SUSTAINABLE MUNICIPAL WASTEWATER MANAGEMENT FOR A CRAFT VILLAGE IN NHUỆ - ĐÁY RIVER BASIN

S. GROTHE, R. EMMERICH AND J. KASBOHM

 Institute of Geography and Geology, University of Greifswald,
Makarenkostr. 22, 17487 Greifswald, Germany

Abstract: Clean water supply and hygienic sanitation in rural areas are central development goals in Việt Nam. This paper presents and discusses key issues of household water supply and sanitation against the background of the socio-economic situation in a typical craft village within the Nhuệ-Đáy river basin. Based on data from interviews of households and experts a relationship between the income situation and the household water supply and sanitation situation is revealed. Poor households have a lower supply degree of clean water (61%) and a higher share of waterless latrines not meeting the national hygiene standard (60%). In not-poor households the supply degree with clean water (77%) is higher as also the share of flushing toilets meeting national hygiene standard (65%). Especially in poor households a traditional source separating system (faeces and urine separation) with nutrient recycling is practised. The use of flushing toilets causes a significant higher tap water consumption (84 litres per person per day) compared to households equipped with waterless latrines (40 litres per person per day). With regard to the results different sanitation options are discussed, concluding that cost-effective decentralised solutions are to be preferred under the given socio-economic situation.

I. INTRODUCTION

The strength of the current economic development is one of the greatest pressures on water resources and the water sector in Việt Nam. In rural areas craft villages are promoting industrialisation, generating incomes up to 5 times higher than in agriculture villages. Approximately 400 craft villages are located in the Nhuệ-Đáy river basin, a sub-catchment of the Red-Thái Bình river basin where about 60% of Việt Nam’s craft villages are situated [1, 11]. Recently water pollution from craft villages is increasingly considered a serious and growing problem. The “Overall scheme on environmental protection in the Nhuệ-Đáy river basin” [6] among others sets up measures for clean water supply, wastewater drainage and treatment in craft villages. Nevertheless sanitation efforts are limited to industrial zones, disregarding residential areas.

To meet the Millennium Development Goals in Việt Nam the improvement of clean water supply and hygienic sanitation in rural areas, especially of poor households is essential [17]. In Việt Nam over 40 million rural people are without access to clean water with much more having no hygienic sanitation. The National Target Program II (NTP II) is linked to international goals fostering rural water supply and sanitation [5]. But already in its pilot phase, not yet covering all provinces, this program has serious delays [1]. Thus the challenge is to develop cost-effective and feasible solutions for rural areas to keep up with the high pace of socio-economic changes in Việt Nam. Though sustainable household sanitation development must not be restricted to the facilities, but has to improve the transport, treatment and use of domestic wastewater and its components [19].

In this study key issues of household water supply and sanitation in a typical craft village were recorded and evaluated to derive sanitation options. Therefore end-of-pipe technology with sewer system and central wastewater treatment was compared with innovative decentralised concepts following the ecological sanitation approach [14]. Here source separating systems and cost-effective on-site cluster solutions were reviewed. All options were examined regarding the given legal basis of the national water sector and the socio-economic situation of households in the craft village with special consideration of the poor.

II. METHODS

To record socio-economic and water related data individual interviews were carried out during spring 2007 with representatives from 320 households in the residential area of Tòng Xá. The data was processed and analysed using SPSS statistical software. To understand the communal planning deputies of the local authority were interviewed and communal development plans were reviewed. An expert interview was also conducted at the local waterworks. Additional tap water consumption data was delivered by Ý Yên Water Supply Company located in Lâm town.

III. RESULTS AND DISCUSSION

1. Local geography

Tòng Xá is located about 80 km southeast of Hà Nội in the province Nam Định. With 900 years of tradition in foundry Tòng Xá is a typical craft village within the Nhuệ-Đáy river basin. Together with the villages Bạc 12 and Cô Liêu, Tòng Xá constitutes Yên Xá commune with an area of approximately 200 ha. By the year 2000 having 3,297 inhabitants population density in the commune was 1,655 people per km². In 2006 the total number of households in Tòng Xá was 551 [12], according to own results the average number of people per household is 5.

Because wet rice cultivation is the dominating land use (62% in 2005), land resource is scarce for other purposes. Recently land for agriculture is being converted into land for industrial use. Since 2001 about 30 companies and enterprises are centralised to an industrial zone with an area of 6 ha in the immediate vicinity of the residential area. Further casting production sites are distributed all over the residential area as individual household business [15].

2. Income sources and poverty

In Tòng Xá the determined mean monthly income per person is 871,920 VND similar the mean income in urban areas (815,430 VND) and over 2 times higher than the average income in rural areas of Việt Nam (378,090 VND) [7]. In the village 37% of households are to be considered as poor according the poverty line for rural areas (200,000 VND per person per month) as published by the Việt Namese General Statistics Office [8]. About 70% of the poor in Tòng Xá are farmers. The poverty rate is much lower among households with other income sources as private business and labour in a casting company or at civil service.

3. Household water use situation

The traditional water sources used in Tòng Xá are groundwater both dug and drilled, and rainwater from cisterns. Since 2001 tap water is available for households in Tòng Xá. For food and drinking purposes Tòng Xá residents prefer rainwater. Groundwater is used for washing and cleaning, and for other purposes like animal breeding or production. Tap water is used as multi-purpose source (Fig. 1).

As reported by deputies of the local authority in 2008 the Đáy River had a too low water level for the first time since abstraction of tap water. Further the limited capacity of the water work and regularly power blackouts lower the supply guarantee for tap water.

Figure 1.  Water sources and their uses by households in Tòng Xá, 2007

 

Project results from the National Institute of Labour Protection (NILP) reveal that Pb-contents of rainwater in the cisterns exceed the appropriate limitation value for clean water [10]. Reportedly the pollution source is dust from casting production sites in the industrial zone of Tòng Xá.

4. Income and water use

The kind of water supply and water use is related to the income situation of the households. Local water supplies (groundwater, rainwater sources) are used in nearly all poor households, whereas the supply degree with tap water is much lower. In non-poor households the means of water supply are uniformly distributed. The share of local water supply in low-income households is higher than in non-poor households, which in return have a higher share of tap water (Table 1). The reduction of local water supplies and the increase of tap water supply since 2001 are clearer in households above poverty line. The mean tap water consumption in non-poor households (81 litres per person per day) is nearly 100 percent higher than in poor households (41 litres per person per day).

Table 1. Household water supply infrastructure and its relation to poverty in Tòng Xá,
 2007 (n=270).

Water Supply / Sources

Within poor households

Within non-poor households

Within all households

Local Water Supply

Groundwater

(dug, drilled well)

91%

(81%, 8%)

75%

(48%, 24%)

81%

(62%, 17%)

Rainwater

80%

63%

69%

Central Water Supply

Tap water

57%

69%

64%

 

The household water supply in Tòng Xá comprises all clean water sources as defined by Wells [18] for the Red River delta region (tap water, drilled well water, rainwater). Referring to this nearly all poor households (97%) and non-poor households (98%) have access to a clean water source. But rainwater cannot be considered a clean water source in Tòng Xá since industrial activities cause Pb-pollution. Following only 77% of non-poor households and 61% of low-income households have access to a clean water source. Thus the supply degree with clean water drops below NTP II goal for 2010 whereby 85% of rural households shall have clean water supply [5]. The lower access rate to a clean water source of poor households, results from a higher linkage to rainwater source, and a lower linkage to drilled well water and tap water.

5. Household sanitation situation

Most of households in Tòng Xá dispose their wastewater via private connection channels into the main sewer (75%). Others dispose directly to fields (16%), to a private pond (7%) or by infiltration (2%). The existing canalisation is widely designed as an open stormwater drainage system which is also used for the drainage of wastewater. Because of the even surface topography with a low natural gradient drainage by gravity over longer distances is problematic.

The domestic wastewater is a mixture of greywater and blackwater [19]. Where household based business activities occur commercial wastewater is admixed to the wastewater flow. Especially in the summer external rainwater inflow is remarkable. The municipal wastewater is not treated before disposal into the receiving water source.

6. Sanitary equipment of households

The main types of toilet used in Tòng Xá are waterless toilets (dry pit latrines, separation latrines) and flushing toilets with septic tank. The traditional type is the dry pit latrine, sometimes combined with separated urine collection (Fig. 2). These toilets do not generate any blackwater flow. The human excreta are deposited along with bulking agents (rice husks and straw, ashes) and are used as fertilizer in agriculture. The retention time in all recorded dry pit latrines is below 6 months. The major type of dry pit latrine is a single chamber latrine. Nearly all waterless toilets do not meet the hygiene standards by means of ventilation, faecal-hole covers, rainwater protection and wall sealing [9]. The faeces are insufficient sanitised before used in agriculture, and flies and mosquitoes can easily get in contact with the human excreta. Typically the waterless toilet installations are situated outside the living house, often close to pig hutches. Some households use the pig hutch for defecation. Hand washing facilities are situated rather distant from the latrine.

Almost all flushing toilets are western style porcelain products. They are installed within a sanitary unit combined with a bathroom in the living house or an adjacent building. The majority of flushing toilets is installed with a septic tank (Fig. 3). The septic tank is located below the sanitary unit. The inflow to the septic tank is blackwater from the toilet, optional with admixed greywater resulting from washing and cleaning activities in the bathroom. The septic tanks are generally constructed as three chamber pits. Their design does not allow any sludge clearance. The septic tank effluent is disposed together with the other wastewater generated by the household.

Small scale biogas digesters are used to treat liquid manure of pigs. They are constructed from bricks in a fixed dome shape [13, 16]. Sometimes flushing toilets are connected to the biogas digester. Therefore they are located in the immediate vicinity of the hutch. Here the blackwater is co-treated with liquid manure. The effluent from the biogas digesters is disposed with the other wastewater generated by the household.

 

                     

Figure 2. Waterless toilet (left), urine separation (right) in Tòng Xá, 2007

            

Figure 3. Flushing toilet (left), septic tank under construction (right) in Tòng Xá, 2007

7. Income and sanitation

The study revealed a relation between the type of household based sanitary equipment and the income situation. In poor households the use of dry pit latrines is more widespread than the use of flushing toilets. Flushing latrines are the dominating toilet type of households above poverty line. In low-income households more biogas digesters are installed than in non-poor households (Table 2).

Table 2. Household based sanitary equipment and its relation to poverty
for households in Tòng Xá, 2007 (n=270).

Sanitary equipment

Within poor households

Within non-poor households

Within all households

Waterless toilet

(dry pit latrine, separation toilet)

60%

35%

44%

Flushing toilet

40%

65%

56%

Biogas digester

11%

6%

8%

The biogas digesters were found in farming households, mostly having a larger pig live stock. The higher share of biogas digesters in poor households is linked to the wider distribution of animal husbandry. In Việt Nam the construction of small scale biogas digesters is supported by public programs [16].

Poor households have a lower share of sanitary equipment meeting national hygienic standards for sanitation [10]. The NTP II sanitation goal for 2010 whereby 70% of rural households shall have hygienic sanitation [5], has nearly been reached by households above poverty line.

8. Key issues of water use and sanitation in Tòng Xá

It seems that in Tòng Xá clean water gravitates towards the rich and wastewater towards the poor [17]. Flushing toilets, generally operated with clean tap water, ensure hygienic sanitation of mostly non-poor households. But their insufficient treated effluents pollute receiving water sources causing impacts of public health and environment. Affected are farmers using channel water traditionally for irrigation and the consumers of their products. Children get easily in contact with the wastewater where the drains are open.

Since there is no proper sewage drainage and wastewater treatment the use of flushing toilets does not solve the sanitation problem, but it relocates the hygiene problem from the household to the community. It is a paradox that waterless toilets not meeting national hygiene standards for sanitation affect the community less than their individual users.

Clean water that is not available for all households and thus a scarce resource is used in other households for the flushing of human excreta. The tap water consumption is higher in households above poverty line where flushing toilets are prevalent. Poor households mainly equipped with waterless toilets display lower tap water consumption (Fig. 2).

9. Collection and central treatment of domestic wastewater

Whereas the collection of industrial wastewater and its central treatment in industrial zones of craft villages is oblige by the Law of Environmental Protection (LEP) there is not such a legal obligation for the handling of domestic wastewater. Households are only required to discharge wastewater into a sewer system (Article 53, §1a LEP) [4]. The collection of all domestic wastewater (greywater, blackwater) and its discharge into a receiving water source in the western understanding induces the demand of an adequate wastewater treatment [14]. But improving, maintaining and operating the sewer system to collect the wastewater of every household is costly [2]. Expenses would also arise for the construction and operation of a wastewater treatment plant. But the pockets of the local authority for such investments are empty. Only a fraction of the environmental protection charges for wastewater flows into the budget of the local authorities (Article 8, §1 and 2 Decree 67/2003/ND-CP) [3]. At all the revenue of that fee is low as only households having a tap water supply are charged. Besides the fee is linked to the water price (Article 6, § 1 Decree 67/2003/ND-CP; 5% of the tap water price in Tòng Xá), and that is quiet low (2,667 - 3,143 VND per m³).

 

Figure 4. Sanitary equipment and tap water consumption of households in Tòng Xá, 2007

10. Prevention of wastewater and decentralised solutions

A more confident option for sanitation in Tòng Xá is the prevention of wastewater, further development of sources separating systems and the treatment of wastewater in cost optimised cluster solutions [19].

In Tòng Xá households that use waterless toilets have a mean tap water consumption of 40 litres per person per day. They save about 50% of tap water compared to households using flushing toilets (84 litres per person per day).

When flushing toilets are used nutrients from human excreta are dissolved, diluted and potentially contaminated with pollutants (e.g. heavy metals). The nutrients can only be partly removed and recirculated in wastewater treatment facilities under expenditure of energy. Also after treatment a residual contamination by nutrients is disposed into the water source. The recycling of nutrients from human excreta (faeces, urine) is traditionally anchored in Tòng Xá by the use of waterless toilets. Based on the traditional approach nutrient recycling and subsequent use in agriculture should be fostered under the precondition that waterless toilets comply with the national hygiene standard. Thus it is necessary to upgrade existing waterless toilets. Using double vaults on-site composting toilets sanitised excrements can be used for manure after 6 months retention time [9]. When the design of the composting toilet enables urine separation, this could be further used as fertilizer. Additionally waterless and urine-diverting toilets that can be installed in the living house [19] should be introduced especially to high income households. Using waterless toilets reduces the resulting effluent charge and required treatment capacity (Table 3). The estimation of treatment capacity for Tòng Xá is based on the COD load of domestic wastewater, splitting up for 41% in greywater, 12% in urine and 47% in faeces [14].

Table 3. Estimation of treatment capacity for total effluent charge under consideration
of sanitary equipment of households in Tòng Xá (n=551; PECOD).

Sanitary equipment

Current situation

(56% flushing toilet, 44% waterless toilet)

100% equipped with flushing toilet

100% equipped with waterless toilet

Households with flushing toilet

1,540 PE

2,755 PE

-

Households with waterless toilet

500 PE

-

1,130 PE

Total households

2,040 PE

2,755 PE

1,130 PE

Technical solutions for greywater and sludge treatment should be characterised by rugged design and operate energy saving and service reduced as e.g. constructed wetlands [19]. Solutions for household clusters realised in a participatory wastewater management would reduce total costs and the financial burden for single households. Such self-management activities of population communities in environmental protection are stimulated by Article 53, §1d LEP [4]. Cost-effective cluster solutions would minimise the expanses for the sewer system in terms of network length and pumping demand. On short distance drainage by natural gravity is also feasible in Tòng Xá.

IV. CONCLUSIONS

Prevention of wastewater, further development of traditional source separating systems and wastewater treatment in decentralised cost-effective household cluster solutions realised in a participatory wastewater management is considered a key option for sanitation in Tòng Xá. The end-of-pipe technology approach with sewer system and central wastewater treatment is considered not feasible under the given socio-economic situation. The primary issue is to upgrade existing waterless toilets as mainly used in poor households in order to meet the national hygiene standard for sanitation. The use of waterless toilets reduces the effluent charge and thus the treatment capacity. The tap water consumption is significantly reduced compared to flushing toilets. Currently flushing toilets prevalent in wealthier households only relocate the hygienic risk potential of sanitation from the household to the community affecting public health and the environment negatively, as there are no proper sewage system and wastewater treatment available.

ACKNOWLEDGEMENT

The study was conducted in the frame of an IWRM project in Việt Nam financed by the German Federal Ministry of Education and Research (BMBF: 02WM0765). All work in Tòng Xá village was kindly supported by the Peoples Committee of Yên Xá commune and Nam Định Provincial Department of Science and Technology (DoST).

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