With ~150 dairies and the largest average herd size in the US, New Mexico is currently ranked 9<sup>th</sup> for milk production and 5<sup>th</sup> for cheese production in the nation. More than 75% of the milk volume is produced in the east side of the state, where the main campus of Eastern New Mexico University (ENMU) is located. On a single day, 5.6 million gallons of manure are generated in the industrialized dairies in New Mexico. The Southwest Cheese Co., LLC is also located 15 miles to the northeast of the campus, and produces 1.2-million gallons of cheese whey wastewater daily. The readily accessible wastewater makes ENMU a natural research site to study how to turn the wastewater into green energy and other value-added products. During the past three years, we have been cultivating algae on an outdoor Algal Turf Scrubber® (ATS) from dairy manure effluents. ATS is an engineered system, which flows pulsed wastewater over slopping surfaces with attached and naturally seeded algae. Initially, single-cell phytoplankton dominated the entire floway and no filamentous algal genera were identified, due primarily to the high pH of the effluents and limited carbon sources. Here, we report on our recent efforts in controlling the pH of the effluents by simply covering the carbon recovery unit with shade cloth. The shade cloth reduces ~70% sunlight and ~ 90% UV to the effluents in the unit. As a result, the pH of the effluents drops to ~7.4, and filamentous algae grow in vast booms. We will also talk about our effluent nutrient analysis, biomass productivity, algal strain identification, ash content, and analysis of carbohydrate and fatty acid methyl ester. Because of the modular/flexible design, ATS seems to offer the most economically and environmentally sustainable technology in treating dairy and/or cheese whey wastewater on a large scale.

Algae cultivation on a pilot-scale Algal Turf Scrubber® from dairy wastewater for bioremediation and sustainable biofuel production

253rd National Meeting (2017)

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