A kind of zero-discharge treatment process for industrial wastewater of iron and steel plant
Technical field
The invention belongs to Iron And Steel Industry plumbing field, relate to the technology that a kind of Steel Plant zero discharge of industrial waste water is handled specifically.
Technical background
Steel Plant are as the town water rich and influential family, and its recirculating cooling water system can produce the sewer of the global cycle water yield about 2~5%; Simultaneously, each production plant also can produce a small amount of oily(waste)water, weak acid alkali waste water and flushing waste water.Above-mentioned several waste water compiles the back and is delivered to central water treatment plant as full factory trade effluent by the wastewater drainage pipe net and focuses on the back reuse or efflux.
The Industrial Wastewater Treatment flow process is seen Fig. 1: trade effluent enters equalizing tank, enters efficient air-floating pond, flocculation sedimentation tank and homogeneous filtering material filter tank successively by equalizing tank, finishes basic processing, enters reuse pool; A part is used for the full factory reuse water user not high to water quality requirement, and another part needs further to handle.Accomplish that the reuse of trade effluent need carry out advanced treatment to it, the water of reuse pool is further handled through activated charcoal filter, security personnel's filter depth, and isolated product water enters industrial pond, offers the full service water user of factory; Can produce the strong brine of salt content height, heavy metal ion enrichment in the advanced treatment process.Current do not have effective treatment process as yet to such waste water, substantially all is direct discharging, and receiving water body is caused very big pollution.
Summary of the invention
The state of the art at current domestic and international Steel Plant Industrial Wastewater Treatment, a kind of zero-discharge treatment process for industrial wastewater of iron and steel plant is provided, the present invention saves investment, be convenient to realize, treatment effect obviously, be particularly useful for the Industrial Wastewater Treatment flow process of domestic iron and steel enterprises, realize zero discharge of industrial waste water truly.
Along with China greatly develops recycling economy, realize the continuous propelling of the industry policy of Sustainable development, require steel industry progressively to change to the saving type pattern of " low emission, low consumption and high-level efficiency " by the extensive pattern of " high pollution, high flow rate ".Wastewater Of Steel Industry is realized reuse and even zero release, has in industry progressively begun to promote, and has become the rigid index that part iron factory location local government and environmental administration are proposed.
By technology and measures such as source control, intensive treatment, strong brine decrement, evaporative crystallizations, can realize the zero discharge of industrial waste water of Steel Plant.The invention provides a kind of treatment process, this treatment process comprises:
(1), technique for treating industrial wastewater: trade effluent is carried out source control and strengthens the conventional processing measure, reduce the waste water generation, improve the reuse water utilization ratio, reduce waste water advanced treatment capacity.
(2), strong brine processing technology: to the strong brine advanced treatment.Strong brine is handled through ion exchange resin, security personnel's strainer, brackish water film or seawater membrane reverse osmosis device, the miscellaneous water user of the full factory of the water supply of generation, and strong brine enters the strong brine case, evaporative crystallization or solidification treatment.Strong brine adopts ion exchange resin treatment, removes the big Ca of film influence on system operation
2+, Si
2 +Behind the plasma, adopt seawater film or brackish water film to carry out two-pass reverse osmosis again and handle, make at utmost decrement of strong brine, strong brine is adopted solidify or the processing of low-temperature multi-effect evaporative crystallization at last, solid outward transport landfill is realized wastewater zero discharge truly.The present invention can be widely used in the Industrial Wastewater Treatment of domestic iron and steel enterprises, realizes zero discharge of industrial waste water.
Description of drawings
Fig. 1 is a technique for treating industrial wastewater;
Fig. 2 is a strong brine processing technology.
Embodiment
The invention will be further described below in conjunction with the drawings and specific embodiments, but therefore do not limit the invention among the following concrete mode.
At first trade effluent is carried out the conventional processing of technique for treating industrial wastewater 1 flow process: trade effluent enters equalizing tank, enters efficient air-floating pond, flocculation sedimentation tank and homogeneous filtering material filter tank successively by equalizing tank, finishes basic processing, enters reuse pool; A part is used for the full factory reuse water user not high to water quality requirement, and another part needs further to handle.Accomplish that the reuse of trade effluent need carry out advanced treatment to it, the water of reuse pool is further handled through activated charcoal filter, security personnel's filter depth, and isolated product water enters industrial pond, offers the full service water user of factory; Produce the strong brine of salt content height, heavy metal ion enrichment in the advanced treatment process.
Then strong brine is carried out the advanced treatment of strong brine processing technology 2 flow processs: strong brine is handled through ion exchange resin, security personnel's strainer and seawater membrane reverse osmosis device, the miscellaneous water user of the full factory of water supply who produces, strong brine enters the strong brine case, evaporative crystallization or solidification treatment.
Specific embodiment is as follows:
1,000 ten thousand tons of Steel Plant that reach advanced world standards of certain planning build along the seaside since near state key mariculture base and tourist resort are arranged, requirement can realize the Wastewater Of Steel Industry zero release.
Main design parameters:
The new water consumption of ton steel: 3.9 tons of water/ton steel
New water system water scale: 16.0 ten thousand tons/day
Full factory amount of industrial wastewater: 2.5 ten thousand tons/day
Advanced treatment of industrial waste water amount: 1.0 ten thousand tons/day
By full factory water balance analysis software, each included productive unit of these Steel Plant is carried out ton product and the analysis of ton steel water loss, determine that the international advanced ton steel of 3.9 tons of water/ton steel consumes new water index.According to raw water quality preferably characteristics the average cycles of concentration of full factory circulating water system is promoted to 3, improve water circulation rate, thereby significantly reduce a ton steel wastewater discharge, amount of industrial wastewater only is 2.5 ten thousand tons/day.
Whole Steel Plant are regarded as a big circulating water completely, adopt manifold type salt equilibrium analysis pattern to carry out the water quality equilibrium analysis of full factory, calculating enters system, takes the salt of system out of and draws the salt that adds up in the system, thereby the scale of determining the advanced treatment of industrial waste water desalination system is 1.0 ten thousand tons/day.
The strong brine TDS concentration that advanced treatment of industrial waste water produces about 3500mg/L, through the product water TDS concentration of reverse osmosis desalination about 150mg/L, can be directly as the make up water of factory's industrial circulating water entirely; Reverse osmosis concentrated salt solution TDS concentration is about 13500mg/L.
Above-mentioned reverse osmosis concentrated salt solution is passed through sodium ion exchange resin, with Ca
2+Concentration is reduced within the tolerance band to reduce the fouling risk of reverse osmosis membrane.Because the strong brine saltiness is higher, so, further strong brine is concentrated to ion-exchange effluent adopting seawater membrane reverse osmosis device.Reverse osmosis unit produces water TDS concentration at 600~700mg/L, directly the full miscellaneous water user's of factory of conduct make up water; Reverse osmosis concentrated salt solution TDS concentration is about 22000mg/L, and total amount is about 1800 tons/day.This small portion strong brine employing together is cured processing brickmaking or low-temperature multi-effect evaporative crystallization with mud.
The present invention saves investment, be convenient to realize, treatment effect obviously, be used for the Industrial Wastewater Treatment flow process of iron and steel enterprise, realized zero discharge of industrial waste water truly.