Evaluation of the Nitrous Oxide Emission Reduction Potential of an Aerobic Bioreactor Packed with Carbon Fibres for Swine Wastewater Treatment

Abstract

Nitrous oxide (N 2 O) is a potent greenhouse gas that is emitted from wastewater treatment plants. To reduce emissions of N 2 O from swine wastewater treatment plants, we constructed an experimental aerobic bioreactor packed with carbon fibres (ca. 1 m 3 bioreactor) as an alternative to conventional activated sludge treatment. The N 2 O emission factor for the aerobic bioreactor packed with carbon fibres (CF) was 0.002 g N 2 O-N/g TN-load and the value for the typical activated sludge (AS) reactor was 0.013 g N 2 O-N/g TN-load. The CF treatment method achieved more than 80% reduction of N 2 O 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 N 2 O generation. Specifically, the N 2 O emission factors decreased from 0.040 to 0.005 g N 2 O-N/g TN-load following application of the carrier. This shows that it is possible to reduce N 2 O 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 N 2 O emissions, were detected at a higher frequency in the biofilm on the CF carrier than in the biofilm formed on the AS reactor.

Mechanical Behavior of an Ultisol Under Different Sugarcane Management Systems in Brazil

“…The results for shear strength in the filter cake system, when compared with the vinasse system, agree with others in the literature on incorporation of organic fibers for the improvement of soil shear strength, as observed in Prabakar & Sridhar [48]. These authors obtained good results in the increase of soil resistance with the incorporation of up to 0.75% of sisal fibers in the soil matrix [49][50][51][52].…”

Gaseous emissions from wastewater facilities

“…The N 2 O emission reduction potential was evaluated using an aerobic bioreactor packed with carbon fibers (Yamashita et al., 2019). More than 80% reduction in N 2 O emission was observed with emission factors decreased from 0.04 to 0.005 g N 2 O‐N/g TN‐load following application of the carbon fiber carrier in an actual facility treating swine wastewater.…”

SMART Computational Solutions for the Optimization of Selected Technology Processes as an Innovation and Progress in Improving Energy Efficiency of Smart Cities—A Case Study

“…defined by the controls (30), minimizing the objective function (35), while meeting the constraints (37-43). For the j-th oxygen chamber (j = {1, 2}) the discretized model of oxygen concentration in the j-th oxygen chamber is described by the dependences:…”

“…The manipulating variables are flow rates (internal, external recirculation, recirculation of air to oxygen chambers, and excess sludge removal, dosing of reagents), (Figure 6). The degree of the removal of nitrogen compounds is determined by the ratio of wastewater recirculation from the oxygen chamber to the anoxic one, i.e., the rise of the degree of recirculation results in the rise of removal efficiency of nitrogen compounds [30,31]. The control of the recirculated wastewater and sludge streams depends on the volume of raw sewage stream at the inlet and on the pollution load.…”