Microwave treatment and struvite recovery potential of dairy manure

Microwave digestion of liquid dairy manure was tested for the release of nutrients, such as orthophosphates, ammonia-nitrogen, magnesium, calcium and potassium, both with and without the aid of an oxidizing agent (hydrogen peroxide). The orthophosphate to total phosphorus ratio of the manure increased from 21% to greater than 80% with 5 minutes of microwave treatment. More than 36% of total chemical oxygen demand (t-COD) of the manure was reduced when microwave digestion was assisted with peroxide addition. In addition, the volatile fatty acids (VFAs) distribution shifted to simpler chain acids (acetic acid in particular) with an increase in operating temperature. In the second part of the study, digested manure with increased soluble phosphate was tested for the recovery of struvite (magnesium ammonium phosphate) at different pH. It was found that up to 90% of orthophosphate can be removed from the solution. Overall, it was concluded that the oxidizing agent-assisted microwave digestion process can be used upstream of anaerobic digestion, following which the anaerobically digested manure can be used for struvite recovery. Thus, this microwave digestion process presents the potential for enhanced efficiencies in both manure digestion and struvite recovery.     

Marginal PM25: Nonlinear Aerosol Mass Response to Sulfate Reductions in the Eastern United States

ABSTRACT

Reductions in airborne sulfate concentration may cause inorganic fine particulate matter (PM₂₅) to respond nonlinearly, as nitric acid gas may transfer to the aerosol phase. Where this occurs, reductions in sulfur dioxide (SO₂) emissions will be much less effective than expected at reducing PM_2.5. As a measure of the efficacy of reductions in sulfate concentration on PM , we define marginal PM_2.5 as the local change in PM_2.5 resulting from a small change in sulfate concentration. Using seasonal-average conditions and assuming thermodynamic equilibrium, we find that the conditions for PM_2.5 to respond nonlinearly to sulfate reductions are common in the eastern United States in winter, occurring at half of the sites considered, and uncommon in summer, due primarily to the influence of temperature. Accounting for diurnal and intraseasonal variability, we find that seasonal-average conditions provide a reasonable indicator of the time-averaged PM_2.5 response. These results indicate that reductions in sulfate concentration may be up to 50% less effective at reducing the annual-average PM_2.5 than if the role of nitric acid is neglected. Further, large reductions in sulfate will also cause an increase in aerosol nitrate in many regions that are the most acidic.     

Modeling factors of biogas technology adoption: a roadmap towards environmental sustainability and green revolution

Environmental Science and Pollution Research - In a developing country such as Pakistan, adopting biogas technology is a complicated process. The government has taken several steps to address...     

Impact assessment of urban development patterns on land surface temperature by using remote sensing techniques: a case study of Lahore,Faisalabad and Multan district

Environmental Science and Pollution Research - Urban Heat Island (UHI) is related to the theory of higher atmosphere and surface temperature taking place in the city area as compared to the nearby...     

Correction to: Monitoring of copper accumulation in water,soil, forage,and cows impacted by heavy automobiles

Environmental Science and Pollution Research - A Correction to this paper has been published: https://doi.org/10.1007/s11356-021-13137-9     

Correlation of MSH2 exonic deletions and protein downregulation with breast cancer biomarkers and outcome in Pakistani women/patients

Environmental Science and Pollution Research - Mismatch repair (MMR) pathway is one of the underlying mechanisms of predisposition to breast cancer (BC). The present study explored the association...     

Identification of irrigation potential areas,using multi-criteria analysis in Khyber District,Pakistan

Environmental Science and Pollution Research - This study explores the opportunities for irrigated agriculture in Khyber District of Former Federally Administered Tribal Area (FATA). Agriculture...