Toward Biogas Production from Olive Mill Wastewater (OMWW) and Constructing Anaerobic Lab Scale Bioreactor
Abu Lebdeh, Zain
Abstract Olive oil production is a traditional industry in Palestine; about 20,754 tons of olive oil are produced annually in Palestine. However, Olive Mill Wastewater (OMWW) -which is the black liquid byproduct of the olive oil extraction process- management is a crucial environmental challenge facing the Mediterranean countries including Palestine. Based on previous studies, Co-digestion of OMWW with sludge from the digester in a designed bioreactor under specific conditions provides the possibility to eliminate the OMWW toxicity and produce biogas at the same time. The main goal of this study is to treat the OMWW with sludge at different ratios under anaerobic digestion process at a mesophilic condition with an optimum temperature equal to 37C using a laboratory-scale bioreactor. The project started by constructing and build a laboratory-scale bioreactor. Depending on the economical and qualitative aspects 5 liters in size pressure cooker (four identical pressure cookers) was chosen to be used as a lab-scale bioreactor. Due to the sensitivity of the bacteria and sustainability, stainless steel was considered as a material of construction. The choice of a pressure cooker as a constructed lab-scale bioreactor was basically to perform the digestion process to treat the OMWW samples. Thus, the four pressure cookers were modified in a way to reach the desired construction of the bioreactor. The modifications were done in manner to transform the pressure cooker into a lab-scale bioreactor as follows;¾‶ hole with a PVC pipe was inserted in the led as the feed inlet, a washing nozzle (stainless steel water tap), 2 PVC pipes (¾‶) with 3 elbows were also inserted; lastly, a gas tube was connected with the bike tire for gas collection purpose. The produced biogas will be utilized as the stirring system to prevent bacteria scum. The project work was mostly involved around the construction part as explained above due to the current situations (the spread of Covid-19) but some tests were made to assure that the system is working properly and to check some parameters like leaking and stability. Another test was the cow manure test which was done to confirm the design stability. This project is a continues work for the previous work that was accomplished in the first semester were fresh OMWW samples were collected from Al- Kafryat pressing mill, near Tulkarem and the Wastewater Treatment Plant (WWTP), near Nablus. Characterization of OMWW samples were done based on number of physical and chemical parameters such as chemical oxygen demand (COD), ammonia, total nitrogen, pH and total dissolved solids (TDS). The results that obtained were respectively 60,000 mg/L, 280 mg/L, 630 mg/L, 7.4 and 20,746 mg/L.