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MARKET RESEARCH REPORT WATER SECTOR IN VIETNAM: OVERVIEW, RECENT TRENDS AND OPPORTUNITIES FOR COOPERATION PART 3 WASTEWATER SECTOR IN VIETNAM Prepared by: David Nguyen Daniel Nguyen Paul Smith An Nguyen Vietnam, October 2017 Contents 1. OVERVIEW OF WASTEWATER COLLECTION AND TREATMENT....................................... 1 1.1. Wastewater collection ........................................................................................................................ 1 1.2. Wastewater treatment ......................................................................................................................... 7 2. THE POLLUTION ISSUES ................................................................................................................ 13 2.1. Municipal wastewater pollution ....................................................................................................... 13 2.2. Industrial wastewater pollution ........................................................................................................ 16 2.3. Craft village wastewater pollution ................................................................................................... 20 2.4. Wastewater sludge pollution ............................................................................................................ 24 3. THE RECENT TRENDS ..................................................................................................................... 28 3.1. The legal framework ........................................................................................................................ 28 3.2. The technological aspect .................................................................................................................. 32 4. OPPORTUNITIES FOR COOPERATION ....................................................................................... 37 4.1. Public investment............................................................................................................................. 37 4.2. Private investment ............................................................................................................................ 37 REFERENCES .......................................................................................................................................... 41 ABOUT THE AUTHORS ........................................................................................................................ 43 AUSTRALIAN WATER ASSOCIATION – MARKET RESEARCH REPORT 1. OVERVIEW OF WASTEWATER COLLECTION AND TREATMENT 1.1. Wastewater collection In Vietnam, most of the urban areas in category IV or higher have combined sewerage and drainage systems (CSS), which collect both rainwater and wastewater via pipeline collection networks or drainage canals (Figure 1). The average drainage coverage in Vietnam is about 40–50 %, which is much lower than water supply service of over 70 %. The coverage rate ranges from 70% in large urban areas to only 10–20% in category IV and and only 1–2% in category V urban areas. drainage, and ―taking away‖ domestic wastewater to prevent flooding in the streets. Some newly developed urban areas introduce separate sewer and drainage systems (SSS), such as Buon Ma Thuot city (Figure 2); however, as most urban wastewater is untreated, thus both storm-water and domestic wastewater are finally discharged together into nearby water environments such as rivers, lakes and canals [1]. Table 1 shows the objectives for development of urban drainage and wastewater treatment [2] Table 2: Objectives for development of urban drainage and wastewater treatment [2] Items 2015 2020 2025 40-50% in 60% in 70-80% in categories III categories III categories IV or or or higher urban higher urban higher urban areas areas areas Service 40% in 50% in coverage of categories IV, Wastewater categories V collection and V discharged urban areas treatment urban areas and system and craft villages craft villages Wastewater treatment plants at different Part 3: Wastewater sector in Vietnam Page 1 AUSTRALIAN WATER ASSOCIATION – MARKET RESEARCH REPORT levels of management are located in craft villages The whole wastewater is treated Industrial and All industrial hospital wastewater parks have their own discharge system Pipes, sewers, channels will Public toilets be are 20-30% upgraded to installed in treated prevent Other items categories IV wastewater pollution or will at higher urban be reused. concentrated areas residential areas Part 3: Wastewater sector in Vietnam Page 2 AUSTRALIAN WATER ASSOCIATION – MARKET RESEARCH REPORT Figure 1: To Lich River in Hanoi receives both wastewater and stormwater (Source: http://vovgiaothong.vn) Figure 2: Constructing separate wastewater collection system in Buon Ma Thuat city (Source: https://tintaynguyen.com) Part 3: Wastewater sector in Vietnam Page 3 AUSTRALIAN WATER ASSOCIATION – MARKET RESEARCH REPORT In order to reduce pollution caused by discharging directly wastewater to combined system, septic tank is often used as the pre-treatment facility. However, there are a range of issues related to septic tank operation, which are [2]: Many households have latrine with septic tank but it is not connected to a common sewerage system due to the lack of sewerage network in small lanes. As a result, wastewater flows into open small channels or to surrounding areas or infiltrates into soil. Some households have flush latrine, flushing directly wastewater into the common sewerage system, bypassing septic tanks or other on-site treatment works In general, septic tanks usually have small volume while sludge removal is not carried out periodically. Many households have not conducted sludge removal from their septic tank for tens years. Wastewater; therefore, is discharged into a common sewerage sewer together with sludge from storage tanks, leading to a situation in which it is easy to get sediments in the sewer and there is a serious odor, especially in the dry seasons Activities of sucking, transporting and disposing sludge in septic tanks from households, institutions, enterprises and businesses, services etc. in urban areas have not been controlled (Figure 3). No city has well managed this activity. Private enterprises unpromptedly provide sludge sucking services and mostly dispose sludge into open land sites, channels, drainage sewer or directly into the rivers, lakes etc. close to sludge sucking place (to save transport cost) without being controlled in environmental pollution and disease transmission. Part 3: Wastewater sector in Vietnam Page 4 AUSTRALIAN WATER ASSOCIATION – MARKET RESEARCH REPORT Figure 3: Household septic tank cleaning by vacuum truck (Source: http://cafebiz.vn) Another issue caused by combined rainwater and wastewater collection system is that, the slope sewers are often designed with relative small and can be easily struck by garbage, resulting that they need cleaning very frequently. Not every sewers can be cleaned by vacuum truck, thus in dense populated area or very complex sewers, the works often clean the sewer system manually (Figure 4). The combined system also causes difficulties to the operation of wastewater pumping station, which plays the role of conveying wastewater from deep manholes to the wastewater treatment plant (Figure 5) Part 3: Wastewater sector in Vietnam Page 5 AUSTRALIAN WATER ASSOCIATION – MARKET RESEARCH REPORT Figure 4: Workers are cleaning sewers system manually (source: https://www.vietnambreakingnews.com) Figure 5: Underground wastewater pump station at Bac Ninh City (source: authors) Part 3: Wastewater sector in Vietnam Page 6 AUSTRALIAN WATER ASSOCIATION – MARKET RESEARCH REPORT The key problem regarding wastewater collection system is the sync with wastewater treatment plant. New construction or renovation is often patchy and unplanned from the outset; further, this work has not been carried out in sync with the construction of wastewater treatment plants located along the network. Many sewage treatment plants have not realized their full capacity due to a lack of sewer networks. For example, North Thang Long-Van Tri WWTP was designed and constructed with a capacity of 42,000 m3/day but in reality the plant only operated at the capacity of 7,000 m3/day as the domestic wastewater from the surrounding residential areas have not yet been connected to the plant due to a reason that the sewer networks have not been fully covered in the area. Similar situations have been reported in Phu Ly WWTP in Ha Nam province and a WWTP in Vinh-Nghe An province [1]. The proportion of households connected to the urban drainage network in many places is still very low due to some reasons: Impact of urbanization: Quality of planning is low and incomprehensive; forecasting is still limited Lack of investment capital Many shortcomings in management Awareness of the community. 1.2. Wastewater treatment Regarding wastewater treatment technologies at centralised treatment plants, the most common technologies are based on activated sludge (AS) process, such as aeration tanks or sequencing batch reactors (SBR); for example, North Thang Long WWTP, Yen So WWTP (Figure 6), Bai Chay WWTP, Quang Ninh WWTP. In addition, there are a number of wastewater treatment plants utilising low-cost and environmentally sound sanitation technologies, such as waste stabilisation ponds or constructed wetlands. Examples of these are the WWTPs in Ho Chi Minh City (Binh Hung Hoa WWTP (Figure 7), Da Nang and Buon Ma Thuat [1]. Some smaller