Monitoring Variables at the Outlet of a Clarified Water Loop through Multivariate Extension of Real Process Capability Index
Maura L. Vasquez¹, Teodoro R. Garcia², Guillermo Ramirez¹, Jose R. Garcia³, Carlos M. Martinez², Alberto Camardiel¹
¹Statistics School, Central University of Venezuela, Caracas, DF, Venezuela; ²Industrial Engineering School, University of Carabobo, Valencia, Carabobo, Venezuela; ³Higiene y Seguridad Industrial, Papeles Venezolanos C.A., Guacara, Carabobo, Venezuela

The North-Central area in Venezuela has two restrictions for installing toilet paper factories: First, the only fresh water available in the area should be used for human consumption. On the other hand, all effluents from the area are poured into Valencia Lake. The lake ecosystem presents significant damage due to the effect of biological and chemical wastes. It is recommended to build two closed circuit water treatment plants to minimize the environmental impact and simultaneously supply the huge amounts of water required for the toilet paper factory under study. These treatment plants allowed water to be reused through applying the clarification procedure, which consists of adding flocculants, coagulants and sulfuric acid. The water coming from this type of treatment plant should meet certain quality standards if it is going to be used to manufacture toilet paper. The quality of clarified water depends on the behavior of the following variables: pH, ionic demand, turbidity and total suspended solids. Statistical behavior of these four variables was monitored applying the Multivariate Control Chart. On the other hand, the Multivariate Extension of Real Process Capability Index was used to see that the process worked within standards. This closed circuit has an efficiency of 95%, a 4.77% of paper sludge which is deposited in a landfill and 0.23% of water that must be restored. The combined effects of both plants produce a daily volume of 5,000,000 cubic meters of clarified water. Comparing this figure with the value of 50 liters proposed by the United Nations as the estimate daily amount required by a person for consumption, cooking and cleaning, this complete process creates a saving equivalent to the daily water requirement for 100 million people.

Keywords: Clarified Water; Environmental Impact; Multivariate Process Control; Multivariate Extension of Process Capability Index

Biography: Statistical Science Licensee, Master and Doctor in Statistics. Full Statistic Professor in pre and post graduate studies. Author of several statistic books and articles. Director of Postgraduate of the Faculty of Economic and Social Sciences, Central University of Venezuela, Caracas – Venezuela.