Swine wastewater contains phosphorus, ammonia nitrogen, and heavy metals that affect the struvite purity produced from the wastewater and increase the ecological hazards. In addition, struvite crystallization process is highly dependent on the usage of magnesium sources. Thus, it is necessary to explore the effects of three magnesium sources, including MgCl 2 , Mg(OH) 2 and MgO , on the phosphorus recovery and minimizing Cu and Fe contents via struvite crystallization process. The observations revealed that the predominant parts of Cu and Fe precipitate in the form of hydroxide during pH adjustment. Meanwhile, when using MgCl 2 as the magnesium source, the optimal removal efficiency of phosphorus reached 94.55%, followed by MgO and Mg(OH) 2 . Simultaneously, 90.60% Cu and 98.80% Fe precipitate under MgCl 2 as magnesium source. The redissolution behavior of Cu occurs when MgO and Mg(OH) 2 are used as magnesium sources, increasing the Cu concentration. The smallest operation cost is from MgCl 2 as magnesium source. The potential environmental impact analyzed by life cycle assessment method shows that MgCl 2 in struvite crystallization process saves more fossil energy and protects resource while lessens the nature's eutrophication risk. The technical, economic, and environmental assessments confirm MgCl 2 as a promisable source of magnesium in struvite crystallization process for achieving cleaner production goal.
Cupric (Cu(II)) complexes in industrial wastewater are responsible for the failure of conventional alkaline precipitation, but the properties of cuprous (Cu(I)) complexes at alkaline circumstance have not been focused. This report proposed a novel strategy for the remediation of Cu(II)-complexed wastewater by coupling alkaline precipitation with green benign reductant, namely, hydroxylamine hydrochloride (HA). This remediation process (HA-OH) exhibits superior Cu removal efficiency that cannot be achieved with the same dosage of oxidants (3 mM). The possibility of Cu(I) activated O 2 catalysis and self-decomplexation precipitation were investigated, and the results identified that 1 O 2 was generated from Cu(II)/Cu(I) cycle, but it was insufficient to annihilate organic ligands. Cu(I) self-decomplexation was the dominate mechanism of Cu removal. For real industrial wastewater, HA-OH process can realize the efficient Cu 2 O precipitation and Cu recovery. This novel strategy utilized intrinsic pollutant in wastewater without introducing other metals, complicated materials, and expensive equipment, broadening the insight for the remediation of Cu(II)-complexed wastewater.
危险品化学品经营许可证（带存储）