Publication informationProcess Biochemistry, 46 (1) In this study, beneficial reuse of the alum-contained drinking water treatment sludge is 14 extended into developing a novel constructed wetland system (CWs) using the alum 15 sludge as main substrate. The study reports on the first pilot field-scale alum sludge-based 16CWs operated in the tidal flow mode with enhanced capacity for phosphorus and organic 17 matter removal from animal farm wastewater. The concept of the development is 18 presented and this is followed by the performance analysis of the first CWs of its kind. 19The CWs consists of four identical compartments in series operated using a tidal flow 20 strategy with a hydraulic loading rate of 0.29 m 3 /m 2 .d. First year analysis of the system's 21 performance shows that it is a unique and promising low-cost wastewater treatment 22 system. The mean monthly removal efficiencies obtained was determined to range from 23 57%-84%, 36%-84%, 11%-78%, 49%-93%, 75%-94%, 73%-97% and 46%-83% for 24 BOD 5 , COD, TN, NH 4 -N, TP, P (inorganic phosphorus) and SS. The system showed a 25 distinct phosphorus removal and also, the system was effective in reducing levels of 26 organics and ammonium-nitrogen. More importantly, the system showcases a novel reuse 27 alternative for the alum sludge as opposed to its landfilling, demonstrating a win-win 28 technique with a great potential for larger-scale application. 29 30

Publication informationJournal of Environmental Management, 92 (3): 400-406 Publisher ElsevierLink to online version http://dx.doi.org/10.1016/j.jenvman.2010.11.012Item record/more information http://hdl.handle.net/10197/3117 Constructed wetlands (CWs) for wastewater treatment have evolved substantially over the 12 last decades and have been recognized as an effective means of "green technology" for 13 wastewater treatment. This paper reviews the numerous modeling approaches ranging 14 from simple first-order models to more complex dynamic models of treatment behaviour 15 in CWs. The main objective of the modeling work is to better understand the process in 16 Publisher's statement þÿ T h i s i s t h e a u t h o r s v e r s i o n o f a w o r k t h a t w a s a c c e p t e d f oCWs and optimize design criteria. A brief study in this review discusses the efforts taken 17 to describe the process based model for the efficient removal of pollutants in CWs. 18Obtaining better insights is essential to understand the hydraulic and biochemical 19 processes in CWs. Currently, employed modeling approaches can be seen in two 20 categories, i.e. "black-box models" and "process-based models". It is evident that future 21 development in wetland technology will depend on improved scientific knowledge of 22 internal treatment mechanisms. 23 2

Publication informationBioresource Technology, 111 (May 2012): 27-35Publisher Elsevier Item record/more information http://hdl.handle.net/10197/4021 Publisher's statementThis is the author's version of a work that was accepted for publication in Bioresource Technology resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. is the main nitrogen conversion mechanism. The optimal influent distribution fraction for 2 step-feeding purpose can be estimated from a theoretical basis, which is a function of the influent BCOD/TKN ratio. Therefore the influent distribution fraction should be adjusted according to the variety of influent characteristics, rather than a fixed value.

Publication informationBioresource Technology, 102 (10): 5645-5652Publisher Elsevier AbstractDewatered alum sludge, a widely generated by-product of drinking water treatment plants using aluminium salts as coagulants was used as main substrate in a pilot on-site constructed wetland system treating agricultural wastewater for 11 months. Treatment performance was evaluated and spreadsheet analysis was used to establish correlations between water quality variables. Results showed that removal rates (in g/m 2 .d) of 4.6-249.2 for 5 day biochemical oxygen demand (BOD 5 ), 35.6-502.0 for chemical oxygen demand (COD), 2.5-14.3 for total phosphorus (TP) and 2.7-14.6 for phosphate (PO 4 -P) were achieved. Multiple regression analysis showed that effluent BOD 5 and COD can be predicted to a reasonable accuracy (R 2 =0.665 and 0.588, respectively) by using input variables which can be easily monitored in real time as sole predictor variables. This could provide a rapid and cheap alternative to such laborious and time consuming analyses and also serve as management tools for day-to-day process control.

15Effective management of the industrial waste requires a sustainable approach that maximizes 16 its value of reuse/recycle for other industrial demands and the environment needs. This paper 17 aims in exploring the potential of the intended purposes in the newly developed dewatered 18 aluminum-water treatment sludge (Al-WTS) based engineered wetland (EW) for wastewater 19 treatment. Due to the low energy requirement and aesthetical appearance EW is seen as a 20 "green" wastewater treatment technique worldwide for a wide variety of wastewater treatment. 21The Al-WTS based EW developed at University College Dublin, Ireland, represents the latest 22 initiative at using engineering ingenuity to further improve EWs performance. This paper 23 Alum sludge and its concerns 34It is well noted that the generation of coagulant residual sludge in the current potable water 35 treatment technologies may remain unavoidable. Alum sludge (or Al-water treatment sludge, 36i.e. Al-WTS) is generated at water treatment plants worldwide where aluminium sulphate is 37 used as the primary coagulant (Fig. 1). 38 Although Al-WTS is currently classified as "nonhazardous" by the current EU legislation, the 43 daily production of the increased vast amount is triggering off considerable environmental 44 and economic concerns as well as disposal issues. In Ireland, 18,000 t dry solids of in an annual basis is generated with landfill disposal costs of about €3.2 million. In the UK, 46 about 182,000 t dry solids of waterworks sludge is generated each year, with disposal to 47 landfill as the predominant disposal route. Since the drinking water supply is the number 1 48 priority of the human life, the production of Al-WTS as by-product in water treatment plants 49 is continuous along with the human daily life. Accordingly, the disposal of the AL-WTS has 50 become mandatory for water companies especially in recent years due to increasing 51 environmental awareness, escalating costs, dwindling landfill space and the need for 52 sustainability. Thus, the search for cost effective and eco-friendly disposal option(s) of Al-53 WTS becomes an urgent priority. 54 55 Engineered wetland and its needs for further development 56In Ireland, approximately 82% of Irish urban wastewaters receive secondary treatment. 57Among the treatment facilities, there are 144 engineered wetlands (EWs) under operation 58 across the country according to a survey (Babatunde et al., 2008a). This makes a significant 59 and measurable contribution of EWs to the Irish water environmental control. EW has been 60 well recognised as a "green" wastewater treatment technique worldwide due to its low energy 61 requirement and aesthetical appearance. It has been increasingly applied globally for the 62 treatment of various wastewaters (Vymazal and Kröpfelová , 2009). It is noted that the 63 performance of the EWs is generally good in terms of the removal of organics (termed as 64 COD & BOD 5 ) and suspended solids (SS), but as regards nutrient (N & P) reduction, their 65 perf...