Biogas is one of the most attractive renewable resources due to its ability to convert waste into energy. Biogas is produced during an anaerobic digestion process from different organic waste resources with a combination of mainly CH₄ (~50 mol/mol), CO₂ (~15 mol/mol), and some trace gasses. The percentage of these trace gases is related to operating conditions and feedstocks. Due to the impurities of the trace gases, raw biogas has to be cleaned before use for many applications. Therefore, the cleaning, upgrading, and utilization of biogas has become an important topic that has been widely studied in recent years. In this review, raw biogas components are investigated in relation to feedstock resources. Then, using recent developments, it describes the cleaning methods that have been used to eliminate unwanted components in biogas. Additionally, the upgrading processes are systematically reviewed according to their technology, recovery range, and state of the art methods in this area, regarding obtaining biomethane from biogas. Furthermore, these upgrading methods have been comprehensively reviewed and compared with each other in terms of electricity consumption and methane losses. This comparison revealed that amine scrubbing is one the most promising methods in terms of methane losses and the energy demand of the system. In the section on biogas utilization, raw biogas and biomethane have been assessed with recently available data from the literature according to their usage areas and methods. It seems that biogas can be used as a biofuel to produce energy via CHP and fuel cells with high efficiency. Moreover, it is able to be utilized in an internal combustion engine which reduces exhaust emissions by using biofuels. Lastly, chemical production such as biomethanol, bioethanol, and higher alcohols are in the development stage for utilization of biogas and are discussed in depth. This review reveals that most biogas utilization approaches are in their early stages. The gaps that require further investigations in the field have been identified and highlighted for future research.

The Adrar region (Algeria) has a total of 397,800 date palm trees (Phoenix dactylifera L.). Due to annual palm cleaning, large quantities of lignocellulosic biomass are produced. Depending on the variety, an average of 65 kg of biowaste is obtained per palm tree. Since the value of this biowaste is underrated, most of the palms are burned outdoors, causing air and visual pollution. This work explores the gasification potential of lignocellulosic waste from date palms (Phoenix dactylifera L. Takarbouche variety) into useful energy. The technology investigated is air updraft fixed-bed gasification, thanks to an originally designed and built reactor, with the capability to process 1 kg of feedstock. Four types of palm waste—namely, palms, petioles, bunch, and bunch peduncles—are first characterized (bulk density, proximate analysis, fixed carbon, elemental composition, and calorific value) and then used as feedstock for two gasification tests each. The syngas produced for the four date palm wastes is combustible, with an outlet temperature between 200 and 400 °C. The operating temperature inside the gasifier varies according to the feature of the biomass cuts (from 174 °C for the peduncles to 557 °C for palms). The experimental setup is also equipped with a cyclone, allowing for the recovery of some of the tar produced during the tests. Finally, the results show that the residence time has a positive effect on the conversion rate of date palm waste, which can significantly increase it to values of around 95%.

This work aimed to study anaerobic digestion of a new substrate made from the waste of Algerian date palm (Phoenix dactylifera L.) in order to evaluate its biogas production capacity. The lignocellulosic component biodegradability and the process stability were also tested. Two reactors were launched with the same concentration of 20g total solid (TS)/L. A physical pre-treatment (grinding) of dried leaves lowered the substrate size below 2 mm. The theoretical methane yield (499 - 538 mL CH₄/g of Volatile Solids (VS)) indicated a high substrate methanogen potential. The tested methane and biogas yield reached 130±6 mL CH₄/gVS and 197±6 mL/g VS respectively. The biodegradability through the volatiles solid reduction was 29%. The total alkalinity (TA) value increased from the beginning to the end, due to the substrate nature which gave a high buffering capacity of the medium. During the stable process, a higher Chemical Oxygen Demand (COD) removal was reached with a value of 77.58%. The majority of the biogas yield was generated during the same period, which confirmed that the anaerobic digestion process stability is indispensable. Finally, this study was an opportunity to better exploit local by-products for the bioenergy production.

The pollution of water resources by hazardous contaminants is a major obstacle to the provision of safe and potable water worldwide. Cost-effective, innovative, renewable, and environmentally friendly technologies are essential for wastewater treatment. In the current work, the potential of using raw date palm petiole (DPP) for the removal of Bezaktiv Marine S-BL (SBL) dye is investigated under a wide range of experimental conditions in batch mode. Experimental results show that the removal of SBL dye by DPP is highly dependent on contact time, initial pH, initial dye concentration, and temperature. The removal of SBL dye is relatively rapid where the equilibrium state is reached within a contact time of 120 min. Moreover, the biosorbent exhibits high stability in SBL adsorption ability over a wide pH range (4–12). Furthermore, the SBL dye adsorption increases with increase in initial concentration. The maximum adsorption capacity of the SBL dye on DPP is evaluated to be 110 mg/g, which is much higher than numerous other materials. In addition, a thermodynamic study indicates that the adsorption of SBL dye by DPP is a feasible exothermic and spontaneous process. The findings of the present study indicate that untreated DPP wastes can be considered effective materials for the treatment of textile dyes in wastewater in general and SBL in particular.

In this paper we studied the start-up of an underground digester with a useful volume of 4 m3 in Saharan medium. 320 kg of waste taken from Adrar city slaughterhouses were treated during 60 days. During this study, we followed several parameters evolution such as: pH, volatile fatty acid (VFA), the temperature inside the digester, chemical oxygen demand (COD), pressure and the volume of biogas produced. The results obtained showed in the beginning of anaerobic digestion a fast drop in the pH. The VFA variation was inversely proportional to the pH variation. We noted a temperature decrease inside the digester during hydrolysis phase. Biogas inflammability was obtained since the 25th day of digestion. The results showed also an organic mater reduction in order of 49%.