Wastewater treatment from a residential and commercial building

In 2020, the ClearFox® team received a request from a business partner in Iran to build a wastewater treatment plant for a residential and commercial building. Sivan residential commercial project is a building for modern apartments and offices. The object was built in the north of Iran, directly on the Caspian Sea. During the construction period, the wastewater treatment plant had to treat the site wastewater, to treat the wastewater from the entire building after that. 

The landscape around the construction site is particularly attractive. The client was therefore concerned to protect the aesthetics already during the construction work. 

The challenges were the different loads and components of the wastewater that the treatment plant has to handle. The plant has to treat much more wastewater after construction than during the working process. Although construction site wastewater and hygienic wastewater are generated during the work, these multiply as soon as residents and companies move into the commercial building. The wastewater treatment plant should be designed for a total of 450 PE. The wastewater mainly contains BOD5, which the treatment plant should treat biologically. 

Another challenge was the proximity to the water. The commercial building is located directly on the beach and therefore has direct access to the Caspian Sea. Therefore, the groundwater is very high, which makes the safe installation of the wastewater treatment plant difficult. 

The ClearFox® engineers opted for a QuickOne SBR plant. They designed it to operate at only one-fifth of its capacity during construction, as this was sufficient for the site wastewater generated. Once people occupy the commercial building and work in the offices, the plant ramps up to its full capacity to handle the wastewater load generated. 

To protect the plant from groundwater, the ClearFox® team constructed a concrete tank, about two meters deep and seven meters wide in which to install the plant. In this way, the engineers ensured that only construction site wastewater would flow into the plant at the beginning and that it would not mix with the groundwater. 

At the bottom of the tank, 64 aerator plates are installed, which mix the wastewater via fine air bubbles. At the highest purification stage, the treatment plant requires around 6.75 kg of oxygen per day. This process supports the microorganisms contained in the wastewater, which treat the dissolved substances. After purification, secondary sludge is produced, which settles on the bottom of the plant. This creates a clear water zone which floats on top. An airlift pump removes the treated wastewater, which can then flow into the environment. It is also suitable for watering the local green areas.