Traditional Urine-diversion Practices in Sub-urban Hanoi, Vietnam: Replaced or Promoted?

Northern Vietnam has a history of using urine diversion (i.e., UD) toilets with agricultural use of excreta. This study tried to identify the current practices of UD toilets in suburban Hanoi, Vietnam. An interview survey to 120 households showed that UD toilets were used by 26.7% of households, of which most were double-vault UD toilets. Human wastes were used by 73.0% of vault toilets. It was interpreted that they are still recognized as not wastes but fertilizers especially by farming households in recent sub-urban Hanoi. Double-vaults UD toilets were used in significantly old houses compared to flush toilets with p<0.001. Results indicated the gradual replacement of double-vault UD toilets by water-flush toilets. All households with vault toilets applied additives such as ashes, dry soil and sawdust into vaults, and 24.3% of them applied ashes after every defecation event. Out of 33 vault toilets, 30 retained faeces for a period longer than six months and 28 did for a period longer than 12 months. Still, the application of ashes after every defecation event can be suggested to enhance the disinfection process in vaults, resulting sanitary use of excreta for agriculture.