Linjiangwater Treatment Plant – Case Study

Sodimate China has recently provided 3 PAC (powder activated carbon) dosing units for the Linjiang Water Treatment Plant, operated by OTV (Veolia Water) and SMEDI. This plant, which is located in the Shanghai suburbs in the Pudong area, is one of the biggest water treatment plants in Shanghai. Most of the water produced is used on the World Expo 2010 site. In this particular case, the PAC is used for 2 purposes, removing the remaining heavy metals from the water and removing the organic materials in the water.

The Linjiang Water Treatment Plant treats up to 400 000 m3/hr of water. Such large water flow requires an automatic and safe system to stand the flexible operating conditions.

Technical description
Our system is composed of 3 similar units. 2 of them are operated 24 hr/day and the 3rd one is used when there is a peak water flow. Each unit feeds a 10 m3 concrete preparation tank from which the slurry is pumped into the water to treat.

Each unit is composed of a storage silo, equipped with loading system, dust collector, pressure relief valve and level probes, a mechanical discharger called arch breaker DDS 400 type, a volumetric dosing screw and a wetting unit (to premix the PAC with water).

The mechanical arch breaker is the only alternative to bin activators (which can generate compaction and bridging) or air injection systems (which can generate fluidization and rat holing). It is composed of flexible blades mounted on a central shaft. This shaft rotates, thanks to a geared motor, only when powder is required and keeps the product stored in motion at the lowest part of the cone (where all flowing problems happen). This action combined with the volumetric metering screw offers a constant product flow and an accurate PAC throughput.

The Sodimate advantages
• no alteration of the product thanks to the mechanical arch breaker
• high volumetric accuracy thanks to the combined actions of the arch breaker and the volumetric dosing screw (no wastage of PAC)
• ease of installation
• fully automatic units
• low maintenance
• low power installed
• tailor-made solution, adapted to customer’s need (site conditions and product to handle)
• cost effective solution