in willow plants irrigated by landfill leachate, probably due to its high ionic strength (Stephens et al, 2000).…”