EXERGER an integrated wastewater treatment technology using a multistage thermal distillation method

Cleaning frequency depends on the water composition and the operating mode. For example, one of the units, supplied by ReinnolC, has been in operation at our customer’s Thermal Power Station since 2001 with no cleaning at all. For wastewater treatment units we developed an operating mode for preventing deposits by using scale inhibitors. The mode allows us to completely prevent scaling. Deposit formation is possible, if the operating mode is disrupted (if reagent’s supply is disrupted due to the metering pumps` failure; if purging is reduced, etc.). Cleaning frequency depends on keeping an accurate operating mode and is required no more than once or twice a year. The cleaning process is the same as for conventional shell&tube heat exchangers. The water chambers need to be open and cleaned with a high-pressure water cleaner. Clean-in-place washing with acid solution is also possible.

Reagents’ consumption depends on the unit’s reliability, deposits on the heat surface and the final product of the wastewater treatment. The reagents’ list and consumption are defined in line with priority goals, such as the unit’s reliability and operation without scaling. In certain cases, a higher consumption of reagents is required to obtain low-hazard waste and products for sale. There are low-reagent or reagent-free methods to reduce the water hardness, but often they are incapable of resolving a complex task, unreliable and require a more cautious application.

Water-soluble salts are categorized as a hazardous waste, which makes their disposal problematic. Our technology allows to extract the salt from the brine and use it as a technical product. Also, the unit can convert part of the water-soluble salt – namely, the sulfates – in an insoluble form, and remove it from the unit as calcium sulfate.

Depending on the object specific environment, water composition and the customer’s requirements, the following infrastructure may be required: Recirculation water cooling system; Steam reduction (if necessary); Extra cleaning of distillate to remove volatiles (if present); Express lab; Reagents’ storage; Waste and wastewater treatment products’ storage, packing (if necessary); CIP-washing for equipment; Facility for equipment and maintenance personnel.

You can find the references here. An important note: all types of wastewater are unique in composition. We develop a unit for a specific type of wastewater. The technology combines well-known and tested wastewater treatment methods, such as: Precipitation of hardness salts by liming/soda-liming in clarifier. Concentration at a flash evaporator. Over 30 units based on this technology have been developed for various purposes. Evaporation and crystallization of highly-concentrated wastewater in a conventional vertical evaporator with forced circulation. This technology is commonly used as a typical solution for salt solutions.

The assigned service life of the unit is 30 years, but in fact it’s not limited by this period. Moreover, this service period can be extended up to 60 years due to durable manufacturing materials, for example, to meet the requirement of the nuclear industry.

Pumps, shutoff and control valves, instrumentation and monitoring tools require regular maintenance according to standard practice. Heat transfer tubes made of carbon steel also require maintenance. The modern units are equipped with tubes made of stainless steel, so there is no need for maintenance.

We propose the EP (Engineering and Procurement) cooperation format. The scope of works includes the basic and detailed (optional) engineering. Design and installation are performed by specialized organizations with relevant experience and material and technical base. In this case we take full responsibility for the technological part of the project and can guarantee the final result, as we set up the technical conditions for the unit installation and coordinate the installation project as a whole. Our scope of work also includes installation supervision and commissioning works.

The highly-efficient Exerger® FVE reduces the overall cost of the evaporating unit compared to standard evaporators. It is worth noting that Reverse Osmosis (RO) doesn’t provide a solution for the final goal – the wastewater disposal (RO performs only the wastewater concentration). RO is not quite reliable under the conditions of high salt concentration and variable wastewater composition. It requires more frequent acid cleaning and creates extra wastewater.

You can use other heat sources, like hot water or flue gases, or heat the water by direct fuel combustion (gas). There is also a technology that applies steam mechanical recompression. It allows us to run the unit completely on electricity (with a minimal energy consumption).

The salt content in the distillate depends on the feed water quality and the concentration degree. Normally, it’s quite low. Saving on the water quality is not what we do, however. The resulting water can be used for any technological needs or become a by-product suitable for sale.

The unit is fully auomated and doesn’t need regular control. However, as with any equipment, it needs to be controlled from time to time to correct the operating mode and supply reagents. The unit can be maintained by the personnel of the corresponding shop. In case of a separate facility, the maintenance requires 2 people per shift, and a regular control by a chemical lab technician.

The overall facility dimensions depend on the unit installation scheme, infrastructure and the requirements for the equipment. The height of the unit is defined by the highest equipment unit – the flash evaporator. Its height is 13-15 meters.

Installation is possible in the southern regions. In such an environment, an evaporator, heat exchangers and capacitive equipment can be located outdoors, whereas pumps, power supply cabinets and reagent-related equipment – within the facility.