Gholamreza Bidhendi; Naser Mehrdadi; Mehdi Asadi Ghalhari
Volume 21, Issue 6 , January and February 2015, , Pages 1205-1213
Abstract
Background: Today, production of energy from renewable sources such as biomass is now receiving serious attention to replace fossil fuels. Accordingly, the aim of this study was electricity production due to wastewater treatment.
Materials and Methods: The pilot of the air Cathode microbial fuel cell ...
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Background: Today, production of energy from renewable sources such as biomass is now receiving serious attention to replace fossil fuels. Accordingly, the aim of this study was electricity production due to wastewater treatment.
Materials and Methods: The pilot of the air Cathode microbial fuel cell (MFC) was used at laboratory scale. The external resistance was determined about 1000 Ω using a polarization curve. The system was operated as batch mode. Voltage produced by the system in 25 and 50 mM phosphate buffer solution (PBS) was determined. Then the output power and current density was calculated. To determine the efficiency of the air cathode MFC in wastewater treatment, COD of wastewater (influent and effluent) was also measured.
Results: COD removal efficiencies of wastewater in both 25 and 50mM PBS were 90.86 ± 1.4 and 90.45 ± 0.48%, respectively. The maximum voltage, power and current density were 587mV, 830mW/m2 and 487mA/m2 in 25mM PBS and 596mV, 843mW/m2 and 502mA/m2 in 50mM PBS, respectively. Duration of the voltage produced in 50mM PBS was higher than 25mM PBS (2 times) due to higher resistance against decrease in pH value.
Conclusion: Air cathode microbial fuel cells in addition to compete with conventional systems such as activated sludge, in wastewater treatment, can produce energy simultaneously.
Ahmad Allahabadi; AliAkbar Azimi; Naser Mehrdadi; Abolfazl Rahmani Sani; Ali Torabian
Volume 18, Issue 1 , March and April 2011, , Pages 33-40
Abstract
Background and Purpose: Subsurface flow wetlands are one of the successful treatment methods used for municipal and industrial wastewater treatment، and are economical in terms of energy consumption and workforce. Much research has been conducted on wetland operation output in wastewater treatment، ...
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Background and Purpose: Subsurface flow wetlands are one of the successful treatment methods used for municipal and industrial wastewater treatment، and are economical in terms of energy consumption and workforce. Much research has been conducted on wetland operation output in wastewater treatment، but no enough information is available on their start-up and maintenance. The present study investigates the circumstance of starting up and implementing a wetland.
Methods and Materials: In this experimental study، two subsurface flow wetlands with a two-day detention time and two pretreatment units were built. The former was similar to Primary Settling tank with a 4-hour detention time and the latter was similar to anaerobic pond equipped a with digestion pit with a two-day detention time in a pilot scale. The wastewater (BoD5 = 250 mg/l، Tss=320 mg.l and ph=7.2) from municipal network in Sabzevar، Iran was used for irrigation; the pilot implementation and maintenance took one year.
Results: Pilot operation indicated that the principal factors in implementing subsurface flow wetland were temperature، non-penetrateability of the bed، and wastewater ingredients. However، pretreatment and bed obstruction were the limiting parameters of the wetland maintenance.
Conclusion: Pretreatment of the subsurface flow of wetlands does not yield a high output; and if anaerobic ponds equipped with digestion pits are used، the treatment output is significantly enhanced، and the wetland operation will face minimum barriers.
AA AZIMI; A RAHMANI SANI; N MEHRDADI
Volume 14, Issue 4 , January and February 2008, , Pages 198-204
Abstract
Background and Purpose: Waste stabilization ponds as a natural treatment method have been found among successful methods in municipal wastewater treatment. They are very costeffective in energy and manpower. Low efficiency rates and vast area required are some of their drawbacks which are less attended ...
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Background and Purpose: Waste stabilization ponds as a natural treatment method have been found among successful methods in municipal wastewater treatment. They are very costeffective in energy and manpower. Low efficiency rates and vast area required are some of their drawbacks which are less attended to. Therefore this study intends to research the optimization methods in anaerobic ponds.
Methods and Materials: In this experimental study, two anaerobic ponds were built in pilot scale with 48 hours detention time, 12 m2 area (6x2 m) and 4m depth. The control pond was a conventional pond; the optimized pond was built in two parts: a digestion pit and a detention time of 12 hours, and the anaerobic pond with 8 baffles with a detention time of 36 hours. The wastewater with BOD5=250 mg/l and TSS=320 mg/l from municipal network in Sabzevar, Iran was used; the pilot took one year from December 2006 to December 2007. The collected data were analyzed in Excel and Tsp7.
Result: Average removal efficiency for BOD5 and TSS in the conventional pond were 37% and 53% respectively; the figures for the optimized pond were 68% and 85% respectively. Conclusion: Using optimized anaerobic ponds enhances the removal efficiency rate.