Treatment and Disposal of Sludge at the Municipal Wastewater Treatment Plant of Sarajevo

The wastewater treatment process produces a large number of byproducts, which must be adequately disposed of. One of the byproducts, which is the most common, is sewage sludge (sludge). Sludge is formed in different stages of wastewater treatment. Sewage sludge is often mixed from all process units, such as primary or secondary sludge, and is treated separately in facilities designed for this purpose. The most significant plant in Bosnia and Herzegovina (B&H) is the plant in Sarajevo, with a capacity of 600,000 population equivalent (PE). The plant was reconstructed and extended in 2016, but the final disposal of the sludge remained unresolved. Sludge is thickened, digested, and dehydrated, and then temporarily stored on site until its final disposal, which requires an adequate solution. Several studies have been done to solve the problem of final disposal of sludge and this problem is still active. The amount of temporarily deposited sludge for the period from 2016 to 2022 is approximately 23,000 m3. Of the 17 plants in B&H that are in operation (over 5,000 PE), the plant in Sarajevo produces about 40% of the total sludge. The current method of final disposal of sludge from the plant includes the largest percentage of disposal at the landfill (73.42%). The final disposal of waste sludge has not yet been finally resolved and implemented at the Sarajevo plant. Recommendations were given that the key to effective management of sludge in B&H is in exploiting its potential.