Biodegradation of PAH and DEHP micro-pollutants in mesophilic and thermophilic anaerobic sewage sludge digestion

2006 ◽  
Vol 53 (8) ◽  
pp. 99-107 ◽  
Author(s):  
T. Benabdallah El-Hadj ◽  
J. Dosta ◽  
J. Mata-Álvarez
Keyword(s):  
Anaerobic Digestion ◽  
Wastewater Treatment Plants ◽  
Economic Cost ◽  
Process Efficiency ◽  
Sludge Digestion ◽  
Thermophilic Conditions ◽  
Polycyclic Aromatic ◽  
Positive Effect ◽  
Process Product ◽  
Micro Pollutants

Anaerobic digestion for the treatment of sludge in wastewater treatment plants has been reported to produce a low organic loaded effluent with an acceptable economic cost. But in the last years, new regulations and the increasing sludge production invite us to find an alternative and/or to improve the process efficiency. Moreover, the use of the effluent as fertilizer in agriculture imposes more restrictions on digestion process product and its micropollutant contents to protect the environment. In this study, a performance of the anaerobic digestion under mesophilic and thermophilic conditions at different hydraulic retention times (HRT) is assessed and the removal efficiencies of two important compounds or family compounds (Polycyclic Aromatic Hydrocarbons, PAH, and Di-2-(Ethyl-Hexyl)-Phthalate, DEHP) are evaluated. A positive effect of thermophilic temperature was observed on both micropollutants' biodegradation. However, HRT effect also had an important role for DEHP and low molecular weighted PAH removal.

Effect of anaerobic digestion at 35, 55 and 60 °C on pharmaceuticals and organic contaminants

2014 ◽  
Vol 69 (6) ◽  
pp. 1282-1288 ◽  
Author(s):  
Å. Davidsson ◽  
H. Kjerstadius ◽  
S. Haghighatafshar ◽  
J. Fick ◽  
M. Olsson ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Organic Contaminants ◽  
Wastewater Treatment Plants ◽  
Pharmaceutical Compounds ◽  
Commercial Fertilizer ◽  
Low Concentrations ◽  
Treated Sewage ◽  
Polycyclic Aromatic ◽  
Individual Pahs

The application of treated sewage sludge on farmland is a suggested method for recycling nutrients and reducing demand for commercial fertilizer. However, sludge needs to be safe from possible contaminants which can cause acute and long-term health and environmental problems. Residual pharmaceuticals and organic contaminants are mentioned as emerging threats since wastewater treatment plants are not designed to degrade these substances. The aim of this study was to screen and evaluate the presence, and reduction, of pharmaceuticals and polycyclic aromatic hydrocarbons (PAHs) during anaerobic digestion of mixed primary and waste-activated sludge at 35, 55 and 60 °C and during pasteurization at 70 °C. The study showed the difficulty of analysing pharmaceutical compounds in low concentrations in the sludge matrix. No general reduction of these compounds was seen during treatment, but for individual substances some reduction occured. The PAHs were generally not reduced during digestion or pasteurization, but for three substances (indeno[1,2,3-cd]pyrene and dibenzo[a,h]anthracene (analysed together) and benzo[g,h,i]perylene) reduction (up to 60%) during digestion was seen. Digestion at 35 and 55 °C resulted in about the same order of reduction of the three individual PAHs, which was higher than for digestion at 60 °C.

Relative kinetics of anaerobic digestion under thermophilic and mesophilic conditions

2011 ◽  
Vol 64 (4) ◽  
pp. 848-853 ◽  
Author(s):  
H. Ge ◽  
P. D. Jensen ◽  
D. J. Batstone
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Hydrolysis Rate ◽  
Fermentation Products ◽  
Promising Alternative ◽  
Sludge Digestion ◽  
Increase Glucose Uptake ◽  
Thermophilic Conditions ◽  
Kinetics Of ◽  
Mesophilic Conditions

With several advantages over the conventional mesophilic anaerobic digestion, such as better sludge quality and higher biogas production, thermophilic anaerobic digestion is regarded as a promising alternative for sludge digestion. Primary and activated sludges are complex materials, and historically, analysis of kinetics has been largely on whole sludge, without analysis of individual components. This paper analyses relative digestion kinetics of pure substrates designed to target main stages of sludge digestion under thermophilic and mesophilic conditions. Hydrolysis rate of cellulose was significantly influenced by temperature with hydrolysis coefficients of – at 55 °C (0.7 ± 0.1 day−1), 60 °C (0.8 ± 0.2 day−1), 65 °C (1.1 ± 0.2 day−1) and 70 °C (1.2 ± 0.2 day−1) over 38 °C (0.4 ± 0.1 day−1). This strongly follows the Arrhenius relationship, with an activation energy (EA) of 31 ± 4 kJ mol−1, corresponding to an increase of 1.5x for each 10 °C of temperature increase. Glucose uptake was rapid with a wide variety of fermentation products detected under mesophilic conditions, while uptake was slower under thermophilic conditions with acetate and propionate being dominant products. Propionate acetogenesis and acetate-utilizing methanogenesis kinetics were not influenced by temperatures. Hydrolysis is widely regarded as a rate-limiting step in sludge digestion, thus improvements in hydrolysis rates as measured during this study have the potential for significant improvements in overall apparent sludge digestion rates.

Comparison Between Thermophilic and Mesophilic Anaerobic Digestion of Sewage Sludge Coming from Urban Wastewater Treatment Plants

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2409-2412 ◽  
Author(s):  
F. Cecchi ◽  
P. Pavan ◽  
A. Musacco ◽  
J. Mata-Alvarez ◽  
C. Sans
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Feed Flow Rate ◽  
Organic Fraction ◽  
Urban Wastewater ◽  
Stability Parameters ◽  
Thermophilic Conditions ◽  
Urban Wastewater Treatment

Yields of anaerobic digestion (AD) of sewage sludge carried out at mesophilic and thermophilic conditions at the optimum hydraulic retention times (HRT) found for the semi-dry AD of the mechanically selected organic fraction of municipal solid waste (OFMSW) (15 and 12 days, respectively) are compared. Due to the characteristics of the sludge used in thermophilic conditions (partially stabilized) the specific biogas production was lower. However, stability parameters show a secure process. Based on experience gained digesting OFMSW and hypothesizing a similar ratio between yields at mesophilic and thermophilic conditions, an economic analysis has been carried out. It shows that the increased biogas production is large enough to compensate the additional consumption to heat the feed flow rate to 55°C instead to 35°C.

scholarly journals Free ammonia pretreatment for anaerobic sludge digestion reduces the spread of antibiotic resistance

2020 ◽  
Author(s):  
Zehao Zhang ◽  
Huan Liu ◽  
Qilin Wang
Keyword(s):  
Antibiotic Resistance ◽  
Anaerobic Digestion ◽  
Wastewater Treatment Plants ◽  
Antibiotic Resistance Genes ◽  
Free Ammonia ◽  
Anaerobic Sludge ◽  
Sludge Disposal ◽  
Sludge Digestion ◽  
Gene Copies ◽  
First Time

AbstractSludge from the wastewater treatment plants (WWTPs) has been recognized as a reservoir of antibiotic resistance genes (ARGs). Free ammonia (FA, i.e. NH3-N) pretreatment has been demonstrated to be able to enhance anaerobic digestion, which is a widely used method for sludge treatment. However, the effect of combined FA pretreatment and anaerobic digestion on the fate of ARGs is still unknown. This study demonstrated for the first time that combined FA pretreatment (420 mg NH3-N/L for 24 h) and anaerobic digestion could reduce the abundances of the tested ARGs by 0.06 log10 gene copies/g TS (total solids) compared with the anaerobic digestion alone. Specifically, the experimental results showed that combined FA pretreatment and anaerobic digestion reduced the abundances of aac(6’)-Ib-cr, blaTEM, sul2, tetA, tetB and tetX by 0.07, 0.37, 0.09, 0.32, 0.24 and 0.59 log10 gene copies/g TS compared with anaerobic digestion alone. In contrast, combined FA pretreatment and anaerobic digestion slightly increased the abundance of tetG by 0.05 log10 gene copies/g TS compared with anaerobic digestion alone. In addition, FA pretreatment did not significantly affect the abundance of sul1 and tetM during anaerobic digestion. This study revealed that FA pretreatment for anaerobic digestion could potentially reduce the spread of antibiotic resistance from the sludge to soil (while agriculture reuse is used as the sludge disposal method), thereby protecting the environment and human health.

THEORETICAL STUDY OF THE EFFECT OF GEOMETRICAL PARAMETERS AND LOCATION OF ROTOR IMPACT ELEMENTS OF AN IMPACT-CENTRIFUGAL GRINDER ON SPEED AND ANGLES OF CRUSHED PARTICLES FLIGHT

2020 ◽  
Keyword(s):  
Granulometric Composition ◽  
Theoretical Study ◽  
Process Efficiency ◽  
Geometrical Parameters ◽  
Grinding Process ◽  
Main Work ◽  
Impact Element ◽  
The Impact ◽  
Positive Effect ◽  
Efficiency Indicators

One of efficiency indicators of grain grinders is grain granulometric composition. The basis of mixed fodder is crushed grain, the particles of which must have a leveled granulometric composition for subsequent mixing and obtaining a high-quality feed mixture. In agricultural production, hammer crushers are widely used, in which the destruction of grain occurs due to the impact of a hinged hammer. The main disadvantage of these crushers is that not the entire surface of the hammers is involved in grinding, thus reduces grinding process efficiency. A slightly different principle of material destruction is laid down in the basis of the proposed design of the shock-centrifugal grinder. Main work is performed by flat impact elements located on the rotor, which serve to accelerate crushed particles with subsequent impact of them on the bump elements. An important step in the design of new constructions of shock-centrifugal grinders is to determine size and location of the impact elements on the rotor, without which the grinding process is not possible. In the calculation method presented, the dependencies for determining the velocities and angles of a single particle flight from the surface of a flat impact element for its specified dimensions are proposed. Two variants of an impact element location on the rotor are considered and analyzed: radial and at an angle in the direction of rotor rotation. As a result of research carried out, it is noted that in the case of inclined position of an impact element on the rotor an increase in flight speed and flight angles change in crushed particles, which gives the opportunity to have a positive effect on grinding process.

Sludge minimization by disintegration at different wastewater treatment plants

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Luchien Luning ◽  
Paul Roeleveld ◽  
Victor W.M. Claessen
Keyword(s):  
Organic Matter ◽  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
New Technologies ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Biological Degradation ◽  
Ongoing Research ◽  
Sludge Minimization

In recent years new technologies have been developed to improve the biological degradation of sewage sludge by anaerobic digestion. The paper describes the results of a demonstration of ultrasonic disintegration on the Dutch Wastewater Treatment Plant (WWTP) Land van Cuijk. The effect on the degradation of organic matter is presented, together with the effect on the dewatering characteristics. Recommendations are presented for establishing research conditions in which the effect of sludge disintegration can be determined in a more direct way that is less sensitive to changing conditions in the operation of the WWTP. These recommendations have been implemented in the ongoing research in the Netherlands supported by the National Institute for wastewater research (STOWA).

scholarly journals Sugarcane Bagasse as a Co-Substrate with Oil-Refinery Biological Sludge for Biogas Production Using Batch Mesophilic Anaerobic Co-Digestion Technology: Effect of Carbon/Nitrogen Ratio

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 590
Author(s):  
Aiban Abdulhakim Saeed Ghaleb ◽  
Shamsul Rahman Mohamed Kutty ◽  
Gasim Hayder Ahmed Salih ◽  
Ahmad Hussaini Jagaba ◽  
Azmatullah Noor ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Sugarcane Bagasse ◽  
Organic Waste ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Raw Materials ◽  
Oil Refinery ◽  
Methane Yield ◽  
Oil Refineries ◽  
Biological Sludge

Man-made organic waste leads to the rapid proliferation of pollution around the globe. Effective bio-waste management can help to reduce the adverse effects of organic waste while contributing to the circular economy at the same time. The toxic oily-biological sludge generated from oil refineries’ wastewater treatment plants is a potential source for biogas energy recovery via anaerobic digestion. However, the oily-biological sludge’s carbon/nitrogen (C/N) ratio is lower than the ideal 20–30 ratio required by anaerobic digestion technology for biogas production. Sugarcane bagasse can be digested as a high C/N co-substrate while the oily-biological sludge acts as a substrate and inoculum to improve biogas production. In this study, the best C/N with co-substrate volatile solids (VS)/inoculum VS ratios for the co-digestion process of mixtures were determined empirically through batch experiments at temperatures of 35–37 °C, pH (6–8) and 60 rpm mixing. The raw materials were pre-treated mechanically and thermo-chemically to further enhance the digestibility. The best condition for the sugarcane bagasse delignification process was 1% (w/v) sodium hydroxide, 1:10 solid-liquid ratio, at 100 °C, and 150 rpm for 1 h. The results from a 33-day batch anaerobic digestion experiment indicate that the production of biogas and methane yield were concurrent with the increasing C/N and co-substrate VS/inoculum VS ratios. The total biogas yields from C/N 20.0 with co-substrate VS/inoculum VS 0.06 and C/N 30.0 with co-substrate VS/inoculum VS 0.18 ratios were 2777.0 and 9268.0 mL, respectively, including a methane yield of 980.0 and 3009.3 mL, respectively. The biogas and methane yield from C/N 30.0 were higher than the biogas and methane yields from C/N 20.0 by 70.04 and 67.44%, respectively. The highest biogas and methane yields corresponded with the highest C/N with co-substrate VS/inoculum VS ratios (30.0 and 0.18), being 200.6 mL/g VSremoved and 65.1 mL CH4/g VSremoved, respectively.

scholarly journals Stimulation of Biomethane Productivity in Anaerobic Digestion Using Electro-Conductive Carbon-Nanotube Hollow-Fiber Media

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 179
Author(s):  
Seongmin Yang ◽  
Seungyeob Han ◽  
Yeo-Myeong Yun ◽  
Seoktae Kang
Keyword(s):  
Carbon Nanotube ◽  
Anaerobic Digestion ◽  
Production Rate ◽  
Hollow Fiber ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ch4 Production ◽  
Microscopic Morphology ◽  
Positive Effect

The production of biogas was promoted via direct interspecies electron transfer (DIET) by employing electro-conductive carbon-nanotube hollow-fiber media (CHM) in anaerobic digestion. Experimental results showed a positive effect of CHM presence on CH4 productivity with 34% higher CH4 production rate than that of in the presence of non-electroconductive polymeric hollow fiber media. An increased CH4 production rate was due to the shift in the microbiome with more abundant Pelobacter (10.0%), Geobacter (6.9%), and Methanosaeta (15.7%), which play key roles in promoting CH4 production via syntrophic metabolism associated with DIET. Microscopic morphology analysis, using confocal laser scanning microscopy and scanning electron microscopy, exhibited that several living cells were attached with electro-conductive pili on the CHM surface, thereby facilitated electron transport between microbial cells.

scholarly journals A Mechanistic Model to Assess the Fate of Naphthalene and Benzo(a)pyrene in a Chilean WWTP

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1313
Author(s):  
Antonia Arroyo ◽  
Fabián Provoste ◽  
Montserrat Rodríguez ◽  
Ana L. Prieto
Keyword(s):  
Wastewater Treatment Plants ◽  
Mechanistic Model ◽  
Treated Wastewater ◽  
Urban Centers ◽  
Potable Reuse ◽  
Conventional Activated Sludge ◽  
Regulatory Standards ◽  
Polycyclic Aromatic ◽  
De Facto Reuse

Polycyclic aromatic hydrocarbons (PAHs) are a family of organic compounds of widespread presence in the environment. They are recalcitrant, ubiquitous, prone to bioaccumulation, and potentially carcinogenic. Effluent from wastewater treatment plants (WWTPs) constitutes a major source of PAHs into water bodies, and their presence should be closely monitored, especially considering the increasing applications of potable and non-potable reuse of treated wastewater worldwide. Modeling the fate and distribution of PAHs in WWTPs is a valuable tool to overcome the complexity and cost of monitoring and quantifying PAHs. A mechanistic model was built to evaluate the fate of PAHs in both water and sludge lines of a Chilean WWTP. Naphthalene and benzo(a)pyrene were used as models of low-MW and high-MW PAHs. As there were no reported experimental data available for the case study, the influent load was determined through a statistical approach based on reported values worldwide. For both naphthalene and benzo(a)pyrene, the predominant mechanism in the water line was sorption to sludge, while that in the sludge line was desorption. Compared to other studies in the literature, the model satisfactorily describes the mechanisms involved in the fate and distribution of PAHs in a conventional activated sludge WWTP. Even though there is evidence of the presence of PAHs in urban centers in Chile, local regulatory standards do not consider PAHs in the disposal of WWTP effluents. Monitoring of PAHs in both treated effluents and biosolids is imperative, especially when considering de facto reuse and soil amendment in agricultural activities are currently practiced downstream of the studied WWTP.

scholarly journals Occurrence, Removal, and Mass Balance of Polycyclic Aromatic Hydrocarbons and Their Derivatives in Wastewater Treatment Plants in Northeast China

Toxics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 76
Author(s):  
Rashid Mohammed ◽  
Zi-Feng Zhang ◽  
Chao Jiang ◽  
Ying-Hua Hu ◽  
Li-Yan Liu ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Wastewater Treatment Plants ◽  
Principal Component ◽  
Diagnostic Ratios ◽  
Regression Methods ◽  
Polycyclic Aromatic ◽  
Meta Regression ◽  
Coal Composition

Polycyclic aromatic hydrocarbons (PAHs), 33 methylated PAHs (Me-PAHs), and 14 nitrated PAHs (NPAHs) were measured in wastewater treatment plants (WWTPs) to study the removal efficiency of these compounds through the WWTPs, as well as their source appointment and potential risk in the effluent. The concentrations of ∑PAHs, ∑Me-PAHs, and ∑NPAHs were 2.01–8.91, 23.0–102, and 6.21–171 µg/L in the influent, and 0.17–1.37, 0.06–0.41 and 0.01–2.41 µg/L in the effluent, respectively. Simple Treat 4.0 and meta-regression methods were applied to calculate the removal efficiencies (REs) for the 63 PAHs and their derivatives in 10 WWTPs and the results were compared with the monitoring data. Overall, the ranges of REs were 55.3–95.4% predicated by the Simple Treat and 47.5–97.7% by the meta-regression. The results by diagnostic ratios and principal component analysis PCA showed that “mixed source” biomass, coal composition, and petroleum could be recognized to either petrogenic or pyrogenic sources. The risk assessment of the effluent was also evaluated, indicating that seven carcinogenic PAHs, Benzo[a]pyrene, Dibenz[a,h]anthracene, and Benzo(a)anthracene were major contributors to the toxics equivalency concentrations (TEQs) in the effluent of WWTPs, to which attention should be paid.

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