Enhanced removal of phosphate and ammonium by MgO-biochar composites with NH3·H2O hydrolysis pretreatment.

In this study, a novel MgO-biochar composite was generated for nutrient recovery from biogas slurry using magnesium chloride (MgCl2) and ammonia hydroxide (NH3·H2O). Biochar properties, including pH, CEC, pHpzc, magnesium content, surface area, and total pore volume (Vtotal), were evaluated. Moreover, the removal of NH4+ and PO43- in both single and bi-solute system were investigated. Results indicated that NH3·H2O pretreatment and MgO-coating enhanced biochar pH, CEC, and pHpzc. Additionally, there were generally higher surface area and Vtotal in MgAWS550. The maximum adsorption capacities for NH4+ and PO43-, respectively, increased as WS550 (0.555 and 1.57 mg g-1) < MgWS550 (15.4 and 21.8 mg g-1) < MgAWS550 (17.5 and 31.3 mg g-1). Moreover, higher removal efficiencies were achieved in the bi-solute system, and over 25% and 90% of NH4+ and PO43-, respectively, was removed from biogas slurry by MgASW550. Mechanically, NH4+ removal was mainly attributed to ionic exchange, while PO43- adsorption on MgO-coated biochars was due to electrostatic attraction and precipitation. Furthermore, the formation of struvite (MgNH4PO4·6H2O) further enhanced N and P in the bi-solute system.

Dynamics of fungal diversity and interactions with environmental elements in response to wheat straw biochar amended poultry manure composting.

The fungal dynamics and its correlation with physicochemical and gaseous emission were investigated using metagenomics and Heat map illustrator (HEMI). Five different concentrations of wheat straw biochar (WSB) were applied to poultry manure (PM) and composted for 50 days; those without the WSB treatment were used as a control. The results revealed the dominant phyla to be Chytridiomycota, Mucoromycota, Ascomycota and Basidiomycota, while Batrachochytrium, Rhizophagus, Mucor, and Puccinia were the superior genera. In particular, the diversity of Chytridiomycota and Ascomycota was more abundant among all of the treatments. Overall, the diversity of the fungal species was correspondent, but relative abundance varied significantly among all of the composts. Principle Coordinate Analysis (PCoA) and Non-Metric Multi- Dimensional Scaling (NMDS) indicated that different concentrations of WSB applied treatments have significantly distinct fungal communities. In addition, correlation analyses of fungal interactions with environmental elements via HEMI also indicate a clear difference among the treatments. Ultimately, the relative abundance of fungal composition significantly influenced the PM compost treated by the WSB.

Succession of bacteria diversity in the poultry manure composted mixed with clay: Studies upon its dynamics and associations with physicochemical and gaseous parameters.

In this study, the bacterial community succession and variations were investigated in poultry manure (PM) compost by the using high-throughput sequencing in six different concentration of clay [at 0% (T1), 2% (T2), 4% (T3), 6% (T4), 8% (T5) and 10% (T6) on PM dry weight basis] applied compost. The results indicated that dominant phylum were Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes, while Bacillus, Paenibacillus, Virgibacillus, Oceanobacillus and Clostridium were the dominant genera in all the treatments. Correlation analyses provided useful tools for insight into the bacterial interactions with environmental factors and also extension of the compost maturation and resistance of bacteria. During the course of study, the diversity of bacteria similar but relative abundance variable in each treatments. However, the average and the normalized (to bacterial RAs or copies of sequences) both remained greater in higher dosage of clay applied treatments. Finally, the RAs of various bacterial community composition was affected in PM compost by the clay application.

New insight of tertiary-amine modified bentonite amendment on the nitrogen transformation and volatile fatty acids during the chicken manure composting.

In this study, the main objective was to investigate the potential effect of tertiary-amine modified bentonite (TAMB) on the nitrogen transformation and the volatile fatty acids (VFAs) degradation during the chicken manure (CM) composting. Six dosages of TAMB (0%, 2%, 4%, 6%, 8% and 10%) were amended into the mixture of CM and wheat straw and then composted for 50 days. The results revealed the TAMB amendment could prolong the thermophilic phase and enhance the organic matter (OM) degradation. With the increasing dosage of TAMB, the ammonia volatilization was reduced by 15.41%-65.35%. Meanwhile, the TAMB addition had a positive effect on VFAs degradation and reducing odor unitMAX (OUMAX) by 17.61%-59.24%. Moreover, CH4 was reduced by 12.15%-32.78% in TAMB applied treatments compared to control. Finally, combined with all results, it indicated that TAMB amendment could reduce VFAs, CH4 emission and nitrogen loss to improve the compost quality.