جستجوی مقالات مرتبط با کلیدواژه "wastewater treatment plant" در نشریات گروه "محیط زیست"

Considering that urban and industrial sewage are one of the main factors of pollution entering the environment; environmental effects and technical and operational risks resulting from it have always been considered in the operating phase. But its effects and risks are also important in the construction phase. Therefore, the current research was conducted with the aim of evaluating the environmental and technical risks of the wastewater treatment plant construction project in the west of Ahvaz with the hierarchical analysis process (AHP) in 2021.
Material and After the study phase, information related to the project was collected through the survey method and presence at the site of the treatment plant, and all executive processes, equipment and facilities were examined. For this purpose, the E-FMEA method and the opinions of experts were used to identify environmental and technical risks. Then, Analytic Hierarchy Process (AHP) was used for weighting and prioritizing the parameters of the used method.
In total, 19 environmental risks and 24 technical risks were identified in the processes of the West Ahvaz treatment plant construction project. Environmental and technical risks were similar in the two stages of construction of buildings and installation of tanks and facilities. In other stages, technical risk was more important than environmental. The number difference between the two technical and environmental risks in the stages of excavation, installation of foundation and skeleton of structures was 50, 25 and 66%, respectively.
Discussion and The comparison of all risks showed that technical risks were about 26% more than environmental risks. In general, the results showed that most of the environmental risks were at an acceptable level and 8 technical risks needed to be resolved as soon as possible.

Basis and Goal: 

Today, the most basic action to control pollution from wastewater and their reuse is the construction of a wastewater treatment plant and strict monitoring of their operation. Disposal of non-standard effluents and their use in agriculture or surface water discharge will lead to many health and environmental risks. Therefore, the present study was conducted with the aim of auditing the environmental performance and quality of Birjand wastewater treatment plant for agricultural use.

Method of Studing: 

This study was conducted in 1399 using a cross-sectional study method from 1396 to 1398 on the wastewater treatment plant of Birjand.

The findings showed that the COD index with an average of 225 had the highest non-compliance with the standard in 1396. TSS index with an average of 153 is in the second place, total coliform with an average of 1300 in the third place and gastrointestinal coliform with an average of 502.5 are in the fourth place. In 1398, these indicators are in a standard and optimal condition.

Comparison of the results of the current study with the effluent standards showed that the use of the effluent of this treatment plant for agricultural purposes is recommended due to compliance with the effluent standards. This trend has shown a favorable situation during the years 1396 to 1398.

pharmaceuticals, personal care products and steroid hormones are emerging pollutants whose main production source is human societies. Municipal wastewater treatment plants have a very effective role in reducing and eliminating these pollutants, however, complete elimination of these compounds is usually not possible and some of these pollutants are treated through the treated wastewater stream (As well as residual sludge) enters the environment. Due to the use of treated wastewater in irrigation of fields and orchards, there is a possibility of transferring contaminants to soil, crops and groundwater. Since the negative effect of the presence of these contaminants is visible in very low concentrations, it is necessary to identify and determine their amount.

In this study, the transfer channel of the treatment plant in the south of Tehran (raw wastewater, treated wastewater), farm soil and crops in terms of presence and amount of emerging organic pollutants, from the category of pharmaceuticals and steroid hormones Has been studied. Four samplings of treated wastewater were performed in different places. First, qualitative analysis was performed to identify and select target pollutants (for quantitative measurement). Then, the most important quality assurance and control criteria in the field and laboratory were studied so that the data generated had the highest possible level of quality. Finally, each sample for each category of pollutants separately prepared and extracted (extracted) Solid phase and solvent extraction were ultrasonically analyzed and finally analyzed by gas chromatography-mass spectrometry.

Sampling of raw wastewater, treated wastewater, soil and crop irrigated with treated wastewater and analysis of these samples was performed. Two pharmaceuticals, acetaminophen and sulfamethoxazole, and four steroid hormones, aquiline, estrone, estriol and ethinyl estradiol, were selected as the target contaminants and the most important and continuous ones. All six analytes were identified in a raw wastewater sample and in a treated wastewater sample. In another sample of treated wastewater, the three hormones aquiline, estrone and ethyl estradiol were not found. Contrary to what was thought, all analytes were found in soil samples, but only estrone was found in soil samples. In the plant sample (wheat) all analytes except ethynyl estradiol were seen.

All contaminants were observed in raw and treated wastewater (treatment plant effluent) and a very positive role of the treatment plant in reducing the concentration was observed. On the other hand, changes in the concentration of pollutants along the channel path were observed. Also, it was concluded that soil particles do not adsorb the target contaminants despite their tendency to be absorbed by plants. Therefore, the entry of contaminated water into arable soil will lead to crop contamination and infiltration into groundwater. The presence and amounts of contaminants in the treated wastewater treatment canal are highly dependent on time and place. Mixing and diluting and entering new sources of contamination in the canal path causes significant changes in the concentration and type of contaminants observed in the samples.

Wastewater treatment plants are among the main infrastructures of a city that in addition to considering the topography of the community and the type of wastewater collection network, it is necessary to construct them in a suitable place by considering appropriate criteria. Due to odors and technical and hydraulic problems, it is essential to locate wastewater treatment plants accurately, using a suitable model. The purpose of this study was to investigate the suitability of land for the construction of wastewater treatment plant in the city of Kouhdasht (Lorestan province). For this purpose, three main criteria of geology, environment and economy and eight sub-criteria (percentage of slope, lithology, soil, distance from the settlement, road, river, distance from wells and springs, and land use) were used and assessed. Multi-criteria analysis model (MCA) in combination with GIS was used to weigh the sub-criteria. The results of this study showed that in the study area, three zones or areas in the south of Kouhdasht town are suitable for the construction of municipal wastewater treatment plants. These areas correspond to low slope lands (0-7%) with rainfed agricultural use and had a maximum distance from the city of Kouhdasht and Azadbakht rural complex. Considering the forest use and irrigated agriculture in the north of the area and also the north-south slope in Kouhdasht, it can be said that the areas identified in this study for the construction of municipal wastewater treatment plant have the highest land suitability and are suitable for the purpose under consideration.

Hospital wastewater is one of the most infectious and dangerous wastewaters that may contain large amounts of pathogenic microorganisms, dangerous pollutants of various hormones. More than 80 different types of drugs have been found that are not completely eliminated in biological processes and reach the receiving water. In this study, one of the important hospitals of Tehran, in a crowded area with high volume of referrals, was investigated. The purpose of this study was to investigate the possibility of drugs, especially sedative drug compounds, in hospital treated wastewater. For this purpose, instant sampling was carried out three times from the effluent of the hospital wastewater treatment plant and the samples were conditioned using solid phase extraction (SPE) method. The extracted materials were measured by HPLC equipped with UV and FLD detectors, resulting in the identification of various sedatives (including Diazepam, Oxazepam, Lorazepam, Alprazolam Clonazepam, Chlordiazepoxide, and Bromazepam). The mean concentration of sedatives in the January sampling showed that the highest concentration observed for Lorasepam with a mean of 0.15 ng/l and the lowest one for Chlordiazepoxide with a mean of 0.02 ng/l. The highest and lowest concentrations measured in February were 0.15 and 0.02 ng/l for Lorasepam and Chlordiazepoxide respectively.

An appropriate disinfectant in water and wastewater applications must have acceptable effect on different kind of micro-organisms especially in minor concentrations which should contain ignorable toxicity on human and animals and its environmental side effects must be very low. Studies related to finding non-chlorinated disinfectants which have same effects of chlorine and not contain its adverse by-products are continued in recent years. Hydrogen peroxide solution with stabilized formulation and oligo-dynamic amounts of silver ion (trade mark: Nanosil) recently become a popular disinfectant for fruits, vegetables, surfaces, medical instruments and disinfections. This study was based on determining removal efficiency of fecal coliforms from samples taken from Qom wastewater treatment plant effluents after exposing with hydrogen peroxide-silver ion complex. Disinfectant efficiency was studied in six concentrations. Contact time for all concentrations was one hour. Sample size was 12 and sampling was daily. Results reveal that in concentration; 80mg/l, disinfectant achieves 2.1 logarithmic removals of fecal coliforms. In concentration; 480mg/l, fecal coliforms logarithmic removal was 5.3. In CT value 5800(mg/l). Min and more, the fecal coliforms effluent standard for surface water discharge and agriculture irrigation was achieved (Iranian environmental protection agency act).Use of hydrogen peroxide-silver ion complex as a water and wastewater disinfectant, has various benefits such as; dont remain hazardous by products, measurable residual amount an but because of its oxidation nature when contact the organic materials in wastewater and microbial harboring in suspended solids content of effluent, its application in wastewater effluent is more costly than other usual disinfectants.