Consider a non-biological system - no drain field, mound, leachbed, etc. makes water as clean as rain and goes goes with rainwater - like to a footer drain.
Power consumption is proportional to sewage flow. EPA says DESIGN FOR 100 GAL / PERSON / DAY AND THAT'S FINE BUT AVERAGE WATER...
head pressure @ static conditioon same regardless of size - it's measuring height of a colum of water. the cameron head loss would be the dynamic pressure - i.e. static head less friction loss in nozzle - make sure to account for additional friction loss if there is any associated length of pipe...
look for "Ten states standards" via google
Where are you located ?
Many states have min. standards for dwellings based on home type - e.g. 100 gpd / person if you are going to sanitary sewers.
If you are designing an onsite WWTP that may be a different story.
1 water saver toiler = 1 gallon...
Do not confuse air entrainment with cavitation - cavitation is hydraulic phenomenon - not related to air.
Air entrainment is a function of several items - most important that suction meets minimum submergence in all conditions - usually worst case is maximum flow rate at pump off liquid level...
How dry do you want it ? What is the destination of dry bulk material.
Thermcools' statement on rough approximation is correct - except I don't understand what He means by "heat absorbed by bulk biomass" and "loss to the ambient".
While as a unit operation Themcool is correct on rough...
What sort of a climate are you in ?
Is this domestic sewage or industrial wastewater ?
Are tanks concrete, steel, fiberglass ?
Are tanks in ground or above grade ?
What is typical sludge concentration ?
If it were simply heat transfer through sidewalls and bottom of tank, how would you...
maybe you should loook aflatplates website. They have a java sizing tool that can be extremely helpful. This an a better way than shell & tube for any application.
www.flatplate.com/
www.flatplate.com/software.htm
Whoa a bit here ...
Digestion is a biological process in which there are many and complex reactions are taking place. There are bacteria eating other bacteria and producing gases.
There is digestion of primary sludge (primary digestor) which is essentially large organics, greases, oils...