Estudio del comportamiento de Eisenia foetida y Schoenoplectus californicus en biofiltros de cáscara de maní para el tratamiento de aguas residuales domésticas

Abstract

The project is intended to assess the Eisenia foetida and Schoenoplectus californicus behavior under the peanut´s shells bio-filters to domestic wastewater treatment (DW). The methodology was based on the analysis of toxicity and continuous tests consisting of nine different bio-filters, evaluating the following three conditions: P bio-filters (plants), L bio-filters (earthworms), and LP bio-filters (earthworms and plants) operated to 0.5, 1.0 and 1.5 m3/m2-day and they used DW synthetic. The behavior of earthworms and plants was assessed by using allometric parameters. Concurrently, the removal of organic matter was tested by using Oxygen Chemical Demand (OCD) and Volatile Solids (VS) measurements. The results of Eisenia foetida and Schoenoplectus californicus acute toxicity are concentrations of LC50=97% (v/v) and EC50=78.7% (v/v) peanut shells. With regard to chronic toxicity of Schoenoplectus californicus, the results showed a significant decline of chlorophyll a and b (NOEC=12,5% y LOEC=25% v/v peanut shells). The behavior of Eisenia foetida and Schoenoplectus californicus under the peanut´s shells bio-filters showed a growth of biomass, density of adult´s, juvenile and coconut earthworms greater than 29g, 3537 indv/m3, 28294 indv/m3 and 3242 coconuts /m3 for Eisenia foetida, while Schoenoplectus californicus showed apical heigth and basal bore growth, chlorophyll a and b greater than 41.8 cm, 10.3 mm, 0.96 mg/g and 0, 31 mg /g, respectively. The greater removal efficiency of OCD and SV was presented in LP bio-filter, operating to 0.5 m3/m2-day, the average values of which were 82,4% and 58,1% respectively.