The determination of usage opportunities in various fields of spent coffee grounds

Within this project, espresso and filter spent coffee grounds (SCGs) that were supplied from Starbucks® branches and SCGs that were obtained with the preparation of Turkish coffee in different ways which was purchased from Kurukahveci Mehmet Efendi and Mahdumları were used. Firstly, the contribution of wet SCGs to the development of various living plants as soil conditioner and the use of in the agricultural field with planting of different grains and seeds were investigated. C, H, N amount of SCGs was determined by elemental analysis device that is Kaiyuan CHN 2000 model. Later, wet SCGs that they contain moisture the ratio of 60-65% was dried in the temperature range of 50-70 ? C. Subsequently, dried SCGs were extracted in different solvents (acetone, n-hexane, 2-propanol, chloroform, methanol/petroleum ether, dichloromethane) by Soxhlet extraction, were evaluated in terms of amounts of oil and properties (free fatty acid, fatty acid composition, amount of unsaponifiables, iodine index). It was observed that the amount of obtained oils ranged between 11.8-25.05%, values of iodine index ranged between 33.91-76.59, content of free fatty acid ranged between 2.14-11.72% depending on the type of the solvent. The amount of unsaponifiables is less than 1% for all oil types. It was determined that the oils are rich in linoleic and palmitic acid in terms of fatty acid compositions. Also, oxidation stability of oils was determined by using the Rancimat 743. Moreover, the oils of SCGs were used in production of biodiesel using classic transesterification method. Transesterification experiments that performed in the methanol and KOH catalyzed and with different reaction times, were carried out based on the experimental design. Obtained ester contents from the experiments, that they performed by using Box-Behnken design which have 2-factor-5-level with 4-replicate, were analyzed according to the European standards (EN 14214). According to the reults, the conversion to fatty acid methyl esters was ranged between 71.67-93.43%. In the last step of the study, espresso SCG, oil-free espresso and its coke, as an adsorbent in adsorption experiments containing of purification of wastewater was used. The experiments were performed in different kinds of experimental set-up, various pH, time, and different amounts of adsorbent. The degree of improvement in wastewater was observed by checking the TOC values that was measured with IL 550 TOC-TN analysis device. As a result of obtained data, the most 76% rate improvement occured but SCG provided precious little benefit in this improvement, the main improvement observed as a result of pH of acidic olive mill wastewater with pulling in alkaline environment. However, with addition of the SCG the odour of olive mill wastewater, that has a specific odour, was greatly improved. Moreover, protein contents were determined to investigate the usage of these in the production of fodder as additives. Determined in the elemental analysis device, that is Kaiyuan CHN 2000, the amount of protein that espresso SCG contain is approximately 15%. Finally, the high heating values were investigated to determine the suitability of SCGs for fuel purposes. The high heating values, that were determined by Leco AC500 model calorimeter device, ranged between 5184.18 cal/g (Turkish coffee SCG/made in machine)-5616.51 cal/g (filter SCG).