Various chemometric methods were used to analyze and model potable water quality data. Twenty water quality parameters were measured at 164 different sites in three representative areas (low land, semi-mountainous, and coastal) of the Thessaly region (Greece), for a 3-month period (September to November 2006). Hierarchical cluster analysis (CA) grouped the 164 sample sites into two clusters (CA-group 1 and CA-group 2) based on the similarities of potable water quality characteristics. Discriminant analysis was assigned about 94.5% of the cases grouped by CA. Factor analysis (FA) was applied to standardized log-transformed data sets to examine the differences between the above clusters and identify their latent factors. For each of the above two clusters (CA-group 1 and CA-group 2), FA yielded six latent factors that explain 68.7% and 73.4% of the total variance, respectively. FA was also identified the latent factors that characterize each cluster. The identification was obtained, using (a) descriptive statistics, (b) t test for equality of cluster means, (c) box plot, (d) error bar, (e) factors score plots, (f) matrix scatter score means plot and (g) scatter plot of the six significant latent factors from the factor set of A. Papaioannou (B) · P. Plageras A. Papaioannou et al. all samples group. The classification scheme obtained through cluster analysis was confirmed by discriminant analysis and explained by factor analysis.

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Olive mills are usually small scale enterprises that can not afford the costs of a proper wastewater treatment, unless the treatment is a very simple and cheap procedure. Most treatment technologies however require high investment costs and high level of technological know-how. Thus the design of centralized treatment plants is considered more suitable to treat OMWW produced by several mills. This creates a burden to operational costs, as high transportation costs due to high geographical scattering must be taken into account. In some cases, local conditions may call for separate treatment plants. Several attempts have been recorded concerning the utilization of advanced membrane technology in the case of the olive mills waste water treatment, mainly by involving ultrafiltration membrane technology without any commercial follow out due to serious membrane fouling problems and only partial removal of COD load of the wastewater (only 80% of the total pollution potential was managed to be removed) (Turano et al, 2002;Borsani et al, 1996). However, provided the fouling problem has been overcome, ultrafiltration could be a useful operational step in an integrated scheme of total discharge treatment of the OMWW to produce high value products and agro-materials consuming virtually 100% of the initial wastewater flow.In the context of the present work, it was studied for the first time and in detail a dilution facilitated and due to this fact low membrane fouling UF process which is based on the principle that by diluting the original OMWW its fouling tendency is getting reduced so that UF treatment can be effective and operational. This process is known as Diafiltration.An experimental apparatus was constructed in order to study the feasibility of the application of diafiltration to process Olive Mill Waste Water (OMWW). This apparatus consisted of a tubular membrane accommodation module, a controlled temperature raw material stock tank and a positive displacement pump connected all together by reinforced plastic pipes. Three tubular Ultrafiltration membranes with MWCO 8000 Daltons, 25000 Daltons and 100000 Daltons respectively were used. The performance in terms of UF permeation flux of each one of the three membranes was tested by using four OMWW/water dilutions 1:1, 1:3, 1:5 and 1:10 at three temperatures settings (30˚C, 40˚C, 60˚C) and for each respective temperatures setting at six trans-membrane pressure values adjusted within the range from 1 to 6 bars. In correspondence to the obtained experimental evidence, the overall OMWW diafiltration flux, especially by using the membranes with MWCO 25000 Daltons and 100000 Daltons, was found to be of high magnitude. This fact creates an optimism for the commercial follow-up of the process itself by using it as the main component of a promising hybridic scheme for total handling the OMWW pollution problem in a environmentally friendly and sustainable way, according to adopted by EU environmental principle of zero discharge. The above mentioned scheme is described, and prese...