پلاستیک

Atmospheric precipitation is one of the most important sources providing water for various purposes. Their optimal use, especially snow and rain in arid and semi-arid regions, can play a significant role in meeting water needs in low water seasons, which can be collected and stored before they come into contact with the soil surface and become contaminated so that in times of water shortage, To provide the water needs of industries and factories, green spaces and drinking water for humans and animals. One of the methods of harvesting water from precipitation, including snow and rain, is to make the surface of the earth impermeable and maximize the runoff caused by them. Impermeable surfaces can exist naturally like stone surfaces or by covering the ground surface with materials such as asphalt, concrete, and insulation sheets such as plastic, geomembrane and decamond can be created artificially. In this research, 2 treatments with 3 repetitions were considered, which included the Catchment of geomembrane cover and plastic cover with sand protection, each in a square shape with an area of 4 m2, and were implemented in lands with an average slope of 36%. The total rainfall on the mentioned surfaces during the statistical collection period was 747 mm, of which 430 mm (52 events) was in the form of rain and 317 mm (26 events) was in the form of snow. The results of 26 winter snowfall events during two years of statistics showed that the runoff from normal precipitation in winter for geomembrane and plastic covering with sand protection is equal to 89 and 80% of precipitation, respectively. Therefore, according to the normal rainfall of the winter season (65.4 mm), the volume of runoff collected for the geomembrane cover and the plastic cover with sand protection will be 58.2 and 52.3 lit m-2, respectively in the winter season, if from the short-term statistics. The statistical period should be used, according to the annual rainfall (373.5 mm) and the winter season (158.5 mm), the volume of runoff collected in the winter season for the catchment surfaces covered with geomembrane and plastic cover with sand protection reaches to 141 and 127 lit m-2, respectively.

Wastewater treatment plants are known as an important source of microplastics. Though a major proportion of microplastics are removed in wastewater treatment plants, the effluent of plants contain a significant amount of microplastic particles which eventually release into the environment. Until now there is no investigation on the role of wastewater treatment plants on the release of microplastics in Tehran. This study aims to assess the discharge amount of microplastic particles from wastewater treatment plant in district 22 of Tehran. Sampling was conducted from the influent and effluent of the plant with grab method and sieving through 300, 105 and 25 µm stainless still filters.  Retained samples were treated to remove organic and inorganic materials. Then particles were detected, counted and analyzed under microscope (*10). Results indicate that treatment process has a significant impact on microplastic particles removal. After the treatment process, the average of 2.15 MP/liter were found in the effluent. Larger particles were removed effectively (at the size of ≥300 and 105-300 µm) and smaller particles (25-105 µm) indicated a higher abundance. Among the detected particles fibers had the highest abundance and then fragment were at the second order. This finding indicates that waste water treatment plants can act as a source for microplastic pollution in the urban environment.

Industrial development and rapid population growth due to the increase in consumed materials and the consequent increase in industrial waste is one of the challenges in the world. The purpose of this study is to investigate the quantity of industrial waste production in the industrial group of plastics and synthetic rubber in Guilan province and the conditions of resulting pollution. The results of this study show that the major industrial wastes identified in this group include plastic waste, paint cans, cardboard waste, paint powder, packaging strap, polymer waste, polymer sludge, wood waste, glass and carbon fiber waste. Plastic waste with 136.08 tons is the highest and paint powder with 0.04 tons is the lowest industrial waste produced in this group. The used oil with a total amount of 14092 liters per year is the only hazardous waste identified in this group. From the present study, it is concluded that the main management methods used in this industrial group are recycling and sales, but hazardous waste is not disposed of properly. The proposed method for used oil is refining.

The Global warming and climate change caused changes in rainfall patterns. Instead of snow، rainfalls are as precipitations which are not useful since usually they are lost as runoff or flood. Thus، proper recovery of precipitation especially snow and rain is very important، particularly in arid and semi-arid areas. By establishing rainwater harvesting systems with high runoff coefficients and storage of the runoff we can produce sustainable conditions to meet the water requirement of the plants and forest trees in the dryseasons. For this purpose، three treatment procedures including intact natural surfaces، areas covered with gravel، and use of plastic cover with gravel were selected and repeated thrice. The areas of each constructed experimental plot were 4m2squared shape، and their average slope was 11. 5-18%. The results obtained from 16 occasions of rainfall showed that the recovered runoff obtained from natural surfaces with gravel، intact natural surfaces and plastic cover with gravel treatments were 7، 12 and 48 % of the rainfall، respectively. The rainfall thresholds to initiate runoff flows in the treatments were obtainedto be 4. 4، 3. 5 and 2. 7 mm، respectively. The analysis of variance showed that the runoff from treatments were statistically significant at P<0. 01. The mean comparison revealed that the highest runoff was produced by plastic surfaces with gravel treatment and this system is suggested as an appropriate option to harvest rainwater as a result of this study.