Design and Economic Evaluation of a Proposed Water Treatment Facility in Trinidad and Tobago

Abstract

Trinidad and Tobago (TT), a small island developing stateface the challenge of supplying a steady potable water supply to its population. This paper proposed a processing method for a supplemental source intended to supply anew housing development in East Trinidad. Different supply strategies such as surface water, desalination and wastewater treatment were considered and assessedusing SWOT analysis and surface water treatment was chosen as the most suitable option utilizing the nearby Lopinot River as the raw water source.The flowrate of the Lopinot River was estimated to be 0.083 m3/s. and snapshot analysis of thewater quality indicated that the pH was neutral (7.62), Total Dissolved Solids was 2.60x10-1 mg/l, conductivity was 253 uS/cm, turbidity was 4 NTU, an absent coliform count; values within the accepted range outlined by the World Health Organization.These parameters were utilized in the Superpro Simulation software used forthe water treatment plant design. Equipment sizing, economic and consumer health and environmental safety considerations were factored into the design of the proposed water processing plant.The proposed design has the capacity to produce approximately 2,555,000 m3on an annual basis, in excess of the amount for the Trestrail Lands development by 84%. Despite the economic indicators of Net Present Value (NPV), Internal Rate of Return (IRR) and payback time being unfavourable, the water distribution company in TT is a non-profit organization with highly subsided tariffs. It is expected that the economics would be significantly improved if the excess treated water is sold on the national distribution grid.