**Author details**

*Water Quality - Science, Assessments and Policy*

the system malfunctioning.

**5. Conclusion**

from wastewater.

**Conflict of interest**

Due to their cost-effectiveness, natural wastewater treatment systems are preferred wastewater treatment systems in many low- and middle incomecountries. Adequate maintenance and operation are critical to the performance of natural wastewater treatment systems. However, all too often these systems become overloaded and receive inadequate maintenance. Most factors associated with poor performance of natural wastewater treatment systems are the result of lack of adequate maintenance and repair, abandonment of the systems, or poor design [67]. Inadequate maintenance such as desludging results in sludge accumulation in the systems, which will reduce hydraulic residence of wastewater and sometimes create hydraulic short-circuiting resulting in poor performance of the systems. In CW systems, accumulation of sludge may result in clogging of the system leading to

Generally, natural wastewater treatment systems receive influent wastewater with high concentrations of STH eggs and are capable of producing effluents containing ≤0.01 egg per liter, which is suitable for use or discharge to the environment even when children aged less than 15 years are exposed. The main reason for inadequate maintenance of natural wastewater treatment systems in low-income countries is a decrease in governmental financial support as well as decrease in finance generated by the systems as they become older [37]. In addition to that, poor system design such as errors in system geometry (e.g., length-width ratio) or poor arrangements of inlet and outlet may lead to water turbulence and hydraulic

Countries implementing prophylactic chemotherapy for controlling helminthiasis report high concentrations of STH eggs in wastewater. For the wastewater to be safe for reuse and/or discharge, it requires further treatment. Natural wastewater treatment systems including sedimentation ponds and constructed wetlands work well in assisting STH control through interrupting transmission by removing eggs

short-circuiting resulting in low system performance [60, 67].

The authors declare that there are no conflicts of interests.

**48**

Abdallah Zacharia1 \*, Anne H. Outwater2 and Rob Van Deun3

1 Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania

2 Department of Community Health Nursing, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania

3 Unit Life Sciences and Chemistry, Thomas More University of Applied Sciences, Geel, Belgium

\*Address all correspondence to: naayz@ymail.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
