Atmospheric Properties and Their Observable Correlations with Volatile Organic Compounds Emission Concentration at Some Gas Stations in Port Harcourt City

This study focused on atmospheric properties and their observable correlations with volatile organic compounds (VOCs). Six gas stations and the nearest residential buildings within Port Harcourt City were selected for the study. At each of the gas stations and the nearest buildings, a well calibrated handheld IGERESS VOCs detector was positioned 1.5m above the ground and in the direction of the wind to determine the levels of VOCs concentration. Atmospheric Properties (temperature and relative humidity) of the selected gas stations and the nearest buildings were determined accordingly. These were done in the morning and evening hours for a period of two weeks. The study's findings revealed gas stations emit VOCs and that the VOCs emission concentrations in the morning and evening sessions were within safe limits. But the measured mean VOCs concentration at the gas station (0.343ppm) is above the United States Environmental Protection Agency (USEPA) maximum allowable air concentration Standard of 0.20 ppm. The recorded mean value of the VOCs concentration at the gas stations (0.343ppm) shows that the average exposure limit from the gas stations for the period under study is in agreement with the permissible limits of between 0.3 ppm to 0.5ppm established by World Health Organization (WHO) and the National Institute of Occupational Safety and Health (NIOSH) respectively. The calculated correlation values between VOCs concentration and temperature at the gas stations and nearest buildings are 0.0020 (weak positive correlation) and -0.0111 (negative correlation) respectively. Similarly, VOCs concentration showed a negative correlation with the relative humidity at the gas stations and the nearest residential buildings. The calculated correlation values are -0.1952 and -0.7257, respectively. These results are in agreement with some studies. A number of studies have shown that VOCs emissions are positively correlated with temperature, but that of relative humidity has no uniform conclusions. Volatile organic compounds (VOCs) pose numerous health challenges and serious environmental concerns such as poor air quality and shift in climate. Siting of gas stations far away from residential areas and the use of fuel recovery pumps are essential for the reduction of the impacts of VOCs on humans and the environment

Optimization of Biogas Production from Fresh Cassava Peels and Fresh Cow Dung (Using Pretreatment Chemical): Sodium Hydroxide

This study was conducted on optimization of biogas from fresh cassava peels and fresh cow dung using sodium hydroxide (NaOH). The possibility of producing biogas from fresh cassava peels and fresh cow dung waste was investigated. Fresh cassava peel and fresh cow dung was used in the study. The feed stocks fresh cassava peels, fresh cow dung and fresh cassava peel mixed with fresh cow dung were charged into the bio-digester and used to investigate the anaerobic digestion in generating biogas for 20days retention period. The digesters were charged separately with these wastes in the ratio of 1:2, 1:3 and 1:3 of waste to water respectively. Pretreatment chemical, (NaOH) solution was used in pre-treating the fresh cassava peel and fresh cow dung slurry. The volume of biogas produced were monitored and recorded daily. The result obtained from the biogas production showed that fresh cow dung produced the highest methane content of 67.9 percent, followed by the mixture of fresh cassava peel and fresh cow dung with 59.7 percent methane content and fresh cassava peels has the least methane content of 51.4 percent. The results also showed that the cow dung also had the highest cumulative biogas yield of 93.3litres, followed by the mixture of cassava peel and cow dung with cumulative volume of 73.8litres and the least was cassava peels with cumulative volume of 61.3litres within the same retention period of 20days. Overall results indicate that these wastes which are always available could be source of renewable natural gas if properly treated