Comparative study of municipal solid waste generation and composition in Shiraz city (2014)

Background: Exponential growths of population and urbanization, and the development of social economy have resulted in an increase in the amount of MSW generation throughout the world. Objective: The present study aimed to survey qualitative and quantitative analysis of solid waste in Shiraz city and comparative these results with the world scenario of solid wastes generation for improving the sustainable management of solid waste. Methods: This cross-sectional study was conducted in 2014 in nine municipality regions Shiraz with a total population of approximately 1,549,354 people. Basic data was gathered through Shiraz waste management organization. Then generation (per capita) and constituent percent of the solid waste were evaluated based on the sampling and field analyzing from reliable guidelines. Data were analyzed with Stata-13 and Excel statistical software. Kolmogorov-Smirnov test used for the normality of variables. Means were compared by Student T test and Mann-Whitney test. Findings: The rate of solid waste generated in the Shiraz city was 222.65 kg per person per year in 2014. Statistical analysis showed that the variables of organic materials, paper and cardboard, glass and metal between developed and developing countries were a significant difference (P<0.05) while plastics and textiles and were not significantly different (P>0.05). Conclusion: Solid waste per capita in Shiraz city (about 600g/day) was near to the average amount of solid waste generation in Iran and other developing countries. Due to the high content of organic material in municipal solid waste of Shiraz, minimization of these material and separation of dry and wet solid wastes must be noted from the people and municipalities

Microbial quality assessment of disposal effluent and sludge from four decentralized wastewater

Background and Aims: Lack of adequate supervision on the quality of disposal effluent and sludge from wastewater treatment plants (WWTPS) caused to their discharge by many pollutants into the environment.This study aimed to assess the microbial quality of disposal effluent and waste sludge from decentralized WWTPS in Tehran.Materials and Methods: This cross-sectional study was performed in 12 months on disposal effluent and sludge from 4 decentralized WWTPS in Tehran city. Random sampling was conducted at a monthly period. The microbial quality of disposal effluent and waste sludge were compared with the guidelines of Iranian, and United States Environmental Protection Agency (USEPA), respectively.Results: Effluent and sludge output from these plants typically were used for agricultural purposes. None of the samples of effluent meet Iranian environmental standards. Microbial quality of waste sludge from Shahrak Gharb and Ekbatan WWTPS were higher than class B of USEPA guidelines but, waste sludge from Gheitarieh and Shoosh WWTPS meet this index.Conclusion: At the present time, reuse of effluent and waste sludge from decentralized WWTPS in Tehran city were performed without any health considerations. This is a serious threat to public health; hence, executive and regulatory agencies must take action corrective measures and controls necessary in this regard as soon as possible.Key words: : Microbial quality, effluent, sludge, wastewater treatment plants, Tehran cit

Evaluation of Diethyl phthalate and Diallyl phthalate biodegradation mechanisms in the treatment of synthetic wastewater

Background and Aims: Over the last few years, Phethalic Acid Esters (PAEs) have attracted a widespread attention due to their widespread production and use. These compounds are not only linked to endocrine disruption and cancer but also considered as emerging and hazardous pollutants. Large amounts of PAEs have been detected in industrial wastewaters. Given the widespread use of biological processes in industrialwastewater treatment, this study aimed to identify biodegradation pathways of PAEs and their potential metabolites.Materials and Methods: Two short-chain esters from phthalic acid esters including diethyl phthalate (DEP) and diallyl phthalate (DAP) were selected in the present study. We used the survey of metabolites in a moving bed biofilm reactor effluent to determine biodegradation pathways of designated esters at hydraulic retention times of 1 to 12 hours. Influent concentration of 100 mg/l was also considered throughout the study.Results: Phthalic acid, mono-methyl phthalate, dimethyl phthalate and catechol were identified as the most noteworthy metabolites in biodegradation of both esters. The degradation pathway of both studied compounds was similar and involves either detachment of ester-chain or removal of methyl group, followed by few decomposition steps resulting in the production of benzene ring. The degradation can proceed further with ring cleavage and it ends with 2-hydroxy muconic semi-aldehyde.Conclusion: The main route for removal of studied compounds was de-esterification followed by demethylation. According to identifies degradation pathways and metabolites produced, biodegradation can be considered as a reliable treatment process for industrial wastewaters containing PAEs.Key words: Biodegradation, Phthalic Acid Esters, Synthetic wastewater

Investigation of MPTMS-modified magnetic nanoparticles in the removal of lead and cadmium ions from aqueous solution: equilibrium and kinetic studies

زمینه و اهداف: در سال‌های اخیر، مساله آلودگی محیط‌های آبی با فلزات سنگین بسیار مورد توجه محققان قرار گرفته است. بدین منظور، مطالعه حاضر با هدف کارایی نانوذرات مغناطیسی اکسید آهن اصلاح شده با 3- مرکاپتوپروپیل تری متوکسی سیلان در حذف یون‌های فلزی سرب و کادمیوم را از محیط آبی انجام گرفت. مواد و روش‌ها: در مطالعه حاضر نانوذرات مغناطیسی Fe3O4@SiO2-SH به روش ساده هم‌رسوبی در دمای 80 درجه سلسیوس سنتز شد و سپس ساختار و مورفولوژی آن با استفاده از دستگاه‌های XRD، FT-IR، &nbsp;SEMو TEM مورد شناسایی قرار گرفت. در نهایت آزمایشات جذب بر روی محلول آبی انجام گرفت. در کلیه مراحل انجام پژوهش، موازین اخلاقی، مراعات گردید. &nbsp; یافته‌ها: طبق نتایج، نانوذرات Fe3O4@SiO2-SH دارای توزیع یکنواخت با هسته کروی Fe3O4 و پوسته SiO2 می‌باشد که توسط لیگاندهای تیول اصلاح شده است. همچنین اثر پارامترهایی نظیر pH، دوز جاذب و مدت زمان تماس بر درصد حذف یون‌های فلزی مورد بررسی قرار گرفت. نتایج تحقیق نشان داد pH معادل با 5 و 6 به ترتیب برای سرب و کادمیوم، زمان تماس 40 دقیقه و دوز جاذبg/L&nbsp; 0/8 شرایط بهینه مناسب جهت حذف یون‌های فلزی از محلول است. معادلات کینتیک و ایزوترم بر این نکته تاکید داشت که روند جذب دو یون فلزی از مدل کینتیک شبه درجه دوم (0/98&lt;R2) و ایزوترم دمایی لانگمویر (0/98&lt;R2) تبعیت می‌کند. نتیجه‌گیری: با توجه به نتایج حاصل، نانو ذرات سنتز شده Fe3O4@SiO2-SH تحت شرایط بهینه می‌تواند كارايي مناسبي در حذف یون‌های فلزی سرب و کادمیوم از محلول‌های آبی داشته باشد.Background and Aims:&nbsp;Environmental pollution by heavy metals has received much attention in recent years. Therefore, this study aims to remove lead and cadmium ions by using silica-coated magnetic nanoparticles modified with mercaptopropyltrimethoxysilane (MPTMS) from aqueous solutions.Materials and methods: In this study, Fe3O4@SiO2-SH magnetic nanoparticles were synthesized via the simplified co-precipitation method at 80°C. The structure and morphology properties of synthesized nanoparticles were characterized by XRD, FT-IR, SEM and TEM. Finally, the adsorption experiments were performed in aqueous media. All stages of this research were conducted ethically.Results: According to the results, Fe3O4@SiO2-SH nanoparticles have a uniform distribution with a spherical Fe3O4 core and SiO2 shell, modified by thiol functional groups. The efficiency of synthesized adsorbent in the removal of metal ions was also investigated considering parameters such as pH, adsorbent dose and contact time. The optimum conditions for lead and cadmium removal were obtained at pH 5 to 6, contact time 40 min and absorbent dose 0.8 g/L. The kinetic and isotherm studies underlined that the process of adsorption of both metal ions follows the second-order (R2&gt; 0.98) and Langmuir isotherm (R2&gt;0.98) models.Conclusion: Based on the results obtained, synthesized Fe3O4@SiO2-SH magnetic nanoparticles can present proper efficiency in the removal of lead and cadmium ions from aqueous media under optimum conditions

بررسي امكان بازيابي و تبديل لجن اسيدي به قير در صنايع تصفيه مجدد روغن موتور مصرف شده

Background and Aims:&nbsp;Thousand tons of acidic sludge is produced daily as by-product in the used motor oil refining industries. The acidic sludge contains unsaturated compounds which are non-polar and asphaltene. The objective of this study was performance improvement of acidic sludge by using the additives (bentonite, polymer SBS, sodium hydroxide and the lime) so that recovery to bitumen.Materials and Methods:&nbsp;The polymer styrene - butadiene - styrene (SBS) is bitumen modifier as one of the elastomer - thermoplastic with weight percentages (2 to 4 percent), bentonite due to the chemical structure as fillers, stabilizers and agent concentration with weight percentages (1,2,4,6,8,10) and lime and sodium hydroxide were used to decreasing acidity rate of acidic sludge and promoting the role of bentonite stability in bitumen with ratios equal (1 to 5 g) were mixed with acidic sludge of industry (samples 50 g) and their effect on the acidic sludge was investigated.Results: Evaluation of studies indicated that because of increasing acidic sludge softening point, temperature from 25 to 48 oC , decrease weight loss from 3% to 1.25, promoting the penetration degree to 230 mm, Frass breaking point to -7 and penetration index (PI) to the degree standard set (+1), the acidic sludge properties and performance were modified. The measurement of last three parameters was unavailable in primary sludge.Conclusion:&nbsp;Environmental and health hazards of acidic sludge will be decreases by treatment and neutralization. Also obtained products can be used in the building and road construction according to its specific bitumen criteria and characteristics.زمينه و اهداف: روزانه هزاران تن لجن اسيدي به عنوان محصول جانبي در صنايع تصفيه مجدد روغن موتور مصرف شده توليدمي شود. لجن اسيدي حاوي ترکيبات غير اشباع قطبي و آسفالتين است. دفع اين لجن بصورت خام بسيار خطرناك و صدمات زيستمحيطي و بهداشتي به دنبال خواهد داشت. هدف اين مطالعه بهبود کارايي لجن اسيدي به کمک مواد افزودني (خاک بنتونيت، پليمرسود و آهک) و تبديل آن به قير بود مواد و روش ها: پلیمر استایرن- بوتادین- استایرن، به عنوان اصلاح کننده الاستومر- ترموپلاست قیر با&nbsp; درصدهای وشنی2 تا4 درصد، بنتونیت به دلیل ساختار شیمیایی به عنوان پرکننده، تغلیظ کننده و پایدار کننده با درصدهای وزنی1،2،4،6،8،10، آهنک و سود به منظور کاهش میزان اسیدیته لجن اسیدی و تقویت نقش پایدار کنندگی بنتونیت در قیر به نسیت های مساوی با 50گرم لجن اسیدی مخلوط شدند و تاثیر آنها بر لجن اسیدی بررسی شد. یافته ها: با توجه به مطالعات انجام شده با افزایش نقطه نرمی لجن اسیدی از25 به 48 درجه، کاهش افت وزنی از3&nbsp; به 1/25 درصد، ارتقا درجه نفوذ به 23 میلیمتر، نقطه شکست فراس به -7 درجه و شاخص نفوذپذیری به حد استاندارد تعیین شده در فراورده های به دست آمده، خصوصیات و کارایی لجن اسیدی اصلاح گردید. سه پارامتر نقطه شکست و درجع نفوذ و شاخص نفوذپذیری در لجن اولیه قابل اندازه گیری نبود. نتيجه گيري: با توجه به خنثي سازي اسيديته لجن، خطرات زيست محيطي و بهداشتي محصول بدست آمده بمراتب كاهش مي يابد،همچنين مي توان اين محصول را در مصارف ساختماني و راه سازي با توجه به معيارها و ويژگي هاي اختصاصي قير مصرف نمود

Comparative study of municipal solid waste generation and composition in Shiraz city (2014)

Background: Exponential growths of population and urbanization, and the development of social economy have resulted in an increase in the amount of MSW generation throughout the world. Objective: The present study aimed to survey qualitative and quantitative analysis of solid waste in Shiraz city and comparative these results with the world scenario of solid wastes generation for improving the sustainable management of solid waste. Methods: This cross-sectional study was conducted in 2014 in nine municipality regions Shiraz with a total population of approximately 1,549,354 people. Basic data was gathered through Shiraz waste management organization. Then generation (per capita) and constituent percent of the solid waste were evaluated based on the sampling and field analyzing from reliable guidelines. Data were analyzed with Stata-13 and Excel statistical software. Kolmogorov-Smirnov test used for the normality of variables. Means were compared by Student T test and Mann-Whitney test. Findings: The rate of solid waste generated in the Shiraz city was 222.65 kg per person per year in 2014. Statistical analysis showed that the variables of organic materials, paper and cardboard, glass and metal between developed and developing countries were a significant difference (P<0.05) while plastics and textiles and were not significantly different (P>0.05). Conclusion: Solid waste per capita in Shiraz city (about 600g/day) was near to the average amount of solid waste generation in Iran and other developing countries. Due to the high content of organic material in municipal solid waste of Shiraz, minimization of these material and separation of dry and wet solid wastes must be noted from the people and municipalities

Investigating the source separation rate of municipal solid waste and economical and social determinance in Iran (2017)

Background: Municipal solid waste is a serious environmental issue in human societies. The source separation is a necessity for efficient municipal waste management (MSW). Objective: The aim of this study was to evaluate the source separation rate of MSW in several Iranian cities, as well as to identify the determinance of the participation level in source separation. Methods: In this study, the source separation rate of waste in 12 cities of Iran was evaluated by information from waste management organizations and the economical and social determinance were reviewed. Data were analyzed by Excel. Findings: In some cities, despite the coverage of about 90% of the training plans, the rate of source separation of MSW was less than 40%, and the average of source separation for all studied cities was 13.46%. The value of dry solid waste in all studied cities was estimated 705/000 tons per year which about 610/000 tons are collected as the mix with other wastes. Awareness and education as the cultural factors and social trust, economic issues, and the continuity of the source separation plan as the social factors have been effective in people's participation in these projects. Conclusion: Higher source separation rate in the wastes at the urban area requires consideration of all determinance in the planning and policy of WMS

Bioaugmentation and biostimulation methods for the decontamination of soils contaminated with petroleum compounds: a systematic review

Background and Objective: The purpose of this study is to identify and comprehensively evaluate international studies related to bioaugmentation and biostimulation methods for the remediation of soils contaminated with petroleum compounds. Materials and Methods: This systematic review study was conducted in April 2022. The present systematic review study was conducted to address two main questions: 1) Is biostimulation an effective process in the bioremediation of soils contaminated with petroleum hydrocarbons; and 2) Is bioaugmentation an effective process for bioremediation of soils contaminated with petroleum hydrocarbons? Global electronic databases (PubMed, Web of Science, and Scopus) were used to identify relevant studies. After a comprehensive review of studies, 123 studies consistent with the purpose were selected. Results: The results showed that biostimulation methods can have profound changes in bacterial, Archaebacteria, and soil fungal communities in terms of activity, frequency, and composition. In general, the nutrients and electron receptors added in the biostimulation process improve soil microbial activity, increasing the overall abundance of bacteria, and fungi and promoting selective replication of bacterial, archival, and fungal polyaromatic hydrocarbons (PHC) destroyers. The use of bioaugmentation technology in an environment contaminated with petroleum hydrocarbons has a positive effect on the refining process. However, it is necessary to precisely select the appropriate microbial strains. The most important factor in the removal of hydrocarbons in the soil is the selection of oil-decomposing microorganisms that can survive in high concentrations of pollutants. Conclusion: Therefore, the result indicated that biostimulation and bioaugmentation can efficiently improve the THP removal efficiency in contaminated soil by considering the environmental conditions

Compost Management in Iran: Opportunities and Challenges

Background: According to report of the World Food and Agriculture Organization (FAO), between 33 to 60 percent increase in agricultural production in the world due to the use of chemical fertilizers. Negative effects of fertilizers on the environment and health of living organisms, especially humans, has encountered the country whit challenges such as increasing the number of cancer. Therefore, it is necessary to replace chemical fertilizers whit biofertilizers such as compost. Compost Causes increases in productivity and controls soil erosion. Methods: In order to achieve the objectives of the research, literature review was conducted and to investigate the status of chemical fertilizers and compost in Iran and developed countries through internal and external databases, documents were collected. Results: Use of fertilizers in Europe forecasted to decline 16 million tons in 2030, while in the Iran, rate of fertilizer forecast increases to 6700 thousand tons in 2020. Total supply of compost in the country is 164 thousand tons in 2009 and will be to 590 thousand tons in 2016. The total demand is 472 thousand tons in 2009 and will be to 661 thousand tons in 2016. This indicates that there is 71 thousand tons deficiency in the supply until 2016. Conclusion: Use more of compost in the country, need to a multi-faceted management issue that Ministries, municipalities and recycle of organizations must be working together. Therefore necessary awareness aboute the adverse effects of indiscriminate use of fertilizers and also promote the use compost, in addition to reducing the use of chemical fertilizers, will be cause more demand for consumption of compost