Bioaugmentation of Klebsiella pneumoniae isolate M1 in a continuous sequential phytoreactor integrating Scirpus grossus and Eichhornia crassipes plants for batik effluent treatment

Abstract

Phytoremediation offers a more cost-effective and sustainable treatment for Southeast Asia's heritage fabric industry, batik, which reportedly has high costs and short-skilled labour issues. The long treatment period taken by phytoremediation treatment can be shortened through bioaugmentation with other approaches. This study explored the efficacy of a sequential phytoreactor (sPR) of the emergent plant (Scirpus grossus) and floating plant (Eichhornia crassipes) bioaugmented with Klebsiella pneumoniae isolate M1 for batik wastewater treatment. Four sets of sPRs, (PC (plant control), R (1st stage of sPR with PGPR), WR (1st stage of sPR without PGPR), and control contaminant (CC)) were prepared. All reactors except PC were continuously fed with real batik wastewater (COD: 637 ± 16 mg/L) and monitored for 21 days. At the end of exposure, it was identified that the application of K. pneumoniae isolate M1 had boosted the growth of S. grossus by 123.8 %, increased the COD removal by 13 % and shortened the time taken to reduce the contaminants contents to a certain limit. The effluent COD and colour from the 1st stage of sPR effluent were recorded as 314 mg/L and 207 ADMI, respectively. The effluent COD and colour from the 2nd stage of sPR were recorded as 407 mg/L and 428 ADMI, respectively. Despite both parameters being above standard limits, detailed characterisation of plants, wastewater and K. pneumoniae isolate M1 confirmed the significant removal of contaminant contents from batik wastewater. The analysis also proposed that the contaminants' removal mechanisms by both plants involved rhizodegradation, rhizofiltration, phytostabilisation, phytotransformation/phytodegradation and phytoextraction.