Ecological Engineering 70 (2014) 16–24 Contents lists available at ScienceDirect Ecological Engineering journal h om epa ge: www.elsevier.com/locate/ecoleng An evaluation of the re-circulated vertical flow bioreactor to recycle rural greywater for irrigation under arid Mediterranean bioclimate Tarek G. Ammari a,∗ , Yasin Al-Zu’bi a , Abeer Al-Balawneh b , Ragheb Tahhan c , Muhamad Al-Dabbas b , Rakad A. Ta’any a , Raihan Abu-Harb a a Department of Water Resources and Environmental Management, Faculty of Agricultural Technology, Al-Balqa’ Applied University, Al-Salt 19117, Jordan b National Center for Agricultural Research and Extension (NCARE), Al-Baqa’a, Jordan c Department of Natural Resources and Environment, Faculty of Agriculture, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan a r t i c l e i n f o Article history: Received 1 August 2013 Received in revised form 9 January 2014 Accepted 24 March 2014 Keywords: Constructed wetlands Decentralized treatment systems Environmental pollution Indicator organisms Low quality greywater a b s t r a c t Increasing demand for conservation of water resources has stimulated greywater (GW) recycling. In rural areas of Jordan, low water consumption, GW quality, and user acceptance are the major obstacles. Low cost and easy to operate modified re-circulated vertical flow bioreactor was evaluated in the Jordan Valley under arid conditions. The treatment system efficiently removed BOD 5 , COD, PO 4 , and TSS by up to 97%, 94%, 100%, 90%, respectively. DO was significantly increased by up to 98%. Removal efficiency of NO 3 , Cl, and SO 4 was satisfactory ranging from 19% to 66%, up to 45%, and 55%, respectively. EC and TDS fluctuated considerably with time and quality of untreated GW. TCC and Escherichia coli were considerably reduced by up to 2.5 and 2.3 log, respectively. According to WHO guidelines, treated GW is suitable for irrigation of ornamentals, fruit trees and fodder crops. Removal efficiencies of the treatment system were higher than those of other systems operated in Jordan. The reduction in indicator organisms, however, was not adequate to allow unrestricted reuse of treated GW. Practical disinfection technique can be incorporated into the treatment system. Current treatment system demonstrates great potential for treating low quality GW in rural areas achieving socio-economic and ecological benefits. © 2014 Elsevier B.V. All rights reserved. 1. Introduction It is widely recognized that Jordan is entering an era of severe water shortage. Indeed, there is a tremendous deficit between the supply and the demand; a critical situation that will damage peo- ple’s health and the economy if not properly managed. The negative water balance is mainly attributed to the increasing population, influx of refugees from neighboring countries, urbanization, and absence of new water resources (GTZ, 2007). Consequently, Jordan is obliged to come up with new strategies or enforce previously developed ones to conserve its water resources. The Government of Jordan has put together a long-term plan to increase the effi- ciency of water use, improve the management of the water supply and improve wastewater treatment and reuse. Treated wastewa- ter used in restricted irrigation is forecast to increase to 205 million cubic meters (MCM) by the year 2020 (MWI, 2004). Today, treated wastewater reuse in Jordan reaches one of the highest levels in the ∗ Corresponding author. Tel.: +962 799520021. E-mail address: tarekamm@yahoo.com (T.G. Ammari). world (GTZ, 2007). Another strategy of conserving water resources in Jordan is by recycling greywater for restricted irrigation. Grey- water is untreated domestic wastewater that has not come into contact with toilet waste (i.e. black water). Separating greywater from a residential or commercial wastewater stream allows a large volume of water to be efficiently recycled and reduces the vol- ume of wastewater that has to be collected and treated. In fact, the average amount of domestic greywater ranges from 50% to 80% of the total domestic wastewater generated in households (Jenssen and Vråle, 2003; Flowers, 2004), making greywater a potential sus- tainable water resource. However, this potential non-conventional water resource has marginally contributed to the augmentation and conservation of the water resources in Jordan during the past few decades (GTZ, 2007). In the long run greywater is expected to play an important role in securing a sustainable water supply in Jordan; therefore different technologies (i.e. treatment units) for greywater recycling should be used and continuously developed. Moreover, greywater recycling for irrigation brings about various socio-economic and ecological benefits. These benefits are, partic- ularly, reflected in reduced potable water demand (i.e., reduced freshwater use). Radcliffe (2003) documented that reduction of http://dx.doi.org/10.1016/j.ecoleng.2014.03.009 0925-8574/© 2014 Elsevier B.V. All rights reserved.