The Recovery of Phosphate and Ammonium from Biogas Slurry as Value-Added Fertilizer by Biochar and Struvite Co-Precipitation

Biowaste materials could be considered a renewable source of fertilizer if methods for recovering P from waste can be developed. Over the last few decades, there has been a high level of interest in using biochar to remove contaminants from aqueous solutions. This study was conducted using a range of salts that are commonly found in biogas slurry (ZnCl2, FeCl3, FeCl2, CuCl2, Na2CO3, and NaHCO3). Experiments with a biogas digester and aqueous solution were conducted at pH nine integration with NH4+, Mg2+, and PO43− molar ratios of 1.0, 1.2, and 1.8, respectively. The chemical analysis was measured to find out the composition of the precipitate, and struvite was employed to remove the aqueous solutions. The study found that the most efficient removal of phosphate and ammonium occurred at pH nine in Tongan sludge urban biochar and rice biochar, respectively. Increasing the concentration of phosphate and ammonium increased the phosphate and ammonium content. Moreover, increasing the biochar temperature and increasing the concentration of phosphate and ammonium increased the efficiency of the removal of ammonium and phosphate. The removal efficiency of ammonium and phosphate increased from 15.0% to 71.0% and 18.0% to 99.0%, respectively, by increasing the dose of respective ions K+, Zn2+, Fe3+, Fe2+, Cu2+, and CO32.The elements were increased from 58.0 to 71.0 for HCO3− with the increasing concentration from 30 mg L−1 to 240 mg L−1.This study concluded that phosphate and ammonium can be recovered from mushroom soil biochar and rice biochar, and phosphate can be effectively recovered via the struvite precipitation method

Response of Conjunctive Use of Fresh and Saline Water on Growth and Biomass of Cotton Genotypes

A pot experiment was conducted to study the effects of conjunctive use of saline and fresh water on the growth and biomass of cotton crop and to observe varietal variability for salinity tolerance and ion contents of cotton genotypes. Four cotton genotypes (Sindh-1, BT-121, CRISS-494, CRISS-588) were irrigated with four treatments, C1 (control+ tape water), C2 (EC 4.0 dS m-1, throughout growth period), ( (six irrigation with C2 + six irrigation with C1), C3 (EC 8.0 dS m-1, throughout growth period), (six irrigation C1+ six irrigation C3), (six irrigation C3+ six irrigation C1), C4 (EC 12.0 dS m-1, throughout growth period), (six irrigation C1+ six irrigation C4). The results showed that highest fresh biomass, plant height, number of leaves plant-1, number of bolls and boll weight was obtained in the treatment where tape water was used. Whereas, these parameters were decrease significantly with the increasing salinity levels from 4 to 12 dS m-1 and when saline water was applied continuously throughout growth period. The cotton genotypes Sindh-1 and Bt-21 performed well under conjunctive use of saline and fresh water with maximum values in compare to genotypes CRIS 494 and 588. The Na+ and Cl- accumulation in cotton leaves and in soil significantly increased with rising EC levels of irrigation water. However, Na+ and Cl- contents were found more in CRIS 494 and CRIS 588 than Sindh-1 and Bt1. It is concluded that Sindh-1 and Bt-121 may be cultivated in saline areas with alternate irrigation

Ammonium and Phosphate Recovery from Biogas Slurry: Multivariate Statistical Analysis Approach

Livestock biogas slurry is an effluent containing nutrients such as ammonium and phosphate that are released by the industries. Therefore, recovery and reuse of ammonium and phosphorus is highly necessary. In recent years, many studies have been devoted to the use of different multivariate statistical analyses to investigate the interrelationship of one factor to another factor. The overall objective of this research study was to understand the significance of phosphate and ammonium recovery from biogas slurry using the multivariate statistical approach. This study was conducted using a range of salts that are commonly found in biogas slurry (ZnCl2, FeCl3, FeCl2, CuCl2, Na2CO3, and NaHCO3). Experiments with a biogas digester and aqueous solution were conducted at pH 9, with integration with NH4+, Mg2+, and PO43− molar ratios of 1.0, 1.2, and 1.8, respectively. The removal efficiency of ammonium and phosphate increased from 15.0% to 71.0% and 18.0% to 99.0%, respectively, by increasing the dose of respective ions K+, Zn2+, Fe3+, Fe2+, Cu2+, and CO32−. The elements were increased from 58.0 to 71.0 for HCO3−, with the concentration increasing from 30 mg L−1 to 240 mg L−1. Principal component, regression, path analysis, and Pearson correlation analyses were used to investigate the relationships of phosphate and ammonium recovery under different biochar, pyrolysis temperature, element concentration and removal efficiencies. Multivariate statistical analysis was also used to comprehensively evaluate the biochar and struvite effects on recovery of ammonium and phosphate from biogas slurry. The results showed that combined study of multivariate statistics suggested that all the indicators positively or negatively affected each other. Pearson correlation was insignificant in many ionic concentrations, as all were more than the significant 0.05. The study concluded that temperature, biochar type, and varying levels of components, such as K+, Zn2+, Fe3+, Fe2+, Cu2+, CO32−, and HCO3−, all had a substantial impact on P and NH4+ recovery. Temperature and varying amounts of metal salts enhanced the efficacy of ammonium and phosphate recovery. This research elucidated the methods by which biochar effectively reuses nitrogen and phosphate from biogas slurry, presenting a long-term agricultural solution

Response of Conjunctive Use of Fresh and Saline Water on Growth and Biomass of Cotton Genotypes

A pot experiment was conducted to study the effects of conjunctive use of saline and fresh water on the growth and biomass of cotton crop and to observe varietal variability for salinity tolerance and ion contents of cotton genotypes. Four cotton genotypes (Sindh-1, BT-121, CRISS-494, CRISS-588) were irrigated with four treatments, C1 (control+ tape water), C2 (EC 4.0 dS m-1, throughout growth period), ( (six irrigation with C2 + six irrigation with C1), C3 (EC 8.0 dS m-1, throughout growth period), (six irrigation C1+ six irrigation C3), (six irrigation C3+ six irrigation C1), C4 (EC 12.0 dS m-1, throughout growth period), (six irrigation C1+ six irrigation C4). The results showed that highest fresh biomass, plant height, number of leaves plant-1, number of bolls and boll weight was obtained in the treatment where tape water was used. Whereas, these parameters were decrease significantly with the increasing salinity levels from 4 to 12 dS m-1 and when saline water was applied continuously throughout growth period. The cotton genotypes Sindh-1 and Bt-21 performed well under conjunctive use of saline and fresh water with maximum values in compare to genotypes CRIS 494 and 588. The Na+ and Cl- accumulation in cotton leaves and in soil significantly increased with rising EC levels of irrigation water. However, Na+ and Cl- contents were found more in CRIS 494 and CRIS 588 than Sindh-1 and Bt1. It is concluded that Sindh-1 and Bt-121 may be cultivated in saline areas with alternate irrigation