טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentKostovetsky Alexandra
SubjectEvaluation of Energy Requirement as Influenced
by the Level of the Primary Treatment
Sedimentation
DepartmentDepartment of Chemical Engineering
Supervisor Professor Emeritus Noah Galil (Deceased)
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

Wastewater treatment plants are large energy users with excellent conservation potential. Wastewater treatment energy consumption will increase in the future due to population growth, increasingly restrictive environmental regulations, and demand for wastewater reuse.

This project has performed a general analysis of the influence of different levels of primary treatment on the overall energy consumption in a WWTP. The research objectives were to evaluate the influence of primary treatment on the energy consumption in different stages of the wastewater treatment process and on the overall energy consumption of the plant as well as on the energy production from bio-gas in the anaerobic digester. Another goal was to test the influence of the wastewater quality on the energy consumption in each alternative which was analyzed.

    A mathematical model for energy consumption in WWTP was developed. Via this model six process combinations were tested:
  1. primary treatment biological nutrient removal (BNR) sludge treatment
  2. Regular sedimentation BNR sludge treatment
  3. CEPT BNR sludge treatment
  4. No primary treatment biological treatment for organic material removal sludge treatment
  5. Regular sedimentation biological treatment for organic material removal sludge treatment
  6. CEPT biological treatment for organic material removal sludge treatment

    The main research conclusions:
  • In WWTP, when any type of primary sedimentation, CEPT or regular sedimentation, is performed the overall energy consumption is the lowest.
  • In WWTP with only organic material removal, CEPT has a clear advantage on the other alternatives regarding energy consumption.
  • In both cases of WWTP with and without BNR, the more efficient is the primary treatment the energy from bio-gas is increased.
  • When regular sedimentation or CEPT are performed the WWTP is producing more energy from bio-gas than it consumes for wastewater treatment process. According to the balance, when CEPT is performed more energy is produced than in case of regular sedimentation.