COMPARISON OF MBBR AND Suspended growth BNR Performance at the
HRWTF
Erika L. Bailey, PE NC AWWA WEA Annual Conference November 16, 2015
01 02 03 04 05 Introduction, Drivers, and Challenges
Segregated Treatment Concept 03 MBBR / Suspended Growth Comparison
04 Conclusions 05 Project Status Introduction, PROJECT DRIVERS, AND
CHALLENGES
01 Introduction, PROJECT DRIVERS, AND CHALLENGES HRWTF is a
publicly owned industrial treatment works
Located 20 miles southeast of Richmond, VA 50 mgd capacity,
currently treating 28 mgd Small domestic base flow 23,000 residents
LARGE industrial contribution 85% of flow High Purity Oxygen (HPO)
activated sludge with denitrification No nitrification currently
HRWTF Existing liquid treatment Process
HAP Foul Condensate VAWCO Gravelly Run RockTenn Industrial
Headworks Reaeration Hercules Denit. Basin Industrial
PrimaryClarifiers HPO Aeration Tanks Evonik Final Clarifiers RAS
Honeywell HOCl Domestic Domestic Headworks 2012Improvements (Phase
1) Domestic PrimaryClarifiers & Chlorine Contact Tanks Total
Nutrient Discharge Load by Year (Mlb/yr)
Project Drivers Nitrogen (TN) Reduction Chesapeake Bay Nutrient
TMDL HRWTF currently purchases TN credits Future market for credit
purchases unknown Ammonia (NH3-N) Reduction Current NH3-N limit:
mg/L 30% - 90% reduction anticipated Monthly Avg:2.0 14.2 mg/L
Daily max:3.1 21.6 mg/L Total Nutrient Discharge Load by Year
(Mlb/yr) TP TN HRWTF Waste Load Allocation 0.075 1.83 2005 ND 1.9
2006 1.55 2007 1.7 2008 0.048 1.57 2009 0.013 1.88 2010 0.028 2.02
2011 0.020 1.77 Nitrogen Removal is Challenge at hRWTF
Exceeds upper temperature limit for stable nitrification High
influent temperatures exceed 37 C Cooling creates air permitting
challenges High concentration of VOCs Impacts process performance
stability Variable influent wastewater characteristics Slower
nitrification rates expected (larger aeration tanks) Wastewater
contains nitrification inhibitors Addressing BNR Challenges:
Segregated Treatment Concept
02 Addressing BNR Challenges: Segregated Treatment Concept Project
development approach
Effectively build upon previous studies Segregated Treatment
alternatives to address key challenges Leverage knowledge from
previous testing Effectively address nitrification inhibition 2007
Comprehensive Alternatives Evaluation identified Segregated
Treatment as preferred alternative Unique Segregated Treatment
Approach Addresses Temperature Challenge
Separate high nitrogen and high temperature streams Achieves
biological nutrient removal on portion of flow Eliminates need for
cooling industrial influent BUT Honeywell wastewater contains
nitrification inhibitors Final Effluent Domestic Honeywell
Biological Nutrient Removal Secondary Treatment Combined Influent
Total Influent Ashland RockTenn VAWCO Evonik Primary Segregated
Stream Is there any issue naming all these industrial?Check with
Hopewell, if you havent yet. MBBR: Moving Bed Biofilm Reactor
Segregated Treatment Approach Must Also Address Nitrification
Inhibition Limit Honeywell flow to Segregated Treatment Use MBBR
system for biological treatment High rate process Concentrated
biomass; media provides high surface area to volume environment
Biofilm structure Media contained within separate cells
Self-regulating system (do not manage SRT) MBBR: Moving Bed Biofilm
Reactor Bullets look off.Whats supposed to be happening here?
Anoxic Cell BOD Removal Cell Nitrification Cells Pilot Testing
Conducted to Confirm Design Basis
Side-by-side comparison of suspended growth and MBBR processes Both
processes fed with the same influent flow stream Domestic primary
effluent Gradually increased levels of Honeywell flow Comparison of
MBBR / suspended Growth Performance
03 Comparison of MBBR / suspended Growth Performance Pilot Testing
Configuration Pilot Testing Conditions
Scenario Description Influent % Honeywell 1 40% Design Avg 19% 2
70% Design Avg 29% 3 100% Design Avg 37% What is the 1 superscript
for? What does HW stand for? What is design average? What is the
domestic portion? I dont quite understand this. Scenario 1 40%
Honeywell TN removal in MBBR dropped when internal recycle was
temporarily stopped. TN removal quickly increased to the same
levels as the Suspended Growth system once the recycle stream
resumed. This was done initially to purge any inhibitory compound
remaining in the system following the nitrification inhibition
event on February 28th but was left off for an additional three
weeks to test a theory concerning MEKO. Difficult to read
grey-shaded tables. Scenario 1 40% Honeywell Ammonia reduction
Solids removal
Both systems achieved
