| Title |
Advancing the Design and Operating Conditions for Block Freeze Concentration of Urine-Derived Fertilizer |
| ID_Doc |
24055 |
| Authors |
Noe-Hays, A; Homeyer, RJ; Davis, AP; Love, NG |
| Title |
Advancing the Design and Operating Conditions for Block Freeze Concentration of Urine-Derived Fertilizer |
| Year |
2022 |
| Published |
Acs Es&T Engineering, 2, 3 |
| Abstract |
This paper is focused on evaluating the performance of a scalable block freezing device for concentrating aged, source-separated urine from a community-scale urine collection system that is used to create sustainable fertilizers. Temperature settings for two-stage freeze concentration were determined to be -6.5 degrees C during the first stage, -13 degrees C during the second stage, and 3.0-4.0 degrees C during the thaw stage. These temperatures reflect a smaller range than prior freeze concentration studies and have the potential to reduce energy consumption. The length of freeze and melt periods, the direction of heat transfer within the freeze chamber, and the orientation of the freeze chamber were varied to identify a preferred operating condition. The relative mass of nitrogen (N), phosphorus (P), and potassium (K) was constant during processing, and all were concentrated up to 3.3 times in a single stage with 80% nutrient retention. An iterative mass balance analysis of a two-stage system that incorporated recycling retained 92% of nutrients and achieved a concentration index of 5.8. This experimental concentrator reveals performance and unique operational features that elevate freeze concentration as a scalable option for urine separation systems. |
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