جستجوی مقالات مرتبط با کلیدواژه « compost » در نشریات گروه « پزشکی »

 Composting process as a biological method in waste management has many problems including odor emission. Ammonia, volatile organic compounds and hydrogen sulfide are factors that cause odor. The purpose of this study is to review studies on odor emission and strategies of reducing odor emission in the composting process.

 In this study, the keywords including Odor compost, Food waste composting, Odor emission composting process and Odor composting were searched in scientific databases such as Google scholar, Scopus, ScienceDirect, PrpQuest and PupMed. As a result of this search, more than 200 articles were identified and extracted.

 The results of the investigated studies showed that the major components of odorous gases in the composting process are ammonia gases, hydrogen sulfide and VOCs. Studies on controlling and reducing the emission of odorous gases from the composting process are included in two groups: improvement of the composting process by adjusting environmental conditions and using additives with the aim of reducing odor production.

 The review of studies showed that by adjusting the physical and chemical factors of the composting process, it is only possible to reduce only one of the odorous gases, and due to the composting process is a biochemical procedure and the sensitivity of microorganisms, as well as the production mature fertilizer, the adjustment of the composting conditions is limited and the operable range is very narrow so principally, this method is difficult to control odor in practice. Therefore, the use of additives is suggested as a suitable strategy to control odor emission in the composting process. These additives reduce the odor emission in the composting process by creating porosity, gas absorption, and gas precipitation. 

The presence of pathogenic microorganisms in compost of solid waste can threat public health. Therefore, it is necessary to evaluate the safety of produced composts before its land application as a soil conditioner. This study was conducted to investigate the presence of pathogenic microorganisms in municipal solid waste (MSW) compost and health risks associated with accidental ingestion of compost by children.

In this study, sampling was done from compost piles at different public parks of Isfahan city during the period of compost spreading. Presence and concentration of pathogenic microorganisms including salmonella, campylobacter, cryptosporidium and adenovirus were investigated by culture or real-time PCR methods.

All pathogenic microorganisms were detected in MSW compost in a frequency from 11%-62% with the highest frequency for detection of adenovirus. The health risk assessment showed that the highest risk of daily infection was for Cryptosporidium (7.67 × 10-4 pppy) and the lowest risk was related to adenovirus (8.27 × 10-10 pppy). The annual infection risk from gastrointestinal disease was calculated above guideline infection risk (10-3 pppy).

The results showed contamination of produced compost to pathogenic microorganisms and potential health risks from applying MSW compost in urban green spaces. Therefore, the relevant organizations should pay more attention to the composting process and its microbial quality and application in public access areas.

Toluene is one of the most important volatile organic compounds that threaten human health and introduce many environmental problems. Therefore, the present study aims to determine the performance of a biofilter based on pine cones/compost to remove toluene vapors from polluted air streams.

In this research, a biofilter with a volume of 19.468 L was designed and built. The biofilter bed consisted of two parts 26 cm in height and packed with a mixture of compost and pine cones in 1:1 volumetric ratio. After inoculating the bed with sludge from a municipal wastewater treatment plant and making it compatible with toluene, the performance of the biofilter in different parts of the bed was investigated at the inlet toluene concentrations of 2.5-5.5 g/m3 and Empty Bed Retention Times (EBRTs) of 1.3, 1.7, and 2.43 min. Also, the results were analyzed statistically.

At EBRT of 2.43 min and different inlet toluene concentrations of 2.5-5.5 g/m3, the removal efficiency reached 100 percent. Also, the removal efficiency decreased with the reduction of EBRT. The results showed that removal efficiency was higher in the first part of the biofilter bed relate to the second part. At an inlet toluene concentration of 2.62 g/m3 and EBRT of 1.7 min, the maximum elimination capacity (ECmax) of 2.74 g/m3.min was obtained.

In all experimental conditions the outlet concentration of pine-cone/compost biofilter was below the WHO standard (260 µg/m3). Also, the high elimination capacity of biofilter verified its capability toward toluene removal from polluted gas streams.

The aim of this study was to investigate the effect of seasonal variation on the diversity of fungal airborne species in the composting process.

Samples were taken based on the 0800 NIOSH method at a height of 1.5 m above the ground during the waste separation, turning of windrow and stabilization of compost. Air samples were collected in two various seasons; summer (108 samples) and winter (108 samples) at the composting plant in Shiraz. The culture media consisted of Sabouraud Dextrose Agar with chloramphenicol for the selective isolation of fungi, which was further incubated at 37 and 45°C. The results were analyzed by a t-test method using MATLAB 2018.

The highest mesophilic fungi density was related to the segregation process of composting. The variation of fungi observed was higher during summer throughout separation and stabilization process (p < 0.05). The predominant species were found to be Aspergillus flavus (4449.8 CFU/m3) (p < 0.05) and Paecilomyces (1850.9 CFU/m3) (p < 0.05), respectively. Furthermore, the highest varieties of fungal species in the turning of windrow mass were observed during winter (p < 0.05) and the predominant species was yeast (420.6 CFU/m3). At all stages of composting, the varieties of thermophilic fungal species were higher during summer with the large number of Aspergillus fumigatus, Mucoral, and Paecilomyces.

The density and diversity of mesophilic fungi during summer was higher than winter. The concentration of Aspergillus, was beyond the guidelines set by the EPA, ACGIH, NIOSH and EU. Thus, the use of self-protection is essential.

Compost production is a biological treatment process of organic solid wastes that are used to recovering and volume reducing waste and stabilization programs. The aim of this study was to compare physicochemical and microbiological parameters between compost and vermicompost producing through windrow method from aerobic digestion sludge of Hamedan wastewater treatment plant.

By using the Windrow method, act to produce compost from the sludge of excreted bed of dryer sludge (lagoon) of Hamedan wastewater treatment plant and mixing with bulk materials. At the same time with this activity, vermicompost production from excreted sludge carried out by using Eisenia fetida for 15 weeks. All statistical analyses were done by SPSS software.

There is no significant difference in C/N ratio, pH, moisture, ash, organic matter and sodium parameters between compost and vermicompost, but there is a significant difference in Cu, Cd, Ni, Pb, Zn and temperature, carbon, nitrogen, phosphorus, magnesium, calcium, total and fecal coliform parameters between compost and vermicompost producing from aerobic digestion sludge. Also, the average concentrations of heavy metals in both compost and vermicompost produced from aerobic digestion sludge were lower than the MPC established by EPA.

Concentrations showed that Ni and Pb, C, N, P, Mg values and microbial population of fecal coliform in producing compost is more from vermicompost and Ni and Cu, Cd, Zn amounts and microbial population of total coliform in producing vermicompost is more from compost producing. Therefore, it is concluded that both compost fertilizers could be appropriate quality for agricultural and horticultural uses.

Today, the issue of urban solid waste or urban waste is one of the most serious problems in the whole world. Composting plants have a significant amount of time from the production and production stage to the sale and consumption stage. In this study, the effect of compost age on the quality of the compost factory was carried out in Isfahan City waste management organization.

To conduct this study, a compost mass of about 300 tons of newly produced compost and prepared for sale at a particular site from the plant and was done in a special place of four and nine weeks. There are ammonia, nitrate, ammonium, phosphorus, potassium, total nitrogen, mineral nitrogen, organic nitrogen, sodium, calcium, magnesium, carbon, density, EC, pH, oxygen, sulfur, and the ratio of carbon to nitrogen was done at any time with three iterations of the experiment.

Findings indicate that ammonia, nitrate, ammonium, total nitrogen, mineral nitrogen, EC, pH, moisture, density, and the ration of carbon to nitrogen in the initial compost are respectively as follows: 1800, 58.35, 28.2314, 14000, 2400, 11600, 145.7, 245.7, 85.6, 286, and 54.12. Finally in the 9th week, they changed as follows: 145.873, 325.81, 61.1122, 63.15065, 63.1215, 13850, 71.5, 35.7, 005.5, 5.279 and 04.22. The amount of ammonia, ammonium phosphor, mineral nitrogen, EC, moisture and density was reduced with a significant difference whereas other factors increased with a significant difference. The results of phosphor were not significantly different. Also, the results of the study revealed that ammonia, ammonium, phosphorus, total nitrogen, nitrogen, EC and COD in the zero weeks were respectively as follows: 244.26, 314.05, 298.73, 1153.6, 325.36, 6289.2, 37.088 and 3635.24, whereas in the ninth week, they changed as follows: 110.36, 141.89, 285.43, 366, 148.98, 217, 728.15, 5733.76. The amount of ammonia, nitrate, ammonium, total nitrogen, mineral nitrogen, organic nitrogen, as well as EC reduced with a significant difference, but the amount of COD increased with a significant difference. The results of phosphor and nitrate were not significantly different. 

Ultimately it can be concluded that the quality of compost is decreased with time lapse and the more it passes after the compost production, the less the food elements in the compost consumed by vegetarians would be.