Banca de DEFESA: JOELMA PEREIRA DA SILVA

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STUDENT : JOELMA PEREIRA DA SILVA
DATE: 30/09/2024
TIME: 14:00
LOCAL: sala virtual do google meet
TITLE:

Influence of the type of organic substrate, present in the volumetric organic load, on the production and composition of biogas in a UASB reactor treating sewage from an industrial slaughterhouse

KEY WORDS:

Biogas production; Industrial wastewater; Organic matter

PAGES: 84
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUMMARY:

One of the major socioeconomic and environmental challenges of today is to develop sustainable technologies for energy generation. In this sense, the use of methane generated in industrial slaughterhouse wastewater treatment plants constitutes an alternative source of sustainable energy, since its production in the treatment of this type of industry is high. However, its production depends, among other factors, on the type and quantity of organic matter present in the environment. In view of this problem, this research aims to evaluate the influence of the type of organic substrate present in the volumetric organic load that exerts the greatest influence on the production and composition of biogas in a UASB reactor treating industrial slaughterhouse effluents. For this purpose, a UASB reactor subjected to volumetric organic loads (VOCs) of 0.7 to 2.7 kgCOD/m3.d was used. The influents and effluents of this reactor were monitored by analyzing parameters indicative of the stability of anaerobic digestion (pH, total alkalinity - AT, and its fractions bicarbonate alkalinity - AB and alkalinity due to volatile acids - AAV), in addition to analyzing the Biochemical Oxygen Demand (BOD5), and its filtered (BOD5-filtered) and particulate (BOD5-particulate) fractions, and the Chemical Oxygen Demand (COD) and its filtered (COD-filtered) and particulate (COD-particulate) fractions. The biogas flow rates captured by the phase separator and the compositions of the biogas samples were also determined. From the results obtained, it was verified that the degradability of the organic substrate influent to the UASB reactor was low, since the COD/BOD5 ratio was greater than 2.5. The anaerobic digestion process showed a tendency toward instability, since most of the average values of the AAV/AT and AB/AAV ratios were outside the range considered favorable for anaerobic digestion. Regarding the BOD5 and COD fractions, a slight tendency toward predominance of particulate fractions (BOD5-particulate and COD-particulate) in the reactor influents and of filtered fractions in the effluents (BOD5-filtered and COD-filtered) was observed. When applying the Pearson correlation, a strong correlation was observed between biogas production and VOC expressed as kg. BOD5-filtered/m3.day (rPearson = 0.7 and p-value = 0.02), indicating that even at lower concentrations, filtered BOD5 had a greater influence on methane gas production, which presented wide variability as a function of the variation in the organic loads influent to the reactor. This result suggests that the VOC expressed in the form of COD or BOD5 does not always represent the content of the organic substrate easily available to microorganisms, and therefore, it is more appropriate to consider the filtered BOD5 as a dimension parameter for UASB reactors treating industrial refrigerator effluents to optimize the operational performance of this type of reactor and the collection of methane gas.

COMMITTEE MEMBERS:
Interno - CARLOS WAGNER OLIVEIRA
Externo à Instituição - FERNANDO JOSE ARAUJO DA SILVA - UFC
Externo à Instituição - FLÁVIO CÉSAR BRITO NUNES - UFCG
Presidente - MARIA GORETHE DE SOUSA LIMA BRITO