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Naturally Reducing BOD, COD, and FOG Discharge with Bioaugmentation

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February/March 2018

Many industries are faced with waste discharge problems. Their output of various organic waste materials is high, but they face restrictions on how much they can discharge. Exceeding restrictions results in fines or fees based on the amount of contaminants released. A natural solution to relieve this problem is both desirable and available.

High BOD, COD, and FOG

The amount of contaminants in wastewater is often measured by the effluent’s BOD or COD—biological oxygen demand and chemical oxygen demand. These measurements show how much oxygen is required to degrade the amount of organic contaminants in the wastewater. A higher oxygen demand signifies that there is a higher level of organic waste present. High BOD or COD can be a problem for almost any type of industry that discharges wastewater. Facilities often pay a surcharge based on how much BOD and COD is released into the municipal treatment system. This can add up quickly.

FOG (fats, oils, and greases) is a significant problem for the food and automotive service industry. Restaurants and dairy operations have trouble because of the high levels of waste dairy fats or cooking greases generated. The automotive repair and service industry has to be careful about runoff from automotive oils and greases. FOG from either industry can clog the sewer system—not to mention the drains inside the facility—and cause major problems. The installation of grease traps to capture FOG is typically required at both food and automotive facilities. Exceeding FOG discharge limits can result in expensive surcharges and/or fines. Many waste treatment plants already use microorganisms (i.e., bacteria) to break down wastewater contaminants. Activated sludge systems or lagoons (commonly used in secondary wastewater treatment) accommodate naturally occurring bacteria that “eat” away at contaminants. These bacteria produce enzymes that allow them to break down and digest contaminants as food. The bacteria release carbon dioxide and water as byproducts.

While bacteria already present in sludge can eventually complete the work of degradation, the addition of supplemental microorganisms can enhance performance efficiency and help handle shock loads of contaminants that suddenly flood the system. This addition of specially chosen microorganisms is called bioaugmentation and is often coupled with biostimulation, the application of nutrients that will encourage healthy microbial activity.

Bioaugmentation is not limited to use in the municipal waste treatment plant. It is ideal for industries to use on site before discharging waste. This kind of pretreatment will reduce the level of BOD, COD, and FOG that a facility releases into the municipal system, cutting costs for fines and surcharges.

Specific Treatment Examples

Some bacteria are better than others at producing certain enzymes and should be chosen based on their “appetite” for the target contaminant. Because of this, special microorganism blends have been developed to meet the needs of specific industries based on which contaminants are present in higher concentrations. Contaminants have showed a high response rate to these treatments.

Pulp and Paper Plant BOD, TSS, and Odors

BCP57 is specially designed to decrease both BOD and TSS (total suspended solids) in pulp and paper effluent, and also reduce bad odors. In one case, it was used to treat the effluent at a pulp and paper plant in Chile, where BOD was 800-1000 mg/L. A shock dose of 40 kg of BCP57 was added for 10 days, followed by a daily maintenance dose of 1 kg. By the end of 15 days, BOD had dropped to 300 mg/L, a reduction of approximately 60%. Effluent color had changed from milky to clear brown. After 30 days of treatment, BOD dropped to 70 mg/L, and noxious odors were significantly less. The biomass (the microbial colony) stabilized 45-60 days into the treatment, with BOD at 30 mg/L. By the end of six months, BOD had dropped to 15 mg/L.1

Vegetable Processor BOD and Odors

Some industrial plants use their own lagoon systems to pretreat waste before releasing it into the municipal waste system or surface water. For these systems, BCP60 contains a blend of microorganisms that perform under both aerobic and anaerobic conditions and target a mixture of proteins, fats, carbohydrates, and select hydrocarbons. The overall effect is to reduce sludge and odors and improve effluent. This treatment proved highly effective in the aerated lagoon systems of a Southern Ontario vegetable processor, where heavy organic loading of waste vegetable matter was causing odors so significant that staff and the surrounding community started to complain. BCP60 was added along with STIMULUS (a biostimulant nutrient blend), and the odor problem was resolved within a couple of days. In about one week, the BOD load had decreased by almost 98% (to 10 mg/L) in one lagoon and by more than 50% in the other lagoon (organic loading differed in each lagoon).2

Paint Plant COD Discharge

Companies that release complex organic chemical waste such as surfactants, alcohols, phenols, and benzene compounds stand to benefit from the microorganisms of BCP10. This blend was used to reduce COD at a U.K. paint plant, where COD consent to discharge level was 70,000 mg/L. A treatment period of seven weeks brought the levels down to 33,800 mg/L (see figure 1), allowing the company to save on disposal costs while meeting discharge requirements.3

Figure 1: Paint plant COD discharge levels before and after treatment with BCP10.

Chemical Manufacturing Plant COD Levels

BCP10 was also used at a chemical manufacturing plant in the upper Midwest. The plant had been receiving extra surcharges because of excess COD discharge levels. Addition of BCP10 brought COD levels from a varying range of 4,000-10,000 mg/L down to 2600 mg/L during the six week trial. Six months later, COD levels were down to approximately 1000 mg/L, lower than they had ever been in the facility’s history, even when production levels were lower.4

Image 1: BCP10 was added before releasing waste to the treatment plant. COD levels dropped to the lowest they had ever been in the plant’s history.

Clearing the FOG for Food and Automotive Industries

Aerobic and facultative anaerobic bacteria such as those in BCP22 and BIOBLOC22 are useful for systems that deal with high levels of fat, oils, and greases. When added to grease traps or lagoons, these bacteria visibly reduce grease buildup and minimize accompanying foam and odors. BCP22 can be applied in powder form; whereas BIOBLOC22 is a slow-release block that can be installed in grease traps to fight grease buildup over time (see images 2 and 3). GTC 3X and Eco-Trap are grease trap liquid concentrates that help degrade FOG and are also good for drain maintenance and odor reduction. BCP35 and BIOBLOC35 can be used to degrade petroleum compounds in the automotive industry.

Image 2: BIOBLOC22 is a slow release block that can be placed in grease traps to discourage grease buildup over time.

Image 3: The progressive effect of bioaugmentation on
FOG buildup in a grease trap.

Conclusion

The challenge of high BOD, COD, and FOG loading is not as difficult as it may seem. By pursuing the natural treatment method of bioaugmentation, industries can significantly reduce their discharge levels and lower waste treatment surcharges and fines. Microorganisms are waiting to help accomplish the task with a healthy appetite.


For more information, visit www.bionetix-international.com
Bionetix International
21040 Rue Daoust, Sainte-Anne-de-Bellevue,
Quebec, Canada, H9X4C7
Tel: 514-457-2914 Email: tdecterov@bionetix.ca

References:

1. Bionetix International. “Treatment of Toxic Loadings from a Pulp and Paper Mill in Chile Through the Addition of BCP57.” Case Study. Accessed 7 Feb. 2018 <http://www.bionetix-international.com/resources/casestudies/cs_bcp57_chile.pdf>.

2. “Lagoon Odor Control/BOD Reduction Through the Addition of BCP60 and Stimulus.” Case Study. Accessed 7 Feb. 2018 <http://www.bionetix-international.com/resources/casestudies/cs_bcp60_stimulus_lagoon_odor.pdf>.

3. “The Use of BCP10 to Reduce Discharge Levels from a Paint Plant.” Case Study. Accessed 7 Feb. 2018 <http://www.bionetix-international.com/resources/casestudies/cs_bcp10_paint_plant.pdf>.

4. “The Use of BCP10 to Reduce COD Levels from Chemical Manufacturing Plant.” Case Study. Accessed 7 Feb. 2018 <http://www.bionetix-international.com/resources/casestudies/cs-bcp10-chemical-plant.pdf>.

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