Technical Note A membrane-integrated advanced scheme for treatment of industrial wastewater: Dynamic modeling towards scale up Ramesh Kumar, Parimal Pal ⇑ Environment and Membrane Technology laboratory, Department of Chemical Engineering, National Institute of Technology, Durgapur 713 209, India highlights  Mathematical model developed for an advanced integrated water treatment plant.  Highly integrated scheme is novel in ensuring by-product recovery and water reuse.  Model successfully predicted plant performance.  Study will facilitate industrial scale up of this new and advanced scheme. article info Article history: Received 28 January 2013 Received in revised form 30 April 2013 Accepted 3 May 2013 Available online 2 June 2013 Keywords: Aquatic environment Wastewater treatment Advanced process Mathematical modeling abstract Modeling and simulation was carried out for an advanced membrane-integrated hybrid treatment process that ensures reuse of water with conversion and recovery of ammoniacal nitrogen as value-added struvite fertilizer from coke wastewater. While toxic cyanide was largely removed in a pre-chemical treatment unit using Fenton’s reagents under optimized conditions, more than 95% of NH þ 4 –N could be recovered as a valuable by-product called struvite through addition of appropriate doses of magnesium and phos- phate salts. Water could be turned reusable through a polishing treatment by nanofiltration membranes in a largely fouling free membrane module following a biodegradation step. Mathematical modeling of such an integrated process was done with Haldane–Andrew approach for the associated microbial degra- dation of phenol by Pseudomonas putida. Residual NH þ 4 was degraded by nitrification and denitrification following the modified Monod kinetics. The model could successfully predict the plant performance as reflected in reasonably low relative error (0.03–0.18) and high Willmott d-index (>0.98). Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Since the early 1970s efforts have been directed towards modeling of wastewater treatment processes. Activated sludge process (ASP) is one such wastewater treatment scheme for which some models were developed by the task group of International Water Works Association. However, these models have been used in carbon oxidation, nitrification, denitrification and biological phosphorus removal processes (Gujer and Henze, 1991) primarily for domestic wastewater treatment only and there is significant limitation to their application to industrial wastewater treatment. With development of highly selective membranes in the area of separation and purification, membrane-integrated novel processes are now emerging with the promise of much better quality of treated water. However, modeling studies on such membrane- integrated treatment processes are extremely scanty. In some typical highly water-intensive industries like coke making and metallurgical industries, problems of effective treatment of enor- mous quantities of complex wastewater persist in the absence of scale up confidence. This is where modeling and simulation studies of modern membrane-integrated treatment schemes are abso- lutely essential. Coke wastewater generated in the coal carbonization plants contains substantial amounts of toxic compounds such as thiocya- nate, cyanide along with NH þ 4 and organic compounds like phenols, aromatic nitrogenated compounds and polycyclic aromatic com- pounds. Often wastewater discharges from coke making industries enter into the river bodies causing severe pollution to surface waters. Thus for environmental preservation the enormous quanti- ties of coke plant wastewater should be treated at relatively low cost. This could be done in biological treatment units for major pol- lutants like phenol, NH þ 4 and hydrocarbons but presence of cyanide compounds very often turns survival of the microbes difficult in the environment of the treatment system and this often leads to failure of such plants (Ghose, 2002). Individual studies on cyanide, phenol and nitrogen removal kinetics have been documented. 0045-6535/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.chemosphere.2013.05.006 ⇑ Corresponding author. Tel.: +91 343 2755055; mobile: +91 9434788105; fax: +91 343 2754078. E-mail address: parimalpaul1999@yahoo.co.in (P. Pal). Chemosphere 92 (2013) 1375–1382 Contents lists available at SciVerse ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere