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This study focuses on the possible use and efficacy of the co-treatment of landfill leachate (intermediate-age) with municipal wastewater. The nitrification, denitrification, and dephosphatation capability of activated sludge acclimated with a mixture of raw municipal wastewater (RWW) with gradually increasing amounts of raw landfill leachate (RLL) (from 0.5 to 5% v/v) were tested. Biochemical tests were conducted simultaneously in batch reactors (BRs). According to the obtained data, the ammonia utilization rate (AUR) was 3.68 g N/(kg volatile suspended solids (VSS)·h) for RWW, and it increased to 5.78 g N/(kg VSS·h) with the addition of 5% RLL. The nitrate utilization rate under anoxic conditions (NURAX) remained at a comparable level of 1.55--1.98 g N/(kg VSS·h). During the anoxic phase, both nitrate utilization and phosphorus uptake occurred, suggesting that denitrifying phosphorus-accumulating organisms (DPAOs) utilized N--NO3. With the addition of RLL, the rates of anoxic and aerobic phosphate uptake (PURAX and PURAE) and phosphate release rate (PRR) decreased. The PRR was likely negatively influenced by high N--NO3 concentrations but not completely inhibited due to the availability of a biodegradable fraction of chemical oxygen demand (COD). Thus, monitoring the NH4--N load in wastewater treatment plant influent before co-treatment is more informative than that using hydraulic-based criteria. [ABSTRACT FROM AUTHOR]

The use of fusel oil as an 'alternative' carbon source for denitrification in the mainstream and sidestream treatment processes was studied. Research comprised two kinds of batch experiments as well as acclimation of process biomass to external carbon sources. In the conventional nitrate utilization rate (NUR) measurements (one-phase experiments with non-acclimated biomass), the NUR with fusel oil was 1.4-1.7 g N/(kg VSS·h which was comparable to NUR with ethanol and with slowly biodegradable fraction of the settled wastewater. When fusel oil was added at the beginning of the anoxic phase, preceded by an anaerobic phase (in two-phase experiments with non-acclimated biomass), the NURs of 2.5-2.9 g N/(kg VSS·h) were comparable to the tests without the addition of any external carbon sources. The addition of fusel oil and ethanol resulted in a significant enhancement of the denitrification efficiency in lab-scale sequencing batch reactors treating sludge reject water. The NURs continuously increased from below 1 g N/(kg VSS·h) to over 10 g N/(kg VSS·h) over the entire 4-week operational period, indicating gradual acclimation to the substrate. The overall total N removal efficiency reached ∼90%. [ABSTRACT FROM AUTHOR]