BIOSTIMULANTS AND BIOREMEDIATORS: CONCEPTUAL DIFFERENCES AND APPLICATIONS IN BIOLOGICAL WASTEWATER TREATMENT

Abstract

The biological treatment of wastewater depends on the metabolic activity of microbial communities capable of degrading organic and inorganic compounds present in the medium. The maintenance of efficiency in these processes can be compromised by variations in load, presence of toxins, nutritional deficiencies, or hydraulic shocks. In this context, the use of biostimulants and bioremediators emerges as a biotechnological alternative for the restoration and optimization of microbiota. This article presents a comparative analysis between these two types of products, addressing their operating principles, compositions, mechanisms of action, and practical applications in the treatment of sanitary and industrial wastewater systems.

1. Introduction

Biological wastewater treatment systems such as activated sludge, anaerobic reactors, and aerobic biofilms rely on the ability of microorganisms to degrade organic matter and transform nitrogen, phosphorus, and sulfur compounds into more stable and less polluting forms. However, the stability and efficiency of these systems depend on intrinsic factors (microbial population, functional diversity, and nutritional balance) and extrinsic factors (temperature, pH, organic load, oxygenation, and presence of toxic substances). When disturbances occur in these conditions, biomass efficiency decreases, resulting in increased BOD, COD, and TSS in the treated effluent. To correct such deviations, biotechnological support tools are used, particularly biostimulants and bioremediators.

2. Biostimulants: Concept and Mechanism of Action

Biostimulants are formulations composed of organic and inorganic nutrients, vitamins, amino acids, trace minerals, and sources of carbon, nitrogen, and phosphorus. Their main function is to restore the nutritional balance of the biomass and stimulate the metabolism of the microorganisms already present in the system.

Biostimulants act as metabolic cofactors and energy supplements, promoting increased respiration rates, protein synthesis, and cell replication. Correcting the C:N:P ratio is one of the most relevant effects, as these elements are essential for microbial biomass development.

The use of biostimulants is recommended in situations of gradual decline in biological efficiency, low enzymatic activity, temporary organic overloads, or nutritional deficiencies. Operationally, biostimulants do not introduce new bacteria but enhance the performance of those already present, functioning as a metabolic reinforcement for the microbial ecosystem.

3. Bioremediators: Concept and Mechanism of Action

Bioremediators are biological products containing live, selected, and concentrated microorganisms, typically in the range of 10⁷ to 10⁹ CFU/mL. These bacteria—often from the families Bacillaceae, Pseudomonadaceae, Enterobacteriaceae, and Lactobacillaceae—are chosen for their ability to degrade specific organic compounds such as oils, greases, proteins, starches, surfactants, and hydrocarbons.

The application of bioremediators is based on the concept of targeted inoculation. Once introduced into the system, the microorganisms colonize the medium and establish communities capable of acting synergistically with the native microbiota. These strains generally exhibit high resistance to environmental variations, production of specific extracellular enzymes, and the ability to adhere to solid substrates, favoring biofilm formation and system stability.

Bioremediators are indicated in cases of partial or total biomass loss, toxic shocks, startup of new systems, effluents containing recalcitrant compounds, or recovery of collapsed systems.

4. Comparative Discussion

The main conceptual difference between biostimulants and bioremediators lies in the type of biological action exerted in the treatment system: while biostimulants enhance the metabolism of existing bacteria, bioremediators reintroduce active microorganisms to reestablish ecological balance.

5. Final Considerations

Distinguishing between biostimulants and bioremediators is essential for proper biotechnological management of wastewater treatment systems. The former act preventively and in maintenance, promoting metabolic balance within existing microbiota, while the latter have a corrective and restorative function, reintroducing essential organisms for organic load degradation.

Author: Éverton L. Petronilho, Technical Commercial Specialist

References 

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