Nanofiltration units (NFU) are based on the use of nanofiltration technology – a baromembrane process that consists of filtering of a liquid under pressure through a semipermeable membrane with a pore size of 1-10 nm. The technology occupies an intermediate position between ultrafiltration and reverse osmosis filtration processes, but unlike the latter, in nanofiltration, the selectivity for multi-charged ions is higher than for single-charged ones, and the transmembrane pressure is lower.
Nanofiltration membranes allow removing suspensions, colloids, bacteria and viruses, heavy metal cations, and some high-molecular organic compounds from the liquid.
The nanofiltration plant includes the following components:
- stainless steel load-bearing structure;
- disk operated mechanical filtration filter;
- low and high pressure pump unit;
- membrane block (contains the estimated number of membrane housings complete with rolled nanofiltration elements);
- hydraulic pipeline system with shut-off, control valves, control and measuring devices and automation equipment;
- chemical CIP-washing module for membrane elements;
- reagent dosing unit (if necessary);
- automated control system based on a programmable controller.
Areas of application for nanofiltration units:
- in all industries - preparation and treatment of water (pre-filtration of sea water, softening, correction of salt composition, removal of high-molecular compounds with a decrease in BOD and COD, cleaning of waste cleaning solutions, etc.);
- in the chemical and pharmaceutical industries – for example, for demineralization of dyes and fluorescent clearing agents, concentration of pharmaceutical forms, etc.;
- in the food industry-desalination and concentration of food and dairy products, beverages, by-products (lactoserum, fermentation products), chromacity reduction and processing of food products, etc.
For example, using the nanofiltration process for processing lactoserum allows simultaneous concentration of up to 30-40 %, partial demineralization and mechanical cleaning of the product from impurities.
Especially important is the use of nanofiltration units in conjunction with lactoserum electrodialysis units, which allows not only to increase the degree of serum demineralization up to 95%, but also to improve the organoleptic properties of the product and significantly increase the economic efficiency of production by reducing energy costs. Demineralized serum, as a secondary raw material, can be used further in the production of dairy products.
JSC "Tula dairy plant" (Tula) Electrodialysis plant with a capacity of 30 m3 / day of sour curd whey with a degree of demineralization of 70%.
JSC "Dairy plant Stavropol" (Stavropol) - Nanofiltration plant with a capacity of 300 m3 / day and Electrodialysis plant with a capacity of 30 m3 / day permeate skim milk, cheese and curd whey with a degree of demineralization of 75%.
LLC "Marimilk" (Mari El Republic) – Nanofiltration installation with a capacity of 80 m3/day sweet cheese whey.
LLC Zelenye linii (Ignatovka, Kaluga region) - Nanofiltration unit with a capacity of 20 m3 / day and Electrodialysis unit with a capacity of 8 m3 / day of sour curd whey with a degree of demineralization of 50%.
LLC Alabuga SOTE (Elabuga, the Republic of Tatarstan) - Nanofiltration installation with productivity of 120 m3 / day and Electrodialysis installation with productivity of 40 m3/day of sour curd whey at degree of demineralization of 50%.
LLC Ilyinskoye milk (Ilyinskoye village, Udmurt Republic) - Nanofiltration installation with a capacity of 10 m3 / day of sweet whey.
JSC "Tula dairy plant" (Tula) Electrodialysis plant with a capacity of 33 m3 / day of sour curd whey with a degree of demineralization of 50-60%.
LLC "Mstinskoe Moloko" (Malaya Vishera, Novgorod region) Electrodialysis plant with a capacity of 20 m3 / day of sour curd whey at a degree of demineralization of 50%.