Prediction on effectiveness of road sweeping for highway runoff pollution control

Binzhou section of Changshen highway was selected to study the effectiveness of road sweeping in decreasing the pollutant loads of highway runoff.With on-site continuous sampling the discharge rules of Cu Cd Pb and Zn are analyzed.The total and dissolved event mean concentrations of Cu Pb and Zn are calculated and the loads of heavy metals attached to particles sampled before and after rainfall are also studied.A test section on highway road was swept in different frequencies during a week and the amount of removed particles was measured.Based on the analysis of highway runoff and road sweeping a prediction equation is established to calculate the pollution control efficiency of the sweeping measure and the results indicate that the 1 time/week road sweeping method can remove 47.93% of dissolved Cu 46.87% of Pb and 44.21% of Zn.

Persistent toxic substances in urban highway runoff in Shanghai

Urban highway runoff samples from seventeen rainfall events were collected in Shanghai in 2011. The concentrations of ten heavy metals and sixteen polycyclic aromatic hydrocarbons PAHs are analyzed. The results show that the heavy metal concentrations range within 0.50 to 51.80 As 0 to 20.80 Se 13.67 to 445.80 Zn 0 to 44.20 Pb 0 to 15.80 Ni 39.58 to 264.20 Fe 0 to 253.00 Mn 0 to 8.20 Cr 0 to 124.20 Cu and 159.83 to 536.40 μg/L Al . Se Pb Mn and Al concentrations in most samples exceed their corresponding criterion continuous concentrations CCCs while Zn and Cu concentrations exceed their criterion maximum concentrations CMCs .The concentrations ofΣPAHs range within 37.25 to 114.57 ng/L and concentrations of PAHs are all below their corresponding CCCs.Cu Zn and ΣPAHs show the first flush phenomenon. Analysis results of the modified Nemerow index method NIM indicate that runoff from eight rainfall events may have very strong biological toxicity effects four have strong effects three have moderate effects and only two have insignificant effects.Therefore it is concluded that urban highway runoff is a significant pollution source to aquatic ecosystems and needs immediate purification.

Characterization of suspended solids and particle-bound heavy metals in a first flush of highway runoff

To investigate the dynamic characteristics of total suspended solids (TSS) and their particle-bound heavy metals in a first flush, the runoff sampling together with its flow rate measuring was conducted for three rainfall events at outfalls of highway in Shanghai from June to September 2007. Field samples were analyzed to determine the concentrations of TSS and particle-bound heavy metals, such as Zn, Pb, and Cu. Results show that the wash off behavior of TSS under varying runoff rate condition can be explained by different antecedent dry weather period (ADWP). Contribution of fine fraction (<45 μm) to TSS was generally higher than that of coarse fraction (>45 μm). When the runoff flow increased obviously, a significant contribution of the coarse fraction was observed for a certain rainfall events with long antecedent dry weather condition. The changes of total metals concentration and particle-bound metal concentrations were strongly dependent on the TSS variation. TSS was generally well correlated with most particulate-bound heavy metals. Of the heavy metals, the concentration of Zn was found considerably high and that of Pb was significantly low at North Zhongshan 2 Road, in Shanghai, China, but they are still within the range reported in the literature. Fluctuation of heavy metal contents in the coarse fraction during a first flush period was more significant compared with that in the fine fraction. The results will assist in the development of effective control strategies to minimize heavy metals and solids in highway runoff.

Unified methodology for site-characterization and sampling of highway runoff

Hydrology,roadway traffic conditions,and atmospheric deposition are three essential data categories for the planning and implementation of highway-runoff monitoring and characterization programs.Causal variables pertaining to each data category could be site specific but have been shown to correlate with runoff pollutant loads.These data categories were combined to derive statistical relationships for characterization and prioritization of the respective pollutant loads at highway runoff sites.Storm runoff data of total suspended solids(TSS),total dissolved solid(TDS),chemical oxygen demand(COD),total Kjeldahl nitrogen(TKN)and total phosphorus(TP)collected from three highway sites in Charlotte,North Carolina,USA,were used to illustrate the development of site-specific highway-runoff pollutant loading models.This unified methodology provides a basis for initial assessment of the pollutant-constituent loads from highway runoff using hydrologic component variables.Improved reliability is achievable when additional traffic and/or atmospheric component variables are incorporated into the basic hydrologic regression model.In addition,operational guidance is suggested for implementing highway-runoff monitoring programs that are subject to sampling and resources constraints.