ENERGY RECOVERY AND UTILIZABIRITY OF RESIDURE FOR RICE FIELD BY THERMOPHIRIC ANAEROBIC CO-DIGESTION OF SEWAGE SLUDGE AND RICE STRAW

Author(s):  
Taketo TOGARI ◽  
Takeo MISAKI ◽  
Norihisa MATSUURA ◽  
Aika TANABE ◽  
Takeru HAMAGUCHI ◽  
...  
Archaea ◽  
2005 ◽  
Vol 1 (6) ◽  
pp. 391-397 ◽  
Author(s):  
Atsuo Sugano ◽  
Hidetaka Tsuchimoto ◽  
Tun Cho Cho ◽  
Makoto Kimura ◽  
Susumu Asakawa

The succession and phylogenetic profiles of methanogenic archaeal communities associated with rice straw decomposition in rice-field soil were studied by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis followed by 16S rDNA sequencing. Nylon bags containing either leaf sheaths or blades were buried in the plowed layer of a Japanese rice field under drained conditions during the off-crop season and under flooded conditions after transplanting. In addition, rice straw samples that had been buried in the rice field under drained conditions during the off-crop season were temporarily removed during spring plowing and then re-buried in the same rice field under flooded conditions at transplanting. Populations of methanogenic archaea were examined by amplification of the 16S rRNA genes in the DNA extracted from the rice straw samples. No PCR product was produced for samples of leaf sheath or blade prior to burial or after burial under drained conditions, indicating that the methanogen population was very small during decomposition of rice straw under oxic conditions. Many common bands were observed in rice straw samples of leaf sheath and blade during decomposition of rice straw under flooded conditions. Cluster analysis based on DGGE patterns divided methanogenic archaeal communities into two groups before and after the mid-season drainage. Sequence analysis of DGGE bands that were commonly present were closely related toMethanomicrobialesand Rice cluster I.Methanomicrobiales, Rice cluster I andMethanosarcinaleswere major members before the mid-season drainage, whereas the DGGE bands that characterized methanogenic archaeal communities after the mid-season drainage were closely related toMethanomicrobiales. These results indicate that mid-season drainage affected the methanogenic archaeal communities irrespective of their location on rice straw (sheath and blade) and the previous history of decomposition during the off-crop season.


2018 ◽  
Vol 77 (11) ◽  
pp. 2613-2623 ◽  
Author(s):  
Kerstin Schopf ◽  
Johannes Judex ◽  
Bernhard Schmid ◽  
Thomas Kienberger

Abstract A municipal wastewater treatment plant accounts for a large portion of the total energy consumption of a municipality. Besides their high energy demand, the plants also display a significant bioenergy potential. This is due to the utilisation of the energy content of digester gas and sewage sludge if there exist suitable units. To maximise the energy recovery efficiency of wastewater treatment systems (WWTS), it is important to analyse the amount of digester gas and sludge produced in different types of plants. Therefore, the present paper deals with designing a tool to answer the following research questions: Which bioenergy potentials occur in different plant types? Which mass and energy flows are related to the specific potentials? Which utilisation processes for the potentials can lead to a high energy recovery efficiency of WWTS? Preliminary analyses with the designed tool were focused on estimating the level of electric and thermal energy self-sufficiency of different plant configuration scenarios including or excluding digester gas and/or sludge utilisation units. First results based on the level of self-sufficiency and associated energy and disposal costs show that a digester gas and sewage sludge utilisation should be considered when designing future WWTS.


Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1927 ◽  
Author(s):  
Dinko Đurđević ◽  
Paolo Blecich ◽  
Željko Jurić

Croatia produced 21,366 tonnes of dry matter (DM) sewage sludge (SS) in 2016, a quantity expected to surpass 100,000 tonnes DM by 2024. Annual production rates for future wastewater treatment plants (WWTP) in Croatia are estimated at 5.8–7.3 Nm3/people equivalent (PE) for biogas and 20–25 kgDM/PE of sewage sludge. Biogas can be converted into 12–16 kWhel/PE of electricity and 19–24 kWhth/PE of heat, which is sufficient for 30–40% of electrical and 80–100% of thermal autonomy. The WWTP autonomy can be increased using energy recovery from sewage sludge incineration by 60% for electricity and 100% of thermal energy (10–13 kWhel/PE and 30–38 kWhth/PE). However, energy for sewage sludge drying exceeds energy recovery, unless solar drying is performed. The annual solar drying potential is estimated between 450–750 kgDM/m2 of solar drying surface. The lower heating value of dried sewage sludge is 2–3 kWh/kgDM and this energy can be used for assisting sludge drying or for energy generation and supply to WWTPs. Sewage sludge can be considered a renewable energy source and its incineration generates substantially lower greenhouse gases emissions than energy generation from fossil fuels. For the same amount of energy, sewage sludge emits 58% fewer emissions than natural gas and 80% less than hard coal and fuel oil. Moreover, this paper analysed the feasibility of sludge disposal practices by analysing three scenarios (landfilling, co-incineration, and mono-incineration). The analysis revealed that the most cost-effective sewage sludge disposal method is landfilling for 60% and co-incineration for 40% of the observed WWTPs in Croatia. The lowest CO2 emissions are obtained with landfilling and mono-incineration in 53% and 38% of the cases, respectively.


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