Novel resource utilization of refloated algal sludge to improve the quality of organic fertilizer

Abstract

Without further management, large amounts of refloated algal sludge from Taihu Lake to retrieve nitrogen and phosphorus resources may result in serious secondary environmental pollution. The possibility of utilization of algal sludge to improve the quality of organic fertilizer was investigated in this study. Variations of physicochemical properties, germination index (GI) and microcystin (MC) content were analysed during the composting process. The results showed that the addition of algal sludge improved the contents of nutrients, common free amino acids and total common amino acids in the novel organic fertilizer. Rapid degradation rates of MC-LR and MC-RR, a high GI value and more abundance of culturable protease-producing bacteria were observed during the composting process added with algal sludge. Growth experiments showed that the novel organic fertilizer efficiently promoted plant growth. This study provides a novel resource recovery method to reclaim the Taihu Lake algal sludge and highlights a novel method to produce a high-quality organic fertilizer.

Keywords:

• algal sludge
• resource utilization
• quality of organic fertilizer
• degradation of microcystins
• plant growth promotion