Graduate School of Global Environmental Studies, Kyoto University, Yoshida-honmachi, Sakyo, Kyoto 606-8501, Japan E-mail:
Water Sci Technol. 2010;62(10):2225-34. doi: 10.2166/wst.2010.508.
Urban sanitation issues should be tackled strategically, and may be addressed effectively when sewage development is pursued in conjunction with complementary sanitation measures. Five sanitation improvement scenarios employing sewage, night-soil collection-and-treatment (NSCT) system, and/or septic-tank improvement by annual dislodging were analyzed from the perspective of COD loads, total nitrogen loads, and cost under the conditions found in Hanoi, Vietnam. Compared to the development of sewage alone, the scenario of developing NSCT systems in a complementary manner with sewage development was estimated to be the most effective for a rapid decrease of both COD and total nitrogen loads. However, it may be difficult in some cases to replace ordinary water-flush toilet by the micro-flush toilet that are used in NSCT systems. In this case, the scenario employing septic-tank improvement in conjunction with sewage development may be effective for a rapid decrease of COD in locations where septic tanks are widely used under poor maintenance conditions and nitrogen pollution is not serious compared to COD. It was calculated that the two scenarios above would respectively require cost increases of 16 and 22% over the sewage development scenario.
城市环境卫生问题应采取战略性措施解决，结合污水开发和补充卫生措施，可能会有效地解决这些问题。从 COD 负荷、总氮负荷和成本角度出发，分析了在越南河内条件下采用污水、粪尿收集和处理（NSCT）系统和/或每年搅动化粪池改进的五种卫生改善方案。与单独开发污水相比，开发 NSCT 系统与污水开发相结合的方案估计对 COD 和总氮负荷的快速降低最有效。然而，在某些情况下，可能难以用 NSCT 系统中使用的微冲洗马桶替代普通水冲马桶。在这种情况下，在维护条件差且与 COD 相比氮污染不严重的情况下，广泛使用化粪池的情况下，结合污水开发进行化粪池改进的方案可能对 COD 的快速降低有效。计算结果表明，上述两种方案分别比污水开发方案增加 16%和 22%的成本。
