Monitoring efficacy of constructed wetland for treating domestic effluent - microbiological approach

摘要

Water scarcity and elevated potential in wastewater treatment in the last decades raise attention towards constructed wetlands (CWs). The present study was carried out to evaluate the efficacy of CW for faecal coliform (FC) expulsion and to isolate and characterize the microbial communities. Significant differences were observed between influent and effluent microbial counts of vegetated and control cells (without vegetation) of wetland. FC reduction ranged from 64% to 81%; however, total bacterial, fungal and actinomycetes average poll ranged from 66.67 x 10(5) cfu/g to 142.67 x 10(5) cfu/g, 1.67 x 102 cfu/g to 10.33 x 10(2) cfu/g and 16.00 x 10(3) cfu/g to 53.33 x 10(3) cfu/g respectively, isolated from vegetated and control cells. Results further indicated that bacteria were most abundant, followed by actinomycetes, whereas the number of fungi was least among three groups of microbes, which could be attributed to wide tolerance to the properties of CW. Removal of FC was less apparent initially compared to the later stages of operation, which is of concern for long-term efficiency and stability of wetland. Also, diversity of identified bacterial strains is beneficial for growth and yield enhancement of agriculture crops. The results also demonstrate that CWs are the key habitats for bioactive actinomycetes with paramount medical, scientific and economic potential significance globally in general and developing countries like India in particular. Overall, backwash imparts the baseline compilation of CWs for its management for sustainable agriculture.