Constructed wetlands system and reuse of wastewater treatment in the village of Sarra

Description: Implemented nature-based solutions (NbS) as green infrastructure through CWs with horizontal subsurface flow (HF) and vertical subsurface flow (VF) for wastewater treatment and sustainable drainage systems (SuDS). The plant is composed of: 1. pre-treatment with a mechanical screen (cochlea-type filter); 2. primary treatment with two tanks Imhoff in parallel; 3. secondary treatment using the 1st stage with vertical subsurface flow system (6 tanks in parallel, 1500 m2); 2nd stage (6 tanks in parallel, 3000 m2); each vertical flow system is provided by gravity and takes advantage of the different levels using self-priming siphon; 4. sharpening and accumulation pond for irrigation purposes; 5. CWs systems for the sludge extracted from the Imhoff tanks. (IRIDRA, 2021).

Country: Palestine

City: Sarra (Nablus)

City size: ≈ 0.6 km²

Population: 2523 (2007)

start: 2012

Timeframe: 2 years

Phase: Completed

Nature-based solutions (NBS) : Yes

Initiator: GVC, financed by the European Union

Website source: http://iridra.eu/attachments/article/112/Sarra-Nablus.pdf

Latitude: 32.2131

Longitude: 35.193

Co-benefits

Increased provisioning of ecosystem goods (e.g. Food, water, etc)

Yes, the project increased provisioning of water.

Improved water quality

Yes, through the sustainable drainage systems (SuDS) integration and CWs systems implementation (IRIDRA, 2021).

Biodiversity conservation or increased biodiversity

Yes, CWs can also provide a habitat for wildlife.

Increased quality and quantity of green and blue infrastructures

Yes

Sustainable urbanisation

CWs necessitate significantly lower investment costs. Their principal economic advantage arises from their operation phase due to minimal energy requirements and a limited requirement for maintenance and personnel. As natural treatment technology, CWs can be categorised as sustainable systems, fulfilling sustainability criteria such as effective sanitation, contribution to public health and hygiene aspects, environmental protection and safeguarding of natural resources. (Stefanakis, 2015). The project improved wastewater quality and helped to fulfil the local needs for water, especially for irrigation (the treated wastewater is reused for olive-tree irrigation). In addition, the project improved hygiene and the health status of villagers by setting up a sustainable drainage system (SuDS) and CWs. The 'number of treated persons' equivalent is 4300 PE. (IRIDRA, 2021).

Improved aesthetic value

In contrast to conventional treatment systems, nature-based solutions of the wastewater treatment (such as CWs) may also provide indirect benefits such as aesthetic improvement of the landscape (Goulandris Natural History Museaum, 2021).

Provision of health benefits

Yes, NbS such as CWs play a notable role in treating and purifing the wastewater generated by the many diverse human activities prior to the final discharge, in order to reduce and remove the pollutant load, which is an absolutely essential process not only to safeguard the natural environment and habitat but also to safeguard human health. (Stefanakis, 2015). This project consisting of sustainable sanitation systems integrates also aspects such as increased public health and hygiene (IRIDRA, 2021).

Original problems

Low provisioning of ecosystem goods (e.g. Water, food)

Yes

Low water quality

Yes, , there were also original needs to deal with the problem of improving wastewater quality, because most of it is not treated and is discharged directly in the environment. (IRIDRA, 2021).

Drought and heat risk

Yes, the main factors contributing to the severe levels of drought in the eastern Mediterranean region, which includes Historical Palestine, are deforestation, lack of rain, and a higher degree of evaporation from soil (Cook et al., 2016). Recent extreme droughts (from 1998 to 2012) in the Levant region (of which the State of Palestine forms part) are conspicuous in being roughly 50% drier than the driest period occurring within the past 500 years, and 10%–20% drier than the most severe droughts of the past 912 years (1100–2012). (Cook et al., 2016; Yihdego, Hilmi, Hadi, 2018). The Cook et al. (2016) study revealed that the presentdrought in the Mediterranean region is not merely the most extensive but also the driest that has impacted the region within the last five hundred years, due to its having averaged 20%–30% drier than all the preceding drought spells since the year 1100. (Cook et al., 2016; Yihdego, Hilmi, Hadi, 2018).

Low aesthetic value

Yes

Negative environmental impacts on human health

Yes, there were not integrated a sewage system and wastewater treatment which had a negative impact on villagers' hygiene and health condition (IRIDRA, 2021).

SDGs

Food security (SDG2) Zero Hunger

Yes

Good health and well-being (SDG3)

Yes

Clean water and sanitation (SDG6)

Yes

Industry, innovation and infrastructure (SDG9)

The constructed wetlands (CWs) systems with horizontal subsurface flow (HF) and vertical subsurface flow (VF) represent an innovation in the national scene. (IRIDRA, 2021).

Sustainable cities and communities (SDG11)

In Palestine, exploiting water resource is at the top of the issues, since in many areas the available water is not sufficient to fullfill the local needs, especially when it comes to irrigation. At the same time, there needs to deal with the problem of improving wastewater quality, because most of it is not treated and is discharged directly in the environment. (IRIDRA, 2021).

Climate action, resilience, mitigation and adaptation (SDG13)

Yes, life cycle analysis studies on CWs systems and comparison with alternative scenarios of using conventional treatment methods have also shown that the global warming potential of CWs is lower in terms of CO2 emissions (Stefanakis et al., 2014; Stefanakis, 2015).

Terrestrial biodiversity (SDG15)

Yes

Reference: Cook, B.I., Anchukaitis, K.J., Touchan, R., Meko, D.M., Cook. E.R. (2016). Spatiotemporal drought variability in the Mediterranean over the last 900 years. J. Geophys. Res. Atmos. 121 (5): 2060–2074. Retrieved from: https://doi.org/10.1002/2015JD023929.

Goulandris Natural History Museaum (2021). WASTREAT Project. Information obtained: 2021-02-16. Available at: http://www.ekby.gr/wastreat/CON-WETLANDS_General.htm.

IRIDRA (2021). Nature-based solutions - Sustainable water management. Information obtained: 2021-02-16. Available at: http://iridra.eu/attachments/article/112/Sarra-Nablus.pdf.

Shutes, B.; Revitt, M.; Scholes, L. (2010). Constructed Wetlands for Flood Prevention and Water Reuse. In Proceedings of the 12th International Conference on Wetland Systems for Water Pollution Control, Venice, Italy, 3–6 October 2010. Stefanakis, A. I., Akratos, C. S., & Tsihrintzis, V. A. (2014). Vertical Flow Constructed Wetlands: Eco-engineering Systems for Wastewater and Sludge Treatment (1st ed.). Amsterdam, The Netherlands: Elsevier Publishing. 378 pp. ISBN 978-0-12-404612-2. Retrieved from: https://www.researchgate.net/publication/283046086.

Stefanakis. A. I. (2015). Constructed Wetlands: Description and Benefits of an Eco-Tech Water Treatment System (Chapter 12). In Impact of Water Pollution on Human Health and Environmental Sustainability (Eds: E. McKeown, G. Bugyi ). 1st Edition. Publisher: IGI Global. Retrieved from: https://www.igi-global.com/chapter/constructed-wetlands/140180