Thermal Separation Technologies for Industrial Wastewater Treatment

Water use and conservation is an important issue for global process industries, particularly those affected by the absence of available water sources or insufficient wastewater treatment facilities. Water has many industrial uses: process water, rinse water, scrubbing and cooling water are typical applications. This means there are large quantities of industrial wastewater with varying composition and high contamination levels. The challenge here is to recycle this wastewater in order to protect resources on one hand, and on the other hand to reduce fresh water consumption, recover valuable materials and reduce disposal costs. Cost-effective and environmentally friendly wastewater treatment should be an integral part of the overall planning of a factory or facility. Customers can choose from a wide range of wastewater treatment processes such as mechanical, physical, biological, chemical and thermal processes. Therefore, it is essential to be clear beforehand about what the objectives are and to systematically evaluate the feasibility of all available approaches.

Thermal processes such as evaporation and distillation separate and concentrate water vapour from waste streams. They are particularly suitable in the following cases:

• When wastewater cannot be clearly defined and the composition of the wastewater frequently changes in terms of dry matter content, pH value, and particle size, • When high concentration is desired, i.e. a small amount of concentrated material, • When condensate water is reused as process, cooling or rinse water, • When there is waste energy such as process waste steam and turbine exhaust steam, so that steam generation costs do not arise, or when the mechanical steam recompression principle is applied and electrical energy is used with high efficiency, • When chemical use is reduced or prevented, • When a robust and long-lasting solution is desired that does not require high maintenance and spare parts costs. Evaporation technology is generally an expensive option – however, impressive wastewater recycling rates and energy savings should be taken into account. Some companies choose to evaporate wastewater. Because this is the only feasible option – but this is just one way to solve the wastewater problem. Manufacturers can recover their investment within 3 to 5 years when they reuse the condensate as process water. Evaporation is a separation technique that consumes a lot of energy and also requires significant investment. The investment cost is high, but the equipment is also manufactured to be robust enough to last several generations. The energy consumption required for evaporation can be greatly reduced through thermal or mechanical vapor recompression (MVR) or by using waste energy. An important consideration is the composition of the wastewater, which is often variable, and the composition of each batch differs. Careful testing must be carried out to ensure that the correct physical parameters are taken into account and that the relevant solution can be sized appropriately.

GEA has its own test centre equipped with large-scale laboratory equipment and numerous pilot facilities. Tests typically begin in the laboratory and are then validated in pilot plants. If necessary, a pilot facility can also be set up at the customer's site, allowing for extended testing periods.

GEA has extensive experience in thermal and non-thermal separation technologies in the food, pharmaceutical and chemical industries and also provides ZLD (Zero Liquid Discharge) wastewater treatment plants. ZLD technology offers efficient and environmentally friendly wastewater treatment that requires water reuse, optimizes the recovery of recyclable materials and thus prevents the formation of liquid waste. ZLD plants are complex systems combining many technologies such as centrifugal separation, membrane filtration, evaporation, crystallization and drying. GEA offers modular ZLD plants with capacities up to approximately 10 m³/hour and customized ZLD plants with sizes of 100 m³/hour and larger.

Photo: GEA MVR evaporation plant for 3,000 kg/hour of wastewater from chemical production process

[gallery link="file" ids="eyJ1cmwiOiJodHRwczpcL1wvd3d3LnR1cmtjaGVtLm5ldFwvd3AtY29udGVudFwvdXBsb2Fkc1wvMjAxOVwvMDhcL0dFQV8xLmpwZyIsInRpdGxlIjoiR0VBXzEiLCJjYXB0aW9uIjoiUGhvdG86IEdFQVwvIFdhc3Rld2F0ZXIgZnJvbSBEQVVXRSBGaWJyZSBwcm9kdWN0aW9uIChNREYpIHRyZWF0ZWQgaW4gYW4gTVZSIGV2YXBvcmF0aW9uIHBsYW50LiBXYXRlciB2YXBvciBwcm9kdWN0aW9uOiAxNXQcL3MiLCJhbHQiOiIiLCJkZXNjcmlwdGlvbiI6IiJ9,eyJ1cmwiOiJodHRwczpcL1wvd3d3LnR1cmtjaGVtLm5ldFwvd3AtY29udGVudFwvdXBsb2Fkc1wvMjAxOVwvMDhcL0dFQV8yLmpwZyIsInRpdGxlIjoiR0VBXzIiLCJjYXB0aW9uIjoiUGhvdG86IEdFQSBBIFpMRCBzeXN0ZW0gZm9yIGNoZW1pY2FsIHByZXRyZWF0bWVudCBhdCBhIHByb2R1Y3Rpb24gZmFjaWxpdHkgaW4gTWluZGVuIiwiYWx0IjoiIiwiZGVzY3JpcHRpb24iOiIifQ==,eyJ1cmwiOiJodHRwczpcL1wvd3d3LnR1cmtjaGVtLm5ldFwvd3AtY29udGVudFwvdXBsb2Fkc1wvMjAxOVwvMDhcL0dFQV8zLmpwZyIsInRpdGxlIjoiR0VBXzMiLCJjYXB0aW9uIjoiUGhvdG86IEdFQSBBIFpMRCBwbGFudCB3aXRoIGEgY2FwYWNpdHkgb2YgMTAgbTNcL2hvdXIgZm9yIHdhaWV3YXRlciB0cmVhdG1lbnQiLCJhbHQiOiIiLCJkZXNjcmlwdGlvbiI6IiJ9"] İlker Damar Sales Director Industrial Applications GEA Turkey Andrea Heuser Marketing Director Chemical Applications GEA Germany