Novozymes BioRemove 1100 improved plant stability through enhanced COD reduction
The application of BioRemove 1100 to a paper facility significantly improves COD reduction and maintains plant stability during production changes.
- 16% COD reduction in effluent concentrations
- Reduced effluent variation
Acclimation is the adaptation of an organism to its natural environment. In part, this involves having the genetic capacity to produce the enzymes needed to degrade available organic compounds. Loss of acclimation often occurs with fluctuating wastewater quality, with the result that population dynamics can be impacted such that degrading organisms may be absent prior to the appearance of periodically available compounds. Degrading organisms may also be absent if concentrations of a specific organic compound are too low or if their food source is scarce. Toxicity can also impact acclimation by destroying previously acclimated biomass.
A paper mill had built a new wastewater treatment plant. Due to space limitations the aeration basin was designed too small, and there were concerns that a short hydraulic retention time (HRT) would compromise treatment. The mill processed two varieties of magazine paper and one type of paperboard. The type of paper changed every 3 to 5 days, leading a lack of effective COD reduction, particularly with paperboard. The plant approached Novozymes for a solution to maintain plant stability and improve effluent COD reduction without the need to invest in capital equipment.
Novozymes assessed the situation and determined that BioRemove 1100 could be used to enhance COD reduction in the system. Due to the short retention time, a preacclimation device (PAD) was recommended. A PAD is a 500 gallon (2000 L) on-site aerated reactor that uses influent wastewater to feed and acclimate BioRemove 1100 cultures to the wastewater before releasing them into the aeration basin. The PAD was programmed to discharge a portion of its contents into the aeration basin every 2 hours and refill using influent wastewater.
|Flow||0.5–0.8 million gallons/day
||0.12 million gallons (450 m3)|
Table 1. System flow diagram
A summary of the first month of the program is shown in Table 1. The average discharge COD concentration was 16% lower than it was during the 30 days prior to the start of the program. In addition, the effluent COD was less variable during this time, as demonstrated by a lower standard deviation.
|Flow (m3/d)||COD (mg/L)||
|30 d prior||2,190||1,114||283||115|
Figure 2 below shows a chart of influent and effluent COD over a 3-month period. Every time paperboard was processed, COD reduction spikes were observed in the influent wastewater. Corresponding peaks in the effluent COD were almost always observed prior to the start of the bioaugmentation program. After the program started, these peaks were nearly eliminated.
Fig. 2. While using BioRemove™ 1100, the plant remained stable during heavy loading in December and January.
By using BioRemove 1100, the mill was able to achieve its treatment goals and maintain stability, in spite of frequent production changes. This simplified operations by avoiding having to implement high-effluent COD reduction control measures and lowered costs by minimizing the risk of permit violations.
BioRemove 1100 resulted in:
- Lower operating costs
- Improved plant efficiency through effective COD reduction
- Simplified operations