Partial nitrification activated sludge operation as an appropriate nitrogen removal scheme for the Mediterranean region

Wastewater Treatment Plants (WWTPs) operation under conventional fully nitrifying activated sludge BNR schemes, although favoured by the temperate climate conditions prevailing around the Mediterranean region, may prove quite inefficient in terms of both capital and O&M costs when recipient body characteristics do not pose similar requirements; especially more so, when treated effluents are intended for reuse in agriculture and nitrogen content may well serve as fertilizer. This paper presents some experimental evidence that single-reactor partial nitrification schemes, allowing for nitrogen removal to the extent needed under seasonally varying plant loading conditions and effluent quality requirements, and securing reliable and efficient plant operation, may be a more suitable alternative for similar cases.