Recently, the deterioration of water quality in the coastal zones of Lekki Peninsula area of Lagos due to saltwater infiltration into the freshwater aquifer has become a major concern. With the aim of providing valuable information on the hydrogeologic system of the aquifers, the subsurface lithology and delineating the groundwater salinity, vertical electrical resistivity (VES) sounding survey was carried out utilizing surface Schlumberger electrode arrays, and electrode spacing varying between 1 and 150m. The DC resistivity surveys revealed significant variations in subsurface resistivity. Also, the VES resistivity curves showed a dominant trend of decreasing resistivity with depth (thus increasing salinity). In general, the presence of four distinct resistivity zones were delineated viz.: the unconsolidated dry sand (A) having resistivity values ranging between 125 and 1,028Ωm represent the first layer; the fresh water-saturated soil (zone B) having resistivity values which correspond to 32–256Ωm is the second layer; the third layer (zone C) is interpreted as the mixing (transition) zone of fresh with brackish groundwater. The resistivity of this layer ranges from 4 to 32Ωm; while layer four (zone D) is characterized with resistivities values generally below 4Ωm reflecting an aquifer possibly containing brine. The rock matrix, salinity and water saturation are the major factors controlling the resistivity of the formation. Moreover, this investigation shows that saline water intrusion into the aquifers can be accurately mapped using surface DC resistivity method.

Delineation of saltwater intrusion into the freshwater aquifer of Lekki Peninsula, Lagos, Nigeria

https://backend.orbit.dtu.dk/ws/files/128665565/Post_print_Paper.pdf

Detailed landfill leachate plume mapping using 2D and 3D electrical resistivity tomography - with correlation to ionic strength measured in screens

Cytotoxic and radioactive wastes from hospitals are of major concern in the various types of urban wastes, and in developed countries they are managed by proper regulated methods. Nuclear medicine services are in the increase in many developing countries. Therefore to implement existing regulatory policies and guidelines in terms of handling of radioactive materials used in the treatment of patients and management of wastes arising out of hospitals need a good model. The commonly used radioisotopes in hospitals are: for diagnostic investigations Technetium (Tc), Molybdenum (parent for Tc), Gallium, Thallium, I-MIBG, and I (Capsules of activity 555MBq, 3.7,7.4 GBq(15,100,200mCi)) for therapeutic applications. Positron Emission radiopharmaceuticals do not pose much problem because of their short half lives. National regulatory authorities monitor the issues relating to organized safe use of radiopharmaceuticals in medical applications and give clearance for their use in hospitals. The sequences of protocols insisted are (1) Maintain inventory of receipts and safe custody of received radioisotopes, (2) Constant surveillance in terms of their safe applications during routine use (3) Safe methods of disposal of the radioactive wastes generated from human use of these radioisotopes and chemical formulations. Permissible concentrations of the radioactive waste disposals must take into account the community safety, and the expected degree of dilution is achieved at the discharge point of the institution into the sewage system. The hazard to the general population is insignificant in case the sludge containing radioactive waste material being used as fertilizer material. Depending on the type of radioactive waste from nuclear medicine procedures indicate to simply store the wastes till radioactive decay reduces the activity to a safe level or possibly by disposal of low-activity waste into the sewage system to achieve sufficient dilution. Disposal with permission from the regulatory authority and appropriate monitoring is known as a controlled disposal. Solid wastes (Diagnostic): Syringes, sharps, gloves kept in yellow plastic containers, allowed minimum 2 months decay, monitored by GM survey instrument and released. They bear dates written on them. They go for incineration. General R. Ravichandran (&) National Oncology Center, Royal Hospital, Muscat, Oman e-mail: ravichandranrama@rediffmail.com © Springer Science+Business Media Singapore 2017 D. Sengupta and S. Agrahari (eds.), Modelling Trends in Solid and Hazardous Waste Management, DOI 10.1007/978-981-10-2410-8_1 1 department wastes are sent only after 24 h elapsed, because most of them contain 99m Tc cotton swabs etc., with half-life 6 h. Liquid wastes (Diagnostic): No laboratory work with open isotopes except for some labeling studies in the department. Diagnostic waiting patients’ toilet urine wastes go to delay tank for increase in volume for I-131 patient’s urine storage. Total about 2–4 months decay is ensured. I Therapy Isotope is received in capsule form, and directly administered to patients orally. No liquid operations are carried out these days in the departments. I-131 (therapeutic) patients’ linen, collected in an adjacent room in therapy ward, allowed to decay for varying periods 2–4 months; released to laundry after monitoring the count-rate, by an end-window type GM monitor. Half-life of I is 8.05d, and therefore about 8–10 half lives will reduce the waste activity burden. I therapeutic Solid wastes (nonactive black bags) (active yellow bags) all are monitored, and sent to ‘Decay Waste Box’ kept in the backyard of the hospital, which is innovation by the author based on long experience in the hospital. Whenever the box becomes filled up (about 2–3 months), individual bags are re-monitored to ascertain residual radioactivity. If they reach background count rates, they are released. Waste release with BIN number, informed to regulatory authority for records. A special waste storage trolley help to keep the I-131 solid wastes from wards to allow decay, before these are released to waste treatment plant of the city. Some countries follow, centralized waste collection system which are commercial firms dealing with this operation throughout city, for many busy hospitals. Our local set up has a pair of delay tanks with individual volume total volume 36 M. The urine toilet releases are collected for about 2 months, kept closed for achieving a delay time of 2 months before releasing into the sewage treatment plant (STP) of the hospital. Six releases at 2 monthly intervals take place annually. At the time of releasing the contents of the delay tank, 50 mL samples are collected, and these sample are counted to document released activity of I-131 to confirm whether they are much below recommended levels of bi-monthly release. The released activity calculated showed good statistical correlation with measured values. The safe procedures followed for radioactive waste disposal is enumerated.

Modelling Trends in Solid and Hazardous Waste Management

House societies have become popular with archaeologists in recent years, due to (among other things) their conspicuous material basis (wealth, heirlooms and the houses themselves). As yet, however, most archaeological studies have focused only on individual societies. In this article, we offer a comparative and long-term approach to the phenomenon, using as case studies the Bronze Age and Iron Age communities of the Levant, the Aegean and the central Mediterranean. We describe the elements that define them as house societies and examine their evolution through time. We follow a strictly Levi-Straussian definition of the house that prevents the concept from losing heuristic power. Using this definition, we consider that houses are to be found in ranked societies without centralization and in complex agropastoral systems, like those of the Mediterranean, where agricultural soil is scarce and liable to be monopolized. We argue that the house emerges in these competitive contexts as an institution to control land and retain patrimony undivided. Through a combination of archaeological and written sources, we try to demonstrate that it is possible to document several strategies used by house societies to acquire and retain power and wealth, including dowry, levirate, a bilateral system of marriage alliances, ancestor cults, specific architectures and house treasures. The case studies addressed here offer good comparative material for assessing similar processes elsewhere. At the same time, we argue that the Mediterranean area developed a particular ideology, that of the shepherd ruler, that was essential to legitimate the house.

House Societies in the Ancient Mediterranean (2000–500 BC)

A Review of Electrical Resistivity Tomography Applications in Underground Imaging and Object Detection

A fast smoothness constrained algorithm for the 2-D inversion of direct current and induced polarization data is presented. The procedure is fully automated and accelerated by the use of a Quasi- Newton update of the Jacobian matrix. The need for a fast algorithm is discussed and a detailed presentation of its features is given. The features of the algorithm are presented in detail and comparisons to other techniques are shown. The algorithm is also used to invert Induced Polarization (IP) data sets. Finally, tests of the algorithm with synthetic and real data are presented. The algorithm proves to be robust noise insensitive and produces good quality inversions. The tests with real data indicated that it could be a reliable tool for data interpretation.

A smoothness constrained algorithm for the fast 2-D inversion of DC resistivity and induced polarization data

We present the practical application of a 3D electrical resistivity tomography (ERT) geophysical survey conducted in order to calculate the geometrical features and general structure of a construction and demolition waste layer in an old unregulated landfill prior to redevelopment. As traditional geological/geotechnical investigations comprised of cone penetration tests (CPT) failed to provide reliable results, primarily due to the nature of the underlying waste, a geophysical investigation was commissioned and found to be very effective in providing useful and accurate information to the project’s environmental and engineering team. The ERT survey data were collected in parallel equidistant lines and were subsequently merged and inverted as a single 3D dataset. The processed data depicted clearly the interface between the resistive construction waste and the conductive undisturbed host clay layer ranging at depths between 3 and 11 m. As a result of this successful geophysical investigation the total volume of the solid waste materials was calculated to be about 32500 m3. Following the complete removal of the waste it became evident that the ERT geophysical survey results were particularly accurate. As a result, the reclamation constructor was able to carefully plan the required resources for excavating, moving and disposing of the waste. Interpreted ERT data not only defined the thickness of the debris layer and the total volume with a deviation of less than 10%, but also revealed the inner structure of the solid waste layer.

/pdf/3d-electrical-resistivity-tomography-technique-for-the-2iip7rtiu3.pdf

3D electrical resistivity tomography technique for the investigation of a construction and demolition waste landfill site

P. Tsourlos, G.N. Vargemezis, I. Fikos1 and G.N. Tsokas present four case studies of geoelectrical methods to investigate different types of landfills in Greece.

There is a growing demand for monitoring both operating and rehabilitated municipal solid waste (MSW) landfills. In this framework, geophysical investigation and particularly geoelectrical techniques are considered as a valuable tool in environmental management. The DC geoelectrical methods are probably the most popular geophysical techniques applied to landfill investigations (Meju, 2000). The conductive signature of the leachate renders geoelectrical methods ideal for the investigation of active or decommissioned landfills with respect to mapping their structure (i.e., shape, size) as well as for locating potential leakage and migration of leachate into the deeper geological layers. A large number of relevant studies can be found in literature, among others: Cartwright and McComas, 1968; Klefstad et al., 1995; Barker, 1990; Carpenter et al., 1991; Binley et al., 1997; Stanton and Schrader 2001; Karlik and Kaya, 2001; Porsani et al., 2004.

DC geoelectrical methods applied to landfill investigation: case studies from Greece

https://www.jstor.org/stable/10.2972/hesperia.81.3.0383

Geophysical Survey as an Aid to Excavation at Mitrou. A Preliminary Report

In this work we present the results of the application of the electrical resistivity tomography (ERT) technique into the mapping of the fissures that appeared in the Valtonera area (Amyntaion Munisipality, NW Greece).The results of ERT provide a satisfactory explanation to justify the expression of surface cracks in specific areas and this approach can be used to provide areas that are likely to be associated to fissures in the future.

Application of ERT to Map Earth Fissures at the Valtotnera Area (Amyntaion, NW Greece)

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