Managing and Projecting a Significant Industrial Load Increase At an Enhanced Nutrient Removal Potw

Howard County, Maryland, owns and operates the 25-mgd Little Patuxent Water Reclamation Plant (LPWRP), which is a biological nutrient removal (BNR) wastewater treatment plant. The plant was planning for a major upgrade to achieve enhanced nutrient removal (ENR) to meet future effluent total phosphorus and total nitrogen limits of 0.3 ppm and 4.0 ppm, respectively. Concurrently, a local frozen dairy industry within the LPWRP service area announced plans for a significant production capacity from only six production lines to more than 20 lines (expected range of 23 to 26 lines), with the potential of increasing BOD loading to the LPWRP from less than 10 percent to nearly 40 percent of the total influent BOD load. To develop a strategy for managing the increased industrial loads while meeting very stringent nutrient limits, the County needed to accurately project the increase in industrial loadings over the course of the phased manufacturing expansion. This paper presents the County's efforts and methods to project the future industrial loadings, as well as the management approach for treating the increased wastewater loadings while meeting stringent future nutrient limits.