Nutrients’ behavior and removal in an activated sludge system receiving Olive Mill Wastewater

Co-digestion of waste activated sludge (WAS) with agro-industrial organic wastewaters is a technology that is increasingly being applied in order to produce increased gas yield from the biomass. In this study, the effect of olive mill wastewater (OMW) on the performance of a cascade of two anaerobic continuous stirred tank (CSTR) reactors treating thickened WAS at mesophilic conditions was investigated. The objectives of this work were (a) to evaluate the use of OMW as a co-substrate to improve biogas production, (b) to determine the optimum hydraulic retention time that provides an optimised biodegradation rate or methane production, and (c) to study the system stability after OMW addition in sewage sludge. The biogas production rate at steady state conditions reached 0.73, 0.63, 0.56 and 0.46 lbiogas/lreactor/d for hydraulic retention times (HRTs) of 12.3, 14, 16.4 and 19.7 d. The average removal of soluble chemical oxygen demand (sCOD) ranged between 64 and 72% for organic loading rates between 0.49 and 0.75 g sCOD/l/d. Reduction in the volatile suspended solids ranged between 27 and 30%. In terms of biogas selectivity, values of 0.6 lbiogas/g tCOD removed and 1.1 lbiogas/g TVS removed were measured.

Download Full-text

Towards PHA production from wastes: The bioconversion potential of different activated sludge and food industry wastes into VFAs through acidogenic fermentation

10.21203/rs.3.rs-341352/v1 ◽

2021 ◽

Author(s):

Gabriela Montiel-Jarillo ◽

Teresa Gea ◽

Adriana Artola ◽

Javier Fuentes ◽

Julián Carrera ◽

...

Keyword(s):

Activated Sludge ◽

Low Cost ◽

Carbon Sources ◽

Olive Mill Wastewater ◽

High Rate ◽

Methanogenic Activity ◽

Batch Tests ◽

Acidogenic Fermentation ◽

Pha Production ◽

Olive Mill

Abstract Acidogenic fermentation of wastes produces volatile fatty acid (VFA)-rich streams that can be used as low-cost carbon sources for polyhydroxyalkanoate (PHA) production. In this study, an inoculum collected from an anaerobic reactor of a municipal WWTP was conditioned to suppress methanogenic activity. The heat-shock conditioning method of the inoculum proved to be more efficient than acid and alkaline conditioning methods for methanogen inhibition. Then, the pre-conditioned inoculum was used to determine the acidogenic potential of different wastes: three waste activated sludge (WAS) samples generated at different sludge retention times (SRTs, 2, 7 and 14 days), olive mill wastewater (OMW), glycerol, apple pomace (AP) and winterization oil cake (WOC). Batch tests were performed in quintuplicate at 37°C and pH 7. A higher degree of acidification was observed for high-rate activated sludge (2 days of SRT) (69%), followed by olive mill wastewater (OMW) (43%), while the lowest was for glycerol (16%). The results for the winterization oil cake (WOC) samples interestingly elucidated a high content of propionic acid with a high odd-to-even ratio (0.86) after fermentation. Feeding the VFA profile obtained from WOC into a PHA production system led to a significant production of 0.64 g PHA g− 1 C with 30% polyhydrobutyrate (PHB) to 69% polyhydroxyvalerate (PHV) as monomeric units of HB-co-HV, decoupling the need for a related carbon source for co-polymer production.

Download Full-text

Influence of the heavy metals concentration on the anaerobic co-digestion performance of activated sludge and Olive mill wastewater

10.21203/rs.3.rs-761999/v1 ◽

2021 ◽

Author(s):

khalideh Al bkoor Alrawashdeh

Keyword(s):

Heavy Metals ◽

Activated Sludge ◽

Removal Efficiency ◽

Biogas Production ◽

Olive Mill Wastewater ◽

Organic Load ◽

High Concentration ◽

Digestion Process ◽

The Impact ◽

Olive Mill

Abstract The influence of heavy metals (HMs) on the anaerobic co-digestion process (AD) of activated sludge and olive mill wastewater (50% v/v) was studied. Biogas production, methane CH4 concentration, and removal efficiency of the TS, VS, and TCOD were investigated in mesophilic conditions. The toxicity and inhibitory effects of HMs at different concentrations (15–60 ppm) on the digestion process were specified.A high concentration of HMs has resulted in a significant decrease in AD performance in terms of organic load degradation, biogas production, CH4 content, TCOD removal efficiency, and inhibition of hydrogenotrophic-methanogenic bacteria. The toxicity of HMs can be arranged according to TS removal: Cu > Zn ≈ Cr > Pb, according to TCOD removal efficiency: Cu > Cr > Zn > Pb, biogas production: Cu > Zn ≈ Cr > Pb, CH4 content: Cu > Zn > Cr > Pb. Also, the results showed that the methanogenic stage was influenced negatively and more than the acetogenic stage, where Pb < 30 ppm had a lower inhibitor effect on the digestion, while the lowest concentration of Cu(II) leads to the significant inhibition of the AD process is ≥ 10 ppm. At the concentration of 60 ppm of Pb, Zn, Cr, and Cu, the COD removal efficiency was 17.07%, 15.64%, 19.13%, and 20.53% respectively, TS removal was 17.31%, 13.44%, 16.28%, and 10.37 respectively, the VS removal was 19.4%, 14.445, 7.94% and 5.17%, respectively. Also, at the concentration of 60 ppm, biogas production has decreased by 51.55%, 66.46%, 68.1%, and 73.91%, respectively.Novelty statement This study provides new data specifying the inhibitor HMs concentration and the impact of HMs at the various concentrations on the anaerobic co-digestion of active sludge and olive mill wastewater

Download Full-text

A simple method to evaluate the short-term biogas yield in anaerobic codigestion of WAS and organic wastes

Water Science & Technology ◽

10.2166/wst.2008.502 ◽

2008 ◽

Vol 58 (8) ◽

pp. 1615-1622 ◽

Cited By ~ 13

Author(s):

D. Scaglione ◽

S. Caffaz ◽

E. Ficara ◽

F. Malpei ◽

C. Lubello

Keyword(s):

Activated Sludge ◽

Municipal Solid Waste ◽

Solid Waste ◽

Olive Mill Wastewater ◽

Organic Substrates ◽

Organic Fraction ◽

Short Term ◽

Simple Method ◽

Anaerobic Degradability ◽

Olive Mill

The present study was aimed at setting and applying a procedure to measure the anaerobic degradability of different organic substrates by short-term tests (2–7 days) carried out at lab-scale with a low food to biomass (F/M) ratio. All tests were carried out using an acclimated sludge taken from a pilot-plant anaerobic digester (200 L). Trials were performed with a manometric system. The experimental reliability of the device in measuring the anaerobic degradability was assessed by several preliminary tests carried out using acetate and glucose as reference substrates. The average conversion to methane was 99% for acetate and of 83% for glucose. The results of tests in triplicate showed the high repeatability of the method with an average coefficient of variation lower than 2%. Then, the lab-scale procedure was applied to study the short-term anaerobic degradability of complex organic substrates: thickened waste activated sludge, two kinds of organic fraction of municipal solid waste (a kitchen waste and a fruit and vegetable waste collected at the wholesale market of Florence), olive mill wastewater and freshly harvested grass. Results indicated that organic fraction of municipal solid waste, olive mill wastewater and grass were characterized by a much higher anaerobic degradability if compared to the thickened activated sludge, well in agreement with literature data.

Download Full-text

Oxidation Ditch

10.31219/osf.io/kj6dz ◽

2018 ◽

Author(s):

Gede H Cahyana

Keyword(s):

Activated Sludge ◽

Special Form ◽

Oxidation Ditch ◽

End Point ◽

Activated Sludge System

As a part of activated sludge system, oxidation ditch has a special form like a canal without end point. Rotor is used to diffuse oxygen from air to the water.

Download Full-text

Parameters for Measuring the Activity and Viability of Activated Sludge

Water Quality Research Journal ◽

10.2166/wqrj.1974.022 ◽

1974 ◽

Vol 9 (1) ◽

pp. 235-249 ◽

Cited By ~ 1

Author(s):

S.G. Nutt ◽

K.L. Murphy

Keyword(s):

Organic Carbon ◽

Activated Sludge ◽

Biological System ◽

Analytical Methods ◽

Heterogeneous System ◽

Removal Rate ◽

Bacterial Species ◽

Atp Content ◽

Culture Studies ◽

Activated Sludge System

Abstract Conventional wastewater parameters are accepted as inadequate estimates of the condition of activated sludge but numerous other indices have been suggested as specific measurements of the activity and viability of the biomass. Literature in the related fields of microbiology and biochemistry were reviewed in order to select the most appropriate activity parameters for application to a heterogeneous biological material. Modified analytical methods were applied to a well-controlled biological system containing a single predominant bacterial species to evaluate the relative merit of each as an indicator of viability and activity. The potential of each parameter in a complex heterogeneous system was determined by monitoring each index in a bench activated sludge system. The predominant culture studies indicated that the ATP content of the biomass and the dehydrogenase activity were potential indicators of cell viability in a simple system. However, in the complex activated sludge system, only the ATP content showed significant correlation to the organic carbon removal rate.

Download Full-text