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{latex}$$Q\alpha h$${

{latex}$$Q^2 \alpha h$${latex}

{latex}$$
Q\alpha \sqrt h 
$${

{latex}$$
Q\alpha \sqrt h 
$${latex}

where:

{latex}$$\alpha $${latex}

The connection between the flow control and the flow measurement aspect of the dosing mechanism is important to understand the evolution of dosing mechanisms in AguaClara plants.
Since the nonlinear chemical doser has the same relationship between flow and head at the turbulent ranges; AguaClara plants can be scaled up to much higher flow rates without being limited by the turbulence in the dosing tube. This is a huge advantage of the nonlinear system because it expands the AguaClara plants capabilities to serve much larger communities. The size of AguaClara plants is no longer limited to the flow limitations in the dosing tube.

As mentioned, the nonlinear doser uses the minor losses caused by the orifice instead of a dosing tube (major losses) to control the relationship between changing plant flow rates and chemical dose. The flow rate through the Chemical Dose Controller (CDC) is related to the available head by the equation:

{latex}$$Q_{Cdc}  = K_{orifice}\sqrt {2gh_{Cdc} } $${latex}

where

• Latex
  Wiki Markup
  {latex}$$Q_{Cdc} $${latex}

  is the chemical flow rate

• Latex
  Wiki Markup
  {latex}$$ K_{orifice} $${latex}

  is the orifice coefficient
• h is the available head

The desired chemical dose to the plant can be determined by a mass balance:

{latex}$$C_p  = {{C_c Q_{Cdc} } \over {Q_{Plant} }}$${latex}

where

• C _c is the chemical stock concentration
• C _p is the chemical dose

The influent raw water leaves the entrance tank through the Rapid Mix Tube which is the entry point for the dosing of alum. In the Rapid mix tube, an orifice is located in the tube to generate macro and micro-scale mixing. The entry point for the dosing of alum with the raw water has been redesigned to be submerged in the entrance tank in order to possibly reduce the occurrence of foam in the flocculator. After conversations with Dan Smith, the AguaClara engineer in Honduras, there doesn't appear to be foam forming in the Agalteca plant, where this dosing system has been implemented.
The flow of water through an AguaClara plant can be modeled as minor losses due to flow expansions. The relationship between plant flow rate and head loss through the plant is governed by the minor loss equation shown below.

{latex}$$ h{}_{plant} = K_{plant} {{Q_{plant} ^2 } \over {2g}}$${latex}

where:

{latex}$$ K_{plant} $${latex}

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