Ammonia assimilation: A double-edged sword influencing denitrification of Rhodobacter azotoformans and for nitrogen removal of aquaculture wastewater

ACS Sustainable Chem. Eng.

Shao

et al. 2022

Value-added biochar or hydrochar converted from agricultural waste has the potential to improve soil performance. However, how biochar and hydrochar addition affect ecological responses is not clear. Here, we examined the physicochemical property of biochar and hydrochar from straw (RS) and manure (SM), identified relevant eco-friendly pretreatment methods through life cycle assessment (LCA) methodology, and investigated their influences on soil properties and C and N cycles. The results showed that biochar prepared at 500 and 700 °C and hydrochar prepared at 250 °C for 4, 6, and 8 h had better physicochemical properties. The LCA results revealed that RBC500, RS250-4, and SM250-4 had lower environmental burdens in the preparation process. Moreover, biochar and hydrochar addition could promote the soil C and N cycles to varying degrees, especially in the case of SM250-4, which could simultaneously promote the degradation of cellulose, lignin, and chitin and reduce the emission of CO2 and N2O. Overall, SM250-4 application had a beneficial effect on carbon neutralization. These novel results compensate for the deficiency of research on the phaeozem improvement effects of biochar and hydrochar.

supporting

confidence: 54%

Section: Results and Discussionmentioning

confidence: 51%

Biochar and Hydrochar from Agricultural Residues for Soil Conditioning: Life Cycle Assessment and Microbially Mediated C and N Cycles

ACS Sustainable Chem. Eng.

Shao

et al. 2022

“…Many species in the phyla Proteobacteria and Bacteroidetes have been found to be involved in the cycling of nitrogen and phosphorus in sewage (Ansola et al, 2014; Peralta et al, 2013; Wang et al, 2016). Numerous studies have demonstrated that the amount of denitrifying bacteria in water has a substantial impact on the effectiveness of total nitrogen's denitrification (Deng et al, 2021; Li, Han, et al, 2022; Li, Li, et al, 2022). Ammonia nitrogen and nitrate nitrogen make up most of the total nitrogen among them (Lananan et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

“…Ammonia nitrogen and nitrate nitrogen make up most of the total nitrogen among them (Lananan et al, 2014). The principal differential microbial in the control group C and FR group, Gemmobacter , Rhodobacter , Emticicia and Bosea were discovered to be Proteobacteria by subsequent identification of the experiment's differential microbial (Li, Li, et al, 2022; Rubiyatno et al, 2021; Song et al, 2020). Moreover, these microbial all have the effect of denitrification (Tan et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

Replacing starch with resistant starch (Laminaria japonica) improves water quality, nitrogen and phosphorus budget and microbial community in hybrid snakehead (Channa maculata ♀ × Channa argus ♂)

Zuo

Water Environment Research

et al. 2023

It is essential to increase the use of carbohydrates as an energy source and improve protein synthesis and utilization to reduce ammonia nitrogen emissions. A 60‐day cultural experiment was conducted to assess the impact of resistant starch (kelp meal, Laminaria japonica) replacing starch on water quality, nitrogen and phosphorus budget and microbial community of hybrid snakehead. Approximately 1350 experimental fish (11.4 ± 0.15 g) were randomly divided into control group (C, 20% starch) and four resistant starch groups: low replacement group (LR, 15% starch), medium replacement group (MR, 10% starch), high replacement group (HR, 5% starch) and full replacement group (FR, 0% starch). The crude protein and crude fat content of hybrid snakehead fish fed with the FR diet had the most significant improvement (P < 0.05). However, resistant starch also increased the effectiveness of nitrogen and phosphorus utilization in hybrid snakeheads, which decreased the proportion of total nitrogen and total phosphorus in tail water. The minimum nitrogen and phosphorus emission rate was when the starch level was 6.1%. Denitrifying microbes including Gemmobacter, Rhodobacter, Emticicia and Bosea have become much more prevalent in group FR (P < 0.05). In general, replacing starch with resistant starch can enhance the rate at which nitrogen and phosphorus are used in feeding, lessening water pollution and altering environmental microbial composition. Practitioner Points Resistant starch (RS) improves whole fish nutritional content. Resistant starch improves dietary nitrogen and phosphorus utilization. Resistant starch acts as a carbon source and encourages the colonization of denitrifying bacteria in water.

“…It can be seen that the nitrogen pollution in each water sample was detected to varying degrees; the concentration of ammonia nitrogen in S-1 was the most prominent. The main reason may be that, compared with outdoors, the breeding density of indoor fishponds is higher, and the aquaculture water had not been replaced for a long time, resulting in a large accumulation of highprotein feed and fecal excretion [36]. Therefore, this paper mainly took ammonia nitrogen as an example to design and study the adsorption-enhanced SAT system.…”

Section: Description Of the Study Areamentioning

confidence: 99%

Design of an Enhanced SAT Using Zeolite for the Removal of Ammonia Nitrogen at a Bengbu Aquatic Farm in China

et al. 2022

As one of the artificial recharge technologies, the soil–aquifer treatment (SAT) system is used for the removal of nitrogen pollution from aquaculture wastewater. An adsorption-enhanced SAT system was designed to reduce the level of nitrogen pollution below the threshold stipulated by the standards. Adsorption kinetics experiments were used to measure the adsorption capacity of zeolite and activated carbon for ammonia nitrogen. Both adsorbents can be well described by the Lagergren pseudo-second-order model, and the adsorption rates of zeolite and activated carbon for ammonia nitrogen were 72.16% and 31.40%, respectively. Combining the experimental data and the actual situation, the medium-packing method was determined and the influence of wastewater characteristics and hydrodynamic conditions on the adsorption and retention capacity of the SAT system were considered. Finally, the feasibility of the adsorption-enhanced SAT site design scheme was verified by Hydrus-1D model simulation. The study found that the design scheme for the situation in the study area was feasible; however, the surrounding underground environment still had a risk of pollution during the operation of the site. Therefore, further research is needed for the nitrogen pollution to be completely removed within the scope of the SAT site.