Physical parameters evaluation during production of soil conditioner from aquatic waste: Hydrilla verticillata (L.f.) Royle

Over the decades, composting is a superlative technology to manage organic wastes such as vegetable wastes, sewage sludge, industrial wastes, and aquatic weeds as a soil conditioner. This study focuses on the use of hydrilla verticillata as a substrate material, mixed with cow dung, and sawdust. The combined addition of cow dung and sawdust improved the conditions of the composting process and the quality of compost. Along with, conventional parameters such as volatile solids, pH, total nitrogen, and stability parameters this study also describes the proper understanding of process fundamentals about few important physical parameters such as bulk density, particle density, free air space, and moisture content. These parameters were studied during composting of highly invasive aquatic weed (H. verticillata) in 550 L rotary drum composter. Thermophilic phase (>45 °C) was reached within 24 h of feeding; volume reduction was clearly depicted as, bulk density also increased from 171 to 761 kg m−3 during 20 days composting process. However, the study reveals that particle density of compost varied from 1079.1 to 2313 kg m−3 during composting. Proficient compost production involves detailed understanding the process dynamics of correlation between moisture reductions, free air space, bulk density, and particle density. Few physical properties during composting of H. verticillata are compared with other aquatic weeds reported in literature.