Date of Award

Summer 2017

Degree Type

Thesis

Degree Name

Master of Science (MS)

Committee Chair

Kumar Ganesan

First Advisor

Martha Apple

Second Advisor

William Drury

Third Advisor

Xufei Yang

Abstract

Microalgae from the Coal Bed Methane (CBM) ponds of the Powder River Basin (PRB) in Southeastern Montana have the potential to be utilized as fertilizer for use on the economically important plants of Montana. Three very important economic field crops of Montana (winter wheat - Triticum aestivum, potato - Solanum tuberosum, and flax - Linum usitatissimum) were used for the fertilization experiments. Isolates of unicellular green algae - PW95 (sequenced as Neospongiococcum sp.) from the CBM ponds, and blue-green microalgae – Cyanobacteria (Anabaena Cylindrica) were cultured in the laboratory and the cells were concentrated using gravity sedimentation. Nutrient analysis of the PW95 cultures showed nitrogen as the most abundant component with a concentration of 1240 mg/L. Other components, such as potassium and phosphorus, 264 mg/L and 130 mg/L respectively, were also detected. Concentrated algal slurry was added to the seedlings after the determination of their nutrient composition and the wheat and potatoes were harvested after 120 and 100 days respectively.

Overall, when compared to control wheat grown with only water, or with water and a commercially available fertilizer, the PW95-fertilized wheat had higher chlorophyll content, more tillers (side shoots), and higher ratio of inflorescences (groups of flowers) per stem. Data analysis showed a statistical difference in plant height of wheat fertilized by PW95. In terms of harvest, the average total dry weight for PW95-fertilized wheat was 117% and 47% more than those of water and chemical fertilizer (Miracle-Gro - M.Gro) - treated wheats respectively. Measurements of the seed weights showed that PW95-treated plants are 123% and 58% higher than corresponding measurements for wheat treated with water and M.Gro respectively. The results of this study suggest that PW95 from the CBM ponds may be a viable source of fertilizer for crops and other economically important plants of Montana and may contribute to the development of an economically important and locally obtainable product from the ponds. These results were not as pronounced in PW95-fertilized potatoes.

A major bottleneck to effective implementation and deployment of microalgae as a fertilizing agent is the availability of biomass which originates from noticed deficiencies in biomass harvesting techniques. Experiments conducted using KOH as a flocculating agent for biomass harvesting showed that PW95 cells agglomerate as the pH of the suspension increases. An optimal pH level was found to be 11.5. Highest flocculation efficiencies of 28% and 42% were achieved at optimum pH 11.5 over a settling time of 15 and 30 minutes respectively. However, efficiency at pH 12 (51.82%) was marginally higher (3.4%) than the efficiency at pH 11.5 at 45 minutes.

As widely stated in literature, the use of KOH as flocculant is intended to contaminate, with potassium, the biomass product and lower its quality. However, with potassium being an essential growth agent for most crops, the biomass product from the flocculation experiment could represent an innovative method of increasing the properties and performance of PW95 as a biofertilizer.

Comments

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering

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