# A Low-Temperature and Low-Pressure Distillation Plant for Dairy Wastewater
## 3 Results and Discussion
### Concentrate  
Table 4 reports the results of the experimental trials carried out, concerning the analyzed parameters, identified as main indicators of pollution, related to the concentrated fraction of the whey. These values must be compared with their starting values as reported in Table 3. To this purpose, in Table 5 are reported the final concentrated whey characteristics compared as a ratio to the raw whey initial values reported in Table 3.  
The pH value slightly decreases during the process time; this means that the acidity roughly does not vary. The SC, conductivity, BOD5, COD, TN and TP values greatly increase during the process time, as expected, depending on the trial duration and final reached SC. Therefore, the concentration efficiency must be compared using the final increment reached on the SC value with respect to the raw whey. Hypothesizing a linear relationship between the SC and the conductivity, BOD5, COD, TN and TP values, the concentration efficiency can be estimated regarding the previously mentioned parameters with regard to the reached SC. The slope of the linear model represents the concentration efficiency with respect to the considered characteristics (conductivity, BOD5, COD, TN and TP). The concentration \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Coding** & **Temperature (\({}^{\circ}\)C)** & **Duration** & **SC** & **pH** & **Conductivity** & **BODS** & **COD** & **TN** & **TP** \\  & \({}^{\circ}\)**C** & **(Minutes)** & **(\%)** & **(\%)** & **(mg/s)** & **(mg/s)** & **(mg/s)** & **(g/s)** \\ \hline P1 & & \(140\pm 18\) & \(19.07\pm 4.28\) & \(4.27\pm 0.19\) & \(17.97\pm 2.36\) & \(83.03\pm 1334\) & \(204.06\pm 1839\) & \(8.07\pm 1.19\) & \(3.30\pm 1.41\) \\ P2 & 60 & \(240\pm 21\) & \(47.82\pm 3.34\) & \(4.21\pm 0.18\) & \(36.00\pm 2.27\) & \(220.540\pm 1430\) & \(545.615\pm 2073\) & \(21.00\pm 4.08\) & \(4.69\pm 1.54\) \\ P3 & & \(315\pm 31\) & \(65.92\pm 4.16\) & \(4.09\pm 0.11\) & \(56.90\pm 2.91\) & \(246.914\pm 4455\) & \(701.052\pm 2794\) & \(24.44\pm 3.35\) & \(6.11\pm 1.74\) \\ \hline P4 & & \(269\pm 22\) & \(22.24\pm 2.17\) & \(4.22\pm 0.11\) & \(20.52\pm 2.79\) & \(140.513\pm 2165\) & \(381.928\pm 1903\) & \(8.36\pm 1.81\) & \(3.04\pm 1.73\) \\ P5 & 53 & \(322\pm 25\) & \(43.61\pm 2.23\) & \(4.05\pm 0.11\) & \(37.00\pm 2.48\) & \(166.121\pm 2877\) & \(795.687\pm 1814\) & \(13.93\pm 1.55\) & \(3.17\pm 1.69\) \\ P6 & & \(434\pm 37\) & \(69.92\pm 5.18\) & \(3.99\pm 0.11\) & \(65.41\pm 3.77\) & \(235.294\pm 4672\) & \(2920\) & \(19.41\pm 3.73\) & \(4.36\pm 1.60\) \\ \hline P7 & & \(370\pm 19\) & \(23.43\pm 2.62\) & \(4.34\pm 0.14\) & \(29.58\pm 2.76\) & \(116.279\pm 1209\) & \(507.991\pm 1709\) & \(10.23\pm 1.03\) & \(3.17\pm 1.88\) \\ P8 & 46 & \(475\pm 23\) & \(47.50\pm 3.81\) & \(4.11\pm 0.12\) & \(42.41\pm 2.84\) & \(246.227\pm 1408\) & \(628.993\pm 2340\) & \(17.16\pm 1.80\) & \(3.70\pm 1.77\) \\ P9 & & \(507\pm 35\) & \(63.20\pm 8.24\) & \(4.07\pm 0.13\) & \(60.40\pm 2.32\) & \(276.300\pm 2409\) & \(989.820\pm 4.909\) & \(18.70\pm 2.54\) & \(4.88\pm 1.74\) \\ \hline P10 & & \(487\pm 28\) & \(20.03\pm 2.26\) & \(4.22\pm 0.21\) & \(19.20\pm 2.91\) & \(125.150\pm 1740\) & \(431.943\pm 2290\) & \(6.23\pm 1.78\) & \(3.43\pm 1.96\) \\ P11 & 39 & \(584\pm 37\) & \(40.78\pm 5.24\) & \(4.12\pm 0.31\) & \(39.41\pm 2.51\) & \(199.080\pm 3384\) & \(530.128\pm 4037\) & \(15.77\pm 1.62\) & \(3.91\pm 1.97\) \\ P12 & & \(764\pm 41\) & \(68.30\pm 7.24\) & \(4.05\pm 0.15\) & \(56.53\pm 3.18\) & \(226.36\pm 4821\) & \(933.284\pm 3899\) & \(20.84\pm 2.93\) & \(5.28\pm 1.98\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Final concentrated whey characteristics. The standard deviation is reported after the \(\pm\) character.