Physical and chemical characterization of sewage sludge with different proportions of diatomaceous earth

Fabíola Mendes Braga,Mário Henrique Cardoso Barbosa,Regynaldo Arruda Sampaio,Ely Sandra Alves Oliveira,Claudiana Barbosa Dos Santos,Izabelle De Paula Sousa

doi:10.1590/0034-737x202067010011

Fabíola Mendes Braga, Mário Henrique Cardoso Barbosa + Show 4 more

Open Access

https://doi.org/10.1590/0034-737x202067010011

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Journal: Revista Ceres	Publication Date: Feb 1, 2020
Citations: 1	License type: CC BY 4.0

Affiliation: Universidade Federal de Minas Gerais

Abstract

ABSTRACT The use of residues for agricultural production is an alternative for the achievement of sustainability. When mixed with diatomaceous earth (DE) from biofuel filtration, sewage sludge (SS) plays an important role as soil conditioning agent. As a result, the objective of this work was to make a DE vermicompost at different proportions: 0; 7.53; 15.06; 22.59 and 30.12% v/v in relation to a SS pre-compost (PC) and gardening pruning residues. The experiment was carried out in 100-L containers in a randomized block design, with 5 treatments and 5 replications, in which Eisenia foetida earthworms were used in the pre-composting and vermicomposting processes. After four months, the physical characteristics of the vermicompost were analyzed. It was verified that the diatomaceous earth can be vermicomposted, even when soaked in biofuel oil, at amounts of up to 30.12% v/v, with no visible physical damage to earthworms and plants, and this proportion of DE reduced the concentration of nutrients, but improved the physical properties of the vermicompost, making it an excellent physical conditioner for use as a substrate of plants and fertilization of soils.

Highlights

As a final product of sewage treatment plants, a byproduct called sewage sludge (SS) is generated
The organic matter content of the substrate decreased by 6.34 dag kg-1 as the addition of diatomaceous earth (DE) to sewage sludge and pruning residues to vermicompost was increased (Table 2)
Because it is rich in silica compounds of low solubility in water, DE contributed to the increase of the insoluble mineral residue of the substrate

Summary

Introduction

As a final product of sewage treatment plants, a byproduct called sewage sludge (SS) is generated. This byproduct is considered of great agricultural potential due to its physical and chemical attributes (Caldeira et al, 2013). Vermicomposting is only one of several techniques that can be used to stabilize the SS and provide its use in agriculture. This technique is able to reduce the amount of viable eggs of helminths, using the enzymes and other mechanisms of the digestive process of the earthworms, which confers a result with excellent efficiency (Nascimento et al, 2013). In addition to the attempts to make SS feasible in agriculture, CONAMA Resolution 375 indicates criteria and methodologies for the use of this residue, by means of maximum limits and other precautions that must be followed for its correct use (Brasil, 2006)

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