Seasonal variation in indicator organisms infiltrating from permeable pavement parking lots at the Edison Environmental Center, New Jersey.

Four types of permeable pavements were monitored at the Edison Environmental Center in Edison, New Jersey, for three water quality indicator organisms consisting of fecal coliform, enterococci, and Escherichia coli. This study expands a previously published result based on less than a year of available data. The current study reflects nearly 5 years of data collection with efforts focusing on collection of data in all four seasons to analyze seasonal effects and to understand the effects of pH on infiltrate concentrations. All three indicators were detected in infiltrates from all four permeable surfaces and as well as asphalt and roof runoff. Seasonally, the infiltrate during winter had fewer detections and lower enumerations and was most often significantly different than surface infiltrate and runoff for the other seasons. More significant concentration reductions were observed in summer and fall, and the lowest reduction was observed in winter. Pervious Asphalt treatment removed the most microorganisms for all three indicator organisms. A permeable interlocking concrete pavement (PICP) that was a replacement for pervious concrete during the study performed better than the original PICP most likely due to smaller gap spacing (8 mm compared to 12.7 mm) and correspondingly smaller specified surface aggregate compared to the original PICP. Percent concentration removal reductions based on geometric means were 89% or greater for PC, PA, and PICP for fecal coliform; 75% or better for PC, PA and PICP for E. coli; and 95% or greater for PC and PA for enterococci, while there were no annual removals for enterococci for original or new PICP nor removals for E. coli for original PICP and minimal removal for fecal coliform for original PICP. The major sources of fecal indicators in the stormwater runoff were most likely from the feces of deer, geese, and other wild animals. PRACTITIONER POINTS: The infiltrate during winter had fewer detections and lower enumerations and was most often significantly different than surface infiltrate and runoff for the other seasons. More significant concentration reductions were observed in summer and fall, and the lowest reduction was observed in winter. Pervious Asphalt treatment removed the most microorganisms for all three indicator organisms.

Air Temperature Reductions at the Base of Tree Canopies.

Trees in urban settings have a significant role in regulating urban hydrologic cycles. Urban trees, either as standalone plantings or as part of a tree pit, are an increasingly popular stormwater management tool. Beyond their aesthetic contribution to urban environments, trees are widely accepted as reducing the ambient air temperature. However, there is limited long-term quantitative information regarding the temperature mitigation performed by urban trees through the use of temperature sensors over a large urban area. This study monitored air temperature at locations throughout the city of Camden, New Jersey. Sensors were installed under canopies of trees of different sizes throughout the city using a statistical experimental design. The tree size (small or large) and canopy (intersecting or nonintersecting), along with the street orientation (predominantly north-south or east-west) and time of day (daylight, nighttime, or full-day), were experimental design factors. Sensors attached to poles along the streets or in parking lots served as controls. This study recorded temperatures at 10-min intervals from early August through late November 2017 using logging thermistors mounted in radiation shields about 4 m above the ground surface. Using the maximum daily air temperature at control sites, all temperature data were categorized into three groups of hot, average, and cool days. The groups were analyzed separately using the analysis of variance to test the significance of the categorical variables. During hot days (a maximum temperature larger than 30°C), there was a meaningful statistical difference between recorded mean air temperatures under trees with intersecting canopies and the control sites. A categorical analysis of street orientation for hot and average days showed that during the daytime, east-west streets were hotter than north-south streets, while this trend reversed at night when north-south streets were hotter than east-west streets. For cool days, there were no differences for the studied categorical factors.

Organism Detection in Permeable Pavement Parking Lot Infiltrates at the Edison Environmental Center, New Jersey.

Three types of permeable pavements were monitored at the Edison Environmental Center in Edison, New Jersey, for indicator organisms such as fecal coliform, enterococci, and Escherichia coli. Results showed that porous asphalt had a much lower concentration in monitored infiltrate compared to pervious concrete and permeable interlocking concrete pavers; concentrations of monitored organisms in infiltrate from porous asphalt were consistently below the bathing water quality standard and actually had limited detection. Fecal coliform and enterococci exceeded bathing water quality standards more than 72 and 34% of the time for permeable interlocking concrete pavers and pervious concrete, respectively. Concentration reductions greater than 90% were observed for all three indicator organisms for porous asphalt and fecal coliform and E. coli for pervious concrete when compared to runoff values, while permeable interlocking concrete pavers only had a modest (39%) observable reduction for E. coli only. The near absence of indicator organisms observed in the porous asphalt infiltrate may be due to the high pH potentially due to asphalt processing. Neither rain intensity nor temperature was demonstrated to have an observable effect in both concentrations of organisms and performance of permeable pavement; but this may due to the limitations of the dataset consisting of 16 events over an 8-month period.

Demonstration and Evaluation of Innovative Rehabilitation Technologies for Water Infrastructure Systems.

The needs associated with the deteriorating water infrastructure are immense and have been estimated at more than $1 trillion over the next 20 years for water and wastewater utilities. To meet this growing need, utilities require the use of innovative technologies and procedures for managing their systems. The U.S. Environmental Protection Agency (USEPA) developed a demonstration program for pipe rehabilitation methods to help fill this gap. The program's objective is to evaluate pipe rehabilitation technologies that can increase the effectiveness of the operation, maintenance, and renewal of pipelines. This paper provides an impartial assessment of the effectiveness and cost of four innovative technologies for water distribution and wastewater collection pipes. The technologies demonstrated include spray-on polymeric lining and cured-in-place pipe (CIPP) lining for water mains; and spray applied geopolymer mortar and an internal pipe sealing system for wastewater mains.

Variation of microorganism concentrations in urban stormwater runoff with land use and seasons.

Stormwater runoff samples were collected from outfalls draining small municipal separate storm sewer systems. The samples were collected from three different land use areas based on local designation (high-density residential, low-density residential and landscaped commercial). The concentrations of microorganisms in the stormwater runoff were found to be similar in magnitude to, but less variable than, those reported in the stormwater National Pollutant Discharge Elimination System (NPDES) database. Microorganism concentrations from high-density residential areas were higher than those associated with low-density residential and landscaped commercial areas. Since the outfalls were free of sanitary wastewater cross-connections, the major sources of microorganisms to the stormwater runoff were most likely from the feces of domestic animals and wildlife. Concentrations of microorganisms were significantly affected by the season during which the samples were collected. The lowest concentrations were observed during winter except for Staphylococcus aureus. The Pearson correlation coefficients among different indicators showed weak linear relationships and the relationships were statistically significant. However, the relationships between indicators and pathogens were poorly correlated and were not statistically significant, suggesting the use of indicators as evidence of the presence of pathogens is not appropriate. Further, the correlation between the concentration of the traditionally monitored indicators (total coliforms and fecal coliforms) and the suggested substitutes (enterococci and E. coli) is weak, but statistically significant, suggesting that historical time series will be only a qualitative indicator of impaired waters under the revised criteria for recreational water quality by the US EPA.

Removal of selected pollutants from aqueous media by hardwood mulch.

Generic hardwood mulch, usually used for landscaping, was utilized to remove several selected pollutants (heavy metals and toxic organic compounds) typically found in urban stormwater (SW) runoff. The hardwood mulch sorbed all the selected pollutants from a spiked stormwater mixture, including copper (Cu(2+)), cadmium (Cd(2+)), chromium (Cr(6+)), lead (Pb(2+)), zinc (Zn(2+)), 1,3 dichlorobenzene (DCB), naphthalene (NP), fluoranthene (FA), butylbenzylphthalate (BBP), and benzo(a)pyrene (B[a]P). Masses of the pollutants sorbed depended upon the pollutant species, contact time, and initial concentration which varied from 20 to 100%. Sorption rates of the metals, in general, were more rapid than those of the organics; however, mass removals (percent) of the organics, in contrast to those of the metals, were independent of their initial concentrations. With the exception of Cd, percentages (weight) of the metals removed declined as their initial concentrations decreased. None of the sorbed pollutants desorbed to any significant extent upon extended washing with water. It is quite feasible that in the presence of mulch the uptake of these pollutants by the aquatic species will be reduced significantly.

Effects of sample holding time on concentrations of microorganisms in water samples.

This research investigated the effects of extending the holding time of samples for microbial analysis beyond the standard of 24 hours for purposes such as watershed characterization. Experiments were conducted with both sanitary wastewater and stormwater samples. The refrigerated samples (4 degrees C) were held for up to 9 days before being analyzed for two pathogens (Pseudomonas aeruginosa and Staphylococcus aureus) and five indicator organisms (total coliform, fecal coliform, fecal streptococcus, enterococcus, and Escherichia coli) by membrane filtration. The concentrations (as colony-forming units per 100 mL) were normalized by log10(transformation and used in subsequent statistical analysis testing for significant differences. The results suggested that the concentrations of microorganisms in water samples analyzed on days 1 and 2 did not vary significantly in 8 of 13 analyses. The results of a field study concluded that the concentration of fecal coliform did not change significantly between 7 hours holding time and greater than 24 hours holding time for fecal coliform.

Particle-associated microorganisms in stormwater runoff.

This research investigated the effects of blending and chemical addition before analysis of the concentration of microorganisms in stormwater runoff from a single summer storm to determine whether clumped or particle-associated organisms play a significant role. The standard membrane filtration method was used to enumerate the microorganisms. All organisms, except for Escherichia coli, showed an increase in the measured concentration after blending samples at 22,000 rpm with or without the chemical mixture. Other than fecal streptococci, the organism concentrations decreased with the addition of the Camper's solution in both blended and unblended samples before analyses. There was a statistically significant interaction between the effects of Camper's solution and the effects of blending for all the organisms tested, except for total coliform. Blending did not alter the mean particle size significantly. The results show no correlation between increased total coliform, fecal coliform, and fecal streptococcus concentrations and the mean particle size.