טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentGraif Hagit
SubjectEnergy Balance on Selected Wastewater Treatment Plants
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Emeritus Galil Noah (Deceased)
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

The goal of this research is to present data for the energy (power) consumption during the various treatment stages that are taking place in a WWTPs that are processed by the method Activated Sludge. For that purpose all energy consumption data was collected on a daily basis in six wastewater treatment plants. This work includes two stages:
The first stage, gathering data from main energy consumption spots in various WWTPs in different stages of the process.

The second stage was calculation of energy consumption required to treat one cubic meter of raw sewage entering the WWTP. This energy consumption is called the “specific energy consumption”(S.E.C.)

This S.E.C. was calculated for different sizes of W.W.T.Ps As classified hereinafter:
Small Plants - up to 10,000 cm/day,  Medium Plants - up to 20,000 cm/day and Big Plants - over 20,000 cm/day.
 

    The main conclusions of this research are:
  1. Specific energy consumption per cum of raw sewage (kWh/cum) in small plants is 2.39 times higher than the S.E.C.in big plants.
  2. Growth in the influent flow under constant nutrients contribution caused by natural development reduces S.E.C. parameter of influent entering the W.W.T.
  3. The biological treatment process consumes from 27% to 60% of all the energy demand of the W.W.T.P.
  4. In a WWTP that the sludge treatment is aerobic the total energy consumption for aeration process only varies from 49% to 53% of all energy demand in the plant (Such as Bakaa El Garbiee and Yerucham WWTPs).
  5. In WWTP that applies anaerobic sludge treatment it was found that the total energy demand for aeration  only varies from 27% to 39% out of the total energy consumption in the plant (Such as Herzliya and Kefar Saba-Hod Hasharon WWTPs).
  6. Anaerobic sludge treatment significantly reduces the energy consumption in comparison with to aerobic sludge treatment (assuming that the final goal in both is class "B" treatment).
  7. A.T.A.D. sludge treatment (in Kolchey Hasharon WWTP) demand is some
    4.5 Times higher S.E.C than Mesophillic anaerobic treatment (in Beit Sheaan  WWTP, from same order type and flow) but upgrades sludge treatment from class B to class A.
  8. Considering the potential methane gas (biogas) production, the total required energy consumed through the whole process, sewage & sludge treatment, per day is lower than the energy that can be produced and co-generated.