Use of ION Exchange method for treatment of wastewater

-

 ION EXCHANGE:-

Ion exchange is a process in which ions of a particular species in solution are replaced by ions with a similar charge but of different species attached to an insoluble resin. In essence, ion exchange is a sorption process and can also be considered a reversible chemical reaction. The common appli cations of ion exchange are water softening (removal of "hardness" ions such as CA2+ and Mg2+) and nitrate removal in advanced wastewater treatment operations. These ion exchange resins are either naturally occurring inorganic zeolites or synthetically produced organic resins. The synthetic organic resins are the predominant type used today because their characteristics can be tailored to specific applications.

An organic ion exchange resin consists of an organic or inorganic network structure with attached functional groups that can exchange their mobile ions for ions of similar charge from the surrounding medium. Each resin has a distinct number of mobile ion sites that set the maximum quantity of exchanges per unit of resin. Ion exchange resins are called cationic if they exchange positive ions and anionic if they exchange negative ions. Cation exchange resins have acidic functional groups such as sulfonic, whereas anion exchange resins are often classified by the nature of the functional group as strong acid, weak acid, strong base, and weak base. The strength of the acidic or basic character depends on the degree of ion-ization of the functional groups, similar to the situation with soluble acids or bases. Accordingly, a resin with sulfonic acid groups would act as a strong cation exchange resin.

The ion exchange wastewater treatment - FAQ - Taiyuan Lanlang Technology Industrial Corp.

PROCESS:-

By definition, ions are charged atoms or molecules. When an ionic substance is dissolved in water, its molecules dissociate into cations (positively charged particles) and anions (negatively charged particles). Taking advantage of this characteristic, IX selectively replaces ionic substances based on their electrical charges. This is accomplished by passing an ionic solution through an IX resin that serves as a matrix where the ion exchange reaction is allowed to take place.

Most commonly, IX resins take the form of tiny, porous microbeads, though they are sometimes available as a sheet-like membrane. IX resins are fashioned from organic polymers, such as polystyrene, which form a network of hydrocarbons that electrostatically bind a large number of ionizable groups. As the process or waste stream flows through the IX resin, the loosely held ions on the surface of the resin are replaced by ions with a higher affinity for the resin material.

Over time, the resin becomes saturated with the contaminant ions, and it must be regenerated or recharged. This is accomplished by flushing the resin with a regenerant solution. Typically consisting of a concentrated salt, acid, or caustic solution, the regenerant reverses the IX reaction by replenishing the cations or anions on the resin surface, and releasing the contaminant ions into the waste water.

 

Comments

Post a Comment

Popular posts from this blog

SLUDGE REDUCTION POTENTIAL OF METAZOA

-
Image
 A way to reduce excess sludge production and enhance mineralization is to retain the sludge completely in a treatment plant, which can be achieved by a membrane separation process. There the sludge concentration is expected to stabilize at the level at which energy supplied is fully utilized for maintenance purpose. Another way to enhance mineralization and reduce the sludge production is to exploit the organism in the process that predate on bacteria (sludge), by promoting their growth in an extra “grazing stage”. During energy transfer from bacteria to higher trophic level organisms, energy is lost due to inefficient biomass conversion and thus the predator may make a large contribution to biomass replacement. A long sludge retention period in membrane bioreactors (MBR) is very suitable for the abundant growth of these higher organisms. This predatory population in the system can be exploited to enhance mineralization and reduce sludge production.  High metazoa density leads to high
Read more

Pseudomonas in wastewater treatment

-
Image
Pseudomonas in wastewater treatment-  Source- Céline Slekovec, Julie Plantin, and Didier Hocquet  Pseudomonas is a genus of Gram-negative, Gammaproteobacteria, belonging to the family Pseudomonadaceae and containing 191 validly described species. The members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a wide range of niches. Pseudomonas aeruginosa was isolated consistently from domestic and hospital sewage. In domestic sewage the numbers were usually less than 30,000 per 100 ml whereas counts above 500,000 per 100 ml were frequently obtained in hospital sewage. Correspondingly high counts of Escherichia coli were not found in hospital sewage and the ratio of E. coli to P. aeruginosa was usually less than 25 compared to ratios of over 500 often found in ordinary domestic sewage. During passage through sewage treatment plants the numbers of both bacteria were reduced by about 90% so that their ratio in the effluent remained the same
Read more

ANAEROBIC FERMENTATION

-
Image
  Most of the organics in the sewage sludge were transformed into useful energy by the anaerobic fermentation of microorganism. Plenty of nitrogen, phosphate, potassium could be separated from the leachate produced in this fermentation which makes the recycling of sewage sludge much easier. This method could also help stabilize and decrease the amount of sewage sludge and make it harmless.  Here is a brief account on the mechanism of this process. The sewage sludge samples are taken in conical flasks; the flasks were sealed and kept in an airtight and anaerobic condition. Then the conical flasks were kept in thermostatic water bath box, controlling the temperature at 95°C to improve the efficiency of the anaerobic fermentation of the sewage sludge. The conical flasks were taken out and put into a container with oxygen at the 2th, 7th, 10th, 14th, 17th, 21th, and 28th day after the beginning of the anaerobic fermentation, respectively. When the flasks were taken out, a little of the sew
Read more