This paper presents one case of wastewater management approach in rural area. The design and the implementation of the solution have been developed in close consultation with the stakeholders and national authorities. The objectives are (i) to solve the problems of the uncontrolled wastewater discharged into nature without treatment, and (ii) to set up a robust solution to be recommended for application in rural school in Tunisia, devoid of sanitation system and characterized by limited financial resources for water supply and sanitation services. Several equipments to save water (push-button taps, waterless urinals, rainwater harvesting) is set up. The sanitation system consists of septic tank followed by horizontal subsurface flow constructed wetland. The treated wastewaters are used in the irrigation of the garden. The evaluation of the performances of the system after 3 years is presented.

INTRODUCTION

The millennium objectives are reduction by half, before 2015, the rate of the population which has no access to the drinking water and to the basic sanitation. Tunisia will reach these goals at the national level as regards the potable water supply; on the other hand uncertainties persist to reach these goals for the basic sanitation, particularly in rural areas. Forty percent of the Tunisian population lives in rural areas in small villages or isolated habitat with an access to drinking water, but 83% of them still have very poor sanitation services and their wastewater is discharged directly in the nature without treatment. The sanitation network is absent; and 13.5% of them have sanitary pit or septic tank (Sellami et al. 2007). To set up a strategy and to help the government to identify the best sanitation solutions for small settlements, several experiences were conducted by researchers in Tunisia (Sellami et al. 2007; Kouki et al. 2009; Ghrabi et al. 2011, Ben Saad (2012)).

The purpose of this paper is to present case study of wastewater management approach in rural area in Tunisia (primary school), implemented by Centre of Water Research and Technologies (CERTE). The design and the implementation of the solution have been developed in close consultation with the stakeholders and national authorities managing school and sanitation in Tunisia. The objectives of this study is to solve the problems of the uncontrolled wastewater discharged into nature without treatment, and to set up a robust solution to be recommended for application in rural school in Tunisia, devoid of sanitation system and characterized by limited financial resources for water supply and sanitation services.

MATERIALS AND METHOD

The solution implemented by CERTE in rural primary school (Chorfech, north of Tunis), presents a new approach for local wastewater management. It contains (Figure 1):
  • Implementation of several equipments to save water;

  • Set up of waterless on the place of conventional urinal;

  • Implementation of push-button taps for flushing toilet;

  • Equipment of others taps by push-button (drinking and washing basin);

  • Construction of reservoir to collect rainwater from school roof;

  • Using the rainwater for flashing toilet;

  • Set up a local system for sanitation (collect of wastewater, treatment and reuse in the garden irrigation).

Figure 1

Implementation of water saving equipment's (push-button taps, urinal waterless, and rainwater reservoir and general layout of sanitation).

Figure 1

Implementation of water saving equipment's (push-button taps, urinal waterless, and rainwater reservoir and general layout of sanitation).

The sanitation system consists of septic tank followed by horizontal subsurface flow constructed wetland (Figure 2). The treated wastewaters are used for garden irrigation of the school, planted by fruit trees (fig and pomegranate) and flowers. The irrigation is applied by an automatic underground drop-by-drop system. Basing the data collected and experiments conducted, 3 years before and after implementation of the solution, we present the preliminary results of evaluation.

Figure 2

Main part of sanitation implemented system: horizontal constructed wetland and their characteristics (designed by Iridra, Italy).

Figure 2

Main part of sanitation implemented system: horizontal constructed wetland and their characteristics (designed by Iridra, Italy).

The evaluation is based in water pollution parameters (pH, TSS, COD, BOD, Nitrogen, Phosphate, Fecal coliform and E. Coli). The standard methods are used (APHA/AWWA/WEF 2005).

RESULTS

Water consumption

Since 2005, school has contained seven teachers and a number of students between 65 and 74 students per year. Table 1 shows the different volumes of consumed water of the school before and after the implementation of sanitation system. Before implementation of the system, the average consumption of drinking water in school is more than 21 L/day.pupil. After, this consumption decreases more 50% (10.7 L/day.pupil); see Table 1.

Table 1

Water consumption before and after implementation of the system

Before implementation of the system
 
 After implementation of the system
 
Year 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014* 
Pupil number 65 68 68 Implementation of the system 71 74 73 80 80 79 
Water consumption (m3660 512 423 329 225 306 297 329 122 
Value (L/d.pupil) 27.8 20.6 17 12.7 8.3 11.3 10.9 11.7 8.5 
Average (L/d.pupil) 21.8 10.7 
Before implementation of the system
 
 After implementation of the system
 
Year 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014* 
Pupil number 65 68 68 Implementation of the system 71 74 73 80 80 79 
Water consumption (m3660 512 423 329 225 306 297 329 122 
Value (L/d.pupil) 27.8 20.6 17 12.7 8.3 11.3 10.9 11.7 8.5 
Average (L/d.pupil) 21.8 10.7 

Average calculated on 6 months period.

Sanitation system

Table 2 presents the performance of the sanitation system implemented in the Chorfech 24 primary school. The average of overall removal rates of sanitation system ‘septic tank – constructed wetland’ have been, respectively, equal to 93% for total suspended solids (TSS), 86,7% for chemical oxygen demand (COD), 96,4% for biochemical oxygen demand (BOD5), 68% for NH4+, 71% for NTK, 88,5% for PO4.

Table 2

Removal of the pollution by the system ‘septic tank-constructed wetland’

Parameters Septic tank Horizontal constructed wetland All system Quality of treated wastewater 
pH 6.5 6 8.5 
TSS 63% 81% 93% 81 mg/L 
COD 65.3 61.8% 86.7 153 O2 mg/L 
BOD5 80% 82.1% 96.4 17 O2 mg/L 
NH+4 < 19% 61% 68% 71.4 mg/L 
NTK < 5% 70% 71% 81 mg/L 
PO3−4 34% 81.2% 88.5% 4.8 mg/L 
Fecal coliform 2 log unit 1.5 log unit 3.7 log unit 340 UFC/100 mL 
E. coli 2 log unit 1.7 log unit 3.8 log unit 190 UFC/100 mL 
Parameters Septic tank Horizontal constructed wetland All system Quality of treated wastewater 
pH 6.5 6 8.5 
TSS 63% 81% 93% 81 mg/L 
COD 65.3 61.8% 86.7 153 O2 mg/L 
BOD5 80% 82.1% 96.4 17 O2 mg/L 
NH+4 < 19% 61% 68% 71.4 mg/L 
NTK < 5% 70% 71% 81 mg/L 
PO3−4 34% 81.2% 88.5% 4.8 mg/L 
Fecal coliform 2 log unit 1.5 log unit 3.7 log unit 340 UFC/100 mL 
E. coli 2 log unit 1.7 log unit 3.8 log unit 190 UFC/100 mL 

CONCLUSION

The results show the feasibility of the system composed by septic tank and horizontal subsurface constructed wetland. Regarding the high removal rates obtained, the final quality of treated effluent could be sufficient for garden irrigation. Rainwater could provide an alternative as well as the installation of water saving devices. The pilot activity will also build and reinforce the capacity building and expertise related to the implemented techniques under real conditions. This solution can be recommended for wide application in rural school in Tunisia and could be replicated in similar areas and countries in order to save water and to efficiently treat domestic wastewater avoiding direct discharge of untreated wastewater.

ACKNOWLEDGEMENTS

The sanitation system of primary school was developed and erected in the project ‘Sustainable Concepts towards a Zero Outflow Municipality (Zer0-M)’ and the monitoring was conducted in the FP4BATIW project (www.fp4batiw.eu), both funded by the European Union in the frame of MEDA Water and FP7, respectively.

REFERENCES

REFERENCES
APHA/AWWA/WEF
2005
In:
Standard Methods for the Examination of Water and Wastewater
,
21st Edn
. (
Eaton
A. D.
Clesceri
L. S.
Rice
E. W.
Greenberg
A. E.
, eds).
American Public Health Association/American Water Works Association/Water Environment Federation
,
Washington DC
,
USA
.
Ben saad
M.
2012
Une nouvelle approche pour la gestion locale des effluents en milieu rural. Cas de l'école primaire de Chorfech 24. Master soutenu à l'Institut Supérieur de Biotechnologies de Sfax
.
Kouki
S.
M'hiri
F.
Saïdi
N.
Belaïd
S.
Hassen
A.
2009
Performances of a constructed wetland treating domesticwastewaters during a macrophytes life cycle
.
Desalination
246
(
1–3
),
452
467
.
Sellami
H.
Benabdallah
S.
Charef
A.
2007
Performance of vertical constructed wetland treating domestic wastewater for small community in rural Tunisia
.
Water Waste and Environmental Research
7
(
1–2
),
11
24
.