Volume reduction and concentration of nutrients in human urine

Urine-separation toilets have been proposed as a means of achieving maximum recovery and circulation of nutrients not contaminated by hazardous compounds such as heavy metals. However, the use of human urine is problematic with regard to management, storage and transportation. In this pilot study we present a simple method that can be used to reduce the volume substantially and hence improve the management. By freezing urine at a temperature of - 14 degreesC, approximately 80% of the nutrients can be concentrated in 25% of the original volume. This step can be vital to the development of storage and transport. (C) 2001 Elsevier Science B.V. All rights reserved.