Wealth Creation from Waste With Zero DischargeTechnologies

Related Vendors

Pörner Ingenieurgesellschaft mbH

TRM Filter d.o.o.

ProMinent GmbH

ASC case study

Sodium salt of glycolic acid is present in the effluent stream along with other chemicals. This stream is treated with ASC sol-3 and the pure, white salt precipitates out. Recovery is approximately 95 per cent. Eutectic freeze crystallization Last but not the least, the fourth novel technology is eutectic freeze crystallization (EFC). Many salts have high water solubility.

Conventionally in such cases, water is evaporated to increase the concentration of salts beyond the saturation solubility and thus causing their precipitation. In the due course, large quantity of water needs to be evaporated. The water evaporation step makes this process highly energy-intensive. In almost all industrial wastewater streams, many salts present are in the dissolved form. Hence, the water evaporation step finally leads to precipitated salts but along with various other impurities. EFC involves increasing the concentration of salts by crystallizing the water followed by crystallization of desired salt from the mixture of salts.

Many of the industrially important salts like sodium sulfate, potassium sulfate, ammonium sulfate can be recovered using the EFC technology. Here again, the typical operating cost will be 30-50 per cent of the value of the salt obtained. As the operating temperature required is below room temperature, equipment can be fabricated from less exotic materials.

EFC case study

In case of caustic chlorine industry, sodium sulfate is present as impurity in the brine stream. Using the EFC technology, anhydrous sodium sulfate meeting the Indian standards can be recovered from a mixture of various other salts such as sodium chloride without evaporation of water.

Complete recycling

Complete recycling is achieved as a combination of one or more of the four technologies and if required by way of RO, which is already a standard technology, to achieve zero discharge. The combination of ChD, ReX, ASC and EFC results in the recovery of chemicals in a pure form from waste aqueous streams. The dilute streams can either be recycled (process permitting) or alternatively, since the concentrations are < 1 per cent, they can be subjected to RO. Permeate from RO can be recycled and the concentrated stream can be recycled back to ChD along with fresh effluent. This way profitable zero discharge with complete recycling can be achieved. Effectively, wealth is created out of waste.

(ID:42820067)