زهرا ضمیرایی

Industries play an important role in the development of societies. The generation of large volumes of industrial waste with complex characteristics makes their management a challenge. In addition to occupying the land, the accumulation of these wastes causes environmental pollution. The main purpose of this study is to identify industrial wastes in the industrial zone of Gilan province and to investigate their management system. In this study, 11 industrial zones in Gilan province were investigated in 15 industrial groups. Astara industrial zone has the lowest number of units with six active units, and the largest number of active units under investigation is Sepidroud industrial zone (41 units) and then Rasht industrial zone (37 units). The food industry group with 50 active units (24%) has contributed the most in investigating the type and amount of industrial waste in Gilan province. Based on the data of the study, the total amount of industrial waste is 45926 tons per year. In addition, the main special genaration wastes are 60314 liters of used oils and 16707 tons of different types of wastes per year. The metal industrial group generated the largest amount of industrial waste with the genaration of 32917 tons per year. Also, the cellulose and synthetic oil industrial group units have the highest amount of hazardous waste genaration per year with the genaration of 29,600 liters and 6,300 tons, respectively. Based on the data obtained from the industrial units, the total sales and recycling methods accounted for 54.1% and disposal for 45.9% of cases. Obtaining information on industrial waste flow in Gilan province provides the opportunity to recover and save identified resources. In addition, many economic and environmental benefits are obtained by making a decision and implementing proper waste management.

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.

Natural gas and crude distillates such as naphtha from petroleum refining are used as feedstocks to manufacture a wide range of petrochemicals that are in turn used in the manufacture of consumer goods. Petrochemical plants are typically large and complex, and the combination and sequence of products manufactured are often unique to the plant. Petrochemical plants generate significant amounts of solid wastes and sludges, some of which are hazardous because of the presence of toxic organics and heavy metals. A good practice target for a petrochemical complex is to reduce total organic emissions (including VOCs) from the process units to 0.6% of the throughput. In this paper a variety of control of air emissions techniques is has been studied. Petrochemical waste waters often require a combination of treatment methods to remove oil and other contaminants before discharge. For solid and hazardous wastes, combustion (preceded in some cases by solvent extraction) of toxic organics is considered an effective treatment technology for petrochemical organic wastes. Steam stripping and oxidation are also used for treating organic waste streams. The generation of sludges should be minimized. Wastes containing toxic metals should be stabilized before disposal.

Regarding to the variety of uses of steel in the world and widening its scope of application with the advancement of technology, steel production has changed to keep pace with advances in technology, following the changes; producers have tried to raise productivity and use of cheaper energy and fuels due to its geographical environment. There are the wastes in different stages of steelmaking (coke making, iron making and steelmaking). The generated wastes in this industry are with hazardous substances such as heavy metals, according to the classifications of the wastes, are classified as hazardous wastes. Therefore, identification and analysis and management of such waste in these industries are essential. The release of aforesaid hazardous wastes in nature can be had issues and problems for the environment and human health ultimately exceed the acceptable environmental conditions. The proper management of hazardous wastes in order to reduce and control pollution of the environment is utmost importance.

Complete anaerobic organic matter removal process (CARP), in which diluted wastewaters such as sewage and effluent from a methane fermentation digester were treated under anaerobic condition for post-treatment. The chemical oxygen demand (COD) in wastewater was decreased from 4000 ppm to less than 20 ppm. The dry ammonia-methane two-stage fermentation process (Am-Met process) is useful for the anaerobic treatment of nitrogen-rich wastes such as waste excess sludge and food waste produced without the dilution of the ammonia. The plant generating biogas by the decomposition of volatile solid (VS) at a rate of about 820 N m3 per ton of VS. The hydrogen-methane two-stage fermentation (Hy-Met process) is useful for the treatment of sugar-rich wastewaters, in which 2.67 t/d bread wastes were generated 145 m3 of hydrogen/d which corresponds to 214 kwh with 50% efficiency of the fuel cell the conversion system and 514 m3 methane/d which corresponds to 530 l of oil/d.

Azolla Filiculoides as a non-living fern was used in a batch system to remove "Basic Blue 3", which is a cationic dye and a carcinogenic agent. We used a batch system by applying certain concentrations of dye contaminant and in the presence of a certain amount of adsorbent under optimum conditions. The main groups presenting in the Azolla cell wall were evaluated by acidification and alkalization of Azolla's media and then potentiometric titration with standard basic and acidic solutions. It was observed that the removal efficiency of dye using non-living Azolla in accordance with the Langmuir isotherms was 82% for the initial dye concentration of 200 mg/lit under reaction conditions consisting of contact time 6 h, pH= 6, temperature 25 ˚C, and dose 5 g/lit. Qmax (maximum uptake capacity) by the activated Azolla at three temperatures 5, 25 and 50 ˚C was 0.732, 0.934, and 1.176 mmol/g respectively. ΔG (Gibbs free energy changes) was obtained for these temperatures as -0.457, -0.762, and -1.185 kJ/mol respectively. Removal of basic blue 3 using Azolla is an economically and effective method.

Waste rubber tire has been used for the removal of pesticides from waste water by adsorption phenomenon. By applying chemical and thermal treatment on carbon prepared from waste rubber, a carbonaceous adsorbent is prepared with favorable surface chemistry. Presence of oxygen functional groups as evidenced by FTIR spectra, along with excellent porous and surface properties were the driving force for good adsorption efficiency observed for the studied pesticides. Adsorption studies showed the maximum adsorption of 112 mg/g, 104.9 mg/g and 88.9 mg/g for methoxychlor, atrazine and methyl parathion respectively at a contact time of 60 min. at pH 2 from an initial pesticide concentration of 12 mg/L. This sorbent is inexpensive in comparison to commercial carbon and has a better efficiency than most other adsorbents reported in literatures.

The contemporary removal of organic pollutants from aqueous solution and electricity generation is studied in the present work by means of an experimental device resulting from the combination of a photocatalytic reactor and an electrochemical cell. The proposed system relies on the capability of Cu2‏+‏ ions to reduce in the presence of TiO2, (solar) UV radiations and a sacrificial organic agent. In the anodic solution of the combined photoreactor-cell, Cu0 is oxidized to Cu2‏+ and the latter is reduced again to the lowest oxidation state. The use of different sacrificial agents ranging from formic acid (FA) to glycerol (GLY) to glucose (GLU) is investigated along with the adoption of two different cathodes for the cell, the first based again on the couple Cu2‏+‏/Cu0 and the second on the couple O2/H2O. The results of the present work indicate that it is possible to combine a photocatalytic reactor and an electrochemical cell to achieve a contemporary removal of an organic pollutant from an aqueous solution and generate electricity.