Showing 12 results for Municipal Waste
A.h Sayyahzadeh, M.t Samadi,
Volume 2, Issue 2 (9-2009)
Abstract
Backgrounds and Objectives: Municipal Solid Waste (MSW) management and planning without adequate and reliable data about its physical components and generation rate are not obtainable. Because of MSW collection and landfilling expenses, in last decades, reuse and recycle of its components as an environmental object have been considered.
Materials and Methods:In this research, in order to determine the possibility of source recycling application in Malayer and physical composition of MSW, samples were taken by Truck-Load method and cluster random sampling from autumn 2006 until summer 2007 and analyzed for physical components percents. The obtained data were analyzed by One-Way ANOVA and Tuky statistical test. Also, public partnership was investigated. Public opinion deliberation was accomplished by dividing the city into several clusters. Questionnaires were filled by oral interview conversation.
Results: The results showed that average daily generation rate was 138 Tons and 0.88 Kg per person per day. The average percent of recyclable materials was about 11% of total daily generated wastes. Also 99% of residents had positive response to source recycling plans.
Conclusion: In general, by planning of enforceable reuse and recycling programmes, could avoid of 15 Tons of recyclable materials burial and save 19 millions Rials each day.
M Meschi Nezami, H Ganjidoust, N Mokhtarani, B Ayati,
Volume 3, Issue 4 (1-2011)
Abstract
Backgrounds and Objectives:Owing to the fact that the major environmental problem is production of surplus sludge in wastewater treatment plant, reducing the volume of produced sludge was objective of this research.
Materials and Methods: An anaerobic-aerobic SBR with working volume of 10 L was used to make micro-organism adapted and a polymer production reactor (PPR) with working volume of 1.5 L was used for producing polymer munisipal wastewater which contained different concentration of volatile fatty acids was consodered as the feed source (acetate and propionate) and this system was evaluated with SRT of 5, 7 and 10 days.
Results: The maximum polymer production efficiency observed within 5 days (SRT=5 days) though this efficiency was not significant in comparison with the two others time courses study. In this research the maximum polymer production efficiency at optimum condition was 25% of the sludge dry weight.
Conclusion: Experiment revealed that producing polymer from activated sludge reduced the volume of sludge and the maximum reduced sludge volume was obtained 19%.
Mahdi Kargar, Amir Hossein Mahvi,
Volume 5, Issue 1 (4-2012)
Abstract
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Backgrounds and Objectives: Large quantities of sludge are produced in
biological wastewater treatment. Because this sludge is highly rotten, it
should be stabilized before its disposal. Aerobic and anaerobic digestion is
widely considered as stabilization techniques. Because of high retention time
and sludge dewatering difficulties, reduction in retention time, operation and
maintenance should be given into consideration. Ultrasonic process increases
the enzymatic activity, so decreases the hydrolysis time, a limiting factor in
digestion process, and contributes to the decrease of the detention time. The
objective of this investigation is to determine the effect of ultrasound in
improving dewatering and stabilization of aerobic and anaerobic digested
sludge. In addition, the impact of ultrasonic treatment on improvement of
sludge dewatering and aerobic and anaerobic digestion is compared.
Materials and Methods: In this survey, samples of aerobic and
anaerobic digestion were collected from local full-scale Garb Town
and Tehran South wastewater treatment plant, respectively. The grab samples
were collected for 4 month from July to October 2010. Total numbers of 20
samples were collected biweekly for each type of digestion. Each sample was
sonicated for 15, 30, 60, and 90 min under 35 and 131 kHz frequencies
separately. Total solids, volatile solids , pH, temperature , total COD,
dissolved COD and settle able solids were measured. Ultrasound bath of the
solution in a 300 mL glass reactor was performed as a bath reactor with power
of 500 W.
Result: The results showed that the application of ultrasonic
wave increased dissolved COD and temperature and decreased volatile solid, pH
and settle able solids. Application of ultrasonic wave with frequency of 131
kHz decreased the VS and increased the dewatering of sludge more effective than
the 35 kHz frequency and the highest performance was at 15 min of time and 131
kHz of frequency. Also sonication method showed better efficiency for anaerobic
sludge samples compared to the aerobic sludge samples.
Conclusion: The results obtained showed that digestion
and dewatering properties of sludge improved by ultrasonic application.
Therefore it can be used as an alternative method for the sludge treatment.
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M Aqanaghad, G Moussavi,
Volume 9, Issue 3 (12-2016)
Abstract
Background and Objective: Being low cost of building and operation, anaerobic baffled reactor is considered superior to aerobic methods of wastewater treatment, especially for small communities. However, it needs to be studded for upgrade and overcome of its limitations. The purpose of this study was to evaluate the performance of FABR and RABR reactors for the municipal wastewater treatment at laboratory scale and in field conditions to determine their optimum conditions in reaching effluent discharge standards.
Materials and Methods: This study was conducted in Khoy wastewater treatment plant. FABR was operated for 267 days with hydraulic retention time of 18-48 h and RABR was operated for 90 days with media bad rotation of 10-50 rpm. The reactors were fed in line from the wastewater canal. Using composite sampling, 224 samples were taken from the inflow and outflow of the reactors and each sample was analyzed for parameters of COD, BOD, TSS, VSS, TKN, and TP.
Results: The reactor startup took about 107 days. FABR removal efficiency was 93-80, 21-10, and 30-21% for COD, TKN, and PO4 respectively at HRT of 48-18 h. FABR reached effluent disposal standard of TSS, COD, and BOD in all conditions and optimum HRT of 36 h. RABR reached to these standards at HRT 24 h and 50 rpm. However, none of them could meet the nutrient effluent standards.
Conclusion: FABR is an appropriate system for municipal wastewater treatment but for reaching N and P effluent standard, it should be combined with aerobic post-treatment. Moreover, in order to reuse the reactor's nutrient-rich effluent for irrigation; it can be reused as subsurface irrigation.
R Barati Rashvanlou, M Farzadkia,
Volume 11, Issue 1 (6-2018)
Abstract
Background and Objective: Ultrasonic disintegration is a pretreatment process before stabilization and dewatering that degrades sludge and changes its physical and chemical characteristics. The aim of this study was to investigate the effectiveness of ultrasonic in enhancing hydrolyses, stabilization and dewatering of municipal raw activated sludge.
Materials and Methods: The samples were taken from returned activated sludge and then they were exposed to ultrasonic (Frequency: 20 and 40 kHz) in different times (0.5, 1, 3, 5, 10, 15, 30, and 60 min). The effectiveness of ultrasonic for hydrolysis, stabilization and dewatering processes were determined with measuring TS, TSS, CST, SRF, VS, nVS, VSss, and VSsol.
Results: VSsol was increased by 73% in 15 min and at frequency of 20 kHz, whereas VSsol increas was100% at 10 min and 40 kHz. The reduction of VS was observed at 15 min and 20 kHz. Then after, it was reached 18% after 60 min. For 40 kHz, VS reduction started at 10 min and reached 24% after 60 min. Specific resistance of sludge at two frequencies of 20 and 40 kHz and contact time of 1 min were decreased by 25 and 20% respectively. The capillary suction time at the frequencies of 20 and 40 kHz and contact time of 1 min was decreased 28 and 21%, respectively.
Conclusion: The optimum effectiveness of ultrasonic in hydrolysis of organic matter of raw biological sludge was at the contact time of 10 min and frequency of 40 kHz. The highest stabilization at the frequency of 40 kHz was observed at 60 min contact time. The best condition for sludge dewatering was at frequency of 20 kHz and contact time of 1 min.
Ah Baghaie,
Volume 11, Issue 2 (9-2018)
Abstract
Background and Objective: Today, landfill management of municipal waste and soil pollution with heavy metals are major environmental problems. This research was conducted to evaluate the effect of Shazand municipal waste compost and Saveh pomegranate peel biochar on decreasing Pb availability in soil and sorghum plant.
Materials and Methods: Treatments consisted of applying Shazand municipal waste compost (0, 10 and 20 ton/ha) and Saveh pomegranate peel biochar (0 and 15 g/kg) in a Pb polluted soil (0, 600, 800 and 1000 mg Pb/kg soil). After 8 weeks of sorghum planting (Kimya CV.), the soil physio-chemical properties and soil and plant Pb concentration were measured.
Results: Applying 20 ton/ha municipal waste compost with 15 g/kg biochar increased soil pH by 0.4 units and decreased soil Pb availability by 11%. The similar results were observed for the root and shoot Pb concentrations, when the same amount of manure in a Pb polluted soil was applied (1000mg Pb/kg soil) that decreased the root and shoot Pb concentration by 1.8 and 2.2 times, respectively.
Conclusion: The result of this experiment showed that applying Shazand municipal waste compost and biochar can increase soil sorption properties and decrease soil or plant Pb concentration. However, the role of these organic amendments on supplying plant nutritional needs cannot be ignored.
Mohsen Ansari, Mahdi Farzadkia,
Volume 13, Issue 1 (4-2020)
Abstract
Background and Objective: Considering 829000 annual diarrhoeal deaths due to water pollution worldwide, the World Health Organization has emphasized that countries should reduce this rate by upgrading their wastewater treatment systems. The purpose of this study was to evaluate the performance of a modified up flow septic tanks reactor for treatment of synthetic wastewater.
Materials and Methods: In this experimental study, a modified septic tank system based on the upstream hydraulic regime, and also a conventional septic tank system was designed, manufactured, and operated. The municipal wastewater was used to operate, and synthetic wastewater was used to maintain. The major performance indicators of septic tanks include: volatile solids (VS), volatile suspended solids (VSS), total suspended solids (TSS) and chemical oxygen demand (COD) were sampled and measured in triplicates. The experiments were done in three hydraulic retention times of 24, 48, and 72 hr. Finally, the results of the study were analyzed by statistical tests in the SPSS software.
Results: The average removal of TSS, VS, VSS, and COD in HRT 24 h for the conventional reactor were 55.07, 27.36, 30.82, and 55.52%, respectively, and for the upstream-modified reactor at HRT 24 h were 66.57%, 34.05%, 38.47%, and 65.57%, respectively.
Conclusion: Changing septic tanks to up flow regimes and creating a cylindrical shape in conventional septic tanks, the removal efficiency of conventional septic tanks was improved, and the effluent contamination load was reduced.
Milad Ghaffariraad, Mehdi Ghanbarzadeh Lak,
Volume 13, Issue 2 (8-2020)
Abstract
Background and Objective: One of the major challenges facing landfill operation is the pollution caused by leachate infiltration beneath the landfill site. Comprehensive leachate management requires knowledge of production rate and factors affecting it Therefore, in this study, HELP software was used to calculate leachate quantity and analyze input data.
Materials and Methods: After designing a landfill by the existing conditions in Urmia city, the quantity of leachate was calculated using HELP software. Then, in different scenarios, the effects of precipitation, Curve number, and removal of the geomembrane layer on leachate production -were investigated. Finally, the impact of similar layer aggregation on the simulation process was discussed.
Results: According to the results, 7.67% of precipitation is converted to leachate. NO significant correlation was observed between precipitation and leachate production in a short period of time due to the absorption of rain by landfill layers. However, for the long term, as the absorption capacity was reached leachate produced. With increasing the Curve number from 70 to 90, leachate production decreased by 23%. Also, the removal of geomembrane from the final coating increased the amount of leachate by 78.46%. Furthermore, by replacing a 76cm dense clay layer instead of capping geomembrane layer, the same leachate generation rate was observed. Re- running the software after layer aggregation showed a slight difference in leachate estimation compared to the baseline state.
Conclusion: Leachate generation modeling and identifying influential parameters with the aim of HELP software, may be helpful in landfill leachate management prior to its construction.
Reza Barati Rashvanlou, Mahdi Farzadkia, Abbas Ali Moserzadeh,
Volume 14, Issue 1 (5-2021)
Abstract
Background and Objective: Hydrolysis of fat, oil and grease by ultrasonic waves is a pre-treatment method before anaerobic digestion which can change their physical, chemical and biological properties. The main purpose of this study was to investigate the efficiency of ultrasonic waves to improve the hydrolysis process and its use as an auxiliary substrate to increase the efficiency of anaerobic digestion process along with municipal sewage sludge.
Materials and Methods: Sampling of fat and oil of the degreasing unit and physical preparation by conducting ultrasonic waves with frequencies of 20 kHz and current density of 0.012-0.14 W/mL within 0-12 min were performed. The efficiency of pretreatment process were performed through tests such as soluble chemical oxygen demand (SCOD), and lipase enzyme activity. In addition, the anaerobic digestion process were evaluated by measuring the TS, VS, VA (volatile acidity), alkalinity, biogas production and biogas methane content.
Results: The results showed that the highest increase in the activity of lipase enzyme under ultrasonic effect with a power of 0.1 w/mL was obtained after 8 minutes. Organic loading with 10%, 20% and 40% FOG/MSS ratios: resulted in 55%, 66% and 64% increase in methane production compared to the control samples, respectively. Organic loading over the 40% FOG/MSS caused a limitation in the simultaneous digestion process.
Conclusion: The results show that ultrasonic wave pretreatment with optimal power and time can improve the hydrolysis of TFOG while increasing the activity of lipase enzyme and also its use as an auxiliary substrate can enhance digestion performance and make digestion more stable.
Mohsen Ansari, Mahdi Farzadkia,
Volume 14, Issue 2 (9-2021)
Abstract
Background and Objective: Wastewater treatment and stabilization always imposes costs and consequently a lot of energy on wastewater treatment plants. To achieve the purification and stabilization of as much sludge as possible, breaking complex components into simpler components is considered a critical step. Therefore, this study aimed to evaluate the feasibility of treating the produced sludge in the municipal wastewater treatment plant using ozonation method.
Materials and Methods: In this study, sludge was obtained from the return line of activated sludge from the wastewater treatment plant in the south of Tehran. An ozonation generator with a discharge rate of 3 L/min and an ozone concentration of 40-35 mg/L was discharged to the reactor and the residual ozone concentration was measured by iodometric method. Finally, the total suspended solids and volatile, soluble chemical oxygen demand, total organic carbon, and biochemical oxygen demand during ozonation processes were measured using the Standard Method.
Results: The results of this study showed that the amount of TSS and VSS in the activated return sludge decreased from 4060 to 2100 mg/L and from 3300 to 1850 mg/L during the ozonation process, respectively. However, SCOD, TOC, and SBOD had an upward trend of about 18, 11.7, and 14 times in the same reaction time, respectively.
Conclusion: According to the results of this study, it can be concluded that the ozonation system can be proposed as a suitable process for the decomposition of sludge produced in wastewater treatment plants and increasing the biodegradability of these sludges.
Fariba Ebrahimi Fini, Farzam Babaei Semiromi, Mohammad Reza Tabesh, Mahdi Jalili Ghazizade, Amir Hushang Heidari,
Volume 15, Issue 3 (12-2022)
Abstract
Background and Objective: The critical step of policymaking and planning for the local governments to select appropriate waste management methods, is comprehensive information on solid waste generation. Waste generation rate and composition may vary from year to year because many factors influence it. This research identified the most important factors influencing the future of household waste generation and composition in Tehran, and how these factors affect each other.
Materials and Methods: This research is based on future studies methods which are carried out using a combination of quantitative and qualitative models. Due to the nature of this research, structural analysis, Micmac software and Delphi survey were used.
Results: In this regard, after holding many meetings with 22 of the experts as the statistical population of the research, 14 effective factors were identified. The influential factors were then analyzed in the framework of the Cross-impact matrix in the Micmac software. The results showed that what can be understood from the state of the dispersion page of the variables indicated the system instability, with most of the variables dispersed around the diagonal axis of the screen.
Conclusion: Finally, considering the high scores received by direct and indirect influences, 10 key factors were identified. “Economic Growth”, “Digital Transformation and Technological Advances”, “Amendment of Existing laws, Enactment and Implementation of New and Specialized Laws”, and “Increased Awareness about waste and Attraction of Citizen Participation through Education and Provision of Information” were identified among these 10 factors as the driving forces influencing generation and composition, of household waste in Tehran in the Next Twenty Years.
Sadaf Moeini, Seyed Masoud Monavari, Fariba Zamani Hargolani,
Volume 17, Issue 2 (9-2024)
Abstract
Background and Objective: The increase in waste at integrated urban waste centers, along with the problems and adverse environmental consequences due to their inappropriate establishment have become more apparent. This research was conducted with the aim of determining and investigating environmental pollution in urban waste integration management centers.
Materials and Methods: This research investigated the environmental pollutants in the integrated waste center in Koohak at various distances ranging from 0 to 900 meters. Four main criteria—waste, water pollution, air pollution and sound pollution—were determined, each with 16 sub-criteria. The map of each criterion and sub-criteria were multiplied by the coefficients they received from the weights obtained using the Analytical Network Process (ANP) method. By combining the criteria using the Weighted Linear Combination (WLC) method and superimposing them, finally, the studied area was ultimately classified into three classes: inappropriate, medium, and suitable.
Results: Air pollution, with a weight of 0.26, had the highest rating compared to the other three criteria. Noise pollution (0.25), water pollution (0.24) and waste-related criteria (0.23) were ranked next. The results of the Kruskal-Wallis test indicated a significant difference in pollutant concentrations between different stations (p<0.05). Additionally, the results show that the average concentration of pollutants at distances of 0-300 meters differed significantly from those at all other distances (p<0.05). After determining the suitable zones using the WLC method, the results showed that 62.5 percent of the criteria were approved by the environmental organization.
Conclusion: By examining the results of the methods used in this research, it can be concluded that the combination of ANP and WLC methods provide effectivee results. However, uncertainty in subjective decisions and time constraints in decision-making have posed challenges in assessing waste collection in integrated urban waste centers.
