Public-Private Partnerships in the Water Sector

Abstract

Types of partnerships between public and private companies in water and sewage services are evaluated on the basis of the economic efficiency of the scheme for each partner. Modeling of public-private partnerships involves the formulation of a contract prototype, which determines the roles, functions, and responsibilities as well as the allocation of costs and revenues for each partner. Alternative water management scenarios are used to identify the investments required for meeting the projected demand for water and sewage services. Investment and operational costs as well as revenues from water and sewage services are estimated according to the allocation defined in the contract prototype. The economic efficiency of the scheme is assessed through a cost benefit analysis for each partner. The evaluation of different water management scenarios indicates that, for the Cyclades Islands, Greece, there is a substantial water market where several forms of partnerships could be attractive for both the public and the private sectors. Such partnerships include, among others, lease purchase, temporary privatization, built operate transfer (BOT), and built own operate transfer (BOOT). These forms of public-private partnerships could also be successful in similar regions where significant improvements and expansion of the infrastructure is required while access to the required funds and expertise is restricted for small public water companies.     

Lung fixation by perfusion--a simple method to control the pressure in the perfusion circuit

A simple method which maintains the hydraulic pressure at a constant level during fixation of organs by perfusion is described. This is obtained by means of a glass tube interposed between a peristaltic pump and the organ to be perfused, the specially designed glass tube acting as a safety valve. The efficiency of the system is tested by electromagnetic pressure recording.     

Water supply management approaches using US on the island of Rhodes, Greece

Desalination powered by renewable energy sources (RES) is presented as an alternative option for the water supply augmentation in the semi-arid region of the island of Rhodes. The case study was chosen as the island relies mostly on the exploitation of groundwater resources and faces serious water shortage problems in an already stressed environment. Alternatives are discussed and compared in contrast to the construction of storage dams to meet urban water needs up to the year 2040. Results may indicate that through the use of financial incentives coupled with holistic water management approaches, desalination powered by RES could be an attractive and environmentally friendly option in an effort to solve problems related to water quantity and quality in semi-arid regions with adequate renewable energy potential.     

Water demand management: implementation principles and indicative case studies

Current practices for the efficient use and management of water resources are based on the conjunctive application of water supply and demand measures. Even though options for the augmentation of water supply are widely analysed and assessed, water demand management remains an open field for study, as it is highly dependent on the socio‐economic features of a region and has a site‐specific character. This paper summarizes the guiding principles of demand management and presents some successful application examples of demand management measures from regions that cover a wide range of socioeconomic and environmental conditions in an effort to identify the critical factors for the efficient planning and implementation of demand management plans.     

Multi-parameter performance analysis for decentralized cognitive radio networks

In this paper, we investigate the impact of primary user activity, secondary user activity, interface switching, channel fading and finite-length queuing on the performance of decentralized cognitive radio networks. The individual processes of these service-disruptive effects are modeled as Markov chains based on cross-layer information locally available at the network nodes. A queuing analysis is conducted and various performance measures are derived regarding the packet loss, throughput, spectral efficiency, and packet delay distribution. Numerical results demonstrate the impact of various system parameters on the system performance, providing insights for cross-layer design and autonomous decision making in decentralized cognitive radio networks.     

Simulation of airlift pumps for deep water wells

A mathematical model for the simulation of water airlift pumps is developed, based on the “interspersed continua” approximation for two-phase flow systems, together with an algorithm that selects the appropriate friction correlation for specific flow regimes. The model presented can either predict the water or air flow rate for a given airlift system. Predictions obtained by the model were compared with a series of experiments performed by the Greek Institute of Geological and Mineral Exploration and were found to be in good agreement. The present predictions are far superior to those obtained by an existing simple model currently in general use.     

Water water everywhere… : Desalination powered by renewable energy sources

The reliable and safe provision of fresh water is turning out to be one of the major constraints, which many parts of the world are currently facing. The historical approach of developing new water sources to meet the rapidly increasing demand has reached its limits because inexpensive resources have already been developed and new ones are more expensive.     

Evaluation of the Microbial Safety of Child Food of Animal Origin in Greece

Foodborne illness is a major cause of morbidity and mortality especially for children, even in the developed world. The aim of this study was to assess the microbial safety of food of animal origin intended for consumption by children in Greece. Sampling involved 8 categories of retail products and was completed with a collection of 850 samples. These were tested by PCR and/or culture for Listeria monocytogenes, Campylobacter spp., Escherichia coli O157, Salmonella spp., Cronobacter sakazakii, Brucella spp., and Mycobacterium avium subsp paratuberculosis (MAP). The number of positive results recorded collectively for the pathogens under investigation over the total number of samples tested was 3.52% and 0.12% by PCR and culture, respectively. The most frequently detected pathogen was enterohemorrhagic E. coli (1.29%) followed by Brucella (0.82%) and Listeria (0.82%). DNA belonging to MAP was detected in 0.35% of samples, which was also the percentage of positivity recorded for Campylobacter. The percentage for Salmonella was 0.12%. It can be concluded from the results that there is no indication of noncompliance for the tested food samples. However, detection of DNA belonging to pathogens that are transmissible to humans through food is indicative that constant vigilance regarding food safety is an absolute necessity.     

Solar potential for water heating explored by GIS

A method is presented for the estimation of solar energy and market potential for water heating in the residential sector. The model was developed under a Geographical Information System and provides the tools to handle the spatial and time discrepancies of solar radiation and energy demand. A geographic database with climatic data is used for estimating efficiencies and monthly/annual coverage of water heating load. Financial analysis is conducted on the basis of the energy production cost and the Net Present Value of the investment. Different financial scenarios are considered and the expected energy yields from a large-scale deployment of solar thermal systems in the residential sector of Greece are assessed.     

Solar energy and the abatement of atmospheric emissions

In spite of the fact that solar energy is a “clean” energy form, gaseous pollutants are emitted during the manufacturing of the systems necessary for its utilisation. An attempt is made in this paper to estimate the level of atmospheric pollutants emitted during the successive stages which make up the manufacture process for solar water heating (SWH) systems, and to evaluate these results in comparison with the respective pollutant emission levels attributed to the generation of electricity in Greece's conventional power plants. As energy consumption is recognised as the main source of atmospheric pollution, a Life Cycle Analysis (LCA) method was applied, focusing on the most energy-consuming stages of the SWH system production process. The conclusions of the analysis indicate that the emissions of gaseous pollutants associated with the utilisation of solar energy are considerably lower than those caused by the production of electricity in conventional systems, thereby substantiating that solar energy utilisation can make a notable contribution to the abatement of atmospheric pollution.