scholarly journals THE EFFECT OF IRON SALT ON ANAEROBIC DIGESTION AND PHOSPHATE RELEASE TO SLUDGE LIQUOR / GELEŽIES DRUSKOS ĮTAKA ANAEROBINIO DUMBLO PŪDYMO PROCESUI IR FOSFATŲ IŠSISKYRIMUI Į DUMBLO VANDENĮ

2011 ◽  
Vol 3 (5) ◽  
pp. 123-126
Author(s):  
Svetlana Ofverstrom ◽  
Regimantas Dauknys ◽  
Ieva Sapkaitė
Keyword(s):  
Anaerobic Digestion ◽  
Phosphorus Content ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Iron Salt ◽  
Digested Sludge ◽  
Sludge Treatment ◽  
Primary Sludge ◽  
Digestion Process ◽  
Iron Salts

Iron salts are used at wastewater treatment plants (WWTPs) for several reasons: for removing chemical phosphorus, preventing from struvite formation and reducing the content of hydrogen sulfide (H2S) in biogas. Anaerobic digestion is a common scheme for sludge treatment due to producing biogas that could be used as biofuel. Laboratory analysis has been carried out using anaerobic digestion model W8 (Armfield Ltd, UK) to investigate any possible effect of adding FeCl3 on the anaerobic digestion of primary sludge (PS) and waste activated sludge (WAS) mixture as well as on releasing phosphates to digested sludge liquor. The obtained results showed that FeCl3 negatively impacted the anaerobic digestion process by reducing the volume of produced biogas. Fe-dosed sludge (max) produced 30% less biogas. Biogas production from un-dosed and Fe-dosed sludge (min) was similar to the average of 1.20 L/gVSfed. Biogas composition was not measured during the conducted experiments. Phosphorus content in sludge liquor increased at an average of 38% when digesting sludge without ferric chloride dosing. On the contrary, phosphate content in sludge liquor from digested Fe-dosed sludge decreased by approx. 80%. Santrauka Nuotekų valymo įrenginiuose geležies druskos naudojamos cheminiam fosforui šalinti, sieros vandeniliui biodujose mažinti ir struvito nuogulų formavimosi prevencijai. Tyrimai atlikti laboratorinėmis sąlygomis naudojant anaerobinio pūdymo modelį W8 (Armfield Ltd., Didžioji Britanija) ir pūdant pirminio perteklinio dumblo mišinį, į kurį buvo dedama geležies druskos, siekiant nustatyti geležies druskos naudojimo efektą anarobinio pūdymo procesui ir fosfatų išsiskyrimui į dumblo vandenį. Rezultatai parodė, kad pūdant dumblą be geležies druskos ir dedant geležies druskos minimalią dozę, susidarė vidutiniškai vienodi kiekiai biodujų (mL/gBSMtiekiam.), bet į pūdomą dumblą dedant maksimalią geležies dozę, biodujų išeiga vidutiniškai sumažėjo 30 %. Į pūdomą dumblą nededant geležies chlorido, fosfatų koncentracija dumblo vandenyje vidutiniškai padidėjo 38 %. Ir priešingai, geležies chlorido dozės fosfatų koncentraciją pūdyto dumblo vandenyje sumažino 80 %.

Ultrasonic sludge treatment for enhanced anaerobic digestion

2004 ◽  
Vol 50 (9) ◽  
pp. 25-32 ◽  
Author(s):  
F. Hogan ◽  
S. Mormede ◽  
P. Clark ◽  
M. Crane
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
New Technology ◽  
Downstream Processing ◽  
Full Scale ◽  
Waste Stream ◽  
Site Conditions ◽  
Digested Sludge ◽  
Sludge Treatment ◽  
Primary Sludge

Ultrasound is the term used to describe sound energy at frequencies above 20 kHz. Highpowered ultrasound can be applied to a waste stream via purpose-designed tools in order to induce cavitation. This effect results in the rupture of cellular material and reduction of particle size in the waste stream, making the cells more amenable to downstream processing. sonixTM is a new technology utilising high-powered, concentrated ultrasound for conditioning sludges prior to further treatment. This paper presents recent results from a number of demonstration and full-scale plants treating thickened waste activated sludge (TWAS) prior to anaerobic digestion, therefore enhancing the process. The present studies have proved that the use of ultrasound to enhance anaerobic digestion can be achieved at full scale and effectively result in the TWAS (typically difficult to digest) behaving, after sonication, as if it were a “primary” sludge. The technology presents benefits in terms of increased biogas production, better solids reduction, improved dewatering characteristics of the digested sludge mixture and relatively short payback periods of two years or less subject to the site conditions and practices applicable at that time.

Inactivation of pathogenic bacteria under mesophilic and thermophilic conditions

1997 ◽  
Vol 36 (6-7) ◽  
pp. 25-32 ◽  
Author(s):  
Haruki Watanabe ◽  
Tomokazu Kitamura ◽  
Shuichi Ochi ◽  
Masaaki Ozaki
Keyword(s):  
Anaerobic Digestion ◽  
Fecal Coliform ◽  
Pathogenic Bacteria ◽  
Anaerobic Treatment ◽  
Digested Sludge ◽  
Primary Sludge ◽  
Digestion Process ◽  
Mesophilic Digestion ◽  
Thermophilic Digestion ◽  
Number Of Bacteria

This paper concerns field survey and laboratory experiment on the inactivation of pathogenic bacteria during sludge treatment processes with particular emphasis on anaerobic digestion process. We surveyed the inactivation of pathogenic bacteria processes by sampling various types of sludges from 17 wastewater treatment plants located in Japan and counting the number of bacteria in the sampled sludges. The bacteria we counted included fecal coliform groups, enterococcus and salmonella. The median number of fecal coliform groups in primary sludge was found to be 105 MPN/g, while the number of fecal coliform groups in digested sludge decreased to 103 MPN/g. We also confirmed that the treatments of dewatering using inorganic coagulant, drying and composting are also effective in inactivating pathogenic bacteria. In addition, we studied the performance conditions of anaerobic digestion and the degree of inactivation of pathogenic bacteria in the experiment of anaerobic treatment of the primary sludge. This study showed that the number of fecal coliform groups in mesophilic digestion sludge was in the range of 102 to 104 MPN/g regardless of the HRT, whereas the number of bacteria in thermophilic digestion sludge was of the order of 100 MPN/g, clearly indicating that the number of bacteria substantially decreases when the sludge is digested at thermophilic temperature. The number of enterococcus in digested sludge was in the range of 102 to 105 MPN/g after the sludge was subjected to mesophilic digestion while the number decreased to 100 MPN/g after the sludge was digested at thermophilic temperature. The number of salmonella in digested sludge was in the range of 1.8 to 30 MPN/4g after the sludge was digested at mesophilic temperature, but the number decreased to less than 1.8 MPN/4g after the sludge went through thermophilic digestion process. The thermophilic digestion is thus effective in inactivating pathogenic bacteria.

scholarly journals Coupling Hydrothermal Carbonization with Anaerobic Digestion for Sewage Sludge Treatment: Influence of HTC Liquor and Hydrochar on Biomethane Production

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6262 ◽  
Author(s):  
Roberta Ferrentino ◽  
Fabio Merzari ◽  
Luca Fiori ◽  
Gianni Andreottola
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Wastewater Treatment Plants ◽  
Hydrothermal Carbonization ◽  
Digested Sludge ◽  
Sludge Treatment ◽  
Secondary Sludge ◽  
Sewage Sludge Treatment ◽  
Biomethane Production

The present study addresses the coupling of hydrothermal carbonization (HTC) with anaerobic digestion (AD) in wastewater treatment plants. The improvement in biomethane production due to the recycling back to the anaerobic digester of HTC liquor and hydrochar generated from digested sludge is investigated and proved. Mixtures of different compositions of HTC liquor and hydrochar, as well as individual substrates, were tested. The biomethane yield reached 102 ± 3 mL CH4 g−1 COD when the HTC liquor was cycled back to the AD and treated together with primary and secondary sludge. Thus, the biomethane production was almost doubled compared to that of the AD of primary and secondary sludge (55 ± 20 mL CH4 g−1 COD). The benefit is even more significant when both the HTC liquor and the hydrochar were fed to the AD of primary and secondary sludge. The biomethane yield increased up to 187 ± 18 mL CH4 g−1 COD when 45% of hydrochar, with respect to the total feedstock, was added. These results highlight the improvement that the HTC process can bring to AD, enhancing biomethane production and promoting a sustainable solution for the treatment of the HTC liquor and possibly the hydrochar itself.

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.

Mesophilic and Thermophilic Digestion of Thickened Waste Activated Sludge: A Comparative Study

2010 ◽  
Vol 113-116 ◽  
pp. 450-458 ◽  
Author(s):  
Yong Zhi Chi ◽  
Yu You Li ◽  
Min Ji ◽  
Hong Qiang ◽  
Heng Wei Deng ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Methane Content ◽  
Waste Activated Sludge ◽  
Digested Sludge ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Significant Difference

This paper presents an experimental study over 204 days on anaerobic degradation of thickened waste activated sludge (TWAS) from a municipal wastewater treatment plant (WWTP). The experiments were conducted under thermophilic (55°C) and mesophilic (35°C) condition, respectively, by using the semi-continuous flow completely mixed reactors. The influent total solids (TS), hydraulic retention time (HRT) and chemical oxygen demand (COD) loading levels were around 4%, 30 days and 1.67 kg-CODCr•m-3•d-1 , respectively. During the opration period, the thermophilic anaerobic digestion process (TADP) and the mesophilic anaerobic digestion process (MADP) were stable and well-functioned without ammonia inhibition. Particulate organic matters reduction of TADP was superior to that of MADP. This result implies that TADP has higher sludge reduction efficiency than MADP. According to the simulated chemical formula of TWAS, C5.85H9.75O3.96N, and the stoichiometric equation, the methane content and the ammonia yield in the anaerobic process could be calculated, which were consistent with the experimental results. The methane yield of TADP was a little higher than that of MADP. The statistical mean values of methane content for TADP and MADP were 60.97% and 62.38%, respectively.According to paired t-test, there was a significant difference in methane content between TADP and MADP(α=0.01, n=62). Compared with the mesophilic digested sludge, the dewaterability of thermophilic digested sludge was lower.

Study of thermal hydrolysis as a pretreatment to mesophilic anaerobic digestion of pig slurry

2001 ◽  
Vol 44 (4) ◽  
pp. 109-116 ◽  
Author(s):  
A. Bonmatí ◽  
X. Flotats ◽  
L. Mateu ◽  
E. Campos
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Limiting Factor ◽  
Pig Slurry ◽  
Thermal Hydrolysis ◽  
Organic Matter Degradation ◽  
Thermal Pretreatment ◽  
Digestion Process ◽  
Degradation Tests ◽  
Thermal Phenomena

Feasibility of anaerobic digestion of pig slurry is dependent, among other factors, on the biogas production rate, which is low compared with other organic wastes, and on the profitable uses of surplus thermal energy produced, a limiting factor in warm geographical areas. The objectives of this work are determining whether low temperature thermal pretreatment (<90°C) improves pig slurry anaerobic digestion, and determining whether organic matter degradation during the thermal pretreatment is due to thermal phenomena (80°C) or to enzymatic ones (60°C). The thermal degradation tests showed that hydrolysis occurring during the thermal pretreatment is due to thermal phenomena. The increase in soluble substances were significantly larger at 80°C than at 60°C (both during 3 h). Two types of slurry were used in the batch anaerobic digestion tests. The effect of thermal pretreatment differed with the type of slurry: it was positive with almost non-degraded slurries containing low NH4+-N concentration, and negative (inhibition of the anaerobic digestion process) when using degraded slurries with high NH4+-N content.

scholarly journals Operational Parameters of Biogas Plants: A Review and Evaluation Study

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3761 ◽  
Author(s):  
Abdullah Nsair ◽  
Senem Onen Cinar ◽  
Ayah Alassali ◽  
Hani Abu Qdais ◽  
Kerstin Kuchta
Keyword(s):  
Anaerobic Digestion ◽  
Review Paper ◽  
Biogas Production ◽  
Evaluation Study ◽  
Biogas Plant ◽  
Operational Parameters ◽  
Digestion Process ◽  
Design Considerations ◽  
Biogas Plants ◽  
Main Factors

The biogas production technology has improved over the last years for the aim of reducing the costs of the process, increasing the biogas yields, and minimizing the greenhouse gas emissions. To obtain a stable and efficient biogas production, there are several design considerations and operational parameters to be taken into account. Besides, adapting the process to unanticipated conditions can be achieved by adequate monitoring of various operational parameters. This paper reviews the research that has been conducted over the last years. This review paper summarizes the developments in biogas design and operation, while highlighting the main factors that affect the efficiency of the anaerobic digestion process. The study’s outcomes revealed that the optimum operational values of the main parameters may vary from one biogas plant to another. Additionally, the negative conditions that should be avoided while operating a biogas plant were identified.

Degradation of veterinary antibiotics during anaerobic digestion of dairy manure

2015 ◽  
Vol 10 (3) ◽  
pp. 532-537 ◽  
Author(s):  
Yumika Kitazono ◽  
Ikko Ihara ◽  
Kiyohiko Toyoda ◽  
Kazutaka Umetsu
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Dairy Manure ◽  
Antibiotic Residues ◽  
Veterinary Antibiotics ◽  
Livestock Manure ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Antibiotic Degradation

This study evaluated antibiotic degradation and biogas production during anaerobic digestion of dairy manure contained two common veterinary antibiotics at 37 °C. After 18 days of digestion, the concentration of chlortetracycline (CTC) decreased more than 80% regardless of the initial CTC concentration. The concentration of cefazolin (CEZ) decreased from 10 to 0.08 mg/L in 6 days. Less than 50 mg/L CTC and 10 mg/L CEZ had negligible impact on biogas production during anaerobic digestion process. The result showed that the anaerobic digestion has a potential to degrade antibiotic residues in livestock manure.

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