In the 50s, States began adopting laws and regulati ons hat advanced onsite system design and installation practices, which ensured the proper op eration of systems and lowered the threat of waterborne pathogens. Discharge of septic tank effl uent into gravel-lined subsurface drains then became the norm. This remains the most widely accep ted method for onsite wastewater treatment (WWT), and disposal still relies on soil. In an att empt to respond to more challenging site conditions, the biofiltration concept has evolved f rom natural occurring soil to intermittent sand filter technology using imported sand. Combining ph ysical and biological processes, biofiltration is now recognized as one of the most efficient and robust treatment options. In response to increasing market demand for compact and efficient solutions, enhanced understanding of biofiltration has led to the development of innovat i e systems. Integrating either inorganic or organic media, they are proving to be better-adapte d to today’s site conditions. But how do those more modern treatment approaches compare to convent ional system in term of environmental footprint? Conventional systems require aggregates, or in their more modern version infiltration chambers. Some rely on natural occurring soils and others on imported fill/sand. Innovative systems are often housed into polyethylene or concr ete vessels and require the manufacturing of their proprietary filtering media, textile, polysty rene beads, coconut husk fragments (coco). Whether the approach is conventional or not there a re environmental impacts associated with all the stages of a system life from raw material extra ction through materials processing, manufacture, distribution, use, repair and maintenance, and disp osal or recycling. A life cycle analysis performed on coco-based biofilter technology and co nventional sand based systems, showed that the organic adsorbent filtering media presents a ve ry low environmental footprint and compares favorably to conventional systems despite the commo nly close proximity of the sand used.

This study focused on a pilot-scale infiltration of denitrified wastewater through artificially created soils. The hydraulic performance and sulfide production were evaluated to ensure the system's longevity over the period needed for autotrophic denitrification. Experiments were carried out over a year in two reactors of 200-L capacity. Sandy and sandy loam soils were tested to represent highly permeable (Ks = 0.028 cm/s) and permeable (Ks = 0.0013 cm/s) soils, respectively. The infiltration of denitrified wastewater at a continuous hydraulic rate (130 and 70 L/m(2)/day) through these soils did not lead to the production of large amounts of gaseous hydrogen sulfide [[H2S] < 2.1 parts per million (ppm)] or aqueous sulfides ([HS- + H2S] < 0.7 mg/L) sulfides in both feeding influent and effluents of the 200-L reactors. Considering the hydraulic performance, no loss in the infiltration capacity was recorded for the sandy soil, whereas a clogging phenomenon was observed after 37 days for the sandy loam soil. Two factors were responsible for this clogging phenomenon. A fine brown layer, known as a biomat, was formed on the infiltrative surface (IS) of the soil, which led to the formation of iron ochre at the bottom of the reactor. As an ascertainment attributed to the clogging phenomenon faced, sandy soil appeared to be the best choice as it did not contain organic matter, which could lead to the biomat formation and thus to a clogging phenomenon. (C) 2017 American Society of Civil Engineers.

The aim of this study was to determine the critical operational conditions leading to the generation of sulfide in a domestic wastewater treated by a sulfur-utilizing denitrification process. The influence of various important parameters on the reduction of the sulfates present in denitrified domestic wastewaters to sulfide was studied. Experiments were carried out in batch mode with denitrified domestic wastewaters containing various amounts of both organic matter and sulfates. Preliminary results showed that aqueous sulfide was generated for DOC and sulfate contents higher than 56 mg/L and 371 mg/L, respectively, while DOC and sulfate contents of 77 mg/L and 412 mg/L, respectively, were required to allow the release of gaseous H2S. Good correlations were also observed between gaseous sulfide production and the values of ORP and DOC, while the amounts of dissolved sulfide produced seemed to be correlated with the ORP values and the concentration of sulfates. Additional experiments were conducted using a Box-Behnken methodology to determine if the production of aqueous or gaseous sulfide can be predicted depending on the DOC (from 50 to 90 mg/L) and sulfate contents (from 160 to 380 mg/L) at various temperatures ranging from 5 to 25 °C. The highest sulfide generation (H2S(g) = 84.8 ppm and H2S(aq) = 2.42 mg/L) occurred at 25 °C with DOC and sulfate concentrations starting from 90 mg/L and 270 mg/L, respectively, indicating that the production of sulfides from denitrified domestic wastewaters required conditions not likely to occur at the effluent of a sulfur-based denitrification unit following secondary treatment.

This study aimed to determine the potential of sulfide generation during infiltration through soil of domestic wastewater treated by a sulfur-utilizing denitrification process. Three types of soil with different permeability rates (K s = 0.028, 0.0013, and 0.00015 cm/s) were investigated to evaluate the potential risk of sulfur generation during the infiltration of domestic wastewater treated by a sulfur-utilizing denitrification system. These soils were thoroughly characterized and tested to assess their capacity to be used as drainages for wastewaters. Experiments were conducted under two operating modes (saturated and unsaturated). Sulfate, sulfide, and chemical oxygen demand (COD) levels were determined over a period of 100 days. Despite the high concentration of sulfates (200 mg/L) under anaerobic conditions (ORP = −297 mV), no significant amount of sulfide was generated in the aqueous (<0.2 mg/L) or gaseous (<0.15 ppm) phases. Furthermore, the soil permeability did not have a noticeable effect on the infiltration of domestic wastewater treated by a sulfur-utilizing denitrification system due to low contents of organic matter (i.e., dissolved organic carbon, DOC). The autotrophic denitrification process used to treat the domestic wastewater allowed the reduction of the concentration of biochemical oxygen demand (BOD5) below 5 mg/L, of DOC below 7 mg/L, and of COD below 100 mg/L.

Reed canarygrass (Phalaris arundinacea L.) is a potential biomass crop for energy production but little is known on its optimum management in the northern areas of North America. We determined the effect of three harvest dates (late July, early September, and mid-October) in a one-cut system and four N fertilization (0, 40, 80, and 160 kg N ha−1) on crop biomass and silage characteristics of reed canarygrass seeded in 2007, and harvested and ensiled in 2008 and 2009 following spring N applications. Delaying harvest from late July to mid-October decreased crop biomass dry matter (DM) yield (−0.8 Mg DM ha−1), in vitro true digestibility of DM (IVTD; −79 g kg−1DM), in vitro neutral detergent fiber (NDF) digestibility (NDFD; −126 g kg−1NDF), and K concentration (−7.4 g kg−1DM), while it increased soluble carbohydrate (+14.7 g kg−1DM) and ash (+8.5 g kg−1DM) concentrations. Increasing N fertilization from 0 to 160 kg N ha−1increased crop biomass DM yield (+4.3 Mg DM ha−1), crop biomass NDF (+29 g kg−1DM) and ADF (+32 g kg−1DM) concentrations, decreased IVTD (−65 g kg−1DM) and NDFD (−76 g kg−1NDF), and did not affect ash concentration. Silage pH and concentrations of lactate and NH3-N indicated adequate fermentation irrespective of harvest date and N fertilization.

Biofiltration is a technology recognized for its efficiency and robustness in wastewater treatment, combining both physical and biological processes. This technology evolved at first from rock or slag as filtering media, being more related to trickling filters, to packed bed filters using different types of more complex inorganic or organic media. Performance and aging behavior of most of inorganic filtering media are fairly well documented and predictable. Organic filtering media with their inherent hydrodynamic properties and indigenous microorganisms offer more versatility and improvement possibilities to increase system capacity and capability while maintaining the same treatment efficiency and system passivity. Developing an organic media that will meet the main targeted properties is a source of challenges. It is a sweet balance between the basic properties of the material and how it could be transformed and adapted into a system to provide the performance, reliability and robustness responding to the different requirements and constraints of the markets and the regulations in constant evolution. The evolution of the organic filtering media developed by Premier Tech Aqua was made possible through the comparison of filtering media properties and dynamic behavior, using spatial and temporal measurements of porosity, conductivity, hydraulic profiles, retention time, aging of the media (clogging, potential degradability, biomass accumulation, etc.), mechanical resistance, and treatment performances. The use of a new generation of specifically produced organic filtering media composition contributes to the application of a higher loading rate factor while maintaining the same level of performance and increases the longevity of the filter bed which is mainly associated with the low degradability and high mechanical resistance to compression.

This paper reports a novel psychrophilic dry anaerobic digestion (PDAD) of cow feces (feces) and wheat straw (WS). Three feeding strategies (WS, feces, and feces plus WS) were assessed in pseudo sequential batch reactors (PSBR) during three successive cycles of around 21 days hydraulic retention time (HRT). Average specific methane yields on VS fed (L kg(-1)) of 129 +/- 17 (WS only), 164 +/- 23 (feces only (10-11% TS)) and 152 +/- 6 (a mixture of feces plus WS (16% TS)) were obtained during the last three successive cycles.The average methane production rates on VS fed were 3.5 +/- 1.5 and 3.6 +/- 1.3 and 4.1 +/- 0.4 L kg(-1) d(-1) for the three feeding strategies, respectively. The successive cycles revealed that the psychrophilic anaerobic digestion of high-solid content of cow feces and wheat straw is a reproducible process, practically feasible, and as efficient as mesophilic dry anaerobic digestion given that a well-adapted inoculum is developed and maintained. Crown Copyright (C) 2015 Published by Elsevier Ltd. All rights reserved.

Degrading antibiotics discharged in the livestock manure in a well-controlled bioprocess contributes to a more sustainable and environment-friendly livestock breeding. Although most antibiotics remain stable during manure storage, anaerobic digestion can degrade and remove them to various extents depending on the concentration and class of antibiotic, bioreactor operating conditions, type of feedstock and inoculum sources. Generally, antibiotics are degraded during composting > anaerobic digestion > manure storage > soil. Manure matrix variation influences extraction, quantification, and degradation of antibiotics, but it has not been well investigated. Fractioning of manure-laden antibiotics into liquid and solid phases and its effects on their anaerobic degradation and the contribution of abiotic (physical and chemical) versus biotic degradation mechanisms need to be quantified for various manures, antibiotics types, reactor designs and temperature of operations. More research is required to determine the kinetics of antibiotics' metabolites degradation during anaerobic digestion. Further investigations are required to assess the degradation of antibiotics during psychrophilic anaerobic digestion.

Biofiltration using organic media has long been studied. Even so, no thorough studies looking at inside the process have been made. Three pilot-scale organic media biofilters were operated for 450 days to treat pig manure having different COD/N ratios (approximately 5, 9, 15). Air and liquid sampling was done both on influent and effluent but also at different heights along the biofilter. Satisfactory carbon oxidation and nitrification performances were observed, with chemical oxygen demand (COD) and ammonia (NH4+) removals consistently reaching 95%. From 78 to 88% of total nitrogen removal was achieved, meaning denitrification also occurred although the systems were aerated. Nitrate concentration and N2O emission were related to the nitrogen content in influent more than with the COD/N ratio. All treatment processes occurred mainly in the top 30 cm of the 190 cm biofilters.

Haloacetic acids (HAAs) are disinfection by-products formed as a result of the reaction between chlorine and natural organic matter found in water. HAA concentrations have been observed to decrease at distribution system extremities. This decrease is associated with microbiological degradation by pipe wall biofilm. The objective of this study was to evaluate HAA degradation in a drinking water system in the presence of a biofilm and to identify the factors that influence this degradation. Degradation of dichloracetic acid (DCAA) and trichloroacetic acid (TCAA) was observed in a simulated distribution system. The results obtained showed that different parameters came into play simultaneously in the degradation of HAAs, including retention time, water temperature, biomass, composition of organic matter, and pipe diameter. Seasonal variations had a major effect on HAA degradation and biomass quantity was lower by 1 to 2 logs in the winter and spring compared with the fall. HAA removal decreased with increasingly large pipe diameters. The specific effects of each of these factors were difficult to isolate from each other owing to interactions.

A low-temperature (25 degrees C) anaerobic eight-compartment (PF01 to PF08) cascade reactor simulating a plug-flow reactor (PFR) treating pig manure was monitored for a year. The bioreactor was fed at an average loading rate of 2.4 +/- 0.2 g of total chemical oxygen demand (TCOD) per litre of reactor per day for a theoretical hydraulic retention time (HRT) of 67 +/- 7 d. An average of 79% of TCOD was removed from pig manure (converted into biogas and in sediments), whereas specific methane yields ranging from 397 to 482 NL CH4 kg(-1) VS (148.6 to 171.4 NL CH4 kg(-1) TCOD) were obtained. After 150 d, fluctuating performances of the process were observed, associated with solids accumulation in the upstream compartments, preventing the complete anaerobic digestion of swine manure in the compartments PF01 to PF04. Low-temperature anaerobic PFR represents an interesting alternative for the treatment of pig manure and recovery of green energy. Further investigations regarding a modified design, with better accumulating solids management, are needed to optimize the performance of this low-temperature PFR treating pig manure.

AIMS:Bacterial community structure and composition of a drinking water network were assessed to better understand this ecosystem in relation to haloacetic acid (HAA) degradation and to identify new bacterial species having HAA degradation capacities.METHODS AND RESULTS:Biofilm samples were collected from a model system, simulating the end of the drinking water distribution network and supplied with different concentrations of dichloroacetic and trichloroacetic acids at different periods over the course of a year. The samples were analysed by culturing, denaturing gradient gel electrophoresis (DGGE) and sequencing. Pipe diameter and HAA ratios did not impact the bacterial community profiles, but the season had a clear influence. Based on DGGE profiles, it appeared that a particular biomass has developed during the summer compared with the other seasons. Among the bacteria isolated in this study, those from genus Cupriavidus were able to degrade dichloroacetic acid. Moreover, these bacteria degrade dichloroacetic acid at 18°C but not at 10°C.CONCLUSIONS:The microbial diversity evolved throughout the experiment, but the bacterial community was distinct during the summer. Results obtained on the capacity of Cupriavidus to degrade DCAA only at 18°C but not at 10°C indicate that water temperature is a major element affecting DCAA degradation and confirming observations made regarding season influence on HAA degradation in the drinking water distribution network.SIGNIFICANCE AND IMPACT OF THE STUDY:This is the first demonstration of the HAA biodegradation capacity of the genus Cupriavidus.

Bélanger, G., Savoie, P., Parent, G., Claessens, A., Bertrand, A., Tremblay, G. F., Massé, D., Gilbert, Y. and Babineau, D. 2012. Switchgrass silage for methane production as affected by date of harvest. Can. J. Plant Sci. 92: 1187–1197. Switchgrass (Panicum virgatum L.) is a warm-season grass recognized as a potential biomass crop for energy production in North America, but little information exists on the effect of harvest date on forage and silage characteristics of switchgrass grown in eastern Canada. Our objectives were to determine how harvest date affects several forage and silage characteristics of switchgrass and to relate these to specific methane yield from anaerobically digested switchgrass silage. Switchgrass, seeded in 2002 and 2006, was harvested and ensiled as a one-cut system on three dates in 2007: late July, early September, and early October. The regrowth from the late July harvest was also harvested in early October as a two-cut system. Silage quality parameters [pH, and concentrations of N, N-NH3, total amino acids (TAA), and volatile fatty acids (VFA)] indicated adequate fermentation of all silage samples. In a one-cut system, delaying harvest from late July to early September increased forage dry matter (DM) yield from 9.0 to 11.5 Mg ha−1, forage soluble carbohydrate (SC) concentration from 51 to 85 g kg−1 DM, and silage SC concentration from 13 to 25 g kg−1 DM; delaying harvest from late July to early October decreased forage in vitro true digestibility (IVTD) from 720 to 582 g kg−1 DM, forage in vitro digestibility of the neutral detergent fibre (dNDF) from 590 to 409 g kg−1 DM, and silage acetate concentration from 7.7 to 2.6 g kg−1 DM. The regrowth had higher IVTD and dNDF, lower acid detergent fibre concentration, and higher silage lactate and acetate concentrations than a single harvest taken in early September or early October. The two-cut system and the single harvest in early September produced the highest seasonal forage DM yields (11.5 and 11.9 Mg ha−1). High specific methane yield was (i) correlated with low forage fibre concentration and high DM digestibility and (ii) more correlated to silage concentrations of lactate and acetate than to silage SC concentration.

Methane yields from silage made from switchgrass- and reed canarygrass-seeded plots with two N application rates and three harvest dates were assessed in Eastern Canada. The average specific methane yield from reed canarygrass-seeded plots (0.187 NL CH4 g VS(-1)) was less than from switchgrass-seeded plots (0.212 NL CH4 g VS(-1)). Switchgrass did not establish well and made up only a small proportion of the DM yield. As a consequence, the average methane yield per hectare from reed canarygrass-seeded plots (1.37 GL CH4 ha(-1)) was significantly greater than switchgrass-seeded plots (0.91 GL CH4 ha(-1)). Increased N fertilization reduced specific methane yields but increased methane yield per hectare, primarily because of increased DM yield. Delaying harvest resulted in decreased methane yields per hectare and specific methane yields, particularly for reed canarygrass. Further long-term research could help identify important factors influencing methane yields from crops during a complete stand life cycle.

We describe the potential contribution of on-farm biogas production to reducing greenhouse gas (GHG) emissions and other environmental impacts related to livestock operations. GHG are reduced by production of renewable energy as a substitute for fossil fuels via reduction of fugitive GHG emissions from stored and land applied manures, as well as by reduction in use of chemical fertilizers in crop production. Anaerobic digestion (AD) biotechnologies produce biogas at average rates of 0.30, 0.25 and 0.48 L/g volatile solids from swine, bovine and poultry slurries, respectively. The biogas produced is of high quality with a CH4 concentration of 60-80%. AD may be an acceptable solution to management of P surplus by precipitating up to 25% of it in batch or semi-batch operated bioreactors, and by precipitating and concentrating up to 70% of bioreactor effluent Pin long term storage bottom sludge. Effluents from AD are better balanced to meet crop needs than raw manure slurries, thereby reducing the need for supplementary chemical N and P fertilizers. Both capture of energy and reduced needs for chemical fertilizers will substantially decrease the C footprint of livestock food products. On-farm biogas production contributes to more sustainable livestock operations by substantially reducing other environmental impacts related to manure management. It reduces the risk of water pollution associated with animal manure slurries (i.e., eutrophication) by removing 0.80-0.90 of soluble chemical oxygen demand. In addition, some AD eliminate zoonotic pathogens and parasites in livestock manures. AD also improves human/farm cohabitation in rural regions by reducing odour emissions by 70-95%. This reduction allows more frequent and better timing of manure land application. Both timing of application and improved nutrient balance have the potential to increase nutrient uptake by crops and minimize nutrient losses to the environment. Reduction in the viability of weed seeds during AD reduces the need for herbicides and makes bioreactor effluent more acceptable to organic farmers. Inadequate regulatory polices and incentives are obstacles to widespread implementation of AD in developed and developing countries. However, adoption of AD is an alternative which could substantially reduce the C and environmental footprint of housed livestock operations.This article is part of the special issue entitled: Greenhouse Gases in Animal Agriculture Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister. Section Guest Editors; K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.

Mesophilic methane yield of ensiled switchgrass grown in Eastern Canada was assessed. Switchgrass was harvested at three stages of development, corresponding to mid-summer, late summer and early fall in 2007. The regrowth of plots harvested in mid-summer was also harvested in early fall as a two-cut strategy. Specific methane yields decreased significantly with crop maturity from 0.266 to 0.309 NL CH4g−1 VS in mid-summer to 0.191–0.250 NL CH4g−1 VS in early fall; values were similar for the first harvest in late July and the second harvest (regrowth) in October. Approximately 25% more methane was produced by hectare for the two-cut strategy (2.90–3.44×106 NL CH4ha−1) compared to the one-cut strategy with a harvest in late summer (2.28–2.77×106 NL CH4ha−1). Methane yields from switchgrass grown under the cool humid climate of Eastern Canada suggest that this crop remains an interesting renewable alternative energy source.

Respiratory problems are observed in machinists using soluble metalworking fluid (MWF). Evidences suggest that these problems could be related to the aerosolized microorganisms and their byproducts from MWF. To establish MWF aerosol exposure thresholds and to better understand their effect on human health, these aerosols must be fully characterized. This article evaluates airborne microorganisms and aerosols from soluble MWF in the working environment. Air quality parameters (endotoxin levels, culturable airborne microorganisms, fluid mist, inhalable dust and air exchange rates) were evaluated at 44 sites, in 25 shops in Quebec, Canada. Microorganism concentrations were also measured in MWF. Culturable airborne bacteria concentrations were low, ranging from 1.2 x 10(1) to 1.5 x 10(3) CFU (colony forming units) m(-3), even for metalworking fluid highly contaminated by bacteria (up to 2.4 x 10(9) CFU mL(-1)). Inhalable dust varied between < 0.1 to 2.6 mg m(-3), while air exchange rates were mostly below the standard (4 h(-1)) for this type of workplace, between 0.6 to 14.2 h(-1). Only nine of 44 sites respected the suggested minimum value for air exchange rates. Fluid mist ranged from 0.02 to 0.89 mg m(-3), which is below the threshold limit value (TLV) (ACGIH) of 5 mg m(-3). Airborne endotoxin concentrations ranged from undetectable to 183 EU m(-3) (endotoxin units), showing no correlation with airborne microorganisms or inhalable dust. Most workstations respected the suggested minimum values for fluid mist and showed low concentrations of airborne endotoxin, culturable microorganisms and inhalable dust despite fluid contamination, even when air exchange rates were below the recommendations. Airborne Pseudomonas pseudoalcaligenes was recovered from many sites at significant concentrations. Health-associated risks following exposure to this microorganism should be further investigated.

Aims:Hypersensitivity pneumonitis of machinists associated with metalworking fluids (MWF) was recently linked to Mycobacterium immunogenum. In addition to Mycobacterium, impacts of continuous and massive contact to other micro-organisms, such as Pseudomonas, were little studied. This report intended to quantify and characterize the microbial load of 44 in-use MWF.Methods and Results:The main biodiversity of MWF was assessed using cultural methods, quantitative PCR (qPCR) and denaturing gradient gel electrophoresis (DGGE). Total bacteria concentrations ranged from undetectable to 109 16S rRNA gene copies per millilitre. Concentrations obtained by qPCR were up to five orders of magnitude higher than by culture, suggesting that MWF contamination is generally underestimated. Two samples showed high concentrations of Myco. immunogenum (1 center dot 55 x 107 and 3 center dot 49 x 105 16S rRNA gene copies per millilitre). The overall biodiversity was low, as observed by culture and DGGE, and was comparable to data found in the literature. Pseudomonas pseudoalcaligenes was by far the main bacteria found in MWF samples (33 out of 44), followed by Ochrobactrum anthropi (32 out of 44). There was no significant relationship between the biodiversity profiles and the kind of MWF or equipment used, making it difficult to predict which micro-organisms will colonize each particular MWF.Conclusions:Very high concentrations of bacteria were found in most MWF studied and limited biodiversities were observed. Many species of micro-organisms were retrieved from MWF samples, but they were mostly colonized by Pseudomonas pseudoalcaligenes and Ochrobactrum anthropi.Significance and Impact of the Study:The major micro-organisms observed or recovered in this study from in-use MWF were present in very high concentrations, and thus further studies are needed to confirm their role in workers' respiratory disorders or health-related problems.

The microbial biodiversity of bioaerosols in recently occupied hospital rooms was assessed in a pulmonology unit. Environmental samples and isolates were also screened for antibiotics resistance genes. Biofilms from sink drains were also studied to evaluate whether sink drains constitute a potential source of bioaerosols in this environment and a reservoir for opportunistic bacteria and antibiotic resistance genes. Stenotrophomonas maltophilia was by far the most frequently isolated microorganisms from the biofilm, followed by Enterobacter cloacae. Airborne bacterial concentration ranged from 14 to 74 CFU m−3 and fungi ranged from 50 to 600 CFU m−3. Biofilm bacteria were outnumbered in aerosols by microorganisms affiliated with human skin flora. Nonetheless, they were recovered from air samples in low concentrations. Erythromycin resistance genes were detected in all air samples collected from hospital rooms, and tetracycline resistance genes were detected sporadically. Antibiotic resistance genes were found in a single drain suggesting that genes present in DNA extracts from air samples were not aerosolized from sink drains, but rather from an unknown source. Results obtained in this study suggest that bacteria from sink drains were not aerosolized in significant concentration. They still remain a concern because of the risk of aerial transmission associated with their presence.