MBR fouling control and permeate quality enhancement by polyaluminium chloride dosage: a case study

Water Sci Technol. 2012;66(6):1289-95. doi: 10.2166/wst.2012.315.

Abstract

Scope of this study was to evaluate the effectiveness of a metal salt (polyaluminium chloride, PACl) dosage into a pilot-scale MBR (membrane bioreactor) in terms of fouling control and permeate quality enhancement, especially with reference to specific textile macro-pollutants (dyes and surfactants). The pilot plant was fed with a mixed domestic-textile wastewater (textile wastewater accounted for 65% of total flow and for 70% of total chemical oxygen demand, COD, load) and operated for 7.5 months without flux enhancers (step 1) and 3 months with the addition of PACl (step 2). The optimum dose was defined performing a jar-test campaign between step 1 and step 2 (12.5 mg gMLSS(-1) that corresponds to 0.4 g d(-1)). The addition of PACl resulted in a significant decrease of the filtration resistance due to cake layer formation (R(c), -65.4%) and of the irreversible fouling rate, evaluated as the average variation per unit time of the filtration resistance due to foulants adsorption on membrane pore wall (FR, -45.3%). As for permeate quality, removal rates related to total phosphorus and textile macro-parameters such as colour and anionic surfactants, increased by +64, +16 and +7%, respectively. No significant effect was observed on COD, non-ionic surfactants and nitrogen compounds removal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aluminum Hydroxide / chemistry*
  • Biofouling*
  • Bioreactors*
  • Membranes, Artificial*
  • Pilot Projects
  • Waste Disposal, Fluid / methods*
  • Water Purification / methods

Substances

  • Membranes, Artificial
  • aluminum oxychloride
  • Aluminum Hydroxide