Tom Headley - Profile on Academia.edu (original) (raw)
Papers by Tom Headley
The removal of nutrients from plant nursery irrigation runoff in subsurface horizontal-flow wetlands (Presentation)
In New South Wales (NSW) Australia, the recent introduction of legislation to control runoff and ... more In New South Wales (NSW) Australia, the recent introduction of legislation to control runoff and charge for water used in agricultural production has encouraged commercial plant nurseries to collect and recycle their irrigation drainage. Runoff from a nursery typically contains around 6 mg/L TN (> 70% as NO3), 0.5 mg/L TP (> 50% as P04), and virtually no organic matter (BOD < 5 mg/L; DOC < 20 mg/L). As a result, algal blooms frequently occur in storage dams. This paper describes a study evaluating the effectiveness of subsurface flow wetlands in the removal of nutrients from nursery runoff on the sub-tropical northern coast of NSW, Australia. Four experimental subsurface flow wetlands (1 m x 4 m x 0.5 m water depth) were planted with Phragmites australis in April 1999. TN and TP load removals were > 84% and > 65% respectively at HRTs of between 5 and 2 days, with the majority of out-flowing TN and TP being organic in form. Internal generation of organic N and P resulted in persistent background levels of 0.45 mg/L TN and 0.15 mg/L TP in the reed bed effluent. TN, NH4 and TP removal was affected by HRT (P < 0.05). Greater than 90% load removal of NH4, NO2, NO3 and Ortho-P was achieved at all HRTs, with outlet concentrations generally < 0.01 mg/L for all. For TN, a strong relationship existed between removal rate (g/m2/day) and loading rate (r2 = 0.995), while a weaker relationship existed for TP (r2 = 0.47). It is estimated that a 1 ha nursery would require a reed bed area of 200 m2 for a 2 day HRT.
Seasonal variation in phosphorus removal processes within reed beds - as indicated by mass balance
The phosphorus (P) removal processes in two pairs of High and Low Loaded reed beds were investiga... more The phosphorus (P) removal processes in two pairs of High and Low Loaded reed beds were investigated during five periods within a 27-month study. The uptake/release of P was measured in seven mass balance compartments. With the exception of the first year of operation, the reed beds consistently removed over 96% of the influent P load, with total phosphorus (TP) concentrations being reduced from 0.5 mg/L to generally less than 0.005 mg/L across the range of loading rates and seasons studied. During the first year, uptake by Phragmites australis accounted for greater than 75% of P removed, and was equally distributed between above and below-ground biomass. During the second and third years, three seasonal stages were identified in the uptake and cycling of P by P. australis. A period of rapid above-ground growth and uptake occurred during spring fuelled partly by P reserves accumulated in rhizomes during the previous year. During summer, uptake by above-ground biomass was governed by the influent P loading rate, while the amount of P held in below-ground biomass remained relatively stable. During autumn and winter, P appeared to be translocated from senescent shoots to reserves in the rhizomes. Approximately 85% of the below-ground biomass P occurred in the top 20 cm of the substrate. Gravel fixation increased in importance from 12% in the first year to approximately 30% of P removed in the second year, with a highly significant correlation between the influent P loading rate and P fixed by the gravel. The weakly-bound P fraction from a sequential extraction was the dominant form of P fixed by the gravel. HCI extracts were inappropriate for the examination of sorption processes as they dissolved large amounts of mineral P from within the basaltic gravel. The bottom 30 cm of the substrate became the most important site for gravel fixation during the second year. Incorporation of P into the detritus/microbiota/other compartment increased after the first year to become one of the most important P removal processes, probably consisting mainly of leaf litter and slowly accreted organic sediments.
Performance monitoring of constructed floating wetlands: Treating stormwater runoff during the construction phase of an urban residential development
Science of The Total Environment
Sustainable Treatment of Wastewater Generated by Oil & Gas Drilling Rig Camps
Day 4 Thu, November 03, 2022
Oil & gas exploration and production activities often takes place in remote areas with no immedia... more Oil & gas exploration and production activities often takes place in remote areas with no immediate wastewater treatment access. It is industry practice to establish own treatment facilities or to tanker wastewater long distance to municipal treatment facilities outside the concession areas. The remote setting and harsh operating conditions makes it challenging for mechanical treatment systems to comply to national effluent discharge standards. This paper explores if a nature-based portable solution can help overcome this challenge while promoting sustainability. By deploying a Test Unit (ReedBox®) to Khalifa Industrial Zone Abu Dhabi in the United Arab Emirates, the treatment performance is tested for compliance. Following a 26-week test period, a third-party performance verification confirmed that the Test Unit satisfactorily treated the wastewater producing an effluent in full compliance with the Abu Dhabi Recycled Water and Biosolids Regulations for P1 Unrestricted Reuse. As a r...
Ex-Situ Bioremediation of Hydrocarbon Contaminated Soil - An Example from Oman
SPE Middle East Health, Safety, Environment & Sustainable Development Conference and Exhibition, 2014
A few years ago, an oil company in Oman initiated an approach to deal with hydrocarbon-contaminat... more A few years ago, an oil company in Oman initiated an approach to deal with hydrocarbon-contaminated soils that created environmental problems. These soils where collected in their oilfields and transported to their hazardous waste yards in the country's interior areas. The client entrusted several service providers to carry out de-contamination processes and landfill activities unfortunately with limited success. One of the Waste Yards has stock piled large quantities of hydrocarbon contaminated soil, with contamination concentrations ranging from 15,000 mg/kg total Total Petroleum Hydrocarbons (TPH) soil up to 40,000 mg/kg TPH. The hydrocarbon molecule chains are from various types – starting with short chains i.e. C5 up to long chains C35. In 2012, the client decided to implement a new remediation approach by deploying eco-friendly technologies to properly manage degradation and remediation of the contaminated soil by using modern bio-remediation technology developed and appli...
Constructing a reed bed to treat runoff water - a guide for nurseries
Impacts of partially hydrolyzed polyacrylamide (HPAM) on microbial mats from a constructed wetland treating oilfield produced water
Chemosphere, 2021
Constructed wetlands have been successfully used in the treatment of produced water brought to th... more Constructed wetlands have been successfully used in the treatment of produced water brought to the surface in large quantities during oil extraction activities. However, with the increasing use of partially hydrolyzed polyacrylamide (HPAM) in enhancing oil recovery, the impacts of HPAM on the biological processes of wetlands is still unknown. Microbial mats in wetlands play a key role in hydrocarbon degradation. Here, we compared the bacterial communities of four wetland microbial mats after flooding with different concentrations of HPAM. Two mats (i.e. the HPAM-free and the 500 ppm HPAM pre-exposed mats) were selected to further investigate the effect of HPAM on respiration and biodegradation activities. The field mats exhibited clear differences in their bacterial community structure, where Cyanobacteria and Alphaproteobacteria became dominant in the presence of HPAM. In the laboratory experiments, the generated CO2 by the HPAM-free and the 500 ppm HPAM pre-exposed mats did not vary significantly when HPAM was added, although CO2 values were slightly higher in the presence of oil. Both mats were still able to degrade between 15 ± 14.4 to 50 ± 13.0% of C10 to C30 alkanes in 28 days, and this degradation was not affected by HPAM addition. The HPAM concentration decreased by 22-34% of the initial amount after 28 days of incubation in the HPAM-free mat, versus only 7-18.4% decrease in the 500 ppm HPAM pre-exposed mat. We conclude that the wetland microbial mats seem to have become well adapted to HPAM and could maintain their respiration and hydrocarbon degradation activities.
On-site domestic wastewater treatment by reed bed in the moist subtropics
Water Science and Technology, 2001
This paper summarises the results of studies on four subsurface flow wetlands (reed beds) located... more This paper summarises the results of studies on four subsurface flow wetlands (reed beds) located in the moist sub-tropical north eastern corner of the Australian state of New South Wales. The reed beds, which are subjected to a variety of effluent types, all have a gravel substrate planted with Phragmites australis. All four units were found to maintain satisfactory treatment performance year round. Mean removal efficiencies ranged from 56% to 90% (SS), 70% to 93% (BOD), 38% to 66% (TN), 87% to 99.8% (Faecal coliforms), and 42% to 70% (TP - with one seasonal result of 0% for the eight year old unit) for the four reed beds. After eight years in operation the oldest reed bed was showing signs of phosphorus saturation with outlet TP concentrations exceeding inlet concentrations on some occasions. The youngest reed bed studied appeared to be operating efficiently after five months. A summer water balance on one of the reed beds revealed an average crop factor of 1.6 and a moisture loss...
Water Science and Technology, 2005
Reed beds (horizontal subsurface flow constructed wetlands) have been employed as secondary treat... more Reed beds (horizontal subsurface flow constructed wetlands) have been employed as secondary treatment devices in on-site and decentralised wastewater management systems in the northeast of the Australian state of New South Wales (NSW) for over a decade. This paper summarises some of the practical and research findings that have come to light in that time. Experience with various aspects of reed bed structure is discussed. A study of the evaporative performance of four small beds planted with Phragmites australis yielded an annual crop factor of 2.6. A total of 28 studies on reed beds treating a variety of commonly encountered wastewater streams yielded the following mean pollutant removal efficiencies: total suspended solids (TSS) 83%, biochemical oxygen demand (BOD) 81%, total nitrogen (TN) 57%, total phosphorus (TP) 35% and faecal coliforms (FC) 1.9 logs. The reed bed is becoming the preferred on-site technology for removing TN and BOD and polishing TSS from primary settled domest...
The removal of nutrients from plant nursery irrigation runoff in subsurface horizontal-flow wetlands
Water Science and Technology, 2001
In New South Wales (NSW) Australia, the recent introduction of legislation to control runoff and ... more In New South Wales (NSW) Australia, the recent introduction of legislation to control runoff and charge for water used in agricultural production has encouraged commercial plant nurseries to collect and recycle their irrigation drainage. Runoff from a nursery typically contains around 6 mg/L TN (> 70% as NO3), 0.5 mg/L TP (> 50% as PO4), and virtually no organic matter (BOD <5 mg/L; DOC <20 mg/L). As a result, algal blooms frequently occur in storage dams. This paper describes a study evaluating the effectiveness of subsurface flow wetlands in the removal of nutrients from nursery runoff on the sub-tropical northern coast of NSW, Australia. Four experimental subsurface flow wetlands (1 m×4 m×0.5 m water depth) were planted with Phragmites australis in April 1999. TN and TP load removals were > 84% and > 65% respectively at HRTs of between 5 and 2 days, with the majority of out-flowing TN and TP being organic in form. Internal generation of organic N and P resulted ...
Archives of Agronomy and Soil Science, 2017
Although Phragmites australis is commonly planted in constructed wetlands, very little is known a... more Although Phragmites australis is commonly planted in constructed wetlands, very little is known about its roots-associated bacterial communities, especially in wetlands used for the remediation of oil produced waters. Here, we describe the bacterial diversity, using molecular (illumina MiSeq sequencing) and cultivation techniques, in the rhizosphere soils of P. australis from an oil-polluted wetland in Oman. The obtained isolates were tested for their plant-growth promoting properties. Most sequences belonged to Proteobacteria, Bacteriodetes and Firmicutes. Sequences of potential hydrocarbondegrading bacteria (e.g. Ochrobactrum, and Pseudomonas) were frequently encountered. All soils contained sequences of known sulfur-oxidizing (e.g. Thiobacillus, Thiofaba, Rhodobacter and Sulfurovum) and sulfate-reducing bacteria, although the latter group made up only 0.1% to 3% of total sequences. The obtained isolates from the rhizosphere soils were phylogenetically affiliated to Serratia, Acinetobacter, Xenorhabdus, Escherichia and Salmonella. All strains were able to solubilize phosphate and about half were capable of producing organic acids and 1-aminocyclopropane-1-carboxylate (ACC) deaminase. Around 42% of the strains had the ability to produce indole acetic acid and siderophores. We conclude that the rhizosphere soils of P. australis in oil polluted wetlands harbor diverse bacterial communities that could enhance the wetland performance through hydrocarbon degradation, nutrient cycling and supporting plant growth.
Constructing Wetlands in the Desert: An Example of Sustainable Produced Water Management in Oman
Day 4 Thu, November 13, 2014, 2014
Large volumes of produced water are generated as an associated co-product of oil production in Om... more Large volumes of produced water are generated as an associated co-product of oil production in Oman and other countries; the management of which often imposes a limitation on oil production. In many cases, a portion of this water is re-injected into reservoirs to maintain pressure for the oil wells. The remaining volume is typically disposed of into shallow aquifers or via Deep Well Disposal (DWD) which are environmentally undesirable and operationally energy intensive. Constructed wetlands represent an alternative option for treating produced water and have been trialled in Oman since 2000 with large-scale implementation since 2010. Wetland technology is a phytoremediation process in which native wetland plants facilitate microbial degradation of hydrocarbons. Volume reduction is also achieved through the high evapotranspiration rate of the plants. The advantages of wetland technology include: no or low-energy requirement, low operating cost, no chemical inputs, long life expectanc...
Treatment of nitrified wastewater using reed beds
On-site wastewater treatment by reed bed in the moist subtropics
A comparison of lithium, bromide and rhodamine-b as tracers in gravel-based reed beds
Potential mining of lithium, beryllium and strontium from oilfield wastewater after enrichment in constructed wetlands and ponds
Science of The Total Environment, 2014
Shortages of resources (chemical elements) used by growing industrial activities require new tech... more Shortages of resources (chemical elements) used by growing industrial activities require new techniques for their acquisition. A suitable technique could be the use of wetlands for the enrichment of elements from produced water of the oil industry. Oil industries produce very high amounts of water in the course of oil mining. These waters may contain high amounts of rare elements. To our best knowledge nothing is known about the economic potential regarding rare element mining from produced water. Therefore, we estimated the amount of harvestable rare elements remaining in the effluent of a constructed wetland-pond system which is being used to treat and evaporate vast quantities of produced waters. The examined wetland system is located in the desert of the south-eastern Arabian Peninsula. This system manages 95,000 m(3) per day within 350 ha of surface flow wetlands and 350 ha of evaporation ponds and is designed to be used for at least 20 years. We found a strong enrichment of some chemical elements in the water pathway of the system (e.g. lithium up to 896 μg L(-1) and beryllium up to 139 μg L(-1)). For this wetland, lithium and beryllium are the elements with the highest economic potential resulting from a high price and load. It is calculated that after 20 years retention period 131 t of lithium and 57 t of beryllium could be harvested. This technique may also be useful for acquisition of rare earth elements. Other elements (e.g. strontium) with a high calculated load of 4500 tons in 20 years are not efficiently harvestable due to a relatively low market value. In conclusion, wetland treated waters from the oil industry offer a promising new acquisition technique for elements like lithium and beryllium.
Experiences with eco-technologies for On-site wastewater management in sub-tropical Australia
PLoS ONE, 2014
Various types of cyanobacterial mats were predominant in a wetland, constructed for the remediati... more Various types of cyanobacterial mats were predominant in a wetland, constructed for the remediation of oil-polluted residual waters from an oil field in the desert of the southeastern Arabian Peninsula, although such mats were rarely found in other wetland systems. There is scarce information on the bacterial diversity, spatial distribution and oil-biodegradation capabilities of freshwater wetland oil-polluted mats. Microbial community analysis by Automated Ribosomal Spacer Analysis (ARISA) showed that the different mats hosted distinct microbial communities. Average numbers of operational taxonomic units (OTUs ARISA) were relatively lower in the mats with higher oil levels and the number of shared OTUs ARISA between the mats was ,60% in most cases. Multivariate analyses of fingerprinting profiles indicated that the bacterial communities in the wetland mats were influenced by oil and ammonia levels, but to a lesser extent by plant density. In addition to oil and ammonia, redundancy analysis (RDA) showed also a significant contribution of temperature, dissolved oxygen and sulfate concentration to the variations of the mats' microbial communities. Pyrosequencing yielded 282,706 reads with .90% of the sequences affiliated to Proteobacteria (41% of total sequences), Cyanobacteria (31%), Bacteriodetes (11.5%), Planctomycetes (7%) and Chloroflexi (3%). Known autotrophic (e.g. Rivularia) and heterotrophic (e.g. Azospira) nitrogen-fixing bacteria as well as purple sulfur and non-sulfur bacteria were frequently encountered in all mats. On the other hand, sequences of known sulfate-reducing bacteria (SRBs) were rarely found, indicating that SRBs in the wetland mats probably belong to yetundescribed novel species. The wetland mats were able to degrade 53-100% of
Treatment wetlands in Oceania: experiences and case studies
Ecological Engineering, 2006
This paper describes seven case studies in which ecotechnological approaches are being used to re... more This paper describes seven case studies in which ecotechnological approaches are being used to reduce the discharge of nitrogen to the environment in three local government jurisdictions in the moist subtropical zone of eastern Australia. Both technical performance and factors relating to acceptance of the technologies are examined. Three of the technologies have survived early setbacks to achieve increasing acceptance. Composting toilets and reed beds (sub-surface flow wetlands) have achieved takeoff in the on-site wastewater
The removal of nutrients from plant nursery irrigation runoff in subsurface horizontal-flow wetlands (Presentation)
In New South Wales (NSW) Australia, the recent introduction of legislation to control runoff and ... more In New South Wales (NSW) Australia, the recent introduction of legislation to control runoff and charge for water used in agricultural production has encouraged commercial plant nurseries to collect and recycle their irrigation drainage. Runoff from a nursery typically contains around 6 mg/L TN (> 70% as NO3), 0.5 mg/L TP (> 50% as P04), and virtually no organic matter (BOD < 5 mg/L; DOC < 20 mg/L). As a result, algal blooms frequently occur in storage dams. This paper describes a study evaluating the effectiveness of subsurface flow wetlands in the removal of nutrients from nursery runoff on the sub-tropical northern coast of NSW, Australia. Four experimental subsurface flow wetlands (1 m x 4 m x 0.5 m water depth) were planted with Phragmites australis in April 1999. TN and TP load removals were > 84% and > 65% respectively at HRTs of between 5 and 2 days, with the majority of out-flowing TN and TP being organic in form. Internal generation of organic N and P resulted in persistent background levels of 0.45 mg/L TN and 0.15 mg/L TP in the reed bed effluent. TN, NH4 and TP removal was affected by HRT (P < 0.05). Greater than 90% load removal of NH4, NO2, NO3 and Ortho-P was achieved at all HRTs, with outlet concentrations generally < 0.01 mg/L for all. For TN, a strong relationship existed between removal rate (g/m2/day) and loading rate (r2 = 0.995), while a weaker relationship existed for TP (r2 = 0.47). It is estimated that a 1 ha nursery would require a reed bed area of 200 m2 for a 2 day HRT.
Seasonal variation in phosphorus removal processes within reed beds - as indicated by mass balance
The phosphorus (P) removal processes in two pairs of High and Low Loaded reed beds were investiga... more The phosphorus (P) removal processes in two pairs of High and Low Loaded reed beds were investigated during five periods within a 27-month study. The uptake/release of P was measured in seven mass balance compartments. With the exception of the first year of operation, the reed beds consistently removed over 96% of the influent P load, with total phosphorus (TP) concentrations being reduced from 0.5 mg/L to generally less than 0.005 mg/L across the range of loading rates and seasons studied. During the first year, uptake by Phragmites australis accounted for greater than 75% of P removed, and was equally distributed between above and below-ground biomass. During the second and third years, three seasonal stages were identified in the uptake and cycling of P by P. australis. A period of rapid above-ground growth and uptake occurred during spring fuelled partly by P reserves accumulated in rhizomes during the previous year. During summer, uptake by above-ground biomass was governed by the influent P loading rate, while the amount of P held in below-ground biomass remained relatively stable. During autumn and winter, P appeared to be translocated from senescent shoots to reserves in the rhizomes. Approximately 85% of the below-ground biomass P occurred in the top 20 cm of the substrate. Gravel fixation increased in importance from 12% in the first year to approximately 30% of P removed in the second year, with a highly significant correlation between the influent P loading rate and P fixed by the gravel. The weakly-bound P fraction from a sequential extraction was the dominant form of P fixed by the gravel. HCI extracts were inappropriate for the examination of sorption processes as they dissolved large amounts of mineral P from within the basaltic gravel. The bottom 30 cm of the substrate became the most important site for gravel fixation during the second year. Incorporation of P into the detritus/microbiota/other compartment increased after the first year to become one of the most important P removal processes, probably consisting mainly of leaf litter and slowly accreted organic sediments.
Performance monitoring of constructed floating wetlands: Treating stormwater runoff during the construction phase of an urban residential development
Science of The Total Environment
Sustainable Treatment of Wastewater Generated by Oil & Gas Drilling Rig Camps
Day 4 Thu, November 03, 2022
Oil & gas exploration and production activities often takes place in remote areas with no immedia... more Oil & gas exploration and production activities often takes place in remote areas with no immediate wastewater treatment access. It is industry practice to establish own treatment facilities or to tanker wastewater long distance to municipal treatment facilities outside the concession areas. The remote setting and harsh operating conditions makes it challenging for mechanical treatment systems to comply to national effluent discharge standards. This paper explores if a nature-based portable solution can help overcome this challenge while promoting sustainability. By deploying a Test Unit (ReedBox®) to Khalifa Industrial Zone Abu Dhabi in the United Arab Emirates, the treatment performance is tested for compliance. Following a 26-week test period, a third-party performance verification confirmed that the Test Unit satisfactorily treated the wastewater producing an effluent in full compliance with the Abu Dhabi Recycled Water and Biosolids Regulations for P1 Unrestricted Reuse. As a r...
Ex-Situ Bioremediation of Hydrocarbon Contaminated Soil - An Example from Oman
SPE Middle East Health, Safety, Environment & Sustainable Development Conference and Exhibition, 2014
A few years ago, an oil company in Oman initiated an approach to deal with hydrocarbon-contaminat... more A few years ago, an oil company in Oman initiated an approach to deal with hydrocarbon-contaminated soils that created environmental problems. These soils where collected in their oilfields and transported to their hazardous waste yards in the country's interior areas. The client entrusted several service providers to carry out de-contamination processes and landfill activities unfortunately with limited success. One of the Waste Yards has stock piled large quantities of hydrocarbon contaminated soil, with contamination concentrations ranging from 15,000 mg/kg total Total Petroleum Hydrocarbons (TPH) soil up to 40,000 mg/kg TPH. The hydrocarbon molecule chains are from various types – starting with short chains i.e. C5 up to long chains C35. In 2012, the client decided to implement a new remediation approach by deploying eco-friendly technologies to properly manage degradation and remediation of the contaminated soil by using modern bio-remediation technology developed and appli...
Constructing a reed bed to treat runoff water - a guide for nurseries
Impacts of partially hydrolyzed polyacrylamide (HPAM) on microbial mats from a constructed wetland treating oilfield produced water
Chemosphere, 2021
Constructed wetlands have been successfully used in the treatment of produced water brought to th... more Constructed wetlands have been successfully used in the treatment of produced water brought to the surface in large quantities during oil extraction activities. However, with the increasing use of partially hydrolyzed polyacrylamide (HPAM) in enhancing oil recovery, the impacts of HPAM on the biological processes of wetlands is still unknown. Microbial mats in wetlands play a key role in hydrocarbon degradation. Here, we compared the bacterial communities of four wetland microbial mats after flooding with different concentrations of HPAM. Two mats (i.e. the HPAM-free and the 500 ppm HPAM pre-exposed mats) were selected to further investigate the effect of HPAM on respiration and biodegradation activities. The field mats exhibited clear differences in their bacterial community structure, where Cyanobacteria and Alphaproteobacteria became dominant in the presence of HPAM. In the laboratory experiments, the generated CO2 by the HPAM-free and the 500 ppm HPAM pre-exposed mats did not vary significantly when HPAM was added, although CO2 values were slightly higher in the presence of oil. Both mats were still able to degrade between 15 ± 14.4 to 50 ± 13.0% of C10 to C30 alkanes in 28 days, and this degradation was not affected by HPAM addition. The HPAM concentration decreased by 22-34% of the initial amount after 28 days of incubation in the HPAM-free mat, versus only 7-18.4% decrease in the 500 ppm HPAM pre-exposed mat. We conclude that the wetland microbial mats seem to have become well adapted to HPAM and could maintain their respiration and hydrocarbon degradation activities.
On-site domestic wastewater treatment by reed bed in the moist subtropics
Water Science and Technology, 2001
This paper summarises the results of studies on four subsurface flow wetlands (reed beds) located... more This paper summarises the results of studies on four subsurface flow wetlands (reed beds) located in the moist sub-tropical north eastern corner of the Australian state of New South Wales. The reed beds, which are subjected to a variety of effluent types, all have a gravel substrate planted with Phragmites australis. All four units were found to maintain satisfactory treatment performance year round. Mean removal efficiencies ranged from 56% to 90% (SS), 70% to 93% (BOD), 38% to 66% (TN), 87% to 99.8% (Faecal coliforms), and 42% to 70% (TP - with one seasonal result of 0% for the eight year old unit) for the four reed beds. After eight years in operation the oldest reed bed was showing signs of phosphorus saturation with outlet TP concentrations exceeding inlet concentrations on some occasions. The youngest reed bed studied appeared to be operating efficiently after five months. A summer water balance on one of the reed beds revealed an average crop factor of 1.6 and a moisture loss...
Water Science and Technology, 2005
Reed beds (horizontal subsurface flow constructed wetlands) have been employed as secondary treat... more Reed beds (horizontal subsurface flow constructed wetlands) have been employed as secondary treatment devices in on-site and decentralised wastewater management systems in the northeast of the Australian state of New South Wales (NSW) for over a decade. This paper summarises some of the practical and research findings that have come to light in that time. Experience with various aspects of reed bed structure is discussed. A study of the evaporative performance of four small beds planted with Phragmites australis yielded an annual crop factor of 2.6. A total of 28 studies on reed beds treating a variety of commonly encountered wastewater streams yielded the following mean pollutant removal efficiencies: total suspended solids (TSS) 83%, biochemical oxygen demand (BOD) 81%, total nitrogen (TN) 57%, total phosphorus (TP) 35% and faecal coliforms (FC) 1.9 logs. The reed bed is becoming the preferred on-site technology for removing TN and BOD and polishing TSS from primary settled domest...
The removal of nutrients from plant nursery irrigation runoff in subsurface horizontal-flow wetlands
Water Science and Technology, 2001
In New South Wales (NSW) Australia, the recent introduction of legislation to control runoff and ... more In New South Wales (NSW) Australia, the recent introduction of legislation to control runoff and charge for water used in agricultural production has encouraged commercial plant nurseries to collect and recycle their irrigation drainage. Runoff from a nursery typically contains around 6 mg/L TN (> 70% as NO3), 0.5 mg/L TP (> 50% as PO4), and virtually no organic matter (BOD <5 mg/L; DOC <20 mg/L). As a result, algal blooms frequently occur in storage dams. This paper describes a study evaluating the effectiveness of subsurface flow wetlands in the removal of nutrients from nursery runoff on the sub-tropical northern coast of NSW, Australia. Four experimental subsurface flow wetlands (1 m×4 m×0.5 m water depth) were planted with Phragmites australis in April 1999. TN and TP load removals were > 84% and > 65% respectively at HRTs of between 5 and 2 days, with the majority of out-flowing TN and TP being organic in form. Internal generation of organic N and P resulted ...
Archives of Agronomy and Soil Science, 2017
Although Phragmites australis is commonly planted in constructed wetlands, very little is known a... more Although Phragmites australis is commonly planted in constructed wetlands, very little is known about its roots-associated bacterial communities, especially in wetlands used for the remediation of oil produced waters. Here, we describe the bacterial diversity, using molecular (illumina MiSeq sequencing) and cultivation techniques, in the rhizosphere soils of P. australis from an oil-polluted wetland in Oman. The obtained isolates were tested for their plant-growth promoting properties. Most sequences belonged to Proteobacteria, Bacteriodetes and Firmicutes. Sequences of potential hydrocarbondegrading bacteria (e.g. Ochrobactrum, and Pseudomonas) were frequently encountered. All soils contained sequences of known sulfur-oxidizing (e.g. Thiobacillus, Thiofaba, Rhodobacter and Sulfurovum) and sulfate-reducing bacteria, although the latter group made up only 0.1% to 3% of total sequences. The obtained isolates from the rhizosphere soils were phylogenetically affiliated to Serratia, Acinetobacter, Xenorhabdus, Escherichia and Salmonella. All strains were able to solubilize phosphate and about half were capable of producing organic acids and 1-aminocyclopropane-1-carboxylate (ACC) deaminase. Around 42% of the strains had the ability to produce indole acetic acid and siderophores. We conclude that the rhizosphere soils of P. australis in oil polluted wetlands harbor diverse bacterial communities that could enhance the wetland performance through hydrocarbon degradation, nutrient cycling and supporting plant growth.
Constructing Wetlands in the Desert: An Example of Sustainable Produced Water Management in Oman
Day 4 Thu, November 13, 2014, 2014
Large volumes of produced water are generated as an associated co-product of oil production in Om... more Large volumes of produced water are generated as an associated co-product of oil production in Oman and other countries; the management of which often imposes a limitation on oil production. In many cases, a portion of this water is re-injected into reservoirs to maintain pressure for the oil wells. The remaining volume is typically disposed of into shallow aquifers or via Deep Well Disposal (DWD) which are environmentally undesirable and operationally energy intensive. Constructed wetlands represent an alternative option for treating produced water and have been trialled in Oman since 2000 with large-scale implementation since 2010. Wetland technology is a phytoremediation process in which native wetland plants facilitate microbial degradation of hydrocarbons. Volume reduction is also achieved through the high evapotranspiration rate of the plants. The advantages of wetland technology include: no or low-energy requirement, low operating cost, no chemical inputs, long life expectanc...
Treatment of nitrified wastewater using reed beds
On-site wastewater treatment by reed bed in the moist subtropics
A comparison of lithium, bromide and rhodamine-b as tracers in gravel-based reed beds
Potential mining of lithium, beryllium and strontium from oilfield wastewater after enrichment in constructed wetlands and ponds
Science of The Total Environment, 2014
Shortages of resources (chemical elements) used by growing industrial activities require new tech... more Shortages of resources (chemical elements) used by growing industrial activities require new techniques for their acquisition. A suitable technique could be the use of wetlands for the enrichment of elements from produced water of the oil industry. Oil industries produce very high amounts of water in the course of oil mining. These waters may contain high amounts of rare elements. To our best knowledge nothing is known about the economic potential regarding rare element mining from produced water. Therefore, we estimated the amount of harvestable rare elements remaining in the effluent of a constructed wetland-pond system which is being used to treat and evaporate vast quantities of produced waters. The examined wetland system is located in the desert of the south-eastern Arabian Peninsula. This system manages 95,000 m(3) per day within 350 ha of surface flow wetlands and 350 ha of evaporation ponds and is designed to be used for at least 20 years. We found a strong enrichment of some chemical elements in the water pathway of the system (e.g. lithium up to 896 μg L(-1) and beryllium up to 139 μg L(-1)). For this wetland, lithium and beryllium are the elements with the highest economic potential resulting from a high price and load. It is calculated that after 20 years retention period 131 t of lithium and 57 t of beryllium could be harvested. This technique may also be useful for acquisition of rare earth elements. Other elements (e.g. strontium) with a high calculated load of 4500 tons in 20 years are not efficiently harvestable due to a relatively low market value. In conclusion, wetland treated waters from the oil industry offer a promising new acquisition technique for elements like lithium and beryllium.
Experiences with eco-technologies for On-site wastewater management in sub-tropical Australia
PLoS ONE, 2014
Various types of cyanobacterial mats were predominant in a wetland, constructed for the remediati... more Various types of cyanobacterial mats were predominant in a wetland, constructed for the remediation of oil-polluted residual waters from an oil field in the desert of the southeastern Arabian Peninsula, although such mats were rarely found in other wetland systems. There is scarce information on the bacterial diversity, spatial distribution and oil-biodegradation capabilities of freshwater wetland oil-polluted mats. Microbial community analysis by Automated Ribosomal Spacer Analysis (ARISA) showed that the different mats hosted distinct microbial communities. Average numbers of operational taxonomic units (OTUs ARISA) were relatively lower in the mats with higher oil levels and the number of shared OTUs ARISA between the mats was ,60% in most cases. Multivariate analyses of fingerprinting profiles indicated that the bacterial communities in the wetland mats were influenced by oil and ammonia levels, but to a lesser extent by plant density. In addition to oil and ammonia, redundancy analysis (RDA) showed also a significant contribution of temperature, dissolved oxygen and sulfate concentration to the variations of the mats' microbial communities. Pyrosequencing yielded 282,706 reads with .90% of the sequences affiliated to Proteobacteria (41% of total sequences), Cyanobacteria (31%), Bacteriodetes (11.5%), Planctomycetes (7%) and Chloroflexi (3%). Known autotrophic (e.g. Rivularia) and heterotrophic (e.g. Azospira) nitrogen-fixing bacteria as well as purple sulfur and non-sulfur bacteria were frequently encountered in all mats. On the other hand, sequences of known sulfate-reducing bacteria (SRBs) were rarely found, indicating that SRBs in the wetland mats probably belong to yetundescribed novel species. The wetland mats were able to degrade 53-100% of
Treatment wetlands in Oceania: experiences and case studies
Ecological Engineering, 2006
This paper describes seven case studies in which ecotechnological approaches are being used to re... more This paper describes seven case studies in which ecotechnological approaches are being used to reduce the discharge of nitrogen to the environment in three local government jurisdictions in the moist subtropical zone of eastern Australia. Both technical performance and factors relating to acceptance of the technologies are examined. Three of the technologies have survived early setbacks to achieve increasing acceptance. Composting toilets and reed beds (sub-surface flow wetlands) have achieved takeoff in the on-site wastewater