Chemical and microbial dynamics during composting of herbal pharmaceutical industrial waste

Abstract

A study was performed to analyze the dynamics of chemical, biochemical and microbial parameters during composting of herbal pharmaceutical waste. All the parameters were analyzed at three different intervals of composting (1st, 15th and 60th days). Temperature of the compost pile was initially high (46.2 °C) and on 60th day it dropped to 33.3 °C. The pH of the sample was initially acidic (2.39) and with the progress of decomposition gradually changed to neutrality (7.55). Electrical conductivity (EC) value was high (3.8 mS) during last day of composting compared to other stages. The activity of degradative enzymes namely amylase, invertase and urease were initially high (4.1, 4.79 mg of glucose/g/h and 0.19 mg of ammonia/g/h respectively) while it decreased with composting. The beneficial microbial load was initially low and very high at the last stages of decomposition. The bioassay studies using compost extracts revealed that the 60th day old sample was not phytotoxic in nature.