Reduction and Control of Total Nitrogen in a Cheese Factory

Treatment system enhancement using Microcat ® – DEN Denitrifiers – BSE 099

Problem
The wastewater treatment system receiving wastewater from a cheese factory in the EU has difficulty meeting total nitrogen effluent discharge requirements. The wastewater flow rate is 2000 cubic meters per day. The treatment system consists of two sequencing batch reactors (SBRs) operating in parallel. Since the reactors were overloaded, the operations team believed that it would be impossible to meet the effluent total nitrogen discharge requirements for the plant.
Objective
To meet the total nitrogen discharge requirements without making any physical changes to the treatment plant.

Procedure
Microcat – DEN Denitrifying Microbes is a consortium of denitrifying microbial cultures and microbial growth promoters. The application procedure for this product was very simple:
• Microcat – DEN is a dry powder and was added to one of the two SBRs at the dosage below:
• Days 1 and 2: 3 kilos (6.6 lbs) per day
• Days 3 through 20: 2 kilos (4.4 lbs) per day
• Days 21+: 0.5 kilos (1.1 lbs) per day maintenance
This unique parallel application program design offers the opportunity to isolate the impact of MICROCAT – DEN addition since the performance of the SBR into which the product was added could be directly compared to the SBR operating side by side with it but without the product addition.
Results and Conclusions
After two months of DEN application the SBR receiving the product was achieving total nitrogen discharge levels below permit requirements. Moreover, the SBR receiving the DEN product regularly had Nt levels 50% below those of the non-dosed SBR. An unexpected but welcome finding was that the dosed tank also experienced a significant improvement in sludge settling rate. This allowed the operations team to make cost saving changes in how the SBR process was operated.

Chart 1 – Nt Results with MICROCAT – DEN

 

Chart 2 – Nt Results in Parallel SBR without Product Addition

Chart 3. Comparison of Effluent Nt in Both SBR Reactors

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