Efeito do armazenamento sobre as características de urina e águas amarelas

Abstract

A large part of nutrients such as nitrogen, phosphorus and potassium, which are essential in agriculture, is found in human urine being their amounts, in most cases, significant, more suitable and sustainable than those in commercial fertilizers. Due to the demand for sustainable alternatives in the context of ecological sanitation, reuse of human urine can be faced as a potentially feasible alternative in the context of decentralized wastewater treatment systems. The experimental research which based this work was divided into two stages, in the first the effect of storage, within open and closed recipients, as a treatment of pure urine and yellow water, being used two containers for pure and two for a 7% dilution of urine. In order to verify the effect of storage, monitoring and evaluation were performed by means of physical, chemical and microbiological indicators. Storage of urine proved to be a cost-effective cleaning method of pure and diluted urine and. Containers with lid were more efficient in physical-chemical and biological stabilization process controlling loss of ammonia by volatilization, and contamination by the influence of the external environment. Concentrations of nutrients were maintained in high levels and fecal contamination tended to elimination in a period of 20 days, at room temperature. In the second step, the aim was the recovery of phosphorus by precipitation, carried out in a jar-test apparatus with MgO addition, at several concentrations, to pure and 7%-diluted urine to 7%. Two ranges of concentrations were used - phase A (0; 0.05; 0.15; 0.30 and 0.45 g of MgO/L) and phase B (0; 0.45; 0.60; 0.75 and 0.90 g MgO/L) - under stirring at 120 rpm, for a period of 2 hours. Precipitation and hence the phosphorus recovery was directly related to the concentration of MgO in both phases.