Economic Assessment of Sanitation Interventions in Vietnam - WSP

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Economic Assessment of Sanitation Interventions in Vietnam | National Benefits of Improved Sanitation and HygieneBOX 6. OPTIMIZING WATER AND PHOSPHORUS MANAGEMENT IN THE URBAN ENVIRONMENTAL SANITA-TION SYSTEM OF HANOI, VIETNAMA probabilistic model, simulating the impact of measures on groundwater abstraction and nutrient recovery, wasused to determine the impact of policy changes in Hanoi. The model was used to analyze the impact of changes inthe environmental sanitation and agricultural system on phosphorus recovery. Extreme scenarios were selected toclearly reveal the impact of policy changes. The results obtained reveal that harmonizing environmental sanitationand agricultural systems with one another will considerably increase nutrient recovery for food production, lowerexpenditure for artificial fertilizers and reduce the nutrient load into the environment.Scenario 1 describes the situation for the year 2015 assuming unchanged current trends: persistent high populationgrowth, continued shift from latrines to flush toilets with septic tanks, decrease in paddy fields and increasein fish pond and vegetable area as well as in the number of pigs. A persistent slight increase in mineral fertilizerapplication rate and in industrial production was also assumed.Scenario 2 describes the situation for the year 2015 assuming that Hanoi’s septic tanks are replaced by urinediversion latrines. Furthermore, an increase in organic fertilizer application rate and a decrease in commercialfertilizer use are also presupposed.Scenario 3 describes the situation for the year 2015 assuming that Hanoi’s population eliminates meat from itsdiet. Protein intake is compensated by a higher consumption of fish, vegetables, beans, soybean, and nuts. Organicfertilizer application rate is also higher than in the status quo, and only drainage water is used for irrigation.As in Scenario 2, septic tanks are assumed to be replaced by urine diversion latrines.Groundwater abstraction could be reduced by a third, if the water distribution system is improved, gray water isreused for toilet flushing and if water efficiency of industrial processes is enhanced. Despite these measures, thegroundwater withdrawal rate still exceeds the aquifer recharge rate. Therefore, other strategies are necessary, inparticular, protection of surface water to facilitate its treatment for domestic use.By replacing septic tanks with urine diversion latrines, the percentage of phosphorus in waste products recoveredfor food production could be increased from 18% to 45%. Furthermore, replacing livestock production by a higherproduction of fish, vegetables, beans, soybean, and nuts could further increase recovery of phosphorus from 45%to 82%.(Source: Agnès Montangero et al, 2007)76Box 6 presents results from a study comparing differentscenarios relating to water and phosphorus as resources inthe urban environmental sanitation system of Hanoi city.In Scenario 3 (‘ideal’), groundwater abstraction could bereduced by a third, if the water distribution system is improved,gray water is reused for toilet flushing and if thewater efficiency of industrial processes is enhanced. Despitethese measures, the groundwater withdrawal rate still exceedsthe aquifer recharge rate. Therefore, other strategiesare necessary, in particular the protection of surface water tofacilitate its treatment for domestic use. By replacing septictanks with urine diversion latrines, the percentage of phosphorusin waste products recovered for food productioncould be increased from 18% to 45%. Furthermore, replacinglivestock production with a higher production of fish,vegetables, beans, soybeans and nuts could further increasethe recovery of phosphorus from 45% to 82%.5.4 NATIONAL WATER RESOURCESWater resources in Vietnam are in danger from increasingscarcity as well as pollution, thus adversely impacting uponthe population and economy in a variety of ways. The AsianDevelopment Bank recently published the results of theWater Sector Review Project 2008 (ADB TA 4903-VIE).Information extracted from the project is described in thissection.The Vietnam National Resources Water Strategy (2006)highlights the issue of pending water scarcity in Vietnam.Taking population growth into consideration, by 2025 theaverage per capita surface water availability will be 2,830m 3 (rivers in Vietnam) and 7,660 m 3 (including inflows)per year. According to the standards of the InternationalWater Resources Association (IWRA), nations with averageper capita water availability of less than 4,000 m 3 per yearEconomic Assessment of Sanitation Interventions
Economic Assessment of Sanitation Interventions in Vietnam | National Benefits of Improved Sanitation and Hygieneare considered nations with inadequate water supply. Furthermore,water resources are not evenly distributed overdifferent regions. About 60% of river water is concentratedin the Cuu Long river delta (Mekong River). The remaining40% is spread over nearly 80% of the nation’s populationand over 90% of production, trade and other service activities.Moreover, seasonal variation is considerable: the averagevolume of water in the three to five months of the wetreason makes up 75% to 85% of the total volume (NationalResources Water Strategy, 2006).Pollutants affecting water-related economic activity includemicroorganisms, organics, chemicals, solids, gases and heat.Pollution originates from a variety of sources, includingthose evaluated in the ESI study: households; small industries;leachate from landfill; manufacturing industry;chemical fertilizers; pesticides; treatment of acid-sulfatesoils; animal waste; silt release following build-up behinddams; and salinity intrusion from coastal areas. Water inupstream areas is generally still ‘clean’, while in downstreamareas quality has worsened due to the impact of differentsocio-economic activities, particularly from industry andurban development.At many river segments and river sub-basins, water pollutionhas become severe. For example, in the Nhue-Dayriver sub-basin, the annual average biochemical oxygen demand(BOD) level is about two times the TCVN level Bstandard, and 12 times the level A standard. BOD in waterat some river segments flowing through urban areas in theDong Nai river basin reaches a similar level as at the Nhue-Day sub-basin. Water quality in the dry season is muchworse due to the reduction of water flow. In the Cau riversub-basin, BOD level in many places exceeds the TCVNstandard, level B.Organic substances and suspended solids are the majorpollutants in most of the rivers in Vietnam. However interm of pollution effect, some chemicals and heavy metalsoriginating from industrial and mining activities are a bigconcern as they could pose a high risk to human and ecosystems.Fertilizers and pesticides originating in agriculturalactivity are also toxic substances. According to the Reporton Environmental Status of Vietnam in 2006, the provincesand cities with high water pollution are ranged in thefollowing order: Ho Chi Minh City; Ha Noi; Binh Duong;Hai Phong; and Dong Nai. Four of the 10 provinces withhigh water pollution levels belong to Dong Nai river basin.The three basins with the highest water pollution are theCau, Nhue-Day and Dong Nai (which are sub-basins of theRed river basin). Special concern is given to managementof the basins by both the national and provincial governmentsnts.Pollution levels of rivers in the lower reaches ofthe Dong Nai river basin are the highest in the country.The Thi Vai River is the most polluted basin with a “dead”section of more than 10 km. The river section from the confluenceof the Ca stream and Thi Vai River to the My Xuanindustrial zone – about 2 km – is severely polluted. Onlysome kinds of plankton can survive in this water environment.Some algae species, preferring an environment withhigh BOD, can grow in this area, but there is a high riskthat they could make the environment toxic. There are alsomany other pollution “hot spots” in Dong Nai river basin.The Nhue-Day river sub-basin is also severely polluted inplaces. The Nhue River is the worst and is seriously pollutedin its upper reaches. Even in the flood season, BOD5,DO, NH4+, and coliform all fail to meet TCVN (standardB). Within Hanoi, surface water in rivers, lakes and drainsis also seriously polluted. Levels of DO are low; COD,BOD and coliform far exceed the TCVN standard. As inthe Dong Nai river basin, there are still many other pollution“hot spots” in the sub-basin. The Cau river sectionflowing through Thai Nguyen is highly polluted. Suspendedsolids, BOD and COD exceed TCVN (standard A) bymany times, and the waters contain oil residue. There areother badly polluted areas in the sub-basin, mostly fromorganic pollution. Although some waste water sources havebeen reduced, particularly in Thai Nguyen, the water qualityhas not improved much.It is necessary to note that the use of chemicals and toxicmatter in mining and mineral processing lead to water pollutionin many rivers. Moreover, reservoirs and dams forhydropower generation are structures that can stronglyaffect the water quality of rivers. Although there are notenough data for assessing this effect separately, the changein flow regime under the influence of these structures affectindirectly the water quality of rivers, especially in thedry season. The major reasons for this are associated withthe construction of the structures without appropriate plan-www.wsp.org77
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Economic Assessment ofSanitation In
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Economic Assessment of Sanitation I
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ForewordTarget 10 of the Millennium
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Glossary of TermsBenefit-cost ratio
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AcknowledgmentsThe Economics of San
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V. National Benefits of Improved Sa
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Table 32. Sanitation coverage, and
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Figure 34. What factors were of mos
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Annex Table E1. Level of satisfacti
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Annex Table J1. Site U1 (Dong Thap,
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PopulationSelected Development Indi
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III.Study MethodsThe study methodol
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ANNEX TABLESANNEX A. STUDY METHODST
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