THE PROJECT - Nitrification in cold weather

NINGAN China is a city with 440,000 Population situated in the Northern Province of Heilongjiang. The City is famous for its Ice Sculpture festival and experiencing harsh winter conditions during most of the time of the year.

THE PROBLEM

During the period of 2010, The city was commissioning a BOD removal Sewage Treatment Plant based on Oxidation Ditch Pond Technology for their sewage disposal requirement. However, due to change in the legislation , they required to meet Chinese Class I criteria of BOD,TSS,TN < 15 ppm with Ammonia < 5 ppm. Thus the plant required upgradation to achieve nitrification in cold weather

THE CHALLENGE

  • Very low ambient temperatures of -15 to -25 Degree C having liquid temperature in the range of 8-10 Degree C
  • Already existing STP was under construction and thus utilizing existing infrastructure to its maximum efficiency was a challenge.
  • Achieving Nitrification under such colder climate through out the year was the biggest challenge authorities were facing.

THE SOLUTION: LEVAPOR-IFAS UPGRADE

Based on Levapor’s extensive experience with Colder Climate Nitrification of Municipal Wastewater, a solution was proposed which required to upgrade the existing Activated Sludge system to Levapor based IFAS Process by adding Levapor carriers at 12-15% filling ratio in the existing Aeration Tank basin.

THE DESIGN

For the Upgradation of the Sewage Treatment Plant to achieve Nitrification at winter temperatures , following design was suggested.

nitrification in cold weather

THE: PERFORMANCE

  • The plant was started during the month of October 2010 , which is already winter in Northern Province.
  • Despite start up during winter, the plant achieved remarkable nitrification within 6 weeks time period and remain stable over a wide range of BOD,COD and TKN loads to the plant.
  • The plant then has been performing well under varying conditions of temperature, BOD/COD/TKN fluctuations meeting Chinese Class I criteria of BOD/TSS/TN < 15 ppm through out the year.

 

COD REMOVAL

For the Upgradation of the Sewage Treatment Plant to achieve Nitrification at winter temperatures , following design was suggested.

NITRIFICATION AND TKN REMOVAL:

  • Despite cold winter start up, the Nitrification was established at NINGAN plant with LEVAPOR IFAS Process within 6-8 weeks period and remained stable over a wide range of inlet COD,TKN and temperature conditions.
  • Throughout the year, the plant is consistently meeting the NH4.N and TN criteria. Due to internal porosity of Levapor carriers, remarkable Simultaneous Nitrification and Denitrification is also occurring in the plant achieving TN values in the outlet without Anoxic Denitrification basin.

THE LEVAPOR-IFAS ADVANTAGE ATNINGAN PLANT

  • Consistently Meeting Chinese Class I Criteria of BOD/TSS/TN < 15 ppm through out the period of operation Despite lower temperature of 8-10 Degree C, Achieving Stable Nitrification
  • Achieving COD < 50 ppm and NH4.N < 5 ppm all the times
  • Nearly 40-50% Simultaneous Nitrification and Denitrification reducing Denitrifying Anoxic Reactor requirement.