Underestimated public health risks caused by overestimated VOC removal in wastewater treatment processes

Abstract

The uncontrolled release of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs) and the adverse health effects on the public have been of increasing concern. In this study, a lab-scale bioreactor was prepared to analyze the mass distribution of three aromatic (benzene, toluene, and xylenes) and four chlorinated VOCs (chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene) among the air, water and sludge phases in wastewater treatment processes. The VOC distribution through a full-scale WWTP in northern China was further investigated with respect to the effects of seasonal temperature variations and treatment technologies, followed by the cancer risk assessment using a steady-state Gaussian plume model (Industrial Source Complex) to simulate the atmospheric behaviors of the VOCs emitted from the WWTP. It was found that three aromatic hydrocarbons, notably benzene, were more readily released from the wastewater into the atmosphere, whereas the chlorinated compounds except chloroform were mainly present in the water phase through the treatment processes. The primary clarifier was the technology releasing high levels of VOCs into the atmosphere from the wastewater. The extents of volatilization or biodegradation, two important mechanisms to remove VOCs from wastewater, appeared to be determined by the physicochemical characteristics of the compounds, as the influence of treatment technologies (e.g., aeration) and seasonal temperature variations was rather limited. More importantly, the people living in the areas even more than 4 km away from the WWTP were still potentially exposed to cancer risks exceeding the regulatory threshold limit. The findings described the complex nature of VOC emissions from WWTPs and quantitatively indicated that the associated health impacts on the public near the WWTPs could be severely underestimated, whereas their treatment efficiencies by wastewater treatment technologies were overestimated. Instead of fully controlling the VOC release from WWTPs, the identification and abatement of important VOC species with regard to the atmospheric emission and health concerns is one possible alternative approach to effectively minimize the environmental and public health impacts by VOCs released from this particular source.

Reviewing putative industrial triggering in pemphigus: cluster of pemphigus in the area near the wastewater treatment plant

“…1 km) to the housing estate located uphill 30 m above the level of the settlement tanks, considering the prevalence of western winds in the Greater Poland district [26] and terrain characteristics (slope, natural forest barrier limiting the eastern winds in the area), we suspect a common factor – presumably waterborne and/or volatile waste products. Volatile organic compounds may be dangerous for wastewater treatment plant workers and inhabitants of nearby houses [27, 28]. The highest levels of these compounds are emitted by a primary clarifier, while the concentration of selected chemicals in one reported case exceeded the regulatory threshold limit even within up to 4 km distance from the wastewater treatment plant [28].…”

“…Volatile organic compounds may be dangerous for wastewater treatment plant workers and inhabitants of nearby houses [27, 28]. The highest levels of these compounds are emitted by a primary clarifier, while the concentration of selected chemicals in one reported case exceeded the regulatory threshold limit even within up to 4 km distance from the wastewater treatment plant [28]. …”

Health Effects Associated with Wastewater Treatment, Reuse, and Disposal

“…studied the contribution of oxidative stress caused by occupational health hazards to the impaired lung functions among sewage workers. Statistically significant decreases were observed in several parameters, such as peak expiratory, force expiratory volume in first second, and forced expiratory flow at 25%-75% of volume as percentage of vital capacity, and it was also found that increased levels of serum malondialdehyde in sewage workers were significant Yang, Wang et al (2014). studied the mass distribution of three aromatic (benzene, toluene, and xylenes) and four chlorinated volatile organic compounds (chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene) among the air, water, and sludge phases in wastewater treatment processes with a lab-scale Water Environment Research, Volume 87, Number 10-Copyright © 2015 Water Environment Federation bioreactor and an investigation of a full-scale WWTP in northern China.…”

Food Waste Materials as Low-Cost Adsorbents for the Removal of Volatile Organic Compounds from Wastewater

“…Chlorinated volatile organic compounds (Cl-VOCs) and aromatic hydrocarbons (BTEXs; benzene, toluene, and xylenes) are ubiquitous contaminants frequently detected in the environment. Therefore, human exposure to Cl-VOCs and BTEX is very common; they enter the body through multiple routes, such as inhalation, ingestion, and dermal absorption [3][4][5]. The toxicity of these compounds is increased by the fact that VOCs are strongly lipophilic with a capacity to concentrate in fat deposits by determining a long-term exposure [6,7].…”