~Written by Joann Varickanickal (Contact: joann.varickanickal@gmail.com; Twitter: @joann_s_v)
Bello Wastewater Treatment Plant, Medellin, Colombia (Photo Credit: www.water-technology.net)
The discharge of household and industrial waste can lead to the spread of waterborne diseases if left untreated because of cross contamination with drinking water or other forms of direct contact (Daley et al., 2015). This issue of wastewater sanitation has become prevalent in several low-resource countries, as the treatment of wastewater can often be expensive, and the policies needed to implement low-cost methods do not exist.
One example of this is in Kenya, where sustainable water management practices have yet to be implemented. Furthermore, rapid urbanization and population growth have contributed to this problem (Mburu et al., 2013). Overall, due to the low operational capacities, only 5 percent of the country’s sewage is properly treated (Mburu et al., 2013). Thus, untreated or partially treated domestic wastewater is discharged into local freshwater rivers and lakes, leading to severe contamination. This not only results in the prevalence of diseases such as cholera, but it can also lead to high economic costs due to a decrease in work productivity as well as strains on the healthcare system (Mburu et al., 2013).
Colombia has also faced issues due to ineffective wastewater treatment. While this country has not had issues of water quantity, the issue of water quality remains a problem. In some areas, nutrients, suspended solids and organic matter can be effectively removed using existing methods; however, in some areas, treatment can be difficult due to geographic location and/or cost (García, Paredes, & Cubillos, 2013). Nevertheless, many of the current systems are unable to successfully remove pathogens, which can eventually lead to waterborne diseases (García et al., 2013).
When examining wastewater treatment in any region, in this case low-resource countries such as Kenya and Colombia, sustainable methods must be implemented. Constructed wetlands (CWs) are a possible method that can be used to improve wastewater sanitation. Characterized according to the water flow direction in the system, CWs have been implemented in various regions over the years to treat polluted water (García et al., 2013). These planted and unplanted systems have proven to remove heavy metals, nutrients and pathogens. For example, horizontal subsurface flow constructed wetlands (HSSF-CWs) have been successfully implemented for over four decades in developed countries with temperate-climates. The use of CWs has proven to be inexpensive, as it has minimal energy requirements and low maintenance needs (García et al., 2013). Thus, implementing these systems could greatly benefit many regions, and especially those that are currently facing health risks associated with wastewater treatment.
This issue, like many others related to public health, is complex. Policy-makers, engineers, and health professionals are among the many groups that need to work together to ensure that such systems can be effectively implemented and monitored in order to reduce the health risks that are associated with contaminated water.
References:
1. Daley, K., Castleden, H., Jamieson, R., Furgal, C., & Ell, L. (2015). Water systems, sanitation, and public health risks in remote communities: Inuit resident perspectives from the Canadian Arctic. Social Science & Medicine, 135, 124–132. doi:10.1016/j.socscimed.2015.04.017
2. García, J. a., Paredes, D., & Cubillos, J. a. (2013). Effect of plants and the combination of wetland treatment type systems on pathogen removal in tropical climate conditions. Ecological Engineering, 58, 57–62. doi:10.1016/j.ecoleng.2013.06.010
3. Mburu, N., Tebitendwa, M., S., Rousseau, P.L., D., Bruggen, J. J. A. Van, & Lens, N.L., P. (2013). Performance Evaluation of Horizontal Subsurface Flow-Constructed Wetlands for the Treatment of Domestic Wastewater in the Tropics. Journal of Environmental Engineering, 139(March), 1152–1161. doi:10.1061/(ASCE)EE.1943-7870