RESEARCH AND DEVELOPMENT
COLOUR REMOVAL WITH FUNGINE BIOMASS
In recent years, Fidia Engineering Srl in Scanzorosciate (BG), operating since time in the field of Industrial wastewater purification, in collaboration with Department of Vegetable Applied Biology at University of Turin, at the Mycoteca Universitatis Taurinensis (MUT), has investigated the biological degradation of some types of industrial waste water through the use of fungal biomass and their biocatalysts.
The research has interested Textile and tannary industries, which generate wastewater among the most difficult to treat, both for the considerable water and organic substances load and for the presence of dyes of difficult biodegradability.
With the only aerobic "classic" biological treatment, the release of colored wastewater is still significant both from the aesthetic point of view that for the perturbative ones for its residual toxicity.
In recent years, many studies have focused on innovative biological approaches, investigating the ability of selected microorganisms to degrade or sequestrate organic and inorganic pollutants in industrial wastewaters.
Fungi have long been recognized for their ability to degrade or adsorb a wide range of recalcitrant compounds, such as synthetic dyes. However, their potential has not found a real application yet, mainly due to the difficulty in selecting organisms able to grow and remain active in very variable and restrictive wastewaters conditions.
Biosorption disadvantages consist of in the biomass production’s cost and in the fact that pollutant is not destroyed, but transferred to the biomass to be disposed The biodegradation instead uses a pool of microorganisms, nowadays mainly bacteria but it is thought also to fungi, to degrade organic pollutants to less toxic compounds up to their mineralization.
Despite the huge amount of research on this topic, there are few applications because most of the experiments have been carried out in very simple conditions. Hence, few microorganisms have been selected in representative conditions of industrial wastewaters.
The difficulty of selecting strains suitable for selected applications (textile and pharmaceutical waters), choosing from more than 900 types of fungi belonging to different species and eco-physiological groups, has characterized the first step of the research that led to the final choice of the microorganisms to be tested. The extensive study on the bioremediation potential of huge numbers of strains has led to the identification of some promising basidiomycetes which present advantages in the biodegradation.
To verify the basidiomycetes behavior with real wastewaters, FIDIA Engineering Srl is testing the selected microorganisms on a pilot scale. Tests are performed with wastewaters coming from textile dyeing cotton processes with presence of reactive dyes together with all other pollutants, especially salts, with the most varied pH conditions.
TEST ON PILOT SCALE
The initial results of the biodegradation experiments, executed with the selected basidiomiceto, demonstrate the ability of the microorganism to degrade most of the dye and to detoxify the treated water.
The tested strain is able to resist and remain active in a wide range of pH and in presence of high concentrations of dyes and salts. The treatment was conducted with fungi immobilized on plastic carriers and using a technique similar to a fluid bed; with INJECTION of air, in order to compensate the oxygen requirement and to give fluidity to the system.
The fungus results effective during several cycles in decoloration up to 80%, remaining active for a very long period in non sterile conditions. This versatile behavior could be explained considering the various and effective enzymatic patterns produced by the fungus in the different conditions.
FIDIA Engineering Srl has already planned a further series of tests to check the technology on a semi-industrial scale, especially with the objective of decoloration of textile wastewaters and detoxification of tannery and pharmaceutical wastewaters.