WEC Projects, an EPC contractor working in the water and wastewater treatment sector, has completed the design, engineering and supply of new sewage treatment plants for three different developments in Ghana
The projects are for two hospitals and an apartment complex. All three integrate biological trickle filtration systems.
The plants will be installed at the Kumawu District Hospital, a new medical facility being built in the Sekyere Kumawu District, and the Fomena District Hospital, a new facility located in the Adansi North District. WEC Projects is supplying the Model E trickle filter plant for both hospitals, designed to treat an average of 90 cu/m per day.
Raw sewage is fed into the plant’s screenings box before arriving at the three-chamber below ground septic tank where anaerobic pre-treatment takes place. The wastewater then flows into a recycle sump equipped with vortex pumps with a transfer rate of 25 cu/m per hour across the trickle filter. The wastewater flows down through trickling filter media on the surface of which propagates the biofilm used to breakdown COD and nitrify the wastewater. The wastewater is collected in a basin at the bottom of the packing media and transferred to the clarifier. A splitter box returns some of the wastewater to the trickle filter to ensure a continuous flow through the bioreactor. Phosphorous is removed from the wastewater by introducing ferric chloride to the clarifier. The water then undergoes disinfection using chlorine to meet the required effluent standards before being discharged into the environment. All process control instrumentation and electrics are housed in a six-metre shipping container and the self-contained plants are fully fabricated in South Africa.
The apartment complex, located in the coastal city of Sekondi-Takoradi, is a smaller system with a current flow rate of 16 cu/m per day of effluent which will increase once it reaches its peak flow rate. It features a trickle filter system similar to those of the two hospitals, although on a smaller scale, in a standalone tower.
Ashly Forster, project manager at WEC Projects, commented, “A five-person team from WEC Projects oversaw the installation of the plants and provided training to operators during the commissioning stage. Trickle tower technology was chosen for these projects due to its scalability, low maintenance, operating requirements and simple design. A single operator can oversee and control the plant which is extremely reliable with a long operating lifespan. Ensuring that these plants remain operating efficiently is particularly important in order to ensure that no untreated wastewater enters the environment.”
