Hara, K, 2010 –– Nauru’s Pacific integrated water resources management project
This wastewater management feasibility study for Nauru is a component of the Global Environment Facility – Pacific Integrated Water Resources Management Project (GEF-Pacific IWRM) that aims to assist the country with enhancing its water security.
The wastewater management component focuses on protection of groundwater resources from surface contamination-prone activities, particularly black water disposal methods, through identification and pilot project implementation of appropriate, cost effective sanitation options. The presence of bacteriological contamination in groundwater is largely suspected to be caused by the current use of unsound septic tanks and cesspits by the majority of households.
A range of appropriate technical options and their variations to Nauru’s environmental and social conditions were initially earmarked for consideration. The options were then narrowed down to a manageable number of three through a two-step Multi Criteria Analysis which considered both technical and non-technical factors that can impinge on sustainable wastewater management efforts in Nauru’s context.
Technically, most of Nauru’s soils do not support wastewater disposal methods that involve seepage of effluent into the subsurface. Only within the elevation band between 0 and 24m above Mean Sea Level (MSL) can sandy, unsaturated soils be found that are ideal for facilities such as septic tanks, soakaways and cesspits. Likewise, a groundwater assessment project carried out at the end of a fairly intense rainfall period in March and April of 2010, found the average depth to the water table to be 3.4m (Bouchet & Sinclair 2010).
In such unsaturated soil conditions to a depth of about 2m between groundwater and the soakaway point, Franceys, Pickfold & Reed (1992) have stated that the chances of survival for bacteria and viruses are much less, hence a lower risk for groundwater contamination. Conversely, above elevations of 24m, the soil profiles become predominantly limestone that is fissured and can thus encourage easy infiltration of contaminants into aquifers.
Consequently, household level double compartment septic tanks and composting toilets have been recommended for demonstration projects in the elevation bands below 24m and above 24m, respectively. Yet, a precautionary approach is encouraged to be taken when employing soakways even in the 0 to 24m contour bands when geomorphologic uncertainties are encountered.
However, mitigation of Nauru’s groundwater contamination will require more than technical considerations. This study has therefore, recommended that institutional and policy frameworks which promote sound wastewater management are either strengthened or established.
Furthermore, alongside the demonstration projects, well targeted information dissemination programmes should be undertaken to help society overcome certain social barriers and myths that prevail on the island as a result of lack of information provision.
Kasenga holds a Master of Integrated Water Management attained at the University of Queensland and Bachelor's degree in Civil and Environmental Engineering from the University of Zambia. He also holds certificates in 'ecological sanitation' (from UNESCO-IHE) and 'utility benchmarking' (from the IP3 - America).
Further, he has trained in 'utility regulation and strategy' at the Public Utility Research Centre in Florida, US. He previously worked for Zulu Burrow Limited, an Engineering consulting firm, on a number of structural projects, including design of a medium water treatment plant. In February 2006 he joined the National Water Supply and Sanitation Council of Zambia - a regulatory authority, as Technical Officer, a position he held until September 2010. He currently works as Technical Inspector in the same institution.
In addition, Kasenga is currently a Member of the Water Technical Committee of the Zambia Bureau of Standards; the Inter-Agency Environmental Coordinating Committee; as well as member of the General Civil Engineering Works Sub-Committee of the National Council for Construction (Zambia).
His goal is to see to it that water resources in Zambia are efficiently and sustainably managed and to ensure universal coverage to adequate, affordable and safe water and sanitation services by all.