Hydrogen Sulfide Monitoring Around the Barceloneta Wastewater Treatment Plant

Located on the north coast of Puerto Rico, the Barceloneta Regional Watstewater Treatment Plant (RWWTP) serves several municipalities, as well as several industrial companies. Two residential communities are located east and west of the plant site, while south of the plant site are agricultural fields used to grow pangola grass. As part of a stipulation and settlement agreement, the Puerto Rico Aqueduct and Sewer Authority (PRASA) completed a program of ambient air monitoring for hydrogen sulfide (H2S) at the Barceloneta RWWTP. The program spanned a full year, beginning March 18, 2009, and ending March 17, 2010.This paper provides a description of the monitoring program design and the rationale for the methods used; a summary of the full year of hydrogen sulfide concentration data; description of the meteorological data and discussion of weather impacts on hydrogen sulfide dispersion; and conclusions on the overall monitoring program as it relates to the court mandate.The H2S monitoring program included recording H2S concentrations within and outside the Barceloneta RWWTP's fence line. Onsite data collection consisted of four fence line H2S monitors and one onsite meteorological station. The meteorological station was positioned to capture representative ambient onsite conditions, with minimal influence resulting from wake effects from structures. The four onsite H2S monitors were positioned to be able to evaluate the RWWTP sources and allow for flexibility in the event of temporary equipment downtime. The offsite monitoring was conducted within the communities of La Boca and Punta Palmas. Monitors were located near the community baseball fields, which serve as recreational areas and central gathering places for each of the communities.The monitoring program was set up and executed in order to provide coverage, accuracy, and precision sufficient to exceed the intent and requirements of the settlement agreement. It succeeded in meeting those requirements.