La Pellofa d’arròs per al tractament d’aigües grises : estudi preliminar en batch de l’alliberament de carboni orgànic i característiques de l’aigua tractada

Abstract

Rice husk (RH) is an agricultural by-product produced in large quantities but currently underutilized. During the last few years, it has begun to investigate its possible uses in different modalities and it has been possible to check its adsorption capacity for some compounds. Reusing RH as an adsorbent can be of particular relevance to ensure the sustainability of nature-based solutions (NBS) for greywater treatment. Its ability to adsorb nutrients, together with the ability to release organic carbon, suggests that it may be a promising material for maintaining colonies of denitrifying microorganisms. In this work, we’ve carried out part of a preliminary batch study of the adsorbent capacity of RH towards nitrates and other compounds, and also of its total organic carbon (TOC) release capacity. To do this, in addition, real gray water has been used. Our results state that RH could be a viable material as a carbon source for use as a substrate in green walls or other NBS. It has been shown to release significant amounts of TOC. However, it has not been possible to determine an adsorption capacity for nitrates. A positive correlation between

TOC, Conductivity and some released ions has also been described. A mechanism has

been proposed to explain these correlations, although specific studies would be needed to

confirm it. A fit analysis of the TOC desorption kinetics has been performed comparing it

with pseudo-first-order and pseudo-second-order models. The fit is good in both models,

but the pseudo-first-order one seems better. Possible lines of research would be the study of

RH directly used in NBS pilot plants, the study of the adsorption or desorption capacity

of nitrates with synthetic gray waters or the analysis of the load of microorganisms in

function of TOC degradation, especially those with denitrifying capacity