AUTHIGENIC MINERALS OF VOLCANOGENIC-SEDIMENTARY ROCKS OF THE PALEOZOIC–CENOZOIC AGE OF THE SOUTHERN PRIMORYE

Authigenic minerals in volcanogenic-sedimentary and sedimentary rocks of Southern Primorye from Permian to Miocene time have been studied. Corrensite, rectorite, highly ordered mixed-layer differences of the chlorite-smectite (corrensite-like) and mica-smectite (rectorite-like) types, mica, vermiculite-like differences (?), chlorite, defective chlorite, kaolinite, smectite, calcite, and zeolites were found. Such a set of minerals indicates that the sedimentary layer in the studied sedimentary basins could be three to five kilometer thick, and the temperature of their formation is more than 150°C. The formation of the Lower Cretaceous and Paleocene sedimentary strata has similar features, and probably proceeded first in a shallow sea basin setting of the continental margin (rift stage), sometimes under conditions close to evaporitic (presence of corrensite?), with a frequent change of the facial situation from shallow to deep sedimentation, episodic supplies of volcanic material, and gradual deepening of sedimentation basins. It can be assumed that in Early Cretaceous and Paleogene times, a series of discrete sedimentation basins along the northeastern Asia continental margin developed in a single mineralogical, tectonic, and sedimentological regime of crustal extension: minerals accumulated in the sediments, which in the process of epigenesis transformed in the following directions: a) smectite-rectorite-mica; and b) smectite (palygorskite, sepiolite?) - corrensite-chlorite. In the studied sedimentary complexes three mineralogical «layers» are distinguished: 1) chlorite-mica – mica-chlorite (Permian - Cretaceous); 2) transitional from chlorite and mica to smectite - developed are corrensite, rectorite and highly ordered mixed-layer corrensite-like and rectorite-like minerals (Cretaceous - Paleocene-Eocene), and 3) smectite (from Oligocene to the present).

Phosphorus solubilization in stormwater ponds: rapid field assessment to identify ponds with excessive total phosphorus concentrations

Wet stormwater ponds are sedimentation basins used for phosphorus (P) removal in urban watersheds.

Evaluation of the Efficiency and Quality of the Water of the Al-Hartha Water Treatment Plant in Basra City

This study was conducted on the Al-Hartha Water Treatment Plant (HWTP), the largest water treatment plant in the city of Basra, during the period from December 2017 to March 2018. This study gives a description of the units and components of the HWTP, and aimed to evaluate the efficiency of the plant by calculating the efficiency of its sedimentation, filtration and sterilisation basins. Additionally, it aimed to examine its water quality by examining the physical and chemical characteristics of the raw water and treated water at this plant and then comparing the findings with the World Health Organisation (WHO) and Iraqi standard limitations. The results of this study showed that the efficiency of the sedimentation basins is 57%, while the efficiency of the filtration basins is 13.3%, and the sterilisation efficiency ranges from 27 to 50%. The laboratory results for the treated water quality have shown that the turbidity is equal to 12.8 NTU, electrical conductivity (EC) is equal to 7750 µs/cm, the total salt concentration of the total dissolved solids (TDS) is equal to 5200 mg/l, and the concentration of the total suspended solids (TSS) is equal to 65 mg/l of the water outside from the HWTP. All these water quality results are higher than the WHO and Iraqi standard limitations, except the pH value of 6.95, which is within the permissible limits.

Combining Chemical Flocculation and Disc Filtration with Managed Aquifer Recharge

Natural organic matter (NOM) is a growing concern for artificial recharge plants. In the future, it is predicted that warmer climates and more precipitation will cause higher NOM production in lakes and more NOM transport to lakes. This, coupled with increasing drinking water demand due to the population increase, is pushing operators of water treatment plants (WTPs) to find new ways to treat water. In this study, the possibility of reducing the organic load in infiltration basins through a compact pre-treatment technique utilizing microsieves, or disc filters, instead of bulky sedimentation basins and rapid sand filters after chemical flocculation to separate flocs, was investigated. The experiments were conducted using a laboratory-scale flocculator, bench-scale disc filters (10 µm and 40 µm), FeCl3, an anionic synthetic polymer, and water from Lake Vomb, a lake in southern Sweden. Raw water was flocculated using FeCl3 and the polymer, and the filtrated samples were analyzed by measuring UV–VIS absorbance, total organic carbon (TOC), and permeate volume. The results when using 10-µm and 40-µm disc filters demonstrate that it is possible to reduce NOM (by approximately 50%) and separate flocs from raw water. The experiments also highlight the importance of sufficient flocculation times and the use of appropriate polymer dosage to achieve higher permeate volumes and avoid residual polymers in the effluent. In this paper, the possibility of using this technique as a standalone treatment step or as a pre-treatment step in order to manage the aquifer recharge is demonstrated.

Characterizing and modelling the trapping efficiency of sedimentation basins downstream of harvested peat bog

Peat moss harvesting is an important industry in Canada. To harvest peat, the water table of the peatland must be lowered to allow the surficial peat layer to dry and be harvested. Drainage water can contain suspended sediments, so at most harvesting sites, the water is routed through sedimentation basins. This work focuses on characterizing and modelling their trapping efficiency. Eight basins with different volume/watershed area ratios (705 to 4170 m3/km2) were studied in three Quebec regions. Suspended sediment concentration and discharge were monitored up- and downstream of each basin during the ice-free season. Basins with high ratios of volume/drainage area, multiple basin configurations (i.e., two basins in series or in parallel), and those equipped with a flow regulation structure were more efficient than regular basins. Moreover, the nature of sediments (size, decomposition level, and organic content) influences loads, but not the trapping efficiency. Finally, two empirical models developed to predict trapping efficiency of municipal sedimentation basins were tested and adapted for basins that capture peat sediments.