Fellow: Swati Sharma
Adviser: Halis Simsek

This study focused on the reduction of dissolved inorganic nitrogen, dissolved organic nitrogen (DON), soluble chemical oxygen demand (sCOD) and dissolved organic carbon (DOC) from animal feedlot and domestic wastewaters using pretreatment with electrocoagulation (EC) and following biological treatment with a mixed culture of bacteria and a pure strain of algae Chlamydomonas reinhardtii. Wastewater samples were collected from two different sources; (i) the animal feedlot wastewater samples were collected from Animal Nutrition and Physiology Centre (ANPC), North Dakota State University (NDSU), Fargo, North Dakota and (ii) the domestic wastewater samples were collected from the City of Fargo Wastewater Treatment Plant (WWTP).

The wastewater samples were subject to pretreatment with EC at 20V, 0.9A for 25 mins until the water become clear. Aluminum electrodes was used for the process. The samples were then analyzed for the presence of COD, DOC and DON. The EC effluent samples were further inoculated using mixed culture bacteria and pure strain algae. The amount of bacterial and algal inocula introduced to the samples were 2 mL and 3 mL, respectively. All the samples in the bottles were incubated for 21 days and the bottles were aerated once daily. All the samples were agitated at 100 rpm using an orbital shaker. After 21 days of incubation, COD, DOC and DON were measured.

Significance of Research:

The livestock wastewaters contain high concentration of organic compounds with high turbidity and color. Hence, direct application of biological treatment methods to raw livestock wastewater is challenging. EC has been efficient as a pretreatment method in the removal of color as well as reduction of organic carbon concentration in various wastewaters including livestock and domestic wastewaters. Degradation of nitrogen compounds through biological treatment has been widely accepted in domestic wastewater. Thus, integrating these two methods for treatment of wastewater derived-nutrients could be successful in improving the quality of receiving waters. An effort to further present a comparative study of batch and continuous operation was proposed to optimize the removal efficiency of both the methods in the degradation of organic nitrogen and carbon. The findings of this research will be presented at national and/or regional conferences and will be submitted for publication in a peer review journal. A final report containing all the information on the project including raw data will be delivered at the end of the project.

Significant Findings:

The application of EC using aluminum electrodes into animal feedlot wastewater samples resulted in 50% removal of SCOD at the end of 45 mins of operation time. The initial concentration of SCOD was measured at 539 mg/. The concentration of dissolved NH3, NO2 and NO3 remained unchanged. However, the TN reduced from 135 mg/L to 113 mg/L which can inferred as DON reduction from readily available organic nitrogenous compounds. The EC samples were then introduced to a mixed culture bacteria and pure strain algae for removal or conversion of DON to inorganic nitrogen taken up by algae as growth nutrients. The biological process is still under progress and the complete findings will be reported in the final report.

Publications

     Sharma, S., H. Simsek. 2018. Mixed cultured algal and bacterial remediation of dissolved organic nitrogen under low solid retention time condition. Journal Desalination and Water Treatment, accepted.

     Sharma, S., O. C. Taner, M. Hammed, D. Nawarathna, H. Simsek. 2017. Organic pollutant removal from edible oil process wastewater using electrocoagulation. Proceedings of ICSAE 2017 4th International Conference on Sustainable Agriculture and Environment, Aug 10-12, Solo City, Indonesia.

Presentations

     Sharma, S., O. C. Taner, M. Hammed, D. Nawarathna, H. Simsek. 2017. Organic pollutant removal from edible oil process wastewater using electrocoagulation. Proceeding at ICSAE 2017 4th International Conference on Sustainable Agriculture and Environment, Aug 10-12, Solo City, Indonesia.