Monitoring the oxygen transfer efficiency of full-scale aeration systems: investigation method and experimental results

2014 ◽  
Vol 70 (1) ◽  
pp. 8-14 ◽  
Author(s):  
Riccardo Gori ◽  
Alice Balducci ◽  
Cecilia Caretti ◽  
Claudio Lubello
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Oxygen Transfer ◽  
Treatment Plant ◽  
Transfer Efficiency ◽  
Chemical Cleaning ◽  
Total Recovery ◽  
Aeration System ◽  
Oxygen Transfer Efficiency ◽  
Urban Wastewater Treatment

This paper reports the results of a series of off-gas tests aimed at monitoring the evolution of the oxygen transfer efficiency in an urban wastewater treatment plant (3,500 population equivalent) located in Tuscany (Italy). The tests were conducted over a 2-year period starting with the testing of the aeration system. It was found that in the absence of membrane-panel cleaning operations, the oxygen transfer efficiency under standard conditions in process water (αSOTE) dropped from 18 to 9.5% in 2 years. This gives rise to a 40% increase in the wastewater treatment plant annual energy costs. The on-site chemical cleaning of the diffusers allowed for an almost total recovery of the transfer efficiency (αSOTE equal to 16%). The use of the off-gas method for monitoring the oxygen transfer efficiency over time is therefore essential for enabling correct planning of the cleaning operations of the diffusers and for cutting the energy consumption and operating costs of the aeration system.

Microplastic contamination in a conventional wastewater treatment plant in Thailand

2021 ◽  
pp. 0734242X2098205
Author(s):  
Katekanya Tadsuwan ◽  
Sandhya Babel
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Environmental Concern ◽  
Liquid Fraction ◽  
Treatment Plant ◽  
Dry Weight ◽  
Plastic Waste ◽  
Sludge Sample ◽  
Global Environmental ◽  
Urban Wastewater Treatment

Plastic waste has become a global environmental concern. One type of plastic waste is microplastics (MPs), which can spread easily in the environment. Wastewater effluent is one of the land-based sources of MPs. This study investigates the amount of microplastic (MP) pollution in an urban wastewater treatment plant (WWTP) in Thailand. Water samples were collected and examined to find the types, morphology and sources of MPs. Wastewater was filtered through a set of sieves ranging from 5 mm to 0.05 mm. Sludge samples were also collected to find the potential risk from the application of dried sewage sludge. Fourier-transform infrared spectroscopy (FTIR) was used to confirm the types of MPs. The amount of MPs in the influent was 26.6 ± 11.8 MPs/L. More than one-third of MP particles were removed after a grit trap, followed by 14.24% removal in the secondary treatment. If the peak flow rate of the WWTP is reached, 2.32 × 109 MP particles can be released daily. The amount of MPs in a sludge sample was 8.12 ± 0.28 × 103 particles/kg dry weight. Dry sludge is one of the potential sources of MP contamination in agricultural soil. Most MPs in the liquid fraction and sludge sample were fibres. Results from FTIR analysis showed that the major types of MPs in the WWTP were polyester fibres, followed by polypropylene, polyethylene, silicone polymer and polystyrene. This finding indicates that a conventional WWTP may act as a path by which MPs enter the environment.

Life Cycle Assessment of Urban Wastewater Treatment

2014 ◽  
Vol 535 ◽  
pp. 346-349
Author(s):  
Mei Wang ◽  
Ming Yang ◽  
Jun Liu ◽  
Jian Fen Li
Keyword(s):  
Wastewater Treatment ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Wastewater Treatment Plant ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
Urban Wastewater ◽  
Urban Sewage ◽  
Urban Wastewater Treatment ◽  
Whole Life Cycle

Effect and benefits of a product or service could be analyzed and evaluated by life cycle assessment during the whole life cycle. Urban sewage treatment plants could improve and control urban water pollution escalating, but it also had certain harm to environment. Effect and benefits of urban wastewater treatment plant A and B were analyzed and evaluated, 13 factors were selected, and comprehensive benefits were researched quantificationally using the method of analytic hierarchy process. It found that urban wastewater treatment plant A who applied A/O process had better benefits than urban wastewater treatment plant B who applied BIOLAK process.

Volatile organic compound emissions during the composting of biosolids from a domestic wastewater treatment plant

2002 ◽  
Vol 46 (10) ◽  
pp. 195-198 ◽  
Author(s):  
C.X. Ramos ◽  
S.L. Estévez ◽  
E. Giraldo
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Solid Phase ◽  
Treatment Plant ◽  
Domestic Wastewater ◽  
Aeration System ◽  
Domestic Wastewater Treatment ◽  
Emission Behavior ◽  
Volatile Organic Compound Emissions ◽  
Aliphatic And Aromatic Hydrocarbons

VOCs emitted by two composting static piles of biosolids coming from the “El Salitre” wastewater treatment plant (Bogotá, Colombia) were analysed during the composting process. Each pile in its sampling time was maintained with a different aeration system. The sampling was made using Solid Phase Microextraction (SPME); separation and identifications were made using Gas Chromatography (GC) coupled to Mass Spectrometry (MS). Aliphatic and aromatic hydrocarbons, chlorinated compounds, ketones, mercaptans, alcohols and amines were identified in concentrations greater than the norms stipulated by the EPA for inhalation in humans beings. The emission behavior varied according to the aeration system used.

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