Nutrients Removal from Aquaculture Wastewater by Biofilter/Antibiotic-Resistant Bacteria Systems

Nicoleta-Oana Nicula,Ortansa Csutak,Ioannis A. Ieropoulos,Gimi A. Rimbu,Eduard-Marius Lungulescu

doi:10.3390/w14040607

Abstract

The presence of nutrients in aquaculture water bodies causes serious problems for aquatic ecosystems, requiring the development of technical solutions to reduce their amounts. This work identifies some bacterial strains that are able to reduce nutrient quantities and studies the effect of antibiotics on bacterial growth, on the ability to form biofilms on different solid supports, and on the ability to reduce nutrients in aquaculture wastewater. Bacterial biofilm adhesion on different substrates depends on the surface properties of the substrate, on the bacterial types that form the biofilm, but also on biofilm–substrate interactions. The obtained results revealed the high capacity of biofilm-forming bacterial strains of Pseudomonas aeruginosa and Chromobacterium violaceum to eliminate up to 87% of nitrate and nitrite ions and up to 62% of phosphate ions in the presence of concentrations of 0.1–0.4 µg/mL of oxytetracycline antibiotic from aquaculture wastewater.

Highlights

In the last two decades, global human fish consumption increased rapidly to meet the demands of the growing population
It results in eutrophication of aquatic ecosystems with adverse effects, such as the accumulation of organic carbon, the reduction of light penetration, and loss of submerged aquatic vegetation, producing an imbalance of nutrient ratios that create conditions, such as oxygen depletion, which are favorable for toxic algal blooms [8]
The reduction of nitrate concentrations in synthetic culture media is explained by the fact that both types of P. aeruginosa and C. violaceum strains are denitrifying bacteria, using nitrogen in specific metabolic processes, participating in the elimination of this nutrient from the aqueous environment [51]. These results indicate that the studied biofilters are effective devices in fixing bacterial mass capable of consuming nitrates from water and can be used successfully in practical bioremediation applications [48], providing a degree of nitrate reduction of about 86% [52]

Summary

Introduction

In the last two decades, global human fish consumption increased rapidly to meet the demands of the growing population. Quality, the reduction of the fishery resource, as well as the increase of water treatment costs [11] Their removal is usually performed by sedimentation, followed by sand or mechanical filtration. Reducing the volume of water used by combining recirculation with the addition of oxygen is a way to improve water usage and reduce the volume of spent effluent discharged into the environment because of improved treatment efficiency [12]. Under these conditions, water treatment system operations could be minimized, reducing the capital and operating costs [13]

Methods

Results

Conclusion