{'fraction_non_alphanumeric': 0.022998296422487224, 'fraction_numerical': 0.016183986371379896, 'mean_word_length': 5.069767441860465, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Comparative study on treatment of cassava wastewater using free, immobilized and biofilm of Trichoderma harzianum - Trichoderma viride consortium

Cassava (Manihot esculenta) being rich in starch is one of the critical industries in the agro-industrial sector. The present study aims to do a comparative study on the treatment of cassava wastewater using biological and eco-friendly treatment approaches consisting of native bacterial species and fungal consortium in free, immobilized and biofilm batch mode. Studies were performed using the mixed culture of native bacteria, and the results were compared with that of a mixed fungal consortium of Trichoderma harzianum and Trichoderma viride which were known for its cyanide degrading efficiency and reducing COD burden. Cyanide and COD were two critical pollutants for the study. The effect of treatment time on cyanide and COD removal was investigated without adding any buffer to the wastewater. The maximum cyanide and COD removal efficiency for wastewater by using mixed native bacterial were 41.12% and 53.07% respectively. The removal efficiency by mixed bacterial culture was not too high owing to the low pH of cassava wastewater. Even in the low pH of cassava wastewater the maximum cyanide and COD removal efficiency using fungal consortium were 63.77% and 74.3% respectively. The growth pattern of fungal consortium reveals that six days treatment period showed maximum biomass of 3.721 g/L of dry weight. Thus, six days of treatment of fungal consortium can be used for the treatment of cassava wastewater. Furthermore, the optimized value of temperature and inoculums dosage for fungal consortium was found to be 30°C and 4% (v/v) of wastewater. Under optimized condition free, immobilized and biofilm batch reactors were setup. Biofilm batch reactor gave COD removal efficiency of 88% followed by suspension with 83.5% and least in an immobilized batch reactor with 76.5%. Cyanide removal efficiencies of 98.19%, 77%, and 87% were obtained in a biofilm, suspension and immobilized system respectively. The experimental results showed that final pH after treatment in all three systems was in dischargeable limits. The study revealed that the biofilm batch reactor which gave the highest removal efficiency could be considered as the best method for treatment of cassava wastewater.