ORIGINAL PAPER Phosphorus removal efficiency from wastewater under different loading conditions using sand biofilters augmented with biochar A. El Hanandeh 1 • M. Gharaibeh 2 • A. A. Albalasmeh 2 Received: 20 September 2016 / Revised: 25 October 2016 / Accepted: 19 July 2017 Ó Islamic Azad University (IAU) 2017 Abstract Treated wastewater is a valuable resource, par- ticularly in countries facing water shortage such as Jordan. Nevertheless, excess nutrients, especially phosphorus, may have detrimental impacts on receiving waterbodies. Trea- ted wastewater in Jordan often exceeds the recommended levels set by the Jordanian Standards for wastewater reuse and discharge. Therefore, it is important to reduce phos- phorus loads to acceptable levels before discharge. Biofil- tration is a low-cost technology that has shown good potential for wastewater treatment. The performance of biofilters largely depends on the media used. In this study, local sand and sand augmented with biochar prepared from the olive oil processing waste (SBC) were used as filter media for phosphorus removal from clarified secondary treated wastewater. The two media types were tested under different hydraulic and phosphorus loading conditions to simulate shock, flooding, and inundation conditions. The results showed that sand media was more effective in removing phosphorus (90.8 ± 2.6%) than sand amended with biochar (83.3 ± 3.2%). Both media showed resilience under extreme loading conditions. Although phosphorus removal efficiency was negatively affected following the extreme loading events, the observed effects were tempo- rary. The simulated inundation event further showed that the media was able to retain the adsorbed phosphorus. Furthermore, the phosphorus concentration in the effluent remained within the prescribed discharge guidelines at all times. Keywords Wastewater treatment Á Biofiltration Á Phosphorus removal Á Low-cost technology Á Biochar Introduction In countries with severe water shortage such as Jordan, wastewater is an important resource with potential use in the agricultural sector. In addition to its water value, wastewater contains beneficial nutrients essential for plant growth. However, excessive amounts of nutrients may be counterproductive as it may have negative effect on plant growth and productivity (Tian et al. 2012). Furthermore, nutrient loads from wastewater discharges are a major cause of eutrophication of surface waterbodies. Strict guidelines on nutrient discharge are set by many countries. In Jordan, for example, the reclaimed domestic wastewater standard JS893/2006 recommends that the total phosphorus concentration should not exceed 30 mg/L-PO 4 for irriga- tion purposes (Jordan Institute for Standards and Metrology 2007). This limit is set to \ 15 mg/L-PO 4 for discharges to waterbodies and intermittent streams, known locally as ‘‘wadis’’. Yet, the average concentration of total phos- phorus (TP) in treated wastewater in Jordan often exceeds these limits and is usually in the range of 20–45 mg/L-PO 4 (Ulimat 2012). Therefore, it is important to ensure that wastewater is sufficiently treated and nutrient loads are within the appropriate limits for its intended use. Traditional treatment methods for phosphorus removal, such as precipitation or adsorption using activated carbon are costly. Thus, it is important to find effective and Editorial responsibility: M. Abbaspour. & A. El Hanandeh a.elhanandeh@griffith.edu.au 1 School of Engineering, Griffith University, Nathan, QLD 4113, Australia 2 Department of Natural Resources and Environment, Jordan University of Science and Technology, Irbid, Jordan 123 Int. J. Environ. Sci. Technol. DOI 10.1007/s13762-017-1474-0