Anaerobic digestion: impact of future greenhouse gases mitigation policies on methane generation and usage

2005 ◽  
Vol 52 (1-2) ◽  
pp. 39-47 ◽  
Author(s):  
P.F. Greenfield ◽  
D.J. Batstone

The debate as to whether carbon dioxide, methane, nitrous oxide and other greenhouse gas emissions will become subject to increasing regulation, increased restrictions, and probably to some form of carbon tax, has moved from a simple “yes” or “no” to “when”. Wastewater treatment plants will be significantly impacted by increased energy costs and by specific regulations and/or penalties associated with emissions of methane and nitrous oxide. In this paper, the greenhouse gases emissions of different wastewater process options are estimated. The paper outlines the increasing need for wastewater treatment plants to factor greenhouse gas mitigation issues into their medium- as and long-term strategies, and identifies anaerobic enhouse as processes as being at the core of such strategies. Further, the paper identifies a number of key research challenges to be addressed if such strategies are to play a larger role in attenuating the likely impacts of GHG mitigation requirements on wastewater treatment plant design and operation.

2020 ◽  
Vol 150 ◽  
pp. 01012
Author(s):  
Yassine Bahi ◽  
Ahmed Akhssas ◽  
Mohamed Khamar ◽  
Lahcen Bahi ◽  
Hanane Souidi

The process of removing organic components from wastewater as BOD5 through wastewater treatment plants has been proven to be a significant source of greenhouse gas emissions, mainly methane CH4, carbon dioxide CO2 and nitrous oxide N2O. The reduction of these emissions has attracted more interest given their major contribution to global warming. This study was able to identify and estimate the amount of methane and CO2 emissions on a monthly basis by a simple modeling approach and an empirical method (IPCC) for N2O emissions, in the case of Ain-Taoujdate wastewater treatment plant, throughout the years 2013, 2018 and 2019. The results showed that anaerobic ponds were the main source of on-site emissions with 66% of total contribution and 33% for facultative ponds, followed by the energy consumption of the pumping station as off-site GHG emissions.


Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1013 ◽  
Author(s):  
Takahiro Yamashita ◽  
Makoto Shiraishi ◽  
Hiroshi Yokoyama ◽  
Akifumi Ogino ◽  
Ryoko Yamamoto-Ikemoto ◽  
...  

Nitrous oxide (N2O) is a potent greenhouse gas that is emitted from wastewater treatment plants. To reduce emissions of N2O from swine wastewater treatment plants, we constructed an experimental aerobic bioreactor packed with carbon fibres (ca. 1 m3 bioreactor) as an alternative to conventional activated sludge treatment. The N2O emission factor for the aerobic bioreactor packed with carbon fibres (CF) was 0.002 g N2O-N/g TN-load and the value for the typical activated sludge (AS) reactor was 0.013 g N2O-N/g TN-load. The CF treatment method achieved more than 80% reduction of N2O emissions, compared with the AS treatment method. The experimental introduction of a CF carrier into an actual wastewater treatment plant also resulted in a large reduction in N2O generation. Specifically, the N2O emission factors decreased from 0.040 to 0.005 g N2O-N/g TN-load following application of the carrier. This shows that it is possible to reduce N2O generation by more than 80% by using a CF carrier during the operation of an actual wastewater treatment plant. Some bacteria from the phylum Chloroflexi, which are capable of reducing N2O emissions, were detected at a higher frequency in the biofilm on the CF carrier than in the biofilm formed on the AS reactor.


2016 ◽  
Vol 11 (2) ◽  
pp. 423-428 ◽  
Author(s):  
Sandeep Malyan

Rice fields are significant contributors of greenhouse gases mainly methane and nitrous oxide to the atmosphere. Increasing concentrations of these greenhouse gases play significant role in changing atmospheric chemistry such as mean air temperature, rainfall pattern, drought, and flood frequency. Mitigation of greenhouse gases for achieving sustainable agriculture without affecting economical production is one the biggest challenge of twenty first century at national and global scale. On the basis of published scientific studies, we hereby assess the use of nitrification inhibitors for greenhouse gas mitigation from rice soil. Biologically oxidation of ammonium to nitrate is termed as nitrification and materials which suppress this process are known as nitrification inhibitors. Soil amendment by addition of certain nitrification inhibitors such as neem oil coated urea, nimin-coated urea; dicyandiamide, encapsulated calcium carbide, and hydroquinone reduce cumulative methane and nitrous oxide emission from rice. Firstly, these inhibitors reduce nitrous oxide emissions both directly by nitrification (by reducing NH4+ to NO3-) as well as indirectly by de-nitrification (by reducing NO3- availability in soil). Secondly, methane emission from rice soil can be reduced by enhancing methane oxidation and suppressing methane production and further by reducing the aerenchymal transportation through rice plant. Application of some of the nitrification inhibitors such as calcium carbide and encapsulated calcium carbide reduce methane production by releasing acetylene gas which helps in reducing the population of methanogenic microbes in the soil. Application of nitrification inhibitors also helps to maintain soil redox potential at higher level subsequently reducing cumulative methane emission from soil. Plant derived organic nitrification inhibitors (neem oil, neem cake, karanja seed extract) are eco-friendly and possess substantial greenhouse gas mitigation potential from rice. In the current scenario of global warming and environmental pollution, application of organic plant derived nitrification inhibitors is much needed for sustainable agriculture.


1980 ◽  
Vol 15 (2) ◽  
pp. 121-142 ◽  
Author(s):  
R.M. Narbaitz ◽  
B.J. Adams

Abstract A computer based design methodology was developed to facilitate and improve the preliminary design of wastewater treatment plants. It aids design by choosing the least cost treatment system (including sludge treatment and disposal) which meets all the constraints of the particular application. This methodology not only chooses the best alternative treatment system among numerous alternatives but also finds the optimal values of the independent design variables of the processes forming the optimal treatment system. In addition, it has two advantages over currently available design methodologies in that it optimizes wastewater treatment design with respect to the removal of more than one water quality parameter and it considers that sludges produced by different processes have different qualities. This methodology is based on a nonlinear programming method termed optimization by random search and systematic reduction of the size of search region. The design procedure was used to analyze a particular example problem.


2002 ◽  
Vol 46 (9) ◽  
pp. 11-20 ◽  
Author(s):  
J. Vollertsen ◽  
T. Hvitved-Jacobsen ◽  
Z. Ujang ◽  
S.A. Talib

Sewer system design must be integrated with wastewater treatment plant design when moving towards a more sustainable urban wastewater management. This integration allows an optimization of the design of both systems to achieve a better and more cost-effective wastewater management. Hitherto integrated process design has not been an option because the tools to predict in-sewer wastewater transformations have been inadequate. In this study the WATS model - being a new and validated tool for in-sewer microbial process simulations - is presented and its application for integrated sewer and treatment plant design is exemplified. A case study on a Malaysian catchment illustrates this integration. The effects of centralization of wastewater treatment and the subsequently longer transport distances are addressed. The layout of the intercepting sewer is optimized to meet the requirements of different treatment scenarios.


2010 ◽  
Vol 2 (5) ◽  
pp. 97-102
Author(s):  
Ala Sokolova ◽  
Mindaugas Rimeika

The paper analyzes the impact of the way of mounting a tube diffuser, the design of an aeration tank and the presence of a fixed carrier on the operational parameters of aeration systems used in small wastewater treatment plants. It was found out that the vertically mounted tube diffuser decreased standard oxygen transfer rate (SOTR) of the aeration system by approximately 20% and standard oxygen transfer efficiency (SOTE) by 25% comparing to the horizontally mounted tube diffuser. It was also defined that the design of the aeration tank might have an impact on the operation parameters of the aeration system: when the centre shell used to protect a diffuser was dismantled from a test tank, SOTR and SOTE increased by approximately 20%. It was also established that the presence of the fixed carrier in the aeration tank did not have an impact on the performance of aeration systems. Finally, research was carried out to compare the operational parameters of two diffusers of different types offered on the market and used in small wastewater treatment plants. It was found out that the performance different type diffusers might vary considerably.


1995 ◽  
Vol 32 (7) ◽  
pp. 111-117
Author(s):  
G. J. Hatziconstantinou ◽  
C. M. Kalergis ◽  
A. P. Grivas

This paper presents the case of a small wastewater treatment plant taken out of service due to insufficient design and equipment installed. Design assumptions and decisions made for plant restoration based on treatment requirements are outlined and plant operation aspects regarding revealed wastewater characteristics, process efficiency, sludge settling behaviour and equipment control, are discussed. The importance of wastewater characterization as a necessary procedure prior to plant design and construction, is stressed and the feasibility of nutrient removal in small wastewater treatment plants under minimum supervision, is assessed. A simplified mathematical model, as a useful tool to operators, for plant performance evaluation and prediction, is presented.


2012 ◽  
Vol 367 (1593) ◽  
pp. 1265-1277 ◽  
Author(s):  
Yingyu Law ◽  
Liu Ye ◽  
Yuting Pan ◽  
Zhiguo Yuan

Nitrous oxide (N 2 O) emissions from wastewater treatment plants vary substantially between plants, ranging from negligible to substantial (a few per cent of the total nitrogen load), probably because of different designs and operational conditions. In general, plants that achieve high levels of nitrogen removal emit less N 2 O, indicating that no compromise is required between high water quality and lower N 2 O emissions. N 2 O emissions primarily occur in aerated zones/compartments/periods owing to active stripping, and ammonia-oxidizing bacteria, rather than heterotrophic denitrifiers, are the main contributors. However, the detailed mechanisms remain to be fully elucidated, despite strong evidence suggesting that both nitrifier denitrification and the chemical breakdown of intermediates of hydroxylamine oxidation are probably involved. With increased understanding of the fundamental reactions responsible for N 2 O production in wastewater treatment systems and the conditions that stimulate their occurrence, reduction of N 2 O emissions from wastewater treatment systems through improved plant design and operation will be achieved in the near future.


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