Photodegradation is the chemical conversion of large, toxic, and complex molecules into non-toxic, simpler, and lower molecular weight species due to light exposure. Heterogeneous photocatalysis has sufficient potential to degrade toxic organic pollutants present in wastewater. As industries discharge their effluents containing organic pollutants into natural water bodies, which penetrate into the subsurface through connected pores it is necessary to study this process in natural or tap water. Tap water (TW) is mainly obtained from underground wells having inorganic salts in a minute quantity with a conductivity of 500 μS/cm. TW contains inorganic anions, which affect the photocatalytic activity and photocatalysis process. The aim of this review is to evaluate the effect of TW on the photo-degradation of organic pollutants such as dyes, pharmaceutical products, pesticides, etc., with the support of the literature. The TW had a diverse effect on the photodegradation of organic pollutants; either it may enhance or decrease the rate of pollutants’ photodegradation.

Estimating the quantity of seepage through the foundation and body of a dam using proper health and safety monitoring is critical to the effective management of disaster risk in a reservoir downstream of the dam. In this study, a deep learning model was constructed to predict the extent of seepage through Pakistan’s Tarbela dam, the world’s second largest clay and rock dam. The dataset included hydro-climatological, geophysical, and engineering characteristics for peak-to-peak water inflows into the dam from 2014 to 2020. In addition, the data are time series, recurring neural networks (RNN), and long short-term memory (LSTM) as time series algorithms. The RNN–LSTM model has an average mean square error of 0.12, and a model performance of 0.9451, with minimal losses and high accuracy, resulting in the best-predicted dam seepage result. Damage was projected using a deep learning system that addressed the limitations of the model, the difficulties of calculating human activity schedules, and the need for a different set of input data to make good predictions.

The pore system in carbonates is complicated because of the associated biological and chemical activity. Secondary porosity, on the other hand, is the result of chemical reactions that occur during diagenetic processes. A thorough understanding of the carbonate pore system is essential to hydrocarbon prospecting. Porosity classification schemes are currently limited to accurately forecast the petrophysical parameters of different reservoirs with various origins and depositional environments. Although rock classification offers a way to describe lithofacies, it has no impact on the application of the poro-perm correlation. An outstanding example of pore complexity (both in terms of type and origin) may be found in the Central Luconia carbonate system (Malaysia), which has been altered by diagenetic processes. Using transmitted light microscopy, 32 high-resolution pictures were collected of each thin segment for quantitative examination. An FESEM picture and a petrographic study of thin sections were used to quantify the grains, matrix, cement, and macroporosity (pore types). Microporosity was determined by subtracting macroporosity from total porosity using a point-counting technique. Moldic porosity (macroporosity) was shown to be the predominant type of porosity in thin sections, whereas microporosity seems to account for 40 to 50% of the overall porosity. Carbonates from the Miocene have been shown to possess a substantial quantity of microporosity, making hydrocarbon estimate and production much more difficult. It might lead to a higher level of uncertainty in the estimation of hydrocarbon reserves if ignored. Existing porosity classifications cannot be used to better understand the poro-perm correlation because of the wide range of geological characteristics. However, by considering pore types and pore structures, which may be separated into macro- and microporosity, the classification can be enhanced. Microporosity identification and classification investigations have become a key problem in limestone reservoirs across the globe.

An integrated study based on field observation, petrography, and scanning electron microscopy (SEM) on the Early–Middle Eocene carbonate rocks has been carried out, which were deposited in the Ceno-Tethys Ocean. The study area of the Yadgaar Section lies on the eastern margin of the Upper Indus Basin, Pakistan. The Early–Middle Eocene Margalla Hill Limestone and Chorgali Formation act as reservoir rocks in other parts of the basin and are also present in the Yadgaar Section. The lack of comprehensive study in this area makes these reservoir rocks highly attractive for sedimentological evaluations and future exploration of hydrocarbons. The Early–Middle Eocene carbonate rocks are divided into nine microfacies: dolomicritic foraminiferal mudstone–wackestone microfacies (EMI); green algae dominated, mixed foraminiferal wackestone–packstone microfacies (EMII); ostracod, green algae and gypsum dominating mudstone–wackestone microfacies (EMIII); algae and mixed foraminiferal wackestone–packstone microfacies (EMIV); Nummulites dominating mudstone–wackestone microfacies (EMV); algal limestone mudstone microfacies (EMVI); Assilina bed wackestone–packstone microfacies (EMVII); micritized larger benthic foraminiferal wackestone–packstone microfacies (EMVIII); and algal limestone, mudstone microfacies (EMIX). The transgressive-regressive environment in the Ceno-Tethys Ocean leads to the deposition of these microfacies in the platform interior, open marine platform, platform edge, platform margin reef, toe of the slope apron, arid–humid platform interior, platform edge, open marine platform interior, and restricted marine platform interior, respectively. Initial post-depositional diagenetic stages are identified from the base to the top of the strata by their respective cement types, i.e., the base–lower middle part of the strata demonstrates an eogenetic sub-stage with the appearance of drusy cement, the middle section indicates a mesogenetic sub-stage by the appearance of blocky cement, while the top portion again reveals an eogenetic sub-stage of diagenesis by the presence of drusy and blocky types of cement. The ascending–descending hierarchy of cement generations is directly proportional to the grade of diagenesis from the base to the top of the carbonate strata. Variable diagenetic effects on the various microfacies also increase the secondary porosity range and enhance the reservoir characteristics of the Formations. The presence of foraminifera microfossils determined that these carbonate formations date from the Early–Middle Eocene.

In this paper, the depositional environment, age, and tectonic context of the Sub-Himalayan Kuldana Formation are discussed in detail. To determine the Kuldana Formation’s depositional environment, age, and tectonic setting, sedimentological, palaeontological, and petrographic investigations have been conducted accordingly. The Kuldana Formation lithologically consists of both siliciclastic and carbonate rocks. Petrographically, the Kuldana Formation’s sandstone is divided into litharenite and feldspathic litharenite petrofacies. The sandstone plots on the QtFL and QmFLt suggest that the sandstone of the Kuldana Formation derived from a recycled orogen provenance field that developed during the collision of the Indian and Eurasian plates in the Lesser and Higher Himalayas. The plots in the diamond diagram further demonstrate that the detritus of the Kuldana Formation was derived from low and middle-to-upper rank metamorphic rocks of the Himalayas. Throughout the deposition of sandstone, paleo-climate conditions were semi-humid to semiarid. Dolostone and limestone are the two main types of carbonate rocks found in the Kuldana Formation. According to Dunham’s Classification, the Kuldana Formation limestone is classified as mudstone, wackstone, and packstone. These petrofacies suggest that the limestone was deposited in an inner-outer ramp setting. The bioclasts include bivalves, brachiopods, crinoid, gastropods, Globigerinoides spp., Lockhartia pustulosa, miliolids, Nummulites atacicus, Nummulites discorbina, Nummulites mamillatus, Nummulites djodjokartae, Nummulites vascus, and ostracods suggesting that the age of Kuldana Formation is Middle Eocene-early Oligocene. The Kuldana Formation was deposited during the initial stages of the Himalayan Orogeny as a result of the Ceno-Tethys Ocean’s regression and transgression, as revealed by a succession of siliciclastic and non-clastic rocks.

The Upper Indus Basin, in Pakistan’s western Salt Range, is home to the Zaluch Gorge. The sedimentary rocks found in this Gorge, belonging to the Chhidru Formation, were studied in terms of sedimentology and stratigraphy, and provide new insights into the basin paleogeographic evolution from the Precambrian to the Jurassic period. Facies analysis in the Chhidru Formation deposits allowed the recognition of three lithofacies (the limestone facies—CF1, the limestone with clay interbeds facies—CF2, and the sandy limestone facies—CF3) with five microfacies types (mudstone biomicrite—MF-1, wackestone-biomicrite—MF-2, wackestone-biosparite—MF-3, pack-stone-biomicrite—MF-4, and packstone-biosparite—MF-5), as well as their depositional characteristics. The identified carbonate and siliciclastic formations display various facies in a shallow marine environment, with different lithologies, sedimentary features, and energy conditions. It is thought that the depositional characteristics of these microfacies are closer to those of the middle to outer shelf. Because of the progressively coarsening outcrop sequence, this formation seems to be at the very top of the high stand system tract (HST). A modified dynamic depositional model of the Chhidru Formation is further built using outcrop data, facies information, and stratigraphy. According to this concept, the formation was deposited in the middle to inner shelf area of the shallow marine environment, during the Late-Permian period. The Permo-Triassic Boundary (PTB), which is the end of the type-1 series, is marked by this formation’s top.