Hydrolyzed urine for enhanced valorization and toxicant degradation of wet coffee processing wastes: Implications for soil contamination and health risk reductions

Effective reduction of carbon-containing pollutants in coffee cherry pulping wastewater using natural polysaccharide from Tamarindus indica L. seeds

The wastewater produced during coffee cherry pulping is known for containing harmful pollutants, particularly organic compounds containing carbon, which pose significant risks to the environment and human health. This research aimed to evaluate the effectiveness of Tamarindus indica L. seed polysaccharides in treating coffee effluent. Varying doses (ranging from 0.05 to 0.30 g) of the isolated polysaccharides were added to samples of the effluent to determine their ability to remove contaminants, especially those of organic carbon origin. Notably, a dosage of 0.10 g demonstrated optimal efficacy, resulting in a 55% decrease in total dissolved solids and an 80% decrease in chemical oxygen demand. Additionally, Fourier-transform infrared and zeta potential analysis of both the polysaccharides and the treated effluent samples revealed the presence of functional groups potentially pivotal for the pollutant removal activity of the isolated polysaccharides. This provides insights into the coagulation mechanism of Tamarindus indica L. seed polysaccharides in eliminating organic carbon-based pollutants. These findings highlight the potential of Tamarindus polysaccharides as a sustainable alternative to chemical agents for removing pollutants, thus promoting environmental sustainability and human well-being.

Addition of plantation waste to the bioconversion of pig manure by black soldier fly larvae: Effects on heavy metal content and bioavailability

During the conversion of pig manure by black soldier fly larvae (BSFL), the accumulation and speciation changes of heavy metals (HMs) have adverse effects on the environment. In this study, corn straw, rice straw, bamboo chips (BC), wood chips, and rice husk char were added to a bioconversion system to study the accumulation, migration, speciation changes, and microbial correlations of HMs. The results indicated that the addition of BC was most beneficial for the accumulation of HMs (47-72 %) in the BSFL body. In the BC group, the accumulation effect of the BSFL body on zinc (Zn) and arsenic (As) was the most evident (72 and 71 %, respectively). The results of linear fitting (R2 > 0.90) and redundancy analysis (RDA; 90 %) indicated that the bacterium Bacillaceae (Bacillus) was beneficial for increasing the larval weight (LW) of BSFL, and a higher LW accumulated HMs. The addition of BC helped reduce the total amount (6-51 %) of available states (weak acid extraction and reducible states) in the BSFL residue. The RDA results indicated that bacteria (55-92 %) affected the transformation of HM speciation. For example, Zn and cadmium were mainly affected by Firmicutes, whereas copper and chromium were affected by Bacteroidetes. Proteobacteria and Pseudomonas formosensis affected the conversion of lead and As. This study provides important insights into the adsorption of HMs from pig manure by BSFL.