On-site ’07 Armidale Beal et al. 1 CLOSING THE NUTRIENT LOOP: A URINE-SEPARATION AND REUSE TRIAL IN THE CURRUMBIN ECOVILLAGE, QLD Cara Beal 1 , Ted Gardner 1 , Warish Ahmed 1 , Chris Walton 2 , and David Hamlyn-Harris 3 1 Department of Natural Resources and Water, Brisbane 2 The Ecovillage at Currumbin, Currumbin Valley. 3 Bligh Tanner Pty Ltd, Brisbane. Corresponding author’s email: cara.beal@nrw.qld.gov.au ABSTRACT Urine-separating toilets (UST) have been used as an effective means of separating the urine from faeces in many parts of Europe for years, but are yet to be adopted as a viable technology in Australia. The purpose of UST is to separate nutrients (N, P, K) at the source. Although up to about 80% of N, 50% of P and 60% of K are contained in urine, its volumetric fraction of total wastewater flow is only around 1%. By first separating the urine, many nutrients can be captured and reused without intensive, expensive and time-consuming treatment required when urine is combined with faeces. Urine can be reused as a concentrated fertiliser with only limited treatment prior to land application. The aims of this paper are to report on the use of UST technologies in Europe and to describe the initial stages of a urine diversion and reuse demonstration project at a high-profile Ecovillage under construction in Currumbin, southeast Queensland. Keywords: source separation, urine diversion, sustainable development, nutrient recovery, urine reuse 1 INTRODUCTION Urine-separating toilets (UST) have been used as an effective source control measure in many parts of Europe for years, but are yet to be adopted as a viable technology in Australia. Recent advances in water conservation and recycling technologies have allowed for a greater opportunity to close (e.g. recycle) the water balance, particularly with decentralised systems. However, closing the loop on nutrients for these systems has been a much more difficult task, largely due to the existing systems that collect, store and treat nutrients and water in combination. UST separate nutrients (N, P, K) at source to avoid mixing with faecal matter. Urine separation reduces water use and nutrient discharge to treatment systems and the receiving environment, and increases the potential for closing the nutrient cycle. UST technology ranges from single and dual flush systems to dry (composting) toilets. This paper provides a background on UST and the reuse of urine in Europe, then describes the urine separation demonstration project at The Ecovillage at Currumbin. 2 BACKGROUND ON URINE-SEPARATION 2.1 Advantages of Source Separation Although up to about 80% of N, 50% of P and 60% of K are contained in urine, its fraction of total volumetric wastewater flow is only around 1% (Figure 1). The purpose of UST is to separate nutrients (N, P, K) at the source, to avoid mixing with faecal matter. The urine can then be reused as a concentrated fertiliser with only limited treatment prior to land application. By separating the urine, many nutrients can be captured and reused without intensive, expensive and time-consuming treatment traditionally required when urine is mixed with faeces. Urine separation can reduce the peaks flows of ammonia in sewage treatment plants (STP) by 30% and reduce the impact of sewer overflows on the aquatic environment (Wilsenach and Loosdrecht 2006). Although N is abundant in the atmosphere, its industrial fixation is energy and resource intensive. Urine provides a ready source of fixed nitrogen that can be recycled back into the system (via land application, crop uptake and crop consumption). The main source of P is via extraction of phosphate rock, of which there is a critical global shortage. The P in urine can be made bioavailable by the relatively simple process of struvite production. Another advantage of UST is their lower water use. Johansson et al. (2002) report about 0.1 to 0.3 L of water is required to flush the urine. This is a