Search results for "Aeration"
showing 10 items of 73 documents
Removal of DEHP in composting and aeration of sewage sludge.
2003
The potential of composting and aeration to remove bis(2-ethylhexyl) phthalate (DEHP) from municipal sewage sludge was studied with two dewatered sludges: raw sludge and anaerobically digested sludge. Composting removed 58% of the DEHP content of the raw sludge and 34% of that of the anaerobically digested sludge during 85 days stabilisation in compost bins. A similar removal for the anaerobically digested sludge was achieved in a rotary drum in 28 days. Less than 1% of DEHP was removed with the compost leachate. Although DEHP removal was greater from raw sludge compost than anaerobically digested sludge compost, the total and volatile solids removals were on the same level in the two compo…
Comparative study of laboratory-scale thermophilic and mesophilic activated sludge processes.
2005
Laboratory-scale mesophilic (20-35 degrees C) and thermophilic (55 degrees C) activated sludge processes (ASPs) treating diluted molasses wastewater were compared in effluent quality, removal of different COD fractions, sludge yield, floc size, and sludge settleability. The effect of polyaluminium chloride (PAC) with high cationic charge on sludge settleability and effluent quality was also studied. In the ASPs, the hydraulic retention time was 12h in both processes, corresponding to a volumetric loading rate of 3.2+/-1.0 kg COD(filt) m(-3)d(-1). The mesophilic ASP gave 79+/-18% and 90+/-2% and the thermophilic ASP gave 50+/-6% and 67+/-11% total COD (COD(tot)) and GF/A-filtered COD (COD(fi…
An innovative respirometric method to assess the autotrophic active fraction: Application to an alternate oxic-anoxic MBR pilot plant
2016
An innovative respirometric method was applied to evaluate the autotrophic active fraction in an alternate anoxic/oxic membrane bioreactor (MBR) pilot plant. The alternate cycle (AC) produces a complex microbiological environment that allows the development of both autotrophic and heterotrophic species in one reactor. The present study aimed to evaluate autotrophic and heterotrophic active fractions and highlight the effect of different aeration/non aeration ratios in a AC-MBR pilot plant using respirometry. The results outlined that the autotrophic active fraction values were consistent with the nitrification efficiency and FISH analyses, which suggests its usefulness for estimating the ni…
Quantifying the contribution of nitrification and denitrification to the nitrous oxide flux using 15N tracers.
2006
8 pages; International audience; Microbial transformations of nitrification and denitrification are the main sources of nitrous oxide (N2O) from soils. Relative contributions of both processes to N2O emissions were estimated on an agricultural soil using 15N isotope tracers (15NH4+ or 15NO3-), for a 10-day batch experiment. Under unsaturated and saturated conditions, both processes were significantly involved in N2O production. Under unsaturated conditions, 60% of N-N2O came from nitrification, while denitrification contributed around 85-90% under saturated conditions. Estimated nitrification rates were not significantly different whatever the soil moisture content, whereas the proportion o…
Biological nutrient removal using intermittent aeration in a hybrid moving bed biofilm reactor
2012
The paper presents an experimental study on a lab scale pilot plant in a Hybrid Moving Bed Biofilm Reactor. The pilot plant was fed with synthetic wastewater and was in operation considering two different operating conditions: continuous aeration and intermittent aeration. Both continuous and intermittent aeration were monitored and compared in order to seek the best conditions for carbon and nitrogen removal. At the beginning of the experimentation, an initial period of about 90 days was considered during which the pilot plant worked in bench scale configuration for allowing the formation of biofilm on the carriers. Once the biofilm growth was accomplished, the pilot plant worked for a fir…
The Carini Experimental Station for Wastewater Reuse in Agriculture – Preliminary Indications
1992
A two year experiment, to study the feasibility of wastewater reuse for a safe irrigation in the Sicilian context, has been initiated. Eight plots in two fields, totalling 629 m2, were planted with cowpeas (Vigna unguiculata L. Walp.), the irrigation water being supplied by a pilot plant treating 22 m3/day of municipal wastewater. The plant consists of an extended aeration biological system followed by rapid sand filtration and a choice of disinfection systems. Analyses performed on all waters used in the experiment indicate that safe irrigation water, virtually pathogen-free, can be produced if careful operational techniques are adopted. Despite all possible care, however, soil samples tak…
Effect of Aeration on the Microelectrochemical Characterization of Al[sub 2]Cu Intermetallic Phases
2009
Local probing of the galvanic coupling between micrometer-sized Al 2 Cu phases and the surrounding aluminum-based matrix of a specially heat-treated 2011 alloy is investigated using a microcapillary electrochemical cell. The aging of an isolated Al 2 Cu particle, i.e., selective dissolution of aluminum, is controlled by the aeration condition at the tip of the capillary due to the nature of the silicon membrane used as a gasket. The local electrochemical behavior of an isolated particle after aging confirms the mass transport control of the oxygen reduction on the galvanic coupling of the particle with the surrounding matrix.
Aggregative behavior of cohesive magnesium carbonate powders during fluidization and aerated discharge
2014
In this paper we studied the aerated discharge of two magnesium carbonate powders differing in their average diameter and particle size distribution. These samples were characterized by means of fluidization experiments and rheology shear tests carried out in a rotating shear cell. In the hopper discharge experiments, besides the discharge rates and the mass of residual solids as a function of the aeration rate, the aggregative behavior was observed by means of photographic techniques. Solids aggregates were actually visible within the aerated beds of solids during the fluidization experiments and in the streams of the discharging solids. Experimental data on the powder flow properties and …
Comparison of Cu-B Alloy and Stainless Steel as Electrode Material for Microbial Fuel Cell
2019
The microbial fuel cell (MFC) is a technical devices that electricity produces during wastewater treatment. One of the problems of MFCs is a low current density. Thus, it is necessary to search for new electrodes for MFC. The comparison of Cu-B alloy and stainless steel as catalyst for MFCs cathode is presented in this paper. The research included measurements of the concentration of COD, NH4+ and NO3− in three types of reactors: without aeration, with aeration and with using a MFC (with Cu-B and stainless steel cathode). It has been shown that effectiveness of MFC with Cu-B electrode is higher than effectiveness of MFC with stainless steel electrode.
Selective enrichment of heterotrophic nitrifiers <em>Alcaligenaceae</em> and <em>Alcanivorax</em> spp. from industrial wastew…
2020
Removal of nitrogen from wastewaters (WW) represents a global problem. The low nitrification rate during WW treatment is often caused by ecotoxicity. This problem is attributed mostly to the industrial WW. Our study was focused on the testing of industrial WW and activated sludge (AS) with the aim to reveal the abundance of nitrifiers and increase their biomass, thus, providing the additional step, i.e., bioaugmentation, within the technological process of WW treatment. Plating of AS on the selective solidified media designated for the 1st and 2nd nitrification stages, resulted in the shift in bacterial community structure with dominated Alcaligenaceae and Alcanivorax for the 1st stage, and…