Evaluation of anaerobic digestion processes for short sludge-age waste activated sludge combined with anammox treatment of digestate liquor

2015 ◽  
Vol 73 (5) ◽  
pp. 1052-1060 ◽  
Author(s):  
Huoqing Ge ◽  
Damien Batstone ◽  
Jurg Keller
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Removal Rate ◽  
Ammonia Solution ◽  
High Rate ◽  
Meat Processing ◽  
Sludge Digestion ◽  
Volatile Solids ◽  
Anammox Activity ◽  
Solids Retention

The need to reduce energy input and enhance energy recovery from wastewater is driving renewed interest in high-rate activated sludge treatment (i.e. short hydraulic and solids retention times (HRT and SRT, respectively)). This process generates short SRT activated sludge stream, which should be highly degradable. However, the evaluation of anaerobic digestion of short SRT sludge has been limited. This paper assesses anaerobic digestion of short SRT sludge digestion derived from meat processing wastewater under thermophilic and mesophilic conditions. The thermophilic digestion system (55°C) achieved 60 and 68% volatile solids destruction at 8 day and 10 day HRT, respectively, compared with 50% in the mesophilic digestion system (35°C, 10 day HRT). The digestion effluents from the thermophilic (8–10 day HRT) and mesophilic systems were stable, as assessed by residual methane potentials. The ammonia rich sludge dewatering liquor was effectively treated by a batch anammox process, which exhibited comparable nitrogen removal rate as the tests using a control synthetic ammonia solution, indicating that the dewatering liquor did not have inhibiting/toxic effects on the anammox activity.

scholarly journals High-Rate Anaerobic Digestion of Waste Activated Sludge by Integration of Electro-Fenton Process

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 626 ◽  
Author(s):  
Emna Feki ◽  
Audrey Battimelli ◽  
Sami Sayadi ◽  
Abdelhafidh Dhouib ◽  
Sonia Khoufi
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Volatile Fatty Acids ◽  
Continuous Fermentation ◽  
Removal Rate ◽  
High Rate ◽  
Organic Loading Rate ◽  
Waste Activated Sludge ◽  
Capillary Suction ◽  
Biogas Yield

Anaerobic digestion (AD), being the most effective treatment method of waste activated sludge (WAS), allows for safe disposal. The present study deals with the electro-Fenton (EF) pretreatment for enhancing the WAS biogas potential with low-cost iron electrodes. The effect of pretreatment on the physicochemical characteristics of sludge was assessed. Following EF pretreatment, the pH, conductivity, soluble chemical oxygen demand (SCOD), and volatile fatty acids (VFA) increased to 7.5, 13.72 mS/cm, 4.1 g/L, and 925 mg/L, respectively. Capillary suction time (CST) analysis highlighted the dewaterability effect of EF on WAS, as demonstrated by the decrease in CST from 429 to 180 s following 30 min of pretreatment. Batch digestion assays presented an increase in the biogas yield to 0.135 L/g volatile solids (VS) after 60 min of EF pretreatment in comparison to raw sludge (0.08 L/g VS). Production of biogas was also found to improve during semi-continuous fermentation of EF-pretreated sludge conducted in a lab-scale reactor. In comparison to raw sludge, EF-pretreated sludge produced the highest biogas yield (0.81 L biogas/g VS) with a high COD removal rate, reaching 96.6% at an organic loading rate (OLR) of 2.5 g VS/L. d. Results revealed that the EF process could be an effective WAS disintegration method with maximum recovery of bioenergy during AD.

Anaerobic digestion of waste activated sludge combined with ozone post-treatment and recycling

2003 ◽  
Vol 48 (4) ◽  
pp. 61-68 ◽  
Author(s):  
A. Battimelli ◽  
C. Millet ◽  
J.P. Delgenès ◽  
R. Moletta
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Removal Rate ◽  
Operating Conditions ◽  
Cod Removal ◽  
Process Efficiency ◽  
Recycling Rate ◽  
Waste Activated Sludge ◽  
Digested Sludge ◽  
Combined Process

The aim of the study was to determine the performances of a combined ozone/anaerobic digestion system for waste activated sludge reduction. The objective was the estimation of the process efficiency and stability when keeping constant influent flow while increasing recycled chemically treated flow. The ozonation step consisted in a partial oxidation (0.16 g O3/g SS) of the anaerobic mesophilic digested sludge. Chemical treatment of digested sludge resulted in a threefold COD solubilization and a decrease of SS of 22%. Some of the advantages of digested sludge ozonation were: deodorization, better settlement and a reduction in viscosity. However there were drawbacks: foaming during ozonation and, at high ozone doses, poorer filterability. The anaerobic digestion was carried out over 6 months with an increasing recycling of ozonated flow. Suspended solids removal rate and COD removal rate were compared with initial operating conditions for the biological reactor and the whole combined process. The optimum recycling rate was 25% with increases of SS removal and COD removal of 54% and 66% respectively when considering the combined process; corresponding to a decrease of the hydraulic retention time from 24 days to 19 days.

scholarly journals Methanosarcinaceae and Acetate-Oxidizing Pathways Dominate in High-Rate Thermophilic Anaerobic Digestion of Waste-Activated Sludge

2013 ◽  
Vol 79 (20) ◽  
pp. 6491-6500 ◽  
Author(s):  
Dang P. Ho ◽  
Paul D. Jensen ◽  
Damien J. Batstone
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Retention Time ◽  
Elevated Temperatures ◽  
Stable Carbon Isotope ◽  
High Rate ◽  
Continuous Reactor ◽  
Waste Activated Sludge ◽  
Acetate Oxidation ◽  
Syntrophic Acetate Oxidation

ABSTRACTThis study investigated the process of high-rate, high-temperature methanogenesis to enable very-high-volume loading during anaerobic digestion of waste-activated sludge. Reducing the hydraulic retention time (HRT) from 15 to 20 days in mesophilic digestion down to 3 days was achievable at a thermophilic temperature (55°C) with stable digester performance and methanogenic activity. A volatile solids (VS) destruction efficiency of 33 to 35% was achieved on waste-activated sludge, comparable to that obtained via mesophilic processes with low organic acid levels (<200 mg/liter chemical oxygen demand [COD]). Methane yield (VS basis) was 150 to 180 liters of CH4/kg of VSadded. According to 16S rRNA pyrotag sequencing and fluorescence in situ hybridization (FISH), the methanogenic community was dominated by members of theMethanosarcinaceae, which have a high level of metabolic capability, including acetoclastic and hydrogenotrophic methanogenesis. Loss of function at an HRT of 2 days was accompanied by a loss of the methanogens, according to pyrotag sequencing. The two acetate conversion pathways, namely, acetoclastic methanogenesis and syntrophic acetate oxidation, were quantified by stable carbon isotope ratio mass spectrometry. The results showed that the majority of methane was generated by nonacetoclastic pathways, both in the reactors and in off-line batch tests, confirming that syntrophic acetate oxidation is a key pathway at elevated temperatures. The proportion of methane due to acetate cleavage increased later in the batch, and it is likely that stable oxidation in the continuous reactor was maintained by application of the consistently low retention time.

High rate mesophilic, thermophilic, and temperature phased anaerobic digestion of waste activated sludge: A pilot scale study

2012 ◽  
Vol 32 (6) ◽  
pp. 1196-1201 ◽  
Author(s):  
David Bolzonella ◽  
Cristina Cavinato ◽  
Francesco Fatone ◽  
Paolo Pavan ◽  
Franco Cecchi
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Pilot Scale ◽  
High Rate ◽  
Waste Activated Sludge

scholarly journals Temperature Phased Anaerobic Digestion at the Intermediate Zone of 45 °C: Performances, Stability and Pathogen Deactivation

2021 ◽  
Vol 50 (7) ◽  
pp. 1827-1841
Author(s):  
Nuruol Syuhadaa Mohd ◽  
Baoqiang Li ◽  
Shaliza Ibrahim ◽  
Rumana Riffat
Keyword(s):  
Anaerobic Digestion ◽  
Intermediate Zone ◽  
Second Stage ◽  
Class A ◽  
Volatile Solids ◽  
Solids Retention ◽  
High Alkalinity ◽  
Acetate Accumulation ◽  
Better Than ◽  
Class A Biosolids

Temperature phased anaerobic digestion (TPAD) systems with conventional sequences (first stage of 55 ℃ and second stage of 35 ℃) have been widely studied. However, very limited studies were available on TPAD system with the first stage operated at the intermediate zone of 45 °C, mainly due to the notion that limited microbial activity occurs within this zone. The objective of this research was to evaluate the performance, stability and the capability of 45 °C TPAD in producing class A biosolids, in comparison to a conventional TPAD. Four combinations of TPAD systems were studied, 45 ℃ TPAD 2.5/10 (1st stage solids retention time (SRT) 2.5 days/2nd stage SRT 10 days), 45 ℃ TPAD 7.5/10, 55 ℃ TPAD 2.5/10 and 55 ℃ TPAD 7.5/10. Among all, 45 ℃ TPAD 7.5/10 was found to have the best performances, attributed to its high volatile solids (VS) destruction (58%), minimal acetate accumulation (127 mg/L), high methane yield (0.58 m3 CH4/kg VS removed), high COD destruction solid COD (sCOD; 74% and total COD (tCOD) 54%) and minimal free NH3 content (67.5 mg/L). As for stability, stable pH distribution, high alkalinity content and low VFA to alkalinity ratio, indicated a well-buffered system. Additionally, the system had also able to produce class A biosolids. Therefore, proved that TPAD system operated at the intermediate zone of 45 ℃ can perform better than the conventional TPAD, hence, highlighting its economic advantage.

Design of Anaerobic Digestion of Lime Sludges

1984 ◽  
Vol 16 (12) ◽  
pp. 375-386
Author(s):  
B A Bell ◽  
E A Kobylinski
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Energy Requirements ◽  
Treatment Facility ◽  
Sludge Treatment ◽  
Phosphorous Removal ◽  
Conventional Activated Sludge ◽  
Volatile Solids ◽  
Lime Addition

Previous work has demonstrated that inhibition of volatile solids destruction during anaerobic digestion occurs at elevated calcium levels. In this work, calcium inhibition has been taken into account in the design of a treatment facility digesting sludges which contain lime from phosphorous removal. A conventional activated sludge treatment facility has been designed along with a facility removing phosphorous by lime addition to primary clarifiers. Unit sizing, costs and energy requirements are compared and discussed.

Membrane-coupled anaerobic digestion of municipal sewage sludge

2005 ◽  
Vol 52 (1-2) ◽  
pp. 253-258 ◽  
Author(s):  
A. Pierkiel ◽  
J. Lanting
Keyword(s):  
Anaerobic Digestion ◽  
Cross Flow ◽  
Inhibitory Effect ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Utilization Rate ◽  
Sludge Digestion ◽  
Solids Concentration ◽  
Volatile Solids ◽  
Anaerobic Biomass

Membrane-coupled anaerobic digestion utilizes a concept of simultaneous sludge digestion and thickening. Membranes may successfully be applied to eliminate the need for thickening polymers and avoid their likely inhibitory effect on anaerobic biomass. A 550 L completely mixed anaerobic digester was operated under mesophilic conditions (35 °C). Two ultrafiltration membrane systems were evaluated for their potential in membrane-coupled anaerobic digestion: vibrating and cross flow. A volatile solids reduction of 59% was achieved at an average mixed liquor suspended solids concentration of 1.8%. The substrate utilization rate was 1.3 d−1. The vibrating membrane operated at a flux of 1.6–2.0 m3/m2-d and the tubular membrane fluxes in the range 3.4–3.6 m3/m2-d.

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