Contents lists available at ScienceDirect Renewable and Sustainable Energy Reviews journal homepage: www.elsevier.com/locate/rser Bioremediation of textile wastewater and successive biodiesel production using microalgae Tahir Fazal b , Azeem Mushtaq b , Fahad Rehman b , Asad Ullah Khan a,b , Naim Rashid b , Wasif Farooq c , Muhammad Saif Ur Rehman a,b,e, ⁎ , Jian Xu d,e, ⁎⁎ a National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China b Department of Chemical Engineering, COMSATS Institute of Information Technology, Lahore, Pakistan c Department of Chemical Engineering, King Fahad University of Petroleum and Minerals, Dhahran 31261, Kingdom of Saudi Arabia d School of Chemistry and Chemical Engineering, Anhui University of Technology, Ma’anshan, China e Biochemical Engineering Research Center, Anhui University of Technology, Ma’anshan, China ARTICLE INFO Keywords: Microalgae Textile wastewater Bioremediation Biodiesel Sustainability ABSTRACT Microalgal biodiesel has emerged as an environment friendly alternative to the existing fossil fuels. The com- mercial production of this biodiesel is still challenging due to several technical and economic issues, which span from mass cultivation of microalgae to the biodiesel production. Mass cultivation is the most critical step in terms of water and nutrient requirement. Industrial wastewater such as textile wastewater (TWW) is a cheap source for water, which additionally contains necessary nutrients (phosphate, nitrates, micronutrients etc.) and organic dyes (potential carbon source) for algae cultivation. The application of microalgae for biodiesel pro- duction employing single objective strategy is not sustainable. Microalgae can be effectively employed to bioremediate TWW (dyes and nutrients removal) and to produce biodiesel from grown microalgae. This process integration (bioremediation-biodiesel production) can potentially improve biodiesel production and wastewater treatment. However, this process coupling needs to be thoroughly investigated to identify and optimize critical process factors (algal species, cultivation and harvesting methods, bioremediation mechanism etc.). This study has reviewed the status of TWW as potential source of water and nutrients, role of different algal species in the bioremediation of TWW, different cultivation systems, harvesting and biodiesel production methods. This review also suggests future research and development challenges for coupled textile wastewater treatment and mi- croalgal biodiesel production. 1. Introduction The growing human population has posed several challenges to the global economy particularly in terms of environmental conservation and energy security. Global economy is mainly relying on non-renewable and finite fossil fuels [1–4]. This overuse of fossil fuels has resulted in two highly correlated challenges of environmental pollution and energy in- security. These fossil fuels have considerably contributed to greenhouse gas (GHG) emissions where CO 2 level has approached up to 400 ppm [5–8]. Besides the use of fossil fuels in vehicular emissions, they are also use in diesel generators to produce electricity for small and medium en- terprises (SMEs) in developing countries like Pakistan. This excessive use of fossil fuel (i.e. diesel) does not only cause financial liability to the local industry. Thus, local industry needs to look for alternative strategies to make their production cost competitive and environment friendly. Textile industry is one of the most important industrial sectors of Pakistan that contributes a huge financial share. Recently, this in- dustrial sector has confronted energy shortage that caused financial loss. This industry switched their energy sources from national grid to in-house diesel run generators to meet energy requirements. Although this strategy has partly worked and provided continuous energy to the industry but it also added financial liability. In order to save local textile industry, there is an immediate need to search for sustainable energy sources. Besides energy supply, textile industry is also facing the challenge of wastewater management. Textile industry consumes sev- eral hundred thousand gallons of water each day, and proportionally produces huge volume of wastewater [9]. Textile wastewater contains variety of dyes and auxiliary chemicals which may pose serious risks to the environmental recipients [10–14]. The global concerns of energy demand and non-tariff bindings regarding environmental conservation http://dx.doi.org/10.1016/j.rser.2017.10.029 Received 17 February 2017; Received in revised form 22 August 2017; Accepted 26 October 2017 ⁎ Corresponding author at: Department of Chemical Engineering, COMSATS Institute of Information Technology, Lahore, Pakistan. ⁎⁎ Corresponding author. E-mail addresses: drmsrehman@ciitlahore.edu.pk (M.S.U. Rehman), jianxu@ahut.edu.cn (J. Xu). Renewable and Sustainable Energy Reviews xxx (xxxx) xxx–xxx 1364-0321/ © 2017 Elsevier Ltd. All rights reserved. Please cite this article as: Fazal, T., Renewable and Sustainable Energy Reviews (2017), https://doi.org/10.1016/j.rser.2017.10.029