WASTEWATER TREATMENT PLANT PROCESS DESIGN
by Vernon Smokey Stack, P.E., D.E.E.

The information in this web site is directed to environmental engineers (young or old) who might need help with conceptual design of wastewater treatment plants. 

ESTIMATION OF TANK OR BASIN TEMPERATURE

Estimation of water temperature in a reactor can be important as related to mesophilic or thermophilic operating conditions: 

• Aerobic digesters will increase in temperature due to heat released from VSS destruction and from mechanical heating through aeration.  With the addition of solar heating In summer, operational problem may arise if the temperature moves in to thermophilic region.
• Activated sludge reactors that receive strong wastewater will increase in temperature as heat is released from biological reactions.  With the added solar heating in summer, actions may be necessary to keep the temperature mesophilic, such as cool the air used for aeration.

A discussion of factors influencing water temperature is found in “ESTIMATION OF TANK OR BASIN TEMPERATURE” that can be downloaded from:

A mathematical model that estimate a thermal balance for tanks and basins has been developed.  It arrives at an estimate of tank or basin temperature by balancing thermal energies related to:

• Convective heat transfer
• Long-wave radiation losses to the sky
• Heat lost through evaporation at the surface or to diffused air
• Mechanical energy input
• Heat loss to or gain from the ground
• Solar heating
• Heat released from biological reactions

The model can be downloaded at:

An instruction manual for the model can be downloaded at:

smokeystack@comcast.net