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Summary

Within the contract Pouderoyen Water Rehabilitation Project, financed by the European Commission through the European Development Fund it was decided, prior of the commencement of the construction works, to asses the project design in order to verify, whether the alternative technical solutions proposed by the contractor, mainly for the water treatment process and water pumping, could be of real advantage for the Client and therefore accepted.

The alternative proposed for the treatment process was supposed to realise significant savings in operation and management costs but was rejected, probably because the capital investment (construction cost) was higher than the tendered one and not in line with the financing resources provided by the donor. The alternative technical proposals, related to the characteristics of the electric pumps, where accepted and have permitted substantial savings in energy costs. The LCCP model was adopted to verify, “ex post”, the economic validity of the alternative proposals.

Background

Located in the east cost of the Demerara river, not far from the Capital city Georgetown (Guyana), the Pouderoyen water system serve a population of about 25.000 persons. Raw water is pumped from two boreholes and must be treated prior of distribution, being the dissolved iron content very high. Two water treatment facilities and two booster-pumping stations are interconnected by a 34 km water main. The total handling capacity of the facility is of 6.000 m3 per day.

Project Overview

Financing Institution:	EU – European Development Fund
Project Value:	6.500.000 €
Water treatment and distribution:	6.000 m3/d
Population served:	25,000 ab.
Client	Guyana Water Authority, now (GWI)
Works duration:	24 months

Project operations started in 1999 and the construction works were completed at the beginning of 2002. The start up and the first year of maintenance were under the responsibility and guarantee of the contractor. The final handing-over procedure was completed in 2003. Raw water is pumped from two boreholes 125 meters deep. The water treatment process consists mainly in pH adjustment, aeration, filtration and chlorination. Two clear water reservoirs of 1.360 m3 capacity feed the two booster-pump stations located within the treatment plants areas.

Project Team

General co-ordination :	EC Delegation in Guyana
Project Manager:	Guyana Water Authority, now (GWI)
Contractor:	CIS ECOLOGIA - Italy
Preliminary design:	Garland Ormond - Ireland
Supervision:	Vikab – Guyana

The Project Director and the senior process engineer in charge, for CIS ECOLOGIA, in the Pouderoyen Water Rehabilitation Project ( PWRP ) have been involved in the implementation of this case study.

Project Implementation

The EUROLIFEFORM LCC model was adopted first at the Client Brief level. to evaluate the economic weights of the Capital investment and of O&M within a study period of 35 years. The same model, at the Concept Design level, was used to identify the electric power as the most relevant cost related to O&M. The Detailed design level of the LCC was tested to quantify potential energy savings, especially at the booster pump stations. The outputs of the Deterioration Model (DM), in terms of modification of the expected life of a single component or sub-system, have also been taken in consideration. The Environmental module ENV, has been revised and adapted to the reality of a water treatment facility. Scope of the case study was also to validate the outputs of the model, comparing them with the historic data and the economic results of the Pouderoyen Water Project. In consideration of the probabilistic approach of the model and in view of future applications, it was also decided to widen the company’s cost database with more construction and O&M cost data. related to water facilities, different in size and type of process. An electronic questionnaire was prepared for the purpose and distributed to various water utilities operating in Italy. The calculations of electric power savings and the identification of the characteristics and technical specifications of the electric motors have been conducted with the software Motormaster+ .

Results

The ELF LCC software tool was tested simulating various phases of the project implementation and the outputs were found reasonable and in line with the standards.

The model was tested in particular:

· To evaluate the relative weights of the major class of costs related to the project implementation. The output confirmed the costs originated by the Operation and Maintenance as much more important (three to five times) than those originated by the construction.

· To compare the economic impact of alternative technical solutions on the construction cost (Capital investment) and Expected Present Value, calculated at the end of the 35 years life of the water treatment plant. The output shows that the alternative solution, result of an accurate assessment of the terms of reference and design criteria, is more expensive in terms of construction cost but allow for a substantial saving in terms of LCC. This apply within a reasonable range of values of the financial and economic parameters (Discount rate and Inflation rate).

· The LCCP model, taking advantage of its probabilistic approach, was also used to estimate, with a known degree of confidence, the risk to overspend during the project construction.

Combining the numeric output of the ENV screener with the numeric output of the LCC model, it has been introduced a new, comprehensive, scoring factor: The Environment Value Factor EVF.