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Cycle 6 (2017 Deadline)

Evaluation of algal treatment options for olive mill wastewater to produce energy and biofertilizer 

PI: Sami Sayadi,, Center of Biotechnology of Sfax, Tunisia
U.S. Partners: Anthony Siccardi, Texas A&M University and Walter Mulbry, USDA/ARS
Project dates: December 2017 - November 2020

Project Overview:

The conventional olive mill wastewater (OMW) treatment methods adopted in Tunisia are either costly or ineffective,causing environmental pollution. This project is aimed at developing an eco-friendly and cost-effective microalgal-based process for olive mill waste treatment and recycling. Such a process should result in the production of (1) treated and reusable OMW for ferti-irrigation use, contributing to resolving the water scarcity problem; (2) renewable biomass useful for clean energy production, particularly bio gas; and (3) bio-fertilizers for agricultural use, using the process by-products, bio char and sludge.

The goal of this project is to develop an eco-friendly technology for creating a closed loop process with zero waste. It encompasses several disciplines and couples physical and biological technologies to achieve the target objectives, including pyrolysis, physical adsorption, micro algae cultivation with OMW treatment and CO2 mitigation, anaerobic digestion, and composting. The project will also foster linkages among the R&D sector (universities and research institutes) with enterprises involved in waste production (farms and olive mills), enterprises producing devices necessary for treatments, enterprises interested in the use of by-products, and farmers. This approach will create a cooperative network for reducing agricultural waste impacts on the environment, exchanging know-how and market intelligence, and developing research capacity and new markets. In particular, the enterprises will be involved in the demonstration activities of proposed technologies. Through the project, valuable resources that are not currently utilized will be exploited and thus will generate local added value in Tunisia. Such an integrated eco-technology should facilitate the production of biogas from the produced micro-algal biomass for electrical and heat energy generation, as well as biodiesel production, the extraction of high-added-value molecules for cosmetics and nutraceutical applications, nutrient recovery in the form of sludge and biochar for soil amendments, and treated OMW for ferti-irrigation use. This eco-technology will also improve the quality of life for local residents living near the OMW discharge area by reducing the environmental footprint of the existing evaporation ponds, in particular reducing populations of mosquitoes and noxious odors from the ponds.

Beyond the technological aspects, the project will also involve the collection and assessment of data to support decision-makers for the promotion of sound strategies and best practices for social, economic, and legislative measures at the regional and national levels regarding agricultural waste management. It is expected to generate business opportunities and create jobs in small and innovative companies for commercializing the process outcomes. The research team will also strive to enhance the impacts of the project by organizing roundtables and training workshops for farmers to help them better exploit the anticipated research results with regard to ferti-irrigation and soil fertilization.

Recent Activities:

During the first quarter of the project, the PI, Prof. Sami Sayadi recruited two Post Doc Fellows and one PhD student to work on selected R&D tasks. PhD student, Ms Rabeb Naîmi, has been working on Olive Mill Wastewater (OMW) pretreatment using biochar and activated carbon and carried out several tests for the characterization of the adsorption process of organic matter loaded in the OMW into activated carbon in efforts to iidentify the main parameters affecting the adsorption process using batch experimental tests. After these preliminary experiments, she is going to optimize the process with the assistance of the other project members. Ms Rabeb also carried out pyrolysis experiments using a lab scale pyrolysis reactor for the production of biochar from olive dried sludge and olive pomace. She will investigate the uptake capacity of the produced biochar in the adsorption of the pollutant matter of the OMW. Both  engineers involved in the project have launched other pretreatment tests of OMW using the electrocoagulation, the membrane filtration, and the anaerobic digestion of OMW. The project PI also assigned to the first Post Doc Fellow, Dr Ahlem Jebali, the development and investigation of microalgae culture in the pretreated OMW. Ms Ahlem started the cultivation of four microalgae strains on pretreated samples which were provided by her colleagues. She is  characterizing the different cultivation media and investigating the experimental conditions enabling the growth of the strains. The second Post Doc Fellow, Dr. Ines Dahmen, launched microalgae cultivation tests and is investigating their behavior when different stressful conditions are applied. She will also focus on the characterization of the algal biomass as well as the compounds degraded in the OMW and the metabolites produced by the microalgae during its growth.
During the reporting period, project members working in the Center of Biotechnology of Sfax (CBS) conducted eight meetings to discuss the ongoing R&D work, the obtained preliminary results, and the forthcoming activities. In addition,  virtual meetings were held  with the U.S. partners to discuss the main project objectives regarding the treatment of OMW in an ecofriendly way and the production of useful products such as treated water, energy and biofertilizers.  In turn, U.S. partners presented to the PEER team their activities and the main facilities available in their labs with the focus on indoor and outdoor microalgae cultivation reactors which they are using for  treatment of different wastewater streams. The  PI and his team expressed their interest to visit the U.S. partners to explore the facilities and equipment and to learn from their experience in microalgae cultivation in algal turf scrubber reactors. The US partner, Dr Anthonny Siccardi, confirmed his readiness to accept the fellows for performing trainings in the USA during the period from September to November 2018.
A Kick-off meeting of the project  was held at the CBS on March 15, 2018. The project members including the local R&D partners from the National Institute of Sea Sciences and Technologies and Olive Institute, were invited to participate.  The PI talked about the Project importance and relevance and invited all members to work hardly in order to conduct the planned activities properly in the dedicated time and achieve the outlined objectives. Five presentations were presented by the team. The presenters presented their ongoing research work and the obtained preliminary results. Fruitful discussions took place between the audience about the presented results and the future work.
The project team has also prepared a website for the project which will be released in near future. In the coming three months, the members will continue their work on OMW pretreatment and microalgae cultivation in order to achieve the objectives of the WP1. The comparison of the different OMW pretreatment processes invoked above will be carried out. This comparison should result in the identification of the most adequate, feasible and cost effective OMW pretreatment process. The investigation of the suitable and inhibiting conditions of the microalgae growth in pretreated OMW samples will be conducted. The optimization of algal biomass productivity on OMW samples obtained by different pretreatments and the investigation of metabolites produced during the microalgae growth will also be undertaken.

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