## 1 Introduction  
Cyanobacteria are well known for their ability to produce diverse secondary metabolites including microccystins (MCs) and taste-and-odor (T&O) compounds [1; 2; 3]. Due to the acute and potentially chronic effects of MCs, the World Health Organization [4] issued a guideline value of 1.0 \(\mathrm{\SIUnitSymbolMicro}\)/L for microcystin-LR (MC-LR) in drinking water. T&O compounds include geosmin (GEO) and 2-methyl isoborneol (MIB) with an earthy and musty odor, respectively, and \(\beta\)-cyclodextrin (CYC) and \(\beta\)-ionone (ION) with a tobacco and violet odor, respectively [3]. These compounds are the primary barriers to drinking water safety. Due to extremely low odor threshold concentrations (OTCs) with 4, 15, 19.3 and 7 ng/L for GEO, MIB, CYC and ION, respectively [3], T&O compounds even at low levels in water are a source of complaints by consumers. Although the effects of T&O compounds on human health are still unclear, they are the primary criteria of drinking water safety considered by consumers [3], which pose challenges for drinking water treatment plant (DWTP) management. The occurrence and seasonal dynamics of MCs or T&O compounds have been well studied in surface waters worldwide [5; 6; 7; 8]. Recently, some researchers began to focus upon the co-occurrence of cyanotoxins and T&O compounds in lakes, reservoirs and rivers. During the 2007 summer's odorous tap water crisis in Wuxi (China), an MC-LR of 7.59 \(\mu\)g/L was detected in the source water at the intake [9]. [PERSON] et al. [10] concluded that microcystin co-occurred with geosmin in 87% of the cyanobacterial blooms and MIB in 39% sampled from 23 Midwestern United States lakes. However, seasonal dynamics of MC and T&O compounds may not be so uniform due to their different producers, physicochemical properties, metabolic pathways, and environmental influencing factors [7; 11]. Conflicting results in the relationship between MCs and T&O compounds with positive or no correlations were obtained in different waters [10; 12], which would complicate their removal by treatment processes in DWTPs. Scientific literature has reported that conventional water treatment techniques have been ineffective in removing MCs and T&O compounds from water [13; 14]. However, most previous studies focused on the removal of algal cells and their associated metabolites only in laboratory experiments or along treatment trains, which did not always conform to reality due to a range of uncertainties in actual situations [13; 15; 16]. The scant literature involving cyanobacterial metabolites removal by pilot- or full-scale treatment plants present conflicting results where some plants were said to have removed MCs below the guideline of 1.0 \(\mu\)g/L [17], but, in another case, a MC concentration of 2.47 \(\mu\)g/L was detected in the drinking water [18]. Therefore, it was necessary to investigate the fate of cyanobacteria and their metabolites under typical plant operation conditions to assess the potential removal. Moreover, no studies to date have estimated the efficiency of full-scale DWTPs in removing the mixtures of MCs and T&O compounds co-occurring in the same water source, which is needed to comprehensively assess and minimize the hazards caused by cyanobacteria and their metabolites. To estimate the safety of raw water with cyanobacteria, the Alert Levels Framework (ALF) has been established to define threshold values according to the MC-LR cell quota and the WHO guideline value of MC-LR in drinking water [2]. More than 100 MC variants have been characterized from bloom samples and isolated strains of cyanobacteria [1]; thus, the safety threshold for cyanobacteria was established based on different MC congeners at different cyanobacterial growth periods [19]. To avoid overestimating the risk of cyanobacteria in drinking source water, maximum tolerable (MT) values were calculated involving the toxin removal performance of real treatment trains by [PERSON] et al. [20].