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Soil moisture estimation is critical for environmental and agricultural sustainability, with its spatial and temporal variation playing a key role in drought monitoring and understanding climate change. The region of Prince Edward Island (PEI), Atlantic Canada's largest potato producer, is facing irregular precipitation patterns that stress crop water supplies. This study aims to estimate field-scale soil moisture utilizing satellite-based reflective and thermal infrared bands from Landsat-8 Operational Land Imager (OLI)/Thermal Infrared Sensor (TIRS) and Moderate-resolution Imaging Spectroradiometer (MODIS) over the cloud-based Google Earth Engine (GEE) platform. The GEE data catalog's pre-processed data endured to calculate various indicators for the agricultural seasons of 2021 and 2022 across three designated plots: A, B, and C. The indicators are land surface temperature (LST), normalized difference vegetation index (NDVI), normalized difference water index (NDWI), and normalized difference moisture index (NDMI). NDVI and LST were used to calculate the soil moisture index (SMI), representing the real-time soil moisture at the field scale. The soil moisture data was validated using in situ measurements. The analysis showed good Root Mean Square Error values of 1.43 % (Plot A), 2.12 % (Plot B), and 2.60 % (Plot C). A weak negative association between LST and NDVI was noticed in the study, with R² values of 0.25, 0.38 and 0.26 for Plots A, B and C, respectively. As the LST rises, vegetation declines due to the elevated temperatures in the study area. Second, a significant (p < 0.05) negative correlation (R2 =1) existed between SMI and LST in both the 2021 and 2022 seasons, showing a decrease in the top layer soil moisture with LST. The NDWI exhibited a significant inverse correlation with soil moisture, while NDMI and NDVI are effective predictors. Hence, based on the current study, optical and thermal remote sensing offers valuable insights into soil moisture dynamics and can be a good tool for irrigation control and water conservation.

With the influx of agricultural, industrial and hospital pollutants into surface and groundwater, human health and other living organisms are facing a serious threat. Zarjoub River is one of the most polluted rivers in the country, which passes through the center of Rasht and all kinds of dangerous pollutants such as nitrate, phosphate and dangerous heavy metals flow into it. Artificial wetlands are one of the low-cost and environmentally friendly wastewater treatment methods that have received a lot of attention today. In this study, the use of artificial wetlands in sequential using three different plant species of phragmites, lemna and vetiver with two different arrangements to remove nitrate in autumn of 2019 and summer of 2020 has been investigated. The results showed that the average percentage of nitrate reduction by two plant treatments was 73% and 68%, and for the control treatment it was 35%, which indicates the effect of plants in wetlands. Also, the result showed that the amount of nitrate reduction from the effluent was directly related to temperature changes and growth status of plants. The results showed that the use of hybrid wetlands can have a good removal efficiency for pollutants compared to their individual use, but the difference in plant arrangement in wetlands, although statistically significant at a probability level of 1%, had little effect on the nitrate removal process on effluent.

Urban treated wastewater or urban effluents as one unconventional water resource can be a continuous and controllable source for various uses. Simultaneously, the effluent from the wastewater treatment plant can carry chemical and biochemical contaminants and consequently expose the affected area to hazards and risks. The concept of risk analysis has helped researchers and project managers to assess the risks of treated wastewater applications in various uses to take appropriate action to reduce or manage irreversible effects on the environment and human health in advance. In this study, risk structures are created for use of treated wastewater in agriculture, landscape irrigation, artificial recharge for aquifer balance, and industry by considering environmental, social, economic, and technical criteria. Further, the effluent quality of 27 treatment plants has been evaluated. To calculate the risks, different hazards of treated wastewater applications are listed and hierarchically affect main and overall risk criteria to calculate the risks. The average overall risks of treated wastewater use in agriculture, landscape irrigation, artificial recharge, and industry are evaluated to be 29.7, 24.0, 24.3, and 26.0 percent, respectively. It is also worth mentioning that although the environmental risk of using treated wastewater in most treatment plants is low, but its social risk is high, which can be attributed to a lack of confidence in the quality of wastewater and low awareness of communities.

Many ornamental plants have the ability to extract toxic metals from the soil and are able to store large amounts of metals in their organs with no health problems for humans as they do not enter the human food chain. This study aimed to investigate the effect of sewage sludge application on the performance of Helianthus annuus and to investigate its phytoremediation ability for heavy metals (Pb, Ni and Cd) in soil. This study was carried out with three levels of sewage sludge related to southern Tehran wastewater treatment plant, including 0, 10 and 20 percent by weight of soil in three replications in a completely randomized block design on Helianthus annuus. The results showed that the application of sewage sludge caused a significant increase in the concentration of heavy metals and wet and dry yield of different parts of the flower in the plant. Application of sewage sludge at 20 percent by weight of soil was more suitable for growth index and accumulation of heavy metals in plant in terms of growth index such as wet weight (root 12.03 g and shoot 48.56 g), dry weight (root 1.97 g and shoot 8.69 g), stem diameter (0.78 cm), stem height (19.4 cm) and flower diameter (7.44 cm) as well as concentration of heavy metals Pb (root and shoot 9.09 and 4.35 mg/kg respectively), Ni (root and shoot 3.65 and 2.04 mg/kg respectively) and Cd (root and shoot 0.598 and 0.364 mg/kg respectively). Due to root bioaccumulation factor above 1 and transfer factor less than 1, Helianthus annuus is a plant suitable for the uptake and transfer of heavy metals, which prevents the entry of heavy metals into the shoot parts by a plant stabilization mechanism.

Excessive use of nitrate fertilizers in agriculture causes harm to humans and the environment. The most suitable nitrate removal process is heterotrophic biological denitrification. The purpose of the present study was to evaluate the performance of three shapes of denitrification bioreactors: triangular, rectangular and semicircular. The main element that was used to remove nitrate was beech woodchips. The concentration of inlet nitrate was 75 mg/l and the salinity of the solution was 1 ds/m and 5 ds/m, for a period of six months. The results showed that the efficiency of the triangular bioreactor with a salinity level of 1 ds/m was 90%, which is more efficient than the rectangular and semicircular bioreactors with performances of 55.8% and 53.8%, respectively. The results also indicated that at a salinity level of 5 ds/m, the semicircular bioreactor with a performance of 50.8% inlet nitrate removal was the best of the three shapes of bioreactors tested, the efficiencies of the triangular and rectangular bioreactors were 49.9% and 48.6% respectively. Also, it was observed that at the salinity level of 1 ds/m, a high hydraulic retention time had a high positive effect on denitrification, on the other hand at the salinity level of 5 ds/m, there was better performance of denitrification if the hydraulic retention time was lower.

Today, due to legal restrictions on the methods burying sewage sludge, environmentalists recommend using it as a fertilizer as a fertilizer in agriculture to get rid of the problems caused by sludge produced in treatment plants. Sewage sludge can be the best and cheapest organic fertilizer for agricultural lands due to its high content of organic compounds and nutrients required by the plant. But at the same time toxic factors such as heavy metals in sludge are the most important limiting factor for its use. The purpose of this study was to investigate the effect of sewage sludge application on some soil chemical properties and heavy soil metals. This study was carried out in the Aburaihan Campus Research Greenhouse of Tehran University with three levels of sewage sludge for anaerobic and dehydrated anaerobic wastewater treatment plant south of Tehran containing 0, 10 and 20 g/kg soil, in three replications in a completely randomized block design on Helianthus annuus. After finishing the growing season, the Soil of control and treated pots were sampled. After physical and chemical tests on soil samples, it was observed that application of sewage sludge in soil significantly increased Organic Matter (O.M), Cation Exchange Capacity (CEC), Salinity (EC), total nitrogen, potassium and Heavy metals Pb, Ni, Cd concentrations, and There was a significant decrease in pH in the treated soils compared to the control treatment. Also, treatment of 20 g of sewage sludge per kg soil had the best effect on soil chemical properties.

Groundwater nitrate pollution is nowadays one of the most important environmental issues with significant effect on human and environment health. Due to the importance of this vital water source, methods have been developed for purifying the groundwater contaminated with nitrate. One of the effective and long-lasting purification methods for groundwater contaminated with agricultural drains is the in-situ method of denitrification wall. The general concept of this technology is placing a denitrification wall with carbon material across the nitrate-contaminated groundwater pathway so that it can block the nitrate pollution as nitrate masses pass through the wall due to the groundwater natural hydraulic gradient. Despite widespread acceptance, there are still many unresolved issues regarding the long-term performance of denitrification walls which requires more understanding on the behavior, principles of design and construction methods of such walls. Accordingly the aim of this study was to fully investigate the technology and implementation of denitrification walls in all aspects. The method of this study was library type and the content, explored in simple expressions in different sections, is based on a descriptive-analytical approach to experimental and scientific experiences of this method on contaminated sites. Results showed that denitrification wall can be drilled underground either in form of funnel and gate or continuous configuration and the choice depends on the hydrological characteristics of the site and the cost of materials used in the wall. Also, when water flow contaminated with nitrate passes through the denitrification wall, nitrate pollution is treated with either adsorption or biological removal mechanisms or a combination of them. The right application of the denitrification wall can be economically efficient and the success of the system depends on the use of appropriate tools and solutions for accurate formulation of the problem in the real aquifer environment with its large dimensions and complexity. In this regard, numerical modeling and laboratory studies can help to achieve a detailed understanding of the problem in a real environment.

One of the most important problems in drainage systems is the leaching of nitrate and its entry into surface water resources. Increased concentration of nitrate in water resources causes health problems to human and animals. The denitrification process, as one of the suitable solutions for nitrate removal from contaminated water, faces restrictions in agricultural soils due to lack of the carbon materials. Providing carbon in the soil promotes the process and removes more nitrate from the environment. The use of organic materials as cheap and affordable carbon is one of the best options for this purpose. In fact, biofuel reactor are a simple and relatively inexpensive technology in which carbon sources are used to facilitate denitrification. The intensity of denitrification in biological reactors depends on the type of carbon source, temperature, water soluble oxygen, hydraulic residence time and hydraulic parameters. Studies have shown that biological reactors are capable of removing up to 99 percent of nitrates in agricultural drainage. In recent years, numerous studies have been accomplished on the use of biological reactors and their ability and how they are applied to remove nitrates. In this paper, biological bioreactors of denitrification have been investigated as a method for removing nitrate from agricultural drainage.

This study was carried out to evaluate the effects of different irrigation levels on some morpho-physiological properties of pine (Pinus eldarica Medw.) in Tehran green areas in 2015 and 2016. For this purpose, water requirements of pine in the studied area was estimated using the method recommended by FAO for drip irrigation system and WUCOILSIII method, then the effects of four levels of irrigation (50, 75, 100 and 125% water requirements) on some growth properties of pine species during the growth season were investigated in a split plot experiment in time based on randomized complete block design. The results showed that the amount of rainfall in April (in the first year) and also in April and May (in the second year) were more than the estimated amount of pine water need. The highest amounts of water requirement in both years were estimated in June (204.6 and 246.45 liters per month), wherase the lowest ones in the first and second years (139.5 and 117 liters per month) were determined in May and October, respectively. The treatment of 50% water requirement significantly decreased the branch length, branch diameter, height, tree crown diameter and pine crowns and increased the percentage of leaf and branch dry matters and proline in comparison with the control treatment. Leaf abundance per tree and leaf succulence were not affected by irrigation treatment. In general, the results of this study showed that meanwhile maintaining the important indics of green erea, water consumption for Tehran pine trees in the studied area could be reduced to 50% of the water requirement in the first months of growing season and to 75% of that in the others months of year.