Economic Assessment of Sanitation Interventions in Vietnam - WSP

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