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Wang Z.-C.,Tsinghua University | Xi J.-Y.,Tsinghua University | Xi J.-Y.,State Environmental Protection Key Laboratory of Microorganism Application and Risk Control | Ouyang Y.,Tsinghua University | And 2 more authors.
Research of Environmental Sciences | Year: 2013

Totally 3272 wastewater treatment plants (WWTPs) were built by the end of September 2012 in China. The odor pollution related to WWTPs draws much attention and the odor control in WWTPs becomes more and more important in China. As one of the most typical odorants in WWTPs, H2S is generated from the wastewater and sludge and ρ(H2S) can be determined by characteristics of wastewater or sludge. The correlated parameters of wastewater includes temperature, ρ(DO), pH, ρ(CODMn) and sulfide ρ[S(II)]. The correlated parameters of sludge includes acid volatile sulfide (AVS), oxidation-reduction potential (ORP), temperature and pH. So far, most of studies about the relationship between ρ(H2S) and the characteristic parameters of wastewater or sludge are carried out under laboratory conditions. The concentrations of H2S emitted from pump station, fine screen, aerated grit chamber, sludge thickening tank and sludge storage tank of a municipal wastewater treatment plant were monitored for long period. Meanwhile, wastewater parameters (temperature, ρ(DO), pH, ρ(CODMn), ρ[S(II)]) and sludge parameters (AVS, ORP, temperature, pH) were also monitored. The correlation between ρ(H2S) and the characteristic parameters of wastewater or sludge was analyzed by the single variable and multivariate analyses. The results showed that the ρ(H2S) in the pump station was 0.08~4.27 mg/m3, the ρ(H2S) in fine screen was 0.04~111.61 mg/m3, the ρ(H2S) in aerated grit chamber was 0.16~115.69 mg/m3, the ρ(H2S) in sludge thickening tank was 0.007~0.04 mg/m3 and the ρ(H2S) in sludge storage tank was 0.21~4.00 mg/m3.The results also showed that the ρ(H2S) in the pump station, fine screen and aerated grit chamber had significant positive correlation with wastewater temperature and significant negative correlation with pH or ρ(DO) of the wastewater. When the wastewater temperature is under 15 °C, or ρ(DO) is above 0.20 mg/L, or pH is above 7.2, the ρ(H2S) in pump station, fine screen and aerated grit chamber were quite lower than those under other conditions. Under these conditions, the ρ(H2S) in pumping station, fine screen and aerated grid chamber was kept under 0.27, 3.90 and 7.34 mg/m3. The ρ(H2S) in the sludge thickening tank and sludge storage tank had a significant positive correlation with sludge AVS and a significant negative correlation with sludge ORP.


Xi J.-Y.,Tsinghua University | Xi J.-Y.,State Environmental Protection Key Laboratory of Microorganism Application and Risk Control | Hu H.-Y.,Tsinghua University | Wu J.-L.,Tsinghua University | Kang I.-S.,Tsinghua University
Research of Environmental Sciences | Year: 2014

Recently the air pollution caused by volatile organic compounds (VOCs) is drawing much attention in China. About half of the total VOCs from anthropogenic sources was reported coming from industrial sources, especially point sources. Although many studies related to the emission inventory of VOCs in different industrial types can be found from literatures, little is known about characteristics of industrial point source VOCs before they are treated by different techniques. A total of 552 industrial gaseous VOCs point sources before treatment were collected and analyzed in respect to different industrial categories. The results showed that the flow rates of VOCs from industrial point sources were mainly from 103 to 105 m3/h, while the VOCs concentration ranged from 102 to 104 mg/m3. Food manufacture, timber processing, printing represented the industries with high flow VOCs and their flowrates ranged from 104 to 105 m3/h. Non-metallic products manufacture, agricultural and sideline product processing, oil refinery and chemicals manufacture represented the industries with high VOCs concentration ranging from 103 to 104 mg/m3. There were more groups of VOCs found in chemical and pharmaceutical manufacture than in other industries. Aromatics, esters, alcohols, aldehydes, ketones were typical VOCs in different industries. The results could be used for evaluating different industrial VOCs sources and selecting of control techniques of VOCs pollution.


Ouyang Y.,Tsinghua University | Xi J.-Y.,Tsinghua University | Xi J.-Y.,State Environmental Protection Key Laboratory of Microorganism Application and Risk Control | Wang Z.-C.,Tsinghua University | And 2 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2014

In this study, activated sludge samples were collected from 3 municipal wastewater treatment plants (WWTP) and the performance and impacting factors of sulfides adsorption onto the activated sludge were investigated. The impacting factors include sulfides concentration, temperature, pH and other anions. Adsorption isotherm of sulfide onto the activated sludge can be well described by Langmuir equation. The maximum sulfide adsorption capacity was 15~27 mg/g-dry sludge. At the temperatures ranging from 5to 35°C, adsorption capacity increased by the rise in temperature and this implies the sulfides adsorption was an endothermic process. The pH value had little effect on the adsorption capacity from 2 to 7. But the sulfides adsorption capacity decreased significantly when pH was lower than 2. Sulfides were adsorbed by activated sludge as anions (HS- and S2-) and it was a chemical adsorption process. Cl-ranging from 0 to 25 mg/L or SO4 2- ranging from 0 to 12 mg/L did not affect the sulfides adsorption capacity.

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