Recycle and reuse of wastewater in industrial systems

Water recycling means using of treated wastewater for useful purposes such as irrigation, agriculture and industrial processes, and in some cases urban drinking water. The need to use unconventional water resources is an issue that has emerged today as an inevitable necessity, especially in Iran. In general, treated municipal, agricultural and industrial effluents are widely used, which can replace groundwater and to a large extent effective in conserving various water resources. In some cases, drinking water can be produced by recycling and treating the effluent. As a result, water required for agriculture, irrigation of urban space and artificial nutrition of groundwater aquifers can be provided by water recycling and reuse of wastewater to reduce the use of groundwater and surface water resources to conserve water resources. And deal with the water crisis. Physical, chemical and biological methods have been studied for gray water treatment so far. Due to the properties of gray water, using one method alone is not sufficient to comply with existing environmental standards. In order to achieve the highest efficiency, a physical treatment step is generally used as pre-treatment.

pre-treatment stage, most of the available sediments, suspended solids are separated from the effluent by means of a filter or membrane. After pre-treatment step, the treatment process is completed using the complementary steps. Sequencing Batch Reactor, membrane bioreactors, and rotating biological contactor are among the most important biological methods todays are used for wastewater treatment. The use of wastewater treatment is widespread and are used in almost all industries. In summary, these applications include the following:
• Wastewater treatment and water return to the manufacturing cycle of the steel plant
• Treatment and restoration of wastewater of car washes and carpet cleaning services that contain foam and detergent.
• Wastewater treatment of dairy that is produced by the CIP process or washing tanks and pipes for producing milk, yogurt, butter and cheese that contains fatty substances.
• Wastewater treatment of starch, glucose and gluten factories, which contain large amounts of carbohydrates and are produced by various fermentation and concentration processes.
• Wastewater treatment of dyeing and textile industries with organic materials, dyes and suspended solids and hard biodegradable compounds.
• Wastewater treatment of carton and paper mills and return of consumed water to the beginning of the production line by removing organic compounds
• Treatment of effluents from food industries such as sausages, which are high in protein and fat
• Wastewater treatment of detergent factories containing hard biodegradable compounds and toxic substances
• Wastewater treatment of tanning units and removal of sulfides, solid particles and etc.
The treated effluent can be returned to the manufacturing cycle or used in irrigation and agriculture, disposal to surface water or absorption wells. In addition, if an industrial and production unit has been constructed in the industrial park, the wastewater can be treated and connected to sewage collection.