Pichidegua Sewage Treatment Plant Optimization

Description: The present project corresponds to the optimization of the Wastewater Treatment Plant (PTAS) of Pichidegua and aims to expand the capacity of the Treatment Plant, considering the projected demand by 2025, which is estimated in a population served of 5 847 inhabitants. To do this, it is necessary to modify the project "Improvement of Pichidegua wastewater treatment plant", qualified as environmentally friendly by means of Res. Ex. No. 64 of March 9, 2006 of the Regional Commission for the Environment of the Region. of General Libertador Bernardo O'Higgins, which is attached in Annex 2.1. It should be noted that a pertinence query was submitted regarding the Pichidegua Wastewater Treatment Plant, which had the objective of correcting discrepancies with the original project associated with the periodicity of sludge removal, clarifying concepts regarding Res. Ex N 64/2006 and modifications associated with pretreatment, among others, being resolved by Letter N ° 382/2012, resolving that said changes did not constitute changes of consideration that merited entry to the Environmental Impact Assessment System (SEIA). The letter and the indicated response are attached in Annex 2.2 and Annex 2.3. Originally, the PTAS of Pichidegua had 4 lagoons of the facultative type. This system was modified through the project "Improvement of wastewater treatment plant in Pichidegua" (Res. Ex N ° 64/2006). Through this project, one of the facultative lagoons was converted into a mixed system consisting of an aerated lagoon, followed by two facultative lagoons partially aerated with sedimentation, leaving the other three original facultative lagoons out of service. In this context, currently the Sewage Treatment Plant consists of a preliminary treatment, followed by a secondary treatment in an aeration lagoon with partial mixing, consisting of an aeration lagoon and two sedimentation ponds, removing the sludge at operational requirement (on average every 2 years), and finally a contact chamber for the disinfection of the effluent. The effluent from the plant is discharged to the Cachapoal River in compliance with the limits established in Table No. 1 of DS No. 90/2000 MINSEGPRES, emission standard for the regulation of pollutants associated with discharges of liquid waste to bodies of surface water. On the other hand, the sludge generated in the system is removed, dehydrated and then transferred to an authorized disposal site. The modification of the project contemplates the increase of the useful volume and installation of a deflector baffle in the current aeration lagoon, the replacement / incorporation of aerators for the aeration and sedimentation zones, the installation of a Sewage Elevation Plant (PEAS) of bedside, the replacement of boards in the electrical room associated with the new aerators, the expansion of the current contact chamber, the construction of a hazardous waste warehouse and the creation of a maneuvering yard for the extraction of sludge. On the other hand, the project will regularize the installation of a ferric chloride booth, which is already implemented. Objective The objective of the project is to expand the capacity of the Sewage Treatment Plant of Pichidegua, considering the projected demand by 2025, which is estimated in a population served of 5,847 inhabitants. To do this, it is necessary to modify the project "Improvement of Wastewater Treatment Plant of Pichidegua", qualified as environmentally friendly through RE No. 64 of March 9, 2006 of the Regional Environmental Commission of the Region of Libertador General Bernardo O'Higgins.