Baja California Sur (BCS) is an arid sparsely populated coastal state in northwest Mexico. Population growth, agriculture and booming tourism have lead to severe overexploitation of underground aquifers and saline intrusion. This paper reviews the current water and energy situation in BCS. The state enjoys very high levels of solar radiation, typically above 5 kWh/m2/day, and the suitability of renewable energy powered desalination for BCS is discussed, including past efforts in BCS and present challenges for this technology

Citation: BERMUDEZ-CONTRERAS, A.S. and THOMSON, M., 2010. Modified operation of a small scale energy recovery device for seawater reverse osmosis. Desalination and Water Treatment, 13, Additional Information:• AbstractThe Clark pump reciprocating pressure intensifier is a well established mechanism for highly efficient brine stream energy recovery in small scale seawater reverse osmosis (SWRO) desalination systems. This paper describes operation of a modified Clark pump in which the roles of the two pairs of chambers are reversed and the general arrangement of the complete RO system is substantially altered. In particular, the low-pressure motorised pump that feeds into the standard Clark pump is replaced by a high-pressure motorised pump that sits in parallel with it. A conceptual comparison of the original and modified arrangements is presented, followed by a discussion of the practical modifications made to a standard Clark pump in order to test the concept. The initial tests were successful and results indicating specific energies in the range 3.5 to 4.5 kWh/m 3 are presented.

Mangroves are ecosystems made up of trees or shrubs that develop in the intertidal zone and provide many vital environmental services for livelihoods in coastal areas. They are a habitat for the reproduction of several marine species. They afford protection from hurricanes, tides, sea-level rise and prevent the erosion of the coasts. Just one hectare of mangrove forest can hold up to 1,000 tons of carbon dioxide, more than tropical forests and jungles. Mexico is one of the countries with the greatest abundance of mangroves in the world, with more than 700,000 ha. Blue carbon can be a novel mechanism for promoting communication and cooperation between the investor, the government, the users, and beneficiaries of the environmental services of these ecosystems, creating public–private-social partnerships through mechanisms such as payment for environmental services, credits, or the voluntary carbon market. This chapter explores the possibilities of incorporating blue carbon in emissions markets. We explore the huge potential of Mexico’s blue carbon to sequester CO2. Then we analyse the new market instrument that allows countries to sell or transfer mitigation results internationally: The Sustainable Development Mechanism (SDM), established in the Paris Agreement. Secondly, we present the progress of the Commission for Environmental Cooperation (CEC) to standardize the methodologies to assess their stock and determine the magnitude of the blue carbon sinks. Thirdly, as an opportunity for Mexico, the collaboration with the California cap-and-trade program is analysed. We conclude that blue carbon is a very important mitigation tool to be included in the compensation schemes on regional and global levels. Additionally, mangrove protection is an excellent example of the mitigation-adaptation-sustainable development relationship, as well as fostering of governance by the inclusion of the coastal communities in decision-making and incomes.