Temperature influences swine wastewater treatment by aquatic plants

Carlos Eduardo Weirich,Élcio Silvério Klosowski,Valdemir Aleixo,Camila Silveira Souza,Aldi Feiden,Clarice Rossato Marchetti

doi:10.1590/1678-992x-2019-0325

Abstract

Studies show that aquatic plants are an efficient alternative to minimize the harmful effects of wastewater. Two species of aquatic macrophytes (Pistia stratiotes and Eichhornia crassipes) were chosen to evaluate the temperature effect on the performance of these macrophytes species in a post-treatment system of swine wastewater. The experiment was carried out in the municipality of Toledo, Paraná State, Brazil. For the experimental system, 24 concrete tanks with 80 L capacity were used, each measuring approximately 1.5 m in length, 0.25 m in width and 0.16 m deep. Wastewater characteristics and variables hydrogen potential (pH), electrical conductivity (EC), and dissolved oxygen (DO) were measured weekly. After, we analyzed the aquatic macrophytes and centesimal composition. The use of aquatic macrophytes was efficient for final swine wastewater polishing. Nitrogen removal showed higher efficiency in the summer period for both species studied. The abiotic variables (pH and EC) presented better results during the winter for both species evaluated. Air and wastewater low temperatures did not influence these variables. Dissolved oxygen presented better results in the summer period for E. crassipes species. There was a significant increase in N and P contents in the plant tissue. This fact proves that the use of aquatic macrophytes is an interesting alternative for swine wastewater treatment.

Highlights

In the last ten years, Brazil has increased its swine production by 3 million tons per year, reaching 3.75 million tons in 2017
The results showed high efficiency in total nitrogen (TN) and total phosphorus (TP) removal by both species evaluated
The highest TN efficiency was observed in the summer, with 88 % removal for Pistia stratiotes and 80 % removal for Eichhornia crassipes

Summary

Introduction

In the last ten years, Brazil has increased its swine production by 3 million tons per year, reaching 3.75 million tons in 2017. Most production is consumed by the domestic market (81.5 %), and the states of Paraná, Santa Catarina, and Rio Grande do Sul account for 68.9 % of pig slaughters in 2017 (ABPA, 2018). This practice is considered by environmental agencies as a potential source of contamination and degradation of air, water resources, and soil (Rasheed et al, 2018). Plants absorb water and nutrients, as well as pollutants, through their roots, acting as a biological filter In this sense, the capacity of these plants can be enhanced with the application of species better adapted to bioaccumulation of specific pollutants (Dudai et al, 2018; Gajić et al, 2018). Its ideal temperature range tends to vary among species and case studies are needed to better understand these dynamics (Geneviève et al, 1997)

Methods

Results

Conclusion