Banca de DEFESA: JOELITHON DE LIMA COSTA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JOELITHON DE LIMA COSTA
DATE: 23/02/2022
TIME: 09:00
LOCAL: Auditório Pós-Graduação em Engenharia Civil on line
TITLE:

Evaluation of Linear Alkylbenzene Sulphonate (LAS) Removal in a Real Scale UASB Reactor and Study of the Influence of Different Electron Acceptors

KEY WORDS:

Anionic surfactant; UASB reactor; Electron acceptor; 16S rRNA gene sequencing; Clostridium

PAGES: 107
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

Linear alkylbenzene sulphonate (LAS) is an anionic surfactant applied in several cleansing and personal care products. Despite its biodegradability, its excess in water resources has resulted in environmental problems. Thus, the present work was divided into two studies aiming to evaluate the anaerobic biodegradation of this compound. The first study aimed to evaluate the removal of LAS in a domestic wastewater treatment plant (WWTP Mangueira). In which two climatic periods (rainy and drought) were evaluated. In each period, samples were collected daily from four points: the influent to the UASB reactor (P1), effluent from cell 2 of the UASB (P2), final effluent from the UASB (P3) and effluent from the polishing pond (P4). The characterization of the sewage for organic matter classified it as diluted sewage with concentrations of 208 and 123 mg/L of organic matter for the rainy and dry seasons, respectively. In the UASB reactor, negative LAS removal efficiency was observed with an average of -30%. While in the polishing pond, a removal efficiency close to 90% was observed in both periods. It was concluded that the rain events influenced the sewage dilution, due to the infiltration of rainwater in the sanitary sewage systems. The increase in surfactant concentration after UASB was attributed to the desorption of LAS adsorbed to the biomass. The second study aimed to evaluate the influence of nitrate, sulfate and iron as electron acceptors in the anaerobic degradation of LAS. For this, 500 mL reactors were inoculated with biomass, nutrients, LAS (20 mg/L) and one of the electron acceptors. The influence of the addition of ethanol as a co-substrate was also analyzed. The influence of nitrate, sulfate and iron was evaluated without and with the addition of ethanol. At the end of the experiment, all treatments showed LAS degradation efficiencies greater than 65%. The treatments without ethanol presented the best results for the degradation of the LAS, being the treatment with iron, with efficiency of 94%, the highest of the experiment. The evaluation of microbial diversity showed that the genera that stood out were Clostridium, in addition to Azospira, Bacillus and Alkaliphilus. From the results, it was concluded that the iron treatment showed the best LAS removal efficiency due to its dual functionality as an electron acceptor and an essential component of cellular enzymes. The evaluation of microbial diversity indicated several genera potentially involved in the degradation of LAS because they presented high values of relative abundance.

BANKING MEMBERS:
Externo ao Programa - 3141471 - FABRICIO MOTTERAN
Interna - 1528727 - SAVIA GAVAZZA DOS SANTOS PESSOA
Externa à Instituição - SHYRLANE TORRES SOARES VERAS - UFPE