Separation and Puriﬁcation Technology 57 (2007) 25–36 Fouling behaviour, regeneration options and on-line control of biomass-based power plant efﬂuents using microporous ceramic membranes S. Mahesh Kumar a,1 , G.M. Madhu b , Sukumar Roy c,∗ a Department of Biotechnology, R.V. College of Engineering, Bangalore 560059, India b Department of Chemical Engineering, R.V. College of Engineering, Bangalore 560059, India c Ceramic Technological Institute, Bharat Heavy Electricals Limited, Corporate Research & Development, Bangalore 560012, India Received 22 September 2006; received in revised form 14 February 2007; accepted 3 March 2007 Abstract The work presents an on-line ﬁltration treatment for biomass-based power plant efﬂuents using microporous ceramic symmetric membranes with an emphasis on establishment of fouling mechanisms and regeneration options in the process. The work also establishes the relationships among the membrane ﬁlterability, quality of permeate and ﬂux to that of the pore size of ceramic membranes. For these purposes, two types of ceramic membrane conﬁgurations, i.e., seven-channeled and single-channeled (hollow type) tubes with identical pore size of 1.2 m were selected for the experiments. On the other hand, raw efﬂuents generated by the power plant were ﬁrst pre-ﬁltered using a 0.5 mm sieve and the resultant ﬁltrate was further used for the present microﬁltration trials by varying transmembrane pressure (TMP). Differences in the ﬁlterability of the efﬂuents by the two membrane conﬁgurations at variable levels of TMP were explained using various membrane-fouling models. The ﬁltration resistances that are acting in series were calculated using Darcy’s and Poiseuille’s law. Establishment of fouling mechanism/s of the membranes and its regeneration by adopting chemical cleaning and backﬂushing techniques were also an integral part of the study. The results suggest that microﬁltration of efﬂuents in a continuous crossﬂow mode with backﬂushing in regular intervals offer great advantage over efﬁciency and effectiveness in monitoring the contaminants in the raw efﬂuents by physical methods. The study hence ﬁnds an on-line ﬁltration solution in monitoring biomass-based power plant efﬂuents in a benign way using microporous ceramic membranes. © 2007 Elsevier B.V. All rights reserved. Keywords: Biomass-based power plant efﬂuent; Microﬁltration; Ceramic membrane; Fouling; Regeneration; Backﬂushing 1. Introduction The renewable energy technologies represent a great value in the economy of any nation, but their advantages are hindered by the pollutants they generate in the process that addresses the necessity of integrating the renewable technologies with benign methods of pollution treatment technologies. Biomass- based gasiﬁcation technology is viewed as an alternative method of producing power out of biomass wastes that in turn, also generates substantial amount of pollutants in the waste efﬂu- ents in the process. Increasing interest in regulatory bodies to ∗ Corresponding author. Tel.: +91 80 22182332; fax: +91 80 23344231. E-mail addresses: mahesh@cpdm.iisc.ernet.in (S. Mahesh Kumar), sroy@bhelepd.com (S. Roy). 1 Present address: Ideas Laboratory, CPDM, IISc, Bangalore 560012, India. curtail waste efﬂuent discharge into aquatic streams has driven the advancement of non-conventional techniques for wastewater reclamation and reuse. Conventional methods of waste efﬂuent treatment include several intermediate steps comprising chemical addition (potash alum, lime and polymers), coagulation, ﬂocculation, sedimen- tation, and disinfection usually with chlorine, etc. All these conventional systems based on the physical and chemical prin- ciples indeed cannot give an absolute guarantee in terms of the separation efﬁciency and the efﬂuent quality [1]. Strin- gent standards imposed by the regulatory bodies for wastewater discharge limits are not met by the conventional treatment tech- niques [2]. With this scenario, alternative techniques besides the conventional treatments need to be developed to fulﬁl speciﬁc needs of the hour. In the treatment of wastewater efﬂuents, on- line microﬁltration has been appearing to be attractive because of its potential to produce high-quality reusable water in one 1383-5866/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.seppur.2007.03.002