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Headley T.R.,Southern Cross University of Australia | Headley T.R.,Helmholtz Center for Environmental Research | Headley T.R.,BAUER Nimr LLC | Davison L.,Southern Cross University of Australia | And 2 more authors.
Water Research | Year: 2012

The balance between evapotranspiration (ET) loss and rainfall ingress in treatment wetlands (TWs) can affect their suitability for certain applications. The aim of this paper was to investigate the water balance and seasonal dynamics in ET of subsurface horizontal flow (HF) TWs in a sub-tropical climate. Monthly water balances were compiled for four pilot-scale HF TWs receiving horticultural runoff over a two year period (Sep. 1999-Aug. 2001) on the sub-tropical east-coast of Australia. The mean annual wetland ET rate increased from 7.0 mm/day in the first year to 10.6 mm/day in the second, in response to the development of the reed (Phragmites australis) population. Consequently, the annual crop coefficients (ratio of wetland ET to pan evaporation) increased from 1.9 in the first year to 2.6 in the second. The mean monthly ET rates were generally greater and more variable than the Class-A pan evaporation rates, indicating that transpiration is an important contributor to ET in HF TWs. Evapotranspiration rates were generally highest in the summer and autumn months, and corresponded with the times of peak standing biomass of P. australis. It is likely that ET from the relatively small 1 m wide by 4 m long HF TWs was enhanced by advection through so-called " clothesline" and " oasis" effects, which contributed to the high crop coefficients. For the second year, when the reed population was well established, the annual net loss to the atmosphere (taking into account rainfall inputs) accounted for 6.1-9.6 % of the influent hydraulic load, which is considered negligible. However, the net loss is likely to be higher in arid regions with lower rainfall. The Water Use Efficiency (WUE) of the wetlands in the second year of operation was 1.3 g of above-ground biomass produced per kilogram of water consumed, which is low compared to agricultural crops. It is proposed that system level WUE provides a useful metric for selecting wetland plant species and TW design alternatives to use in arid regions where excessive water loss from constructed wetlands can be problematic. Further research is needed to accrue long-term HF TW water balance data especially in arid climatic zones. © 2011 Elsevier Ltd.

Alexandersen D.K.,BAUER Nimr LLC | Headley T.,BAUER Nimr LLC | Prigent S.,BAUER Nimr LLC | Mahmutoglu I.,Free Consultant
Society of Petroleum Engineers - SPE Middle East Health, Safety, Environment and Sustainable Development Conference and Exhibition, MEHSE 2014 | Year: 2014

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 applied by a renowned German remediation company. The technology brings degradation results of reducing hydrocarbon contamination to less than 50%, lower than the international treatment standards and this within the first few weeks of treatment. This paper will provide an overview of the bio-remediation approach used to treat stockpiled TPH contaminated soil. It will present remediation results from the field, but more over it will look into the opportunities and barriers for reusing the treated soil in civil projects without harming the environment and nature. In this specific case, the treated soil was used in one of the world's largest constructed wetlands, which handles 95,000 m3/day produced water. In April/May 2013, new soil tests will be taken to assess the quality of the soil material and subsequent hydrocarbon degradation after being in the wetland for one year. Copyright © 2014, Society of Petroleum Engineers.

Nivala J.,University of Aarhus | Nivala J.,Helmholtz Center for Environmental Research | Headley T.,Bauer Nimr LLC | Wallace S.,Naturally Wallace Consulting LLC | And 4 more authors.
Ecological Engineering | Year: 2013

The Langenreichenbach ecotechnology research facility contains 15 individual pilot-scale treatment systems of eight different designs or operational variants. The designs differ in terms of flow direction, degree of media saturation, media type, loading regime, and aeration mechanism. Seven systems were constructed as planted and unplanted pairs, in order to elucidate the role of common reed (Phragmites australis) in these technologies. The facility is unique in the fact that it is located adjacent to the wastewater treatment plant for the nearby village, enabling all of the pilot-scale systems to receive the same wastewater. The construction of the Langenreichenbach research facility is placed within the overarching discipline of ecological engineering. An overview of the treatment wetland design spectrum (ranging from passive to highly intensified designs) is discussed and the specific designs implemented at Langenreichenbach are presented in detail, along with the internal sampling methods for both saturated and unsaturated systems. © 2013 Elsevier B.V.

Nivala J.,University of Aarhus | Nivala J.,Helmholtz Center for Environmental Research | Wallace S.,Naturally Wallace Consulting LLC | Headley T.,Bauer Nimr LLC | And 5 more authors.
Ecological Engineering | Year: 2013

Subsurface oxygen availability tends to be one of the main rate-limiting factors for removal of carbonaceous and nitrogenous compounds in subsurface flow (SSF) wetlands used for domestic wastewater treatment. This paper reviews the pertinent literature regarding oxygen transfer and consumption in subsurface flow treatment wetlands, and discusses the factors that influence oxygen availability.We also provide first results from a pilot-scale research facility in Langenreichenbach, Germany (15 individual systems of various designs, both with and without plants). Based on the approach given in Kadlec and Wallace (2009), areal-based oxygen consumption rates for horizontal flow systems were estimated to be between 0.5 and 12.9g/m2-d; for vertical flow systems between 7.9 and 58.6g/m2-d; and for intensified systems between 10.9 and 87.5g/m2-d. In general, as the level of intensification increases, so does subsurface oxygen availability. The use of water or air pumps can result in systems with smaller area requirements (and better treatment performance), but it comes at the cost of increased electricity inputs. As the treatment wetland technology envelope expands, so must methods to compare oxygen consumption rates of traditional and intensified SSF treatment wetland designs. © 2012 Elsevier B.V.

Zhai X.,University of Aarhus | Piwpuan N.,University of Aarhus | Arias C.A.,University of Aarhus | Headley T.,Bauer Nimr LLC | Brix H.,University of Aarhus
Ecological Engineering | Year: 2013

Rooted emergent wetland plants may deliver organic carbon via root exudates to fuel the microbial denitrification process in subsurface flow constructed wetland systems receiving nitrate-rich and low-carbon wastewater. We quantified the amount of dissolved organic carbon (DOC) released from roots of three wetland species, Phragmites australis, Iris pseudacorus and Juncus effusus, which are commonly used in constructed wetlands. Plants were grown hydroponically at two temperatures (10 and 20°C) and three light-regimes (a normal 14h:10h light:dark cycle, continuous light and continuous dark), and the release rates of DOC from the roots as well as the uptake rates of NH4-N, NO3-N, PO4-P and K were analyzed. DOC release rates were significantly different among the three species, and were also affected by temperature and light-regime. At 20°C, higher amounts of DOC were generally released in the root exudates than at 10°C. The average DOC release rate of the three species was nearly two times higher in the light (10.2±0.7μgg-1rootDMh-1) than in the dark (6.8±0.7μgg-1rootDMh-1). As expected, DOC release rates were positively related to the relative growth rate (RGR) and nutrient uptake rate. DOC release rates amounted to 0.6-4.8% of the net photosynthetically fixed carbon. Extrapolating the laboratory measurements to field conditions suggests that plant root exudates may potentially fuel a denitrification rate of 94-267kgNha-1year-1 in subsurface flow constructed wetlands. Hence, root exudates are potentially important as an organic C source for denitrification in lightly loaded subsurface flow constructed wetland systems receiving nitrate-rich water with a low content of BOD (e.g. nitrified effluent or agricultural drainage). © 2013 Elsevier B.V.

Tanner C.C.,NIWA - National Institute of Water and Atmospheric Research | Sukias J.P.S.,NIWA - National Institute of Water and Atmospheric Research | Headley T.R.,NIWA - National Institute of Water and Atmospheric Research | Headley T.R.,Bauer Nimr LLC | And 2 more authors.
Ecological Engineering | Year: 2012

The performance of five alternative treatment trains receiving primary domestic wastewaters was compared in side-by-side trials over an annual period after 2 years maturation. One of the systems was a passive horizontal-flow wetland. The other four hybrid systems comprised different configurations of subsurface horizontal- and/or intermittently-dosed (24/d) vertical-flow constructed wetlands (single pass or recirculating), and attached growth and carbonaceous (wood-chip and coconut husk) denitrifying bioreactors. The scale of the systems ranged from ∼20 to 40% of that required for a single household. Mean biochemical oxygen demand (BOD 5) and total suspended solids (TSS) were reduced by over 94% in all systems. Mean ammonium-N (NH 4-N) concentrations were reduced to between 0.05 and 0.20gm -3 (98-99.8% reduction) in the hybrid wetland and bioreactor systems, compared to ∼13gm -3 (61% reduction) in the horizontal-flow wetland. Mean total nitrogen (TN) removal ranged from 49% in the horizontal-flow wetland to between 58 and 95% in the hybrid systems. Apparent nitrification rates of 3.8-7.3gNm -2d -1 (based on ammonium reduction) were recorded in the vertical-flow wetlands and apparent denitrification rates of 2.8-12.4gNm -3d -1 (based on nitrate reduction) in linked denitrifying bioreactors and horizontal-flow wetlands. Mean total phosphorus (TP) removal ranged from 36 to 65%, while faecal indicator bacteria were reduced by 2.5-4.7log units in the different systems. The results of this study show that simple hybrid systems combining wetland and denitrifying bioreactor components are capable of achieving advanced effluent quality with low energy inputs. The areas required for these hybrid systems were generally half or less of those required for horizontal-flow wetlands. © 2012 Elsevier B.V.

Breuer R.,BAUER Umwelt GmbH | Headley T.R.,BAUER Nimr LLC | Thaker Y.I.,BAUER Nimr LLC | Al Sharji B.,Petroleum Development Oman
Society of Petroleum Engineers - SPE/APPEA Int. Conference on Health, Safety and Environment in Oil and Gas Exploration and Production 2012: Protecting People and the Environment - Evolving Challenges | Year: 2012

One of the largest industrial constructed wetland systems in the world was commissioned at the start of 2011 to sustainably manage more than 45,000 m 3/day of produced water from the Nimr oilfields in Oman. This natural treatment system consists of a passive oil-water separator, 234 hectares of surface flow wetlands and 300 hectares of evaporation ponds andhas been instrumental in reducing the amount of hydrocarbon polluted produced water being disposed to the deep well aquifers. The Nimr Water Treatment Plant (Nimr WTP),being a gravity flow system uses minimal fossil fuel for its operation and therefore results in an enormous saving in energy consumption compared to the conventional, energy-intensive disposal method of pumping the water more than 1.5 km below ground into deep aquifers under high pressure. Maximizing the use of locally available and naturallyoccurring materials for construction, treating and reusing oil contaminated soil from the oilfields and minimizing electricity consumption has decreased thecarbon footprint, greenhouse gas emissions and environmental impacts of the oilfield, thus helping to protect people and the environment.Duringthe first year of operation (2011)an average of 113bbl/day of residual oil were recovered from the produced water which is equal to around 41,100bbls of oil for the year.The average operational power consumption for running the NWTP measured for 2011 was only 0.06 kWh per m3 of produced water treated, compared to 3.6-5.5 kWh/m3 for the deep well disposal that has traditionally been used. This equates to an energy saving of 98.3-98.9% for managing the produced water and represents a huge saving in energy costs, fossil fuel consumption and subsequent green-house gas emissions making the project not only environmentally friendly but also economically successful for the oil producer. The reduction in CO2emissionsin 2011 was between 40,700 and 62,600 tons. The wetlands and ponds also provide a valuable habitat for migratory birds, with close to 100 different bird species having been identified at the site to date. During 2012, an extension to the wetland system (additional 120 hectares) is being constructed to increase the capacity of the plant to 95,000 m3/day. As part of this extension, approximately 167,000 m3 of oil contaminated soil has been biologically treated and reused as soil substrate in the wetland, providing additional environmental benefits. This paper discusses the details of the plant performance, data analysis and the challenges experienced in the first year operation of the Nimr WTP. Copyright 2012, SPE/APPEA International Conference on Health, Safety, and Environment in Oil and Gas Exploration and Production.

Breuer R.,BAUER Nimr LLC | Al-Asmi S.R.,Petroleum Development Oman
Society of Petroleum Engineers - SPE International Conference on Health, Safety and Environment in Oil and Gas Exploration and Production 2010 | Year: 2010

The Nimr Water Treatment Project is to develop and set up an effective water treatment plant for the residual waters produced from the Petroleum Development Oman (PDO) oil wells in its Nimr Oil Field with a capacity to process a minimum of 45,000 m3/day produced water. PDO initially established a pilot project 10 years ago in the Nimr Oilfied in the Sultanate of Oman; see Figure 1 Map of Omani Oilfields - The Nimr Cluster. The technology used was based on a constructed wetland followed by an evaporation pond to remove the produced water contaminants and reduce the effluent. Using the experience of the pilot a Design, Build, Own, Operate and Transfer (DBOOT) tender process was started to upscale the pilot from a capacity of 1,000 m 3/d to 45,000 m3/d in 2007. The project was awarded late in 2008 and based on PDO and the contractor's experience one of the biggest commercial constructed wetlands is build for water treatment. Main technology changes were made based on pilot test results, an extended study of the water characteristics and climate data. The result is the construction of an approximately 600 ha large facility comprising of an Oil/Water Separator to recover remaining crude oil, a surface flow Constructed Wetland and finally an engineered salt works facility to include the option for salt recovery. Additionally, potential benefits of biomass utilisation and carbon credit values are investigated to be potentially included into the project after commissioning. Construction works have commenced in May 2009 and water is bound to flow in January 2011. Copyright 2010, Society of Petroleum Engineers.

Fonder N.,University of Liège | Headley T.,Helmholtz Center for Environmental Research | Headley T.,BAUER Nimr LLC
Ecological Engineering | Year: 2013

This paper proposes a structure for classifying and naming different treatment wetland (TW) design alternatives, based on physical design traits. A classification hierarchy is organised like a polychotomous key, from general classification criteria to wetland type identification. Three characteristics are typical of all TWs: the presence of macrophytic vegetation; the existence of water-logged or saturated substrate conditions for at least part of the time; and inflow of contaminated water with constituents to be removed. Treatment wetlands are further classified based on hydrology and vegetation characteristics. Hydrological traits relate to water position, flow direction, degree of saturation and position of influent loading. Based on the predominant position of water in the system, two main groups are identified: those with surface flow above a benthic substrate and those with subsurface flow through a porous media. The systems with surface flow are divided into three standard types, differentiated by vegetation type: Surface flow (SF), free-floating macrophyte (FFM), and floating emergent macrophyte (FEM) TWs. Subsurface flow systems always contain sessile emergent macrophytes and are divided into four standard types, based on flow direction: horizontal sub-surface flow (HSSF), vertical down flow (VDF), vertical up flow (VUF) and fill and drain (FaD) TWs. Standard types are described with their main applications. Associated variants are identified. An overview of intensified variants, which have elevated energy, chemical or operational inputs in order to increase efficiency or overcome process limitations, is also provided. © 2012 Elsevier B.V.

Breuer R.,BAUER Nimr LLC | Grissemann E.,BAUER Nimr LLC
International Conference on Health, Safety and Environment in Oil and Gas Exploration and Production | Year: 2011

A wetland system is being installed in the Sultanate of Oman to reduce the environmental impact of produced water management. The facility will reduce the disposal of hydrocarbon polluted produced water into deep aquifers, recover hydrocarbons using an additional oil/water separation step, and decrease the overall power consumption of the oil field operation by using a gravity flow system. A discussion on the wetland system covers the use of local materials for the installation of a sealing layer; commissioning phase; results showing that ≤ 60 bpd of crude oil were recovered; and energy requirements of the facility. This is an abstract of a paper presented at the 2011 SPE International Conference on Health, Safety & Environment in Oil and Gas Exploration and Production (Vienna, Austria 2/22-24/2011).

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