عادل بخشی پور

Drying process is an important post-harvest stage of food crops production which accounts for about 20 % of the world’s energy consumption in the industrial sector. One of the effective ways to reduce the share of fossil fuel consumption in the food drying process is to develop new drying systems based on the use of renewable energy sources. In this research, a novel solar-assisted multi-belt conveyor dryer was developed and its performance was analysed. The required thermal energy for drying process was supplied by the combination of solar-gas water heaters and four solar-powered infrared (IR) lamps. The experimental factors included the speed and temperature of the drying air and the power of IR lamps. The performance characteristics were drying time, Overall Specific Energy (OSE), Non-Solar Specific Energy (NSE), Overall Energy Efficiency (OEE), and Solar-Assisted Energy Efficiency (SEE). The optimization process of the drying system was carried out using Response Surface Methodology (RSM) by defining two general modes for the energy sources of the drying system, namely overall mode and solar-assisted mode. Based on the results, the lowest OSE (17.30 MJ/kg water evaporated) was obtained when the speed and temperature of the drying air were equal to 7 m/s and 40 °C, respectively, without using IR power. The lowest NSE (2.71 MJ/kg water evaporated) was achieved by applying the treatment of 7 m/s * 40 °C * 300 W. The maximum OEE was equal to 13.92 % whilst the maximum SEE was obtained as 88.71 %. Both of the mentioned maximum values were obtained at the speed and temperature combination of 7 m/s and 40 °C and their difference was applying     300 W IR power to gain maximum SEE and no IR utilization for the maximum OEE. According to RSM analysis, the optimum working conditions for the drying system included the treatment of 7 m/s * 39.96 ºC * 300 W. Under this condition, the drying time, NSE, and SEE values were equal to 180.95 min, 1.062 MJ/kg water evaporated, and 84.63 %, respectively.

Establishing a good sound waste management system for a community requires a comprehensive knowledge of the current status and issues involved in present waste management system. This research was conducted to identify and prioritize waste management weaknesses in Saravan village of Guilan province, Iran.

Data were gathered through a descriptive-analytical approach using a purposive sampling and researcher-made questionnaire method. Waste management weaknesses were prioritized by Analytic Hierarchy Process (AHP), Fuzzy Analytic Hierarchy Process (FAHP), and Analytic Network Process (ANP).

The most important weakness of rural waste management in the study area was waste management structure, equipment, and infrastructures weakness (index C) with relative importance values of 38.1% in AHP, 37.3% in FAHP, and 38.2% in ANP approaches. The village inhabitants' weakness (index B) with relative importance values of 16.5% in AHP, 17.2% in FAHP, and 1.4% in ANP had the lowest priority among studied weaknesses. Workforce weakness (index A), and educational and cultural weakness (index D) were the second and third important weaknesses, respectively. The most important sub-indices weakness of these weakness indices were non-compliance of Rural Municipality Manager (RMM) with waste management standards, rules, and regulations; Waste disposal by the village inhabitants at the nearest site; failure to establish a solid waste fix station in the village; and lack of training and awareness of villagers about waste management.

In order to establish a successful waste management system in rural areas, it is recommended to develop a comprehensive strategy that involves aspects such as; establishing proper waste management infrastructures, employment of skilled staff, and conducting training plans and motivational programs for staff and inhabitantsThe author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers. 

This paper presents an overview of the current municipal solid waste (MSW) management in Rasht City, Guilan Province, Iran, followed by evaluating the potential for waste-to-energy. The data of different MSW functional elements were collected from previous works, available reports, interviews and meetings with specialists in the field. About 800 tons MSWs are generated in Rasht per day, of those, over 75% are organic wastes followed by paper and cardboard comprising 5.9%. The daily theoretical energy contained in the city MSWs was estimated to be over 591.62 megawatt hour (MWh, over 215942.54 MWh per year). Almost 500 tons of daily MSWs are directly transferred to Saravan as the biggest landfill in north of Iran with an area of about 30 ha, while the remaining portion is treated in the Guilan composting plant. Landfill mining calculations showed that we could recycle about 3008947, 36793, 61443 and 18366  tons of plastics, textile, wood and  rubbers collected from Saravan landfill respectively. A simple assessment of waste-to-energy potentials from organic wastes using operational conversion coefficients revealed that by employing the combination of waste-to-energy and gas turbine technology, an estimated energy of 227.668 MWh can be produced from the Rasht daily food wastes. Although MSW management in Rasht  has been improved over the last decade owing to the establishment of waste recycling and composting organization, however it is still far from the standard situation due to lack of comprehensive waste management planning, financial resources and infrastructures