Annual report on electricity, gas, water, and sewer utilities /

Annual report is submitted in compliance with the Public Utilities Act and specifically addresses the items cited in Section 4-304 of that Act.

Water and sanitation services and utilities privatisation in Latin America

Includes bibliography

Peak residential electricity demand and social practices: Deriving flexibility and greenhouse gas intensities from time use and locational data

Peak residential electricity demand takes place when people conduct simultaneous activities at specific times of the day. Social practices generate patterns of demand and can help understand why, where, with whom and when energy services are used at peak time. The aim of this work is to make use of recent UK time use and locational data to better understand: (i) how a set of component indices on synchronisation, variation, sharing and mobility indicate flexibility to shift demand; and (ii) the links between people’s activities and peaks in greenhouse gases’ intensities. The analysis is based on a recent UK time use dataset, providing 1 minute interval data from GPS devices and 10 minute data from diaries and questionnaires for 175 data days comprising 153 respondents. Findings show how greenhouse gases’ intensities and flexibility to shift activities vary throughout the day. Morning peaks are characterised by high levels of synchronisation, shared activities and occupancy, with low variation of activities. Evening peaks feature low synchronisation, and high spatial mobility variation of activities. From a network operator perspective, the results indicate that periods with lower flexibility may be prone to more significant local network loads due to the synchronization of electricity-demanding activities.

Maine occupational staffing patterns for wholesale and retail trade and selected transportation, communications, electric, gas, and sanitary services, second quarter 1985.

Chiefly tables.

Chemical and bioanalytical assessment of coal seam gas associated water

A comprehensive study was undertaken involving chemical (inorganic and organic) and bioanalytical (a suite of 14 in vitro bioassays) assessments of coal seam gas (coal bed methane) associated water (CSGW) in Queensland, Australia. CSGW is a by-product of the gas extraction process and is generally considered as water of poor quality. This was done to better understand what is known about the potential biological and environmental effects associated with the organic constituents of CSGW in Australia. In Queensland, large amounts of associated water must be withdrawn from coal seams to allow extraction of the gas. CSGW is disposed of via release to surface water, reinjected to groundwater or reused for irrigation of crops or pasture, supplied for power station cooling and or reinjected specifically to augment drinking water aquifers. Groundwater samples were collected from private wells tapping into the Walloon Coal Measures, the same coal aquifer exploited for coal seam gas production in the Surat Basin, Australia. The inorganic characteristics of these water samples were almost identical to the CSGW entering the nearby gas company operated Talinga-Condabri Water Treatment Facility. The water is brackish with a pH of 8 to 9, high sodium, bicarbonate and chloride concentrations but low calcium, magnesium and negligible sulphate concentrations. Only low levels of polyaromatic hydrocarbons (PAHs) were detected in the water samples, and neither phenols nor volatile organic compounds were found. Results from the bioassays showed no genotoxicity, protein damage, or activation of hormone receptors (with the exception of the estrogen receptor). However, five of the 14 bioassays gave positive responses: an arylhydrocarbon-receptor gene activation assay (AhR-CAFLUX), estrogenic endocrine activity (ERα-CALUX), oxidative stress response (AREc32), interference with cytokine production (THP1-CPA) and non-specific toxicity (Microtox). The observed effects were benchmarked against known water sources and were similar to secondary treated wastewater effluent, stormwater and surface water. As mixture toxicity modelling demonstrated, the detected PAHs explained less than 5% of the observed biological effects.

Understanding coal seam gas associated water, regulations and strategies for treatment

The coal seam gas (CSG) industry is globally of potentially great importance economically. This study exemplifies the complex relationship between land use and management, groundwater impact and associated water treatment especially in relation to Queensland where a significant increase in the amount of gas extracted over the past 6 years has occurred. In order to effectively manage the environmental impact of the CSG industry it is necessary to appropriately understand the nature of the gas deposits, methods for gas collection, the physicochemical composition of the by-product associated water and the technologies available for water remediation. Australia is mainly considered arid and semi-arid and thus there is a need to not only beneficially reuse water resources but also protect existing ground water reservoirs such as the Great Artesian Basin (GAB). This paper focussed primarily on the Surat Basin located in Queensland and northern New South Wales. The mechanism for CSG formation, relation to local geological features, extraction approach and the potential impact/benefits of associated water was discussed. An outline of the current legislative requirements on physical and chemical properties of associated water in the Surat Basin was also provided, as well as the current treatment technologies used by the major CSG companies. This review was of significance in relation to the formulation of the most appropriate and cost effective management of associated water, while simultaneously preserving existing water resources and the environment.

Strategies for the management and treatment of coal seam gas associated water

Coal seam gas (CSG) is a growing industry in Queensland and represents a potential major employer and deliverer of financial prosperity for years to come. CSG is a natural gas composed primarily of methane and is found trapped underground in coal beds. During the gas extraction process, significant volumes of associated water are also produced. This associated water could be a valuable resource, however, the associated water comprises of various salt constituents that make it problematic for beneficial use. Consequently, there is a need to implement various water treatment strategies to purify the associated water to comply with Queensland’s strict guidelines and to mitigate environmental risks. The resultant brine is also of importance as ultimately it also has to be dealt with in an economical manner. In some ways it can be considered that the CSG industry does not face a water problem, as this has inherent value to society, but rather has a “salt issue” to solve. This study analyzes the options involved in both the water treatment and salt recovery processes. A brief overview of the constituents present in Queensland CS water is made to illustrate the challenges involved and a range of treatment technologies discussed. Water treatment technologies examined include clarification (ballasted flocculation, dissolved air flotation, electrocoagulation), membrane filtration (ultrafiltration), ion exchange softening and desalination (ion exchange, reverse osmosis desalination and capacitance deionization). In terms of brine management we highlighted reinjection, brine concentration ponds, membrane techniques (membrane distillation, forward osmosis), thermal methods, electrodialysis, electrodialysis reversal, bipolar membrane electrodialysis, wind assisted intensive evaporation, membrane crystallization, eutectic freeze crystallization and vapor compression. As an entirety this investigation is designed to be an important tool in developing CS water treatment management strategies for effective management in Queensland and worldwide.

Forward osmosis as a pre-treatment for treating coal seam gas associated water: Flux and fouling behaviours

In this study, a bench scale forward osmosis (FO) process was operated using two commonly available FO membranes in different orientations in order to examine the removal of foulants in the coal seam gas (CSG) associated water, the water flux and fouling behaviours of the process were also investigated. After 48 h of fouling simulation experiment, the water flux declined by approximately 55 and 35% of its initial level in the TFC-PRO and CTA-PRO modes (support layer facing the feed), respectively, while the flux decline in the TFC-FO and CTA-FO modes (active layer facing the feed) was insignificant. The flux decline in PRO modes was caused by the compounding effects of internal concentration polarisation and membrane fouling. However, the declined flux was completely recovered to its initial level following the hydraulic cleaning using deionised water. Dissolved organic carbon (DOC), adenosine tri-phosphate (ATP) and major inorganic scalants (Ca, Mg and silica) in the CSG feed were effectively removed by using the FO process. The results of this study suggest that the FO process shows promising potential to be employed as an effective pre-treatment for membrane purification of CSG associated water.