Analysis of parameters for leachate treatment in a greenhouse system

Abstract

In this paper is presented an approach for landfill leachate treatment using enhanced natural evaporation. Experimental set up considered using a greenhouse pilot prototype placed into the municipal landfill of Puebla city, México. The greenhouse was built with a basement surface enough to place 9 trays with leachate. Treatment follow up was done through the following parameters: air temperature inside and outside the greenhouse; leachate temperature at surface and middle liquid height. Results of the first set of experiments defined a minimal initial liquid height of 20% in respect to the tray height; the 2nd set allowed defining optimal evaporation rate conditions evaluated in respect of a tray placed outside, considered as reference of 100% efficiency (blank), obtained results showed that morning and night processes provided efficiencies up to 2 times the reference; otherwise, afternoon measurements showed similar temperature values inside and outside. In general collected data at winter season provided efficiencies between 82% and 147%, in periods of 24 h, it was observed that higher liquid reductions took place at North, and lower ones at the South positions. Based on these results it was proposed a 20 days experiment, using stagnant (E) and recharge (R) conditions referred to the blank (L), the R process showed greater efficiency (168%) than the stagnant one (158%). Leachate chemical characterization indicates that pH is highly stable; while total solids, chemical oxygen demand, sulfate and chloride exhibit an increase in concentration reaching values of 1.2–2.5 times the initial concentration, phosphate was the only parameter exhibiting a decreasing trend ending with 40% of its initial concentration.