• Energy Research
• 6. Clean water close
• IT close
• Applied Sciences close

Although new technologies are continuously proposed for water pollutant removal, sorption is still a very effective process used today for this purpose, largely due to its relatively low cost, tunability, and ease of use [...]

The conversion of biogenic residues to fuels and chemicals via gasification and synthesis processes is a promising pathway to replace fossil carbon. In this study, the focus is set on sewage sludge gasification for syngas production. Experiments were carried out in a 20 kW fuel input bubbling fluidized bed facility with steam and oxygen as gasification agent. In-situ produced sewage sludge ash was used as bed material. The sensitivity of the key operation parameters gasifier temperature, oxygen ratio, steam to carbon ratio, and the space velocity on the syngas composition (H2, CO, CO2, CH4, CxHy, H2S, COS, NH3, and tars) was determined. The results show that the produced syngas has high H2 and CO concentrations of up to 0.37 m3 m−3 and 0.18 m3 m−3, respectively, and is thus suitable for synthesis of fuels and chemicals. By adjusting the steam to carbon ratio, the syngas’ H2 to CO ratio can be purposely tailored by the water gas shift reaction for various synthesis products, e.g., synthetic natural gas (H2/CO = 3) or Fischer–Tropsch products (H2/CO = 2). Also, the composition and yields of fly ash and bed ash are presented. Through the gasification process, the cadmium and mercury contents of the bed ash were drastically reduced. The ash is suitable as secondary raw material for phosphorous or phosphate fertilizer production. Overall, a broad database was generated that can be used for process simulation and process design.

A natural antioxidant extract obtained from oil mill wastewater was used for the formulation of basil pesto sauce, with the aim to improve quality and stability during storage. The antioxidant extract was added to traditional ingredients (basil, cheese, oil, etc.) and after preparation, packaging, and thermal treatment it was submitted to storage (monitored for 90 days). Fresh samples were stored at 4 °C and pasteurized samples were stored at room temperature. The effect of natural antioxidant addition on basil pesto sauce was evaluated for the main qualitative attributes, such as: physicochemical, microbiological, and antioxidant parameters. The principal results showed that the addition of a natural phenolic extract led to an evident reduction in pH, attaining food safety values under pH 4. The high oxidative stability observed in the basil pesto sauces fortified with the phenolic extract suggests that the incorporation of phenolic compounds delays the propagation phase of lipid oxidation.

The use of biostimulants and/or biofertilizers has acquired considerable importance and can contribute to the sustainable management agriculture, reducing the use of chemical fertilizers, pesticides, and water. This study aims to assess the effects of Effective Microorganisms (EM) and Olive Mill Wastewater (OMW) on the growth, photosynthetic performance and polyphenols content of the medicinal plant Tanacetum balsamita. The EM and OMW were used at two dilution rates. The EM was added to 5% v/v and 10% v/v, while OMW was added to 2.5% v/v and 5% v/v in plants at the early growth stage. After 75 days of treatment, all the treated plants had a leaf number and leaf area almost 2-fold higher than in the Control plants. Moreover, the treatments, at all the concentrations applied had a positive effect on the photosynthetic activity, with an improvement both in terms of the quantum yield of photosynthesis and electrons transport efficiency. The best photosynthetic and growth performances in the treated plants coincided with the higher production of phenolic compounds; indeed, after 75 days, the content of chlorogenic acid, caffeic acid, and isochlorogenic acid was even 2-fold of the Control plants. Also, rutin content was 1.28–1.50-fold respect to the Control extracts. The highest phenolic compound content was reflected by the highest antiradical activity, found in the extracts of the treated plants. The effectiveness of EM to increase the growth and quality of plants and in particular, the potential use of OMW on the cultivated crop was confirmed to this study.

The paper investigates an alternative treatment plant for the typical wastewater effluent of a cheese-making industry, mainly composed of acid or sweet whey mixed with washing-water. Two variable parameters have been considered during the tests: four treatment temperatures (39, 46, 53 and 60 °C) and three solid content values (30%, 50% and 70%) of the concentrated product. The minimum and maximum values of the removal efficiency (pollutant amount into concentrate related to raw whey) range from 94.6% to 97.7% for conductivity, from 98.3% to 99.5% for BOD5, from 98.7% to 99.6% for COD and from 98.2% to 99.3% for Total Nitrogen. The plant capacity ranges from about 2 L/h (at 39 °C) to 6 L/h (at 60 °C) of processed whey. On the basis of the experimental findings, the proposed purification technology has demonstrated its suitability both to purify the effluent wastewater and to recover high-quality products (e.g., whey protein concentrate, lactose), thanks to its low thermal damage on the treated product and to its relatively low energy consumption from 0.4 kWh/L (at 60 °C) to 1.0 kWh/L (at 39 °C) of processed whey, with a Coefficient of Performance from approximately 0.6 up to 1.5.

Anaerobic digestion (AD) is a promising option to obtain renewable energy in the form of biogas and reduce the anthropogenic impact on the environment. In recent years there has been increasing interest in using pressurized digesters to improve the quality of biogas. However, maintaining high overpressure increases the requirements for the explosion safety of digesters. Consequently, there are natural limitations in the available technologies and facilities suitable for full-scale operation. In this work, we aimed to evaluate the possibility of using overpressure in the digester to improve the efficiency of codigestion of common municipal organic waste–sewage sludge and the organic fraction of municipal solid waste. Three levels of moderate excess pressure (100, 150 and 200 kPa) were used to meet requirements of existing block-modular anaerobic bioreactors based on railway tanks, which are widely utilized for AD in the Russian Federation. There was no significant change in methane content in biogas (65% ± 3%) at different values of overpressure, hydraulic retention time (HRT) and organic loading rate (OLR). The maximum methane and energy production rates (2.365 L/(L·day) and 94.27 kJ/(L·day), respectively) were obtained at an overpressure of 200 kPa, HRT of 5 days and OLR of 14 kg VS/(m3·day). However, the maximum methane yield (202.44 mL/g VS), energy yield (8.07 kJ/g VS) and volatile solids (VS) removal (63.21%) were recorded at an overpressure of 150 kPa, HRT of 7 days and OLR of 10.4 kg VS/(m3·day). The pressured conditions showed better performance in terms of AD stability at high OLRs.

Rapid industrialization and urbanization have led to a decline in environmental quality, especially in coastal aquatic environments (i [...]