The sustainability of toilets in Hanoi, Vietnam.

• Author: Fink, Sasha
• Position: Abstract - Survey

Abstract

Sustainable development must utilize the social infrastructure already in place. Community groups and organizations already present in Hanoi, Vietnam, should play a major role in developing sanitation infrastructure.

In Ancient Chinese the words Ha and Noi mean 'contained by rivers', so with 1.6 million people living on a former rice paddy, water drainage and wastewater disposal are major problems. This paper explores the situation for toilets, septic tanks, sewage and drainage. This paper proves that a large proportion of human waste in Hanoi goes directly to the waterways untreated. Compounding this problem is the inadequacy of joint sewage/drainage pipelines, resulting in the spillover of untreated waste into the streets and onto the footpaths during heavy rain.

A significant component of the research was in-depth interviews conducted in 41 households. Survey answers revealed that most people were concerned about pollution in their area from the septic/sewage system, and many people were actively involved in improving the situation in and around their house.

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The Situation in Hanoi

The French colonial power installed the original joint sewage/drainage pipelines in Hanoi 50 years ago, but they did so for 400,000 people. There are now at least 1.6 million people living in central Hanoi and they are still using the same pipelines, which crumbling and in serious need of repair. Almost all wastewater goes into a combined system of storm water and wastewater.

Infrastructure provision and maintenance in Vietnam are still centrally controlled and supply based. Government revenue is well below that of other countries with similar income levels, hence the limited provision of sanitation infrastructure and services.

The Existing Sewage System in Hanoi City

Hanoi City is located in the Red River delta, the terrain is flat and there are five rivers and around 111 lakes and ponds within the city. Wastewater is conveyed through a joint drainage and sewage system, most of which was constructed before 1954, to the water bodies throughout the city. This waste is not treated, and since the hydraulic gradient of the sewers is small the sewers are prone to heavy silting. As a result there is also serious pollution in the city's many lakes, ponds and rivers and the city is prone to flooding.

The only proper septic tanks in Hanoi are those that were installed more than 50 years ago by the French colonialists. These are the full septic tank systems with two or three tanks, a filtration system and an auto purification process for wastewater to be discharged into the sewage pipelines. These were only installed for rich French colonialist families.

In most cases individual toilets are connected to the sewage system and the waste is usually discharged via a retaining chamber, septic tank or similar styles of pit (bomb shelters not excluded). The distinction therefore between septic and sewage is ambiguous. All liquid waste, that is, human waste products, grey water, hospital waste, industrial waste, flood water and any other liquid waste, go to the same pipelines, which lead to the Kim Nguu and To Lich rivers (interview with Project Officer, Sanitation WATSAN Programme, UNICEF, Hanoi, 7 July 1999).

Cost Recovery for Sanitation Infrastructure

As in many developing cities there is a scarcity of capital for investment in urban infrastructure in Hanoi. Investment in infrastructure in Hanoi is also below that of other cities with similar demographics. Refer to table 3 for a comparison of capital investment in waste and water connections in Hanoi to other cities of similar population sizes, wealth and circumstances.

A Japanese sewage and drainage project underway in Hanoi has been establishing a sewage levy-based system. In 1995 the average operation and maintenance cost for centralised treatment plants was estimated at 5,934,000 USD per year. The sewage levy should at least partially secure finances for the operation and maintenance costs.

Household Sanitation in Hanoi: Household Interviews

Methodological approach

In-depth household interviews were conducted to obtain information about the demographics, housing and sanitation situation, and residents' perceptions of these. These interviews were conducted in 41 households between 11 July and 11 August 1999. The survey was divided into three sections, personal information, housing, and toilets and waste disposal. The third section was the most involved part of the survey, with a range of open-ended and probing questions. Households were randomly selected from a broad range of income and education levels.

The demographics of the survey sample typified Hanoi City. The average household size was 4.1 people, with two generations in most households and three generations in two fifths of the households. Interviewees ranged from 16 to 66 years of age.

Interview results

Septic Tanks

Half of the households interviewed had a septic tank that they did not share with other neighbours, while the remaining households that had toilets shared a septic tank.

Several cases of inadequate septic tanks were found at the houses of interviewees. One of the worst septic tanks, and the families living conditions was Anh's family. To enter Anh's house one must crawl over a large stack of wooden planks. Anh is a carpenter, living and working in an old limestone brick house in central Hanoi. His house was built before the current roads and wastewater drains were constructed, consequently the floors are lower than the road and any rains flood directly into his musty smelling, windowless workshop. He has built barriers across the bottom of the doorways but in heavy rains he has some tiles that he takes out of his workshop floor to allow the dirty water to drain out.

Anh says he wants to build a new toilet because the septic tank is actually an old bomb shelter that they connected to the sewage pipelines ten years ago. He knows that the toilet is not hygienic and he often needs to pour chemicals into the toilet to breakdown the waste in the septic tank, as it is too small.

Septic Waste Removal

One of the best ways to significantly reduce the level of pollution from septic waste in Hanoi is to empty the septic tanks regularly, and dispose of the raw sludge properly. There is enormous potential for sludge to be treated (buried underground for three months) and then sold as fertiliser in rural Vietnam. Instead the household interviews found that almost 50 percent of respondents did not know how their septic tank was emptied, if they needed to do this, or how they would go about it. Less than 20 percent of respondents had URENCO or a small private company come and clean out their septic tank. (URENCO commonly takes the waste to a rubbish ground, close to where people live and scavenge through rubbish, rather than recycling it.)

Just over 20 percent of respondents were using bio-powder and considered this to be a modern approach and effective to sewage disposal, although it is relatively expensive (20-30,000 Vietnam Dong per treatment). Bio-powder is a new product in Vietnam, it is marketed as a low cost alternative to pumping out septic tanks or cleaning out pipelines. It is constituted of biological products such as cellulite, pectin, protein, flour and lipids that digest the organic waste blocking the sewage system, breaking it down and allowing it to be flushed through into the joint sewage/drainage pipelines with a large amount of water.

There is little awareness about how a septic system should be emptied and the environmental impacts. It is becoming increasingly popular to flush the system out with bio-powder, the side effects of which are not researched and not understood.

Householders Views on their Wastewater...