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Monitoring underground water resources in Brazil

The Coca-Cola FENSA plant in Mogi das Cruzes is responsible for bottling mineral water supplied from two ground water sources. The plant is a benchmark for environmental sustainability projects. With this pioneer project the Mogi das Cruzes plant was the first of the Coca-Cola FENSA Group to install an online analysis monitoring, using the OTT PLS and OTT DuoSens datalogger, along with other Hach technologies.


Read a detailed project description here

OTT PLS - vented pressure transducer

OTT PLS - Pressure Level Sensor

Robust ceramic pressure transducer for water level measurement

The OTT PLS, SDI-12 or 4 ... 20 mA pressure probe, measures water level, depth to water, or pressure using an integrated controller and ceramic pressure-measuring cell.

  • Surface water Groundwater
  • Vented pressure cell
  • Water level, Pressure, Temperature
  • Water level and temperature measurement - for use with external data logger
  • 0 … 4, 10, 20, 40, and 100 m
  • ± 0.05% FS
  • No
  • SDI-12, RS-485 (using SDI-12), or 4 … 20 mA

Monitoring Solution

  • The monitoring system consists of a level and temperature probe with a ceramic pressure sensor. It is fitted with a vented cable to compensate for barometric pressure, a digital conductivity sensor, a combined digital pH electrode, a Digital SC200 controller to connect the pH and conductivity sensors via a plug & play type digital interface with a bright LCD display, an OTT Duosens datalogger with SDI12 interface, and an analog extension to interface with the SC200 controller, and GSM / GPRS modem.
  • The level sensor was installed in a 1" tube at a depth of 150m, the pH and conductivity sensors were installed in a flow cell through ½" hole made in the main pipe.
  • All sensors were connected to an OTT Duosens datalogger with a GSM / GPRS modem, transmitting data hourly to the Coca-Cola FENSA FTP server.


  • The SDI-12 serial communication reduces power consumption and enables simultaneous monitoring of the water temperature.
  • The use of a robust ceramic level sensor with a ventilated cable reduces the cost of maintenance and real compensation of the variation in water density of the water column, as a function of temperature.
  • The Kevlar coated cable does not loop and therefore does not give any misleading impressions that the water level is rising with time.
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