Planning Integrated Water Management at College of Marshall Islands: Implementation and Challenges
Abstract:In 2006 the College of the Marshall Islands (CMI) in the Republic of the Marshall Islands embarked on a 5-year redevelopment programme of the Uliga campus. An objective of the Masterplan was to achieve a water utility infrastructure on campus that was as self-sufficient from the municipal water supplies as possible. Rainwater collection, water treatment and sewage treatment and alternative energy options for the campus were to be implemented. The utilities concept was reported in a previous paper (Fullerton R. W., WEFTEC 2007). This paper reports on the implementation and success of the strategy.
During the period 2007 – 2011 three new classroom blocks, an administration block and an energy centre have been constructed. While the general programme of the Masterplan has been followed there have been a number of changes and challenges to implement the strategy.
Early in 2008 it became evident that a severe water shortage was likely in Majuro due to low rainfall and that the municipal water supply would be restricted to intermittent distribution on only 2 days per week. The College currently stored rain water was insufficient to maintain the freshwater supply so the planned installation of the RO seawater desalination plant was brought forward with a temporary installation prior to completion of the utilities centre building. A containerised 100m3/day RO plant was installed with a temporary seawater supply taken from the municipal saltwater toilet flushing reticulation. Difficulties arose from restricted seawater supply and high TDS in the feedwater.
The Masterplan concept for storage of both treated and roof water used flexible “bladder” tanks in building basements due to the difficulty of constructing leakproof below ground concrete tanks in a high saline shallow water table environment. In addition, the sealed bladder tanks also provide a secure uncontaminated water supply should the buildings become flooded by adverse weather conditions. A graphic illustration of the vulnerability of low lying Pacific islands to seawater rise due to climatic conditions occurred in December 2008 when a combination of King tides and a tropical cyclone storm surge overtopped parts of the Majuro coastline and flooded into the partially completed construction excavations. No significant damage was done but the construction programme was delayed.
As part of the overall energy sustainability strategy photovoltaic panels were installed on the completed buildings. An initial installation of 57kW of PV panels provided some 350kWh of grid-connected power daily, which offset the 300kWh power requirements for 12 hours operation of the RO desalination water plant. Ultimately all buildings will be fitted with PV panels to provide up to 250kW with excess power being exported to the local grid. A standby diesel generator has been installed to provide power during municipal grid outages and to maintain operation of the grid connected PV inverters as they require external synchronising power. Operation of the generator with locally produced coconut oil as a substitution for imported diesel will be part of an experimental energy sustainability programme conducted by the College.
Air conditioning is the highest power demand on Campus. To reduce the energy demand an innovative use of seawater cooled marine chillers was trialled to provide building air conditioning. Using the cooler seawater temperature allows the chiller to operate with greater efficiency. There is a saving of up to 20% energy compared with multiple split unit air conditioners of similar cooling capacity. Providing a seawater well in the adjacent reef, with pumping and reticulation for up to 40L/s to service up to four chillers in different buildings was a challenge. Careful consideration of galvanic and stray current corrosion was required to protect the pumps and chillers in a circulating seawater system, and even then some corrosion issues occurred.
The installation of a reticulated seawater supply around the campus to provide air conditioning chiller cooling water provided an additional bonus. The RO desalination plant seawater feed could be taken directly from the reject cooling water, obviating the requirement for a separate reef well and pumping system. The Masterplan intention was to provide separated plumbing for the toilet flushing water within each building to “future proof” the possible use of reclaimed wastewater. With a piped supply of seawater available there is the option to revert to seawater flushing in the event of extreme water shortages, allowing the College to fully utilise the output of the RO desalination plant for potable water use. Because the RO plant 100m3/d capacity exceeds the Campus demand and there is secure potable water bladder storage, the College has been designated as a community emergency water source.
In summary the CMI energy and sustainability implementation has met the broad objectives of the Masterplan. A comprehensive monitoring plant to record energy use is being implemented by the College to quantify the actual performance and to provide guidance for future initiatives.
Document Type: Research Article
Publication date: January 1, 2011
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