نوع مقاله : مقاله پژوهشی
1 سازمان مدیریت پسماند استان گلستان
2 دانشگاه کشاورزی و منابع طبیعی گرگان، گروه خاک،
عنوان مقاله [English]
. At the present study, the maturity and stability of composted municipal solid wastes at a biocompost plant was evaluated by Monitor of the important parameters of the leachate and how it changes to predict the performance and efficiency of the treatment plant, is necessary. The aim of this study was to monitor the changes in EC, COD, pH and TSS parameters in raw leachate of municipal waste by considering the possibility of leachate treatment at 5 stations (raw leachate, anesthesia unit, primary aeration, secondary aeration and final output) of the compost plant. Gorgan's Aq Qala was in different seasons of the year. For this purpose, 135 sampling times were performed in 1258 days from 2016 to 2020, and the changes of the mentioned parameters were investigated. The results of comparing the average EC concentration of raw leachate and output yielded 67.7% elimination efficiency, and the refinery's anaerobic reactor continued to operate without any problems, despite the high EC. The results of comparing the average TSS in the raw leachate and output unit with the elimination efficiency were 97.5%. The mean COD results in raw leachate and outflow units showed a 99% elimination efficiency and the best efficiency was obtained in the final and late fall outflows, which was related to ambient temperature and optimal bacterial activity. The results of the mean pH in the raw leachate unit and output showed high efficiency and optimal performance equal to 99.7, which reached its lowest value in the first half of spring in order to reduce the alkalinity of raw leachate. The anaerobic reactor station had the best efficiency among the measuring stations.Waste leachate has a high pollution load, and its leakage and expansion with groundwater or porous environment causes the transfer of pollution parameters in the underground environment. Due to the different physicochemical and biological nature of waste, it is necessary to measure and analyze its important parameters and how it changes throughout the year to predict the performance and efficiency of the treatment plant.
In this study, the results of a study of 4 important pollution parameters during 1258 days in 135 measurements showed that the highest average decrease for all tested parameters among the measuring stations was obtained in the anaerobic unit. flow Anaerobic Sludge Blanket (UASB) Reactor has been successfully implemented to treat wastewater in ourneighboringcountry, India for more than 20 years and its performance was found to be satisfactory (KUET, Khulna, 2020). The anaerobic reactor, primary and secondary aeration unit, represents the concentration changes in a favorable decreasing trend and shows the optimal performance of the aeration units along with the anaerobic reactor (UASB) in reducing and adjusting the concentration of the studied parameters the application of an up-flow anaerobic sludge blanket (UASB) reactor followed by a self-aerated sponge (SAS) unit as a combined system for the treatment of hazardous landfill leachate (HLL) for 310 days. The removal efficiencies of the integrated UASB/SAS system were 34.5–59.2% for COD total, Issa Alabiad et al,2017).
. The aeration units led the concentration changes to a slope reduction, and the results showed the efficiency of the treatment process over a period of 4 years.
The chart of changes in the COD parameter of raw leachate in anaerobic reactor, primary aeration, secondary aeration and output compared to raw leachate (input) has decreased, but this decrease was much less in primary and secondary aeration units. It seems that the bacterial population in the years after operation, has undergone an optimal process and environmental reactions such as temperature shock and various concentrations in terms of organic pollution load despite the increase in COD concentration in raw leachate, over time They have been less involved in refinery treatment activities. The best results were obtained in late autumn at the final output, which was related to the ambient temperature corresponding to the optimal operating temperature of the bacteria (temperature 18 to 25 O C).
Comparing the average COD in the raw leachate unit and the output leachate with the average yield yield was 99%. The average salinity changes during this period were reduced for 5 stations in the treatment plant treatment process, so that in the output unit a relative stability and relative stability of the untreated leachate was observed. Overall results in the 4-year period showed that despite the relative increase in concentration in raw leachate up to the third year, still the best desired result in all stations in the third year and especially in the fourth year, more favorable result in 4 treatment plants from anaerobic reactor to the final output was very noticeable.
The EC changes in raw and outlet leachate were accompanied by very large changes due to heavy precipitation during the rainy season. The average efficiency of the system salinity removal concentration was calculated to be 67.7%. The average concentration for leachate was the final output with the maximum concentration having the maximum, minimum in the middle of summer and the first half of spring, respectively, which was due to changes in ambient temperature and bacterial population. The anaerobic reactor was able to withstand environmental shocks and pollutant changes throughout the year and adapt over time.( In this treatment plant, anaerobic reactor unit showed the best performance and was able to adapt with high concentrations of TSS and EC)( Rashidi et al. 2014).In monitoring TSS changes, raw leachate and output both showed a significant slope reduction chart, indicating an acceptable yield of 91% removal and optimal performance in anaerobic reactors and an average removal efficiency of 97.5% for the entire system. The lowest concentrations of TSS were obtained in the first half of summer and the highest concentrations in late winter, which are related to the bacterial population and the temperature inside the treatment plant. the lowest efficiency was achieved in Summer
and late winter, which was related to the temperature and bacterial population. ( Rashidi et al. 2014).
The results of the study of pH changes showed that the average in the anaerobic unit compared to the inlet leachate is very small, which indicates the control of environmental conditions and consequently the correct guidance in this time period studied. The pH changes in different seasons of the year in the treatment plants were highly related to the ambient temperature and the quality of the leachate produced in each season. The raw pH of leachate seems to be the highest in winter and the lowest in late summer, which is related to the high consumption of fruits and vegetables in people's diets during the summer. The pH concentration of leachate in the anaerobic unit reached its maximum in late summer with peak heat and in winter to the lowest, and the pH concentration in the primary aeration unit reached its lowest level in mid-autumn, which could be related to bacterial population and ambient temperature shock. Be. Therefore, to compensate for this, by increasing the population of bacteria in the winter in the anaerobic unit and by feeding it with animal manure and compost, which is one month away from the process, improve the treatment process and consequently increase the efficiency of the treatment plant in the cold season, was obtained.