The effect of ceramic filter composition on improving the quality of produced water by reducing total dissolved solids (TDS), barium, and phenol for reverse osmosis (RO) treatment was investigated in the present work. The ceramic filters were fabricated using a residue catalytic cracking (RCC) unit spent catalyst with and without activation, clay, and Dioscorea hispida starch (DHS), at various compositions.  The result showed that the optimum removal of TDS, barium, and phenol in produced water was achieved at a flow rate of sample 7 L/min and an operating time of 90 min. Ceramic filter with the composition of 60% spent catalyst without activation: 37.5% clay: 2.5% DHS reduced 34.84% TDS, 27.97% barium, and 71.11% phenol. While, the ceramic filter with a composition of 37.5% activated spent catalyst: 60% clay: 2.5% DHS was removed 51.44% TDS, 27.93% barium, and 85.29% phenol from produced water. The next steps of treatment of filtrates of the ceramic filter using reverse osmosis (RO) membrane showed that the permeate met the Indonesian standard for oil and gas wastewater. In addition, adsorption of TDS, barium, and phenol from produced water was dominated by clay composition in the ceramic filter.

A mathematical model is presented to simulate the photocatalytic degradation of terbuthylazine in a continuous stirred tank reactor. The flow field is described by the continuity equation and the momentum equation. An advection-diffusion-reaction equation is used to simulate the transport of terbuthylazine.  The chemical reactions take place on the inner wall surface coated with the catalyst, which is described by a third-kind boundary condition.  A transient differential equation is used to describe the variation of inlet concentration with time. All governing equations are solved using the commercial computational fluid software ANSYS Fluent. The simulation results agree with the experimental data at different temperatures and different flow rates. The radial distribution of terbuthylazine in the reactor is discussed in detail. The velocity depicts a parabolic curve with a maximum velocity of  0.0005 m s-1, 0.001 m s-1, 0.00022 m s-1 and 0.0032 m s-1 for 50 mL min-1, 100 mL min-1, 200 mL min-1, and 300 mL min-1, respectively. At the flow rate of 300 mL min-1, concentration of terbuthylazine decreases from 3.6 mg dm-3 to 0.8 mg dm-3 whereas concentration of cyanuric acid increases from 0.05 mg dm-3 to 0.28 mg dm-3. It shows that the radial effect of velocity and concentration should be taken into account. The mathematical model used in this study is suitable for simulating the photocatalytic degradation process of terbuthylazine in continuous stirred tank reactors.

The soil of many places of eastern India contains high amount of arsenic, due to several geogenic activities in this area. In the specific regions of the country where there is no such type of Geogenic activities, the soil is found to be almost free of arsenic. In such places where there are industries, the soil is being contaminated with the arsenic due to anthropogenic activities. One of such site which was selected for the study was in close vicinity to the textile industries in Jaipur, Rajasthan, India discharging their effluents having 423 µg/g arsenic. While the soil sample collected from the far eastern part of Tezpur Assam, India, contaminated by Geogenic sources contained 443µg/g arsenic. Four arsenite resistant bacterial strains were isolated from each of the samples. Strains SE-3 and TB-1 isolated from Jaipur and Tezpur, respectively showed highest minimum inhibitory concentration of 46.5mM and 38.7mM sodium arsenite. Based on 16S rDNA sequencing and nucleotide homology and Phylogenetics analysis strain, SE-3 was identified as Pseudomonas sp. SE-3 (accession no. KP730605) and TB-1 as Bacterium TB-1 (accession no KP866680). Complete oxidation of arsenite to less toxic form arsenate was observed in Pseudomonas sp. SE-3, while 64.6% by Bacterium TB-1. The arsenite oxidation was supported on the molecular level by confirming the presence of aox gene by PCR amplification. The enzyme activity of arsenite oxidase was also established. Arsenic hyper tolerant bacteria isolated from these soils having arsenite oxidizing ability show a promising way for the bioremediation of arsenic in contaminated soil.

This work investigates the possibility of using constructed wetland system for the management of municipal wastewaters with reuse strategies for the irrigation of landscapes in Ouled Djellal city of Biskra, Algeria. The design of this system was based on the characteristics (volume and physico-chemical properties) of wastewaters and the urban plan of the studied city. Results showed that studied effluent is easily biodegradable with COD/BOD5 of  1.84 (< 3), BOD5 (325 - 365 mg/L), COD (620-644 mg/L) and TSS (120-250mg/l). The peak of raw wastewater flow was found to be 32.4 m3 /h, which was used for the calculation of drip network for the landscape irrigation. The selected variant for the configuration of the CW system is HF-VF-HF, which occupies an area of 11.580 m2 and will reduce significantly the water pollution. The treated wastewater will be reused for the irrigation of landscapes via the dimensioned drip network. Results of this study showed that the proposed design for the system (treatment and reuse) would be effective in reducing pollution in the urban environment by ensuring possibility of the reuse of the treated water for irrigation. This gives also a great opportunity for using this strategy in small neighborhoods in other cities.

This article is devoted to the study of the impact of the development of the Lomonosov diamond deposit on the pollution of watercourses with trace metals. The high water cut of the exposed rock strata and the presence of groundwater require the constant pumping of wastewater into the filtration fields, and then to the nearby river. This work shows a significant contribution of discharge processes and drainage waters to the trace metal contents in the surface waters of the Zolotitsa river; an increase in the concentrations of Mg, Sr, Zn, Cu, Cd, As , and Se was noted. The seasonal variations of physicochemical parameters, the trace metal contents, as well as the total uranium and U isotope 234U, 238U, and 235U were analysed. Calculations of water quality indices (HMEI, HMPI, and HMTL) and public health risks (HI and CR) revealed a high level of pollution of certain sections of watercourses. Radiological studies of polluted rivers in the area showed a satisfactory situation. The results of this study can provide a basis for the subsequent monitoring of the impact of anthropogenic activities on nearby watercourses in the development of diamond deposits.

In recent times, the brick kiln contributes to air pollution is one of the most emerging issues worldwide. In this research work, the Peshawar city, ambient air quality was measured, using a fixed air monitoring station to evaluate the impact of gaseous emission from brick kilns on ground level. In this study, the portable gas analyzer (PG-250) was used to quantify brick-based emitting carbon monoxide (CO), sulfur dioxide (SO2) and nitrogen oxide (NOx) from 3 brick kilns in the city of Peshawar. It was noticed that the average concentration of SO2 and NOx exceeds the National Environmental Quality Standards (NEQS) of Pakistan specifically, in terms of air quality. The brick kilns in District Peshawar have shown negative effects on the environment. It is necessary to take various measures to monitor the brick kiln embosom regularly before it becomes a significant risk for individuals. In conclusion, the impact of air pollution on physical activity and sedentary behavior at a specific time may be different.

In this research, the capability of vermiculite in arsenic extraction, associated with characterizing its main properties was evaluated. To address this purpose, vermiculite was artificially contaminated with arsenic at 7 and 28-day intervals. Then, arsenic was extracted from contaminated soils by different extractants. Various physical and mechanical tests were performed to investigate the effect of arsenic as an anionic contaminant on the properties of the vermiculite, as well as to evaluate how the properties of the contaminated soil were altered by the extraction process. The carbonate bonding phase was probably mainly responsible for the adsorption and fixation of arsenic with more than 50% portion among measured fractions at different curing times. Based on the vermiculite condition, hydrochloric acid was the best extractant for removing arsenic in all studied samples (around 3 -18 % more than other extractants). The clay soil demonstrated few changes due to arsenic contamination and modification. In general, the most promising characteristics of vermiculite as clay liner are its stability after contamination due to high CEC and SSA; however, its workability and strength (UCS between 110 to 220 kPa at different soil conditions) is a challenge and must be improved by adding coarser fractions like silt particles. In general, the results of this study regarding the effects of arsenic contamination and extraction onto vermiculite’s physical properties can provide appropriate information for researchers and geo-environmental engineers.

The optimal performances of starches produced from two cassava varieties–Manihot aipi (SMA) and Manihot palmate (SMP) as bioflocculants for the treatment of textile wastewater were investigated in this study. The central composite rotatable design was used to investigate the effects of varying dosages of each cassava starch, wastewater-pH, and settling time on the turbidity removal from the wastewater with alum as the primary coagulant. Highly significant second-order multilinear quadratic regression models were developed from the experimental data, resulting in a very high coefficient of determination (r2) values of 0.999 for the SMA and 1.000 for the SMP models. The optimum cassava doses of 50 and 150 mg/L, pH-values of 6.5 and 8.0, and settling times of 95 and 77 minutes led to predictive maximum turbidity removals of 98.35 and 88.87%% with desirability functions of 0.95 and 0.63 for the SMA and SMP, respectively. The corresponding observed turbidity removal recorded at these optimum conditions were 88.72% and 88.52% for the SMA and SMP, respectively. At these optimum conditions, there was no significant difference between the predicted and observed turbidity removed from the wastewater at a p≤0.05 significance level. Verification of the Jar tests showed a good agreement between the experimental data and the models and confirmed that the SMA was superior to the SMP in supporting the alum to remove turbidity from the textile wastewater. As a result, the study revealed that Manihot aipi starch has more flocculating capability than Manihot palmate for the treatment of textile wastewater.

Textile effluents are highly colored for synthetic dyes, cause significant water pollution due to high pH, TDS, EC, BOD, and COD content, and are harmful to aquatic species. Among different treatment processes, biological treatment process is considered as a promising approach. In this investigation, a mixed aerobic bacterial consortium was used for the treatment of wastewater. In addition, the fenton process with a normal sand filter was used for treatment and compared with the biological method. The mean values of BOD, COD, TDS, EC, DO, and pH in the raw wastewater indicated that the effluent was highly contaminated according to Bangladesh standard (ECR, 1997). Both the biological treatment process and fenton process separately showed promising removal of pollution load. The aerobic mixed bacterial consortium reduced TDS (66.67%), EC (60%), BOD (91.67%), and COD (85.45%) and fenton process reduced TDS (74.71%), EC (55.11%), BOD (88.33%), and COD (83.63%) compared to the raw effluent bacterial consortium simultaneously degraded dyes and decolorized the wastewater from dark deep green to transparent. Color removal for the mixed aerobic bacterial process after 72 hours of aeration was 58.57% and for the fenton process with a normal sand filter was 80%. BOD and COD removal percentages for aerobic mixed bacterial consortium showed higher removal efficiency than the fenton process with a normal sand filter. Though 92 hours of aeration showed the maximum satisfactory result, aeration time could be reduced to 72 hours which also satisfied the Bangladeshi standard (ECR, 1997).

High levels of dioxins and dioxin-like compounds in the food and their adverse effects on human health are of increasing concern. Since milk is one of the most essential human nutritional resources, the present study aims at determining dioxins and PCBs in raw milk samples from four farms in North of Iran and raw and pasteurized samples from three farms and five dairy factories in Vicinity of Tehran (capital of Iran). Total toxic equivalence (TEQ) of dioxin and PCBs have been determined, using the DR-CALUX® bioassay. Results reveal that all samples are contaminated with dioxins and PCBs, comparatively. The total dioxins and PCBs levels in raw milk samples from the north range from 4.08 to 0.97 pg/gfat and for the raw samples and pasteurized samples from Tehran Province from 1.89 to 0.63 pg/gfat and 0.1 to 0.03 pg/gfat, respectively. The mean concentration of dioxins/PCBs is higher in samples from the north of Iran. This may be because of the common method of removing domestic and agricultural disposal in this area.