Bio-organic fertilizer production from industrial waste and insightful analysis on release kinetics.

The present study has been designed to utilize industrial and agricultural solid waste for NPK (Nitrogen-Phosphorus-Potassium) bio-organic fertilizer production and its optimized use. The collagenic material of wet blue leather (WBL) from leather industry was used as nitrogen source, after H3PO4 acid-mediated chromium removal. Chicken meat-bone meal (CMBM) and rice husk ash (RHA) are abundantly available locally, had used as P, K, and Ca sources. The presence of N, P, K, Ca in the produced bio-organic NPK fertilizer were 10.76, 11.03, 3.41, 13.64, respectively as per mixing ratio of ingredients. In this study it was effect on the chili plant (Capsicum annuum L.) growth and revealed 1.15 and 1.03 fold higher plant growth, 1.40 and 1.18 fold higher total chlorophyll content than untreated soil (control), and chemical fertilizer. The liberation of fertilizers components from their source, transport of fertilizer components in the soil, and absorption in plant roots have been studied using mathematical models indicating the optimum fertilizer use for better productivity and to reduce loss of extra fertilizer and eutrophication. The formulation showed excellent water retention capability (3.2 L/kg), which might increase soil water availability to the plants and eventually reduce water demand and labour cost. DNA intercalation study proved there is no harm to use this fertilizer.

Transforming wet blue leather and potato peel into an eco-friendly bio-organic NPK fertilizer for intensifying crop productivity and retrieving value-added recyclable chromium salts.

An attempt has been made to address two important issues, the solid waste management of leather industry and soil fertility. The SEM images revealed altered surface-morphology.The EDS elemental analysis exhibited presence of about 13.2% nitrogen (N), 50.56% carbon (C), 2.69% phosphorus (P) in the collagenous material of wet blue leather (WBL) after chromium removal. In potato peel biochar (PPB) prepared the EDS analysis corroborated the presence of N P K in 5%, 1.4% and 21.64% respectively. In the formulated bio-organic NPK fertilizer, using chromium free WBL and PPB, the percentage of N, P, K, was in 13.10, 2.41, 20.20% respectively which was authenticated by EDS. Its effect on okra (Abelmoschus esculentus) plant showed higher growth (1.11 fold fruit size) and total chlorophyll content (1.61 fold) than in untreated soil (control) but displayed similar result as in presence of chemical fertilizer. The released free ammonia in soil with bio-organic NPK was more (37.02%) than with chemical fertilizer (6.10%). DNA intercalation study showed the non-hazardous impact on soil. The FTIR, XRD, SEM-EDS, AAS further specified the conversion of the WBL extracted acidic chromium-rich solution by MgO into crystalline chromium for commercial use.