Wastewater and organic waste to bioenergy

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
D. L. Parry ◽  
P. Evans
Keyword(s):  
Life Cycle ◽  
Anaerobic Digestion ◽  
Organic Waste ◽  
Organic Wastes ◽  
Economic Life ◽  
Wastewater Sludge ◽  
Food Wastes ◽  
Organic Loading ◽  
Anaerobic Digesters ◽  
Loading Rates

Throughout the world, wastewater and organic waste are increasingly being viewed as energy sources and the practice of converting them into bioenergy through conversion to biogas with anaerobic digestion is growing. This paper presents an overview of planning, research, and full-scale operations of both separate and codigestion of organic waste. Organic waste management methods are compared with respect to economic (life-cycle costs), environmental (equivalent carbon dioxide emissions), social, and operational impacts for a representative 100,000 population community. Management methods include using sewers or trucks to transport the organics to anaerobic digesters at a wastewater treatment plant, using a material recovery facility (MRF) to extract the organics from municipal solid waste for anaerobic digestion, composting the organic waste, or sending the organics to a landfill. Hauling the organics to anaerobic digesters had the lowest equivalent CO2 emissions, while using the sewer to convey organics had the lowest life-cycle cost. An example of codigestion of organic waste with wastewater sludge at the Des Moines Water Reclamation Facility (Iowa, USA) is described. The limits of organic loading rates for digestion of FOG (fats, oils, and grease) with wastewater sludge are presented based on research using 1,000-litre (L) pilot digesters. A specific energy loading rate (SELR) is proposed as an improved parameter for organic loading rates. The SELR is a measure of energy loading relative to the reactor biomass, and is an innovative approach to characterizing digester capacity and stability. Food wastes from the cafeteria at the U.S. Air Force Academy were digested in bench-scale, semi-continuous reactors and monitored using an online respirometer capable of continuously monitoring gas flow rate and gas composition. The biological methane potential (BMP) of several organic wastes were measured in lab-scale digesters. Organic wastes were digested with and without domestic wastewater sludge. Separate digestion of organic wastes was found to be nutrient (cobalt, nickel) deficient, where codigestion with wastewater sludge experienced no deficiencies. Codigestion could also handle a greater amount of FOG being fed to the digesters than separate digestion of food wastes.

Overcoming barriers to codigestion

2016 ◽  
Vol 11 (2) ◽  
pp. 413-422 ◽  
Author(s):  
D. L. Parry ◽  
L. Fillmore
Keyword(s):  
Organic Waste ◽  
Loading Rate ◽  
Biogas Production ◽  
Economic Impacts ◽  
Organic Wastes ◽  
Wastewater Sludge ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Widespread Application ◽  
Loading Rates

Codigestion of organic waste with municipal wastewater sludge is growing rapidly. It has many benefits, including diversion of organic waste from landfills, increased renewable energy from biogas production, and potential for revenue from tipping fees. However, there are still barriers to greater widespread application of codigestion. Economics, need for collaboration between utilities, impacts on wastewater application, unsupportive regulations and risks to core wastewater treatment business are obstacles that slow wider adoption of codigestion throughout the world. The research presented analyzes the economic impacts of codigestion, predicts the additional biogas production, and determines the allowable organic loading rate and fats oils and grease (FOG) addition for stable digestion operation. The economic impacts were analyzed on a life cycle cost basis and presented in terms of required tipping fees for different organic wastes, electric rates and residuals handling costs. Standard biochemical methane potential tests were conducted to estimate biogas production from various organic wastes. The specific energy loading rate (SELR) was used to express the allowable organic loading rate. Results from the economic analysis showed that codigestion using existing digesters at a municipal water reclamation facility is more economical than building new digesters. Codigestion was more economical at facilities with high electricity costs and low cost of residuals. Tipping fees for receiving organic waste would be required to offset the net cost of codigestion for wastes other than FOG. There was a net positive economic benefit of receiving FOG without a tipping fee. The upper limit of FOG for stable digestion was found to be 60 percent of the feed by chemical oxygen demand (COD). Stable digestion can be achieved with an SELR of less than 0.25 kgCOD/day/kgVS. The SELR accounts for the strength or energy content of the organic feed measured in COD. It was observed and accounted for by the SELR that anaerobic digesters loaded at higher solids concentrations (resulting in greater inventory of microorganisms in the digesters) can be fed at higher loading rates. Insights into the economics of codigestion and allowable organic loading rates for high strength organic wastes help to overcome some of the barriers to widespread application of codigestion.

scholarly journals Historical Perspective of the Addition of Magnetic Nanoparticles Into Anaerobic Digesters (2014-2021)

2021 ◽  
Vol 3 ◽  
Author(s):  
Eudald Casals ◽  
Raquel Barrena ◽  
Edgar Gonzalez ◽  
Xavier Font ◽  
Antoni Sánchez ◽  
...  
Keyword(s):  
Organic Matter ◽  
Magnetic Nanoparticles ◽  
Anaerobic Digestion ◽  
Historical Perspective ◽  
Research Field ◽  
Organic Wastes ◽  
Anaerobic Digesters ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Iron Based

The addition of magnetic nanoparticles to batch anaerobic digestion was first reported in 2014. Afterwards, the number of works dealing with this subject has been increasing year by year. The discovery of the enhancement of anaerobic digestion by adding iron-based nanoparticles has created a multidisciplinary emerging research field. As a consequence, in the last years, great efforts have been made to understand the enhancement mechanisms by which magnetic nanoparticles (NPs) addition enhances the anaerobic digestion process of numerous organic wastes. Some hypotheses point to the dissolution of iron as essential iron for anaerobic digestion development, and the state of oxidation of iron NPs that can reduce organic matter to methane. The evolution and trends of this novel topic are discussed in this manuscript. Perspectives on the needed works on this topic are also presented.

Determining Optimal Temperature Combination for Effective Pretreatment and Anaerobic Digestion of Corn Stalk

2021 ◽  
Author(s):  
Juan Li ◽  
Xiujin Li ◽  
Akiber Chufo Wachemo ◽  
Xiaoyu Zuo
Keyword(s):  
Anaerobic Digestion ◽  
Corn Stalk ◽  
Chemical Pretreatment ◽  
Organic Loading ◽  
Factors Affecting ◽  
Stirred Tank Reactors ◽  
Loading Rates ◽  
Hand Temperature ◽  
Thermophilic Anaerobic Digestion ◽  
Pretreatment Temperature

Abstract Temperature is one of the important factors affecting both chemical pretreatment and anaerobic digestion (AD) process of corn stalk (CS). In this work, the combined ways between pretreatment temperature (40℃ and 60℃) and AD temperature (35℃ and 55℃) were selected to investigate the AD performance for sodium hydroxide (NaOH) pretreated CS. Three organic loading rates (OLRs) of 1.6, 1.8 and 2.0 g·L-1·d-1 were studied within 255 days using continuously stirred tank reactors (CSTR). The results revealed that temperature of 40°C was considered as an appropriate for pretreatment whether in mesophilic or thermophilic anaerobic digestion systems. On the other hand, temperature of 35°C and 55°C were chosen as the optimal AD temperatures for lower and higher OLRs, respectively. This study provides a significant insight for exploring the effects of temperatures on the pretreatment and AD of CS.

scholarly journals Performance of Anaerobic Digestion of Acidified Palm Oil Mill Effluent under Various Organic Loading Rates and Temperatures

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2432
Author(s):  
Muhammad Arif Fikri Hamzah ◽  
Peer Mohamed Abdul ◽  
Safa Senan Mahmod ◽  
Azratul Madihah Azahar ◽  
Jamaliah Md. Jahim
Keyword(s):  
Anaerobic Digestion ◽  
Palm Oil ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Oxygen Demand ◽  
Microbial Community Analysis ◽  
Palm Oil Mill Effluent ◽  
Methane Formation ◽  
Organic Loading ◽  
Loading Rates ◽  
Palm Oil Mill

This study compared the performance of thermophilic and mesophilic digesters of an anaerobic digestion system from palm oil mill effluent (POME), in which temperature is a key parameter that can greatly affect the performance of anaerobic digestion. The digesters were incubated at two distinct temperatures of 55 and 37 °C, and operated with varying organic loading rates (OLRs) of 2.4, 3.2, and 4.0 g COD/L.d by altering the chemical oxygen demand (COD) of acidified POME during feeding. The results indicated that the performance of anaerobic digestion increased as the OLR increased from 2.4 to 4.0 g COD/L.d. At the OLR of 4.0 g COD/L.d, the thermophilic condition showed the highest methane yield of 0.31 ± 0.01 L/g COD, accompanied by the highest COD removal and volatile solid reduction, which were found to be higher than the mesophilic condition. Microbial community analysis via denaturing gradient gel electrophoresis (DGGE) revealed that Methanothermobacter sp. emerges as the dominant microbe, which is known to utilize the carbon dioxide pathway with hydrogen acting as an electron donor for methane formation

Anaerobic digestion of food waste to volatile fatty acids and hydrogen at high organic loading rates in immersed membrane bioreactors

2020 ◽  
Vol 152 ◽  
pp. 1140-1148 ◽  
Author(s):  
Steven Wainaina ◽  
Mukesh Kumar Awasthi ◽  
Ilona Sárvári Horváth ◽  
Mohammad J. Taherzadeh
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Food Waste ◽  
Volatile Fatty Acids ◽  
Membrane Bioreactors ◽  
Organic Loading ◽  
Loading Rates

scholarly journals Performance of Anaerobic Digestion of Chicken Manure Under Gradually Elevated Organic Loading Rates

2019 ◽  
Vol 16 (12) ◽  
pp. 2239 ◽  
Author(s):  
Fei Wang ◽  
Mengfu Pei ◽  
Ling Qiu ◽  
Yiqing Yao ◽  
Congguang Zhang ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Poultry Manure ◽  
Ammonia Nitrogen ◽  
Methane Content ◽  
Chicken Manure ◽  
Continuous Stirred Tank Reactor ◽  
Organic Loading ◽  
Biogas Yield ◽  
Loading Rates

Poultry manure is the main source of agricultural and rural non-point source pollution, and its effective disposal through anaerobic digestion (AD) is of great significance; meanwhile, the high nitrogen content of chicken manure makes it a typical feedstock for anaerobic digestion. The performance of chicken-manure-based AD at gradient organic loading rates (OLRs) in a continuous stirred tank reactor (CSTR) was investigated herein. The whole AD process was divided into five stages according to different OLRs, and it lasted for 150 days. The results showed that the biogas yield increased with increasing OLR, which was based on the volatile solids (VS), before reaching up to 11.5 g VS/(L·d), while the methane content was kept relatively stable and maintained at approximately 60%. However, when the VS was further increased to 11.5 g VS/(L·d), the total ammonia nitrogen (TAN), pH, and alkalinity (CaCO3) rose to 2560 mg·L−1, 8.2, and 15,000 mg·L−1, respectively, while the volumetric biogas production rate (VBPR), methane content, and VS removal efficiency decreased to 0.30 L·(L·d)−1, 45%, and 40%, respectively. Therefore, the AD performance immediately deteriorated and ammonia inhibition occurred. Further analysis demonstrated that the microbial biomass yield and concentrations dropped dramatically in this period. These results indicated that the AD stayed steady when the OLR was lower than 11.5 g VS/(L·d); this also provides valuable information for improving the efficiency and stability of AD of a nitrogen-rich substrate.

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