High temperatures and CO2 dissolution can cause nitrogen losses from urine stabilized with base

Human urine is rich in valuable nitrogen which can easily be lost due to biological urea hydrolysis and subsequent ammonia volatilization. While this enzymatic reaction prevented by alkalizing the urine, recent studies suggest that chemical result substantial losses when drying alkalinized at high temperatures. Furthermore, it was previously suggested CO 2 dissolution from air used evaporate water could a pH decrease values allows for losses. This study aimed determine kinetics of human confirm effect with controlled laboratory experiments. We measured change concentration different temperatures real determined corresponding rate constants hydrolysis. showed constant increases as function temperature has negligible on range alkalized (>11). The saturated calcium hydroxide solution were found 0.00147 d ?1 , 0.00595 0.0204 0.0848 25°C, 40°C, 55°C 70°C, respectively. aerating (Ca(OH) ). In order represent hydrolysis, urease added solution. computer simulations experimental results dissociation carbonic acid carbonate ions, bicarbonate ions protons main cause decrease, but CaCO 3 precipitation, NH volatilization foster decrease. However, prevents decreasing below 9. Residual undissolved Ca(OH) shown substantially delay Overall, work provides insights into mechanisms during dehydration, design more efficient decentralized sanitation systems minimize