Abstract

This study describes the first Norwegian microbial source tracking (MST) approach for water quality control and pollution removal from catchment run-off in a nature-based treatment system (NBTS) with a constructed wetland. The applied MST tools combined microbial analyses and molecular tests to detect and define the source(s) and dominant origin(s) of faecal water contamination. Faecal indicator bacteria Escherichia coli and host-specific Bacteroidales 16 s rRNA gene markers have been employed. The study revealed that the newly developed contribution profiling of faecal origin derived from the Bacteroidales DNA could quantitatively distinguish between human and non-human pollution origins. Further, the outcomes of the MST test have been compared with the results of both physicochemical analyses and tests of pharmaceutical and personal care products (PPCPs). A strong positive correlation was discovered between the human marker and PPCPs. Gabapentin was the most frequently detected compound and it showed the uppermost positive correlation with the human marker. The study demonstrated that the NBTS performs satisfactorily with the removal of E. coli but not PPCPs. Interestingly, the presence of PPCPs in the water samples was not correlated with high concentrations of E. coli. Neither has the latter an apparent correlation with the human marker.

To document

Abstract

Many cities and urban areas are located in flood plains because land is fertile and flat which is suitable for agriculture and urban development. Rivers provide water supply for domestic, industrial and irrigation uses; they also provide convenient means for navigation, transportation and communication. Cities have large percentage of impervious areas that prevent effective infiltration of rainfall into soil. To have successful flood control and flood risk management, we should consider not only hydraulic and engineering aspects but also socio-economic and environment aspects. Flood management should have involvement of various stakeholders including concerned authorities such as urban planners, civil and water resources engineers, civil disaster defence authorities, health and social services, etc. The best flood mitigation measures from all main points of view – social, economic and environmental are natural water retention measures. Natural water retention measures cover a diversity of measures that are implemented by different sectors or considered in different planning processes dealing with water, food risk management, biodiversity protection, climate change adaptation or urban planning. Some of these measures aim to directly modify the ecosystem, while others focus on changes of practice of economic operators. The paper presents natural water retention measures suitable for application in urban areas.

Abstract

Water quality problems in Norway are caused mainly by high phosphorus (P) inputs from catchment areas. Multiple pollution sources contributes to P inputs into watercourses, and the two main sources in rural areas are agricultural runoff and discharge from on-site wastewater treatment systems (OWTSs). To reduce these inputs, Constructed wetlands (CWs) treating catchment runoff have been implemented in Norway since early 1990s. These CWs have been proven effective as supplements to agricultural best management practices for water quality improvements and therefore there are more than 1000 CWs established in Norway at present. This study aims to present some overall data on the present status of CWs treating catchment runoff in Norway, and in particular recent results of source tracking and retention of sediments and total phosphorus (TP) in a model, full-scale, long-term operated CW, which in practice treats runoff from a typical rural catchment with pollution from both point and diffuse sources. Nutrient contributions from agricultural runoff and OWTSs have been quantified in eight catchments, while the source tracking and retention of sediments and P has been studied in the model CW. P runoff in the catchments was largely affected by precipitation and runoff situation, and varied both throughout the year (every single year) and from one year to another. Annual TP contribution that origins from OWTSs was in general limited, and only 1 % in the catchment of the model CW. Monthly contribution, however, was higher than 30 % during warm/dry season, and cold months with frost season. For the purpose of source tracking study, faecal indicator bacteria (reported in terms of Escherichia coli - E. coli) and host-specific 16S rRNA gene markers Bacteroidales have been applied. High E.coli concentrations were well associated with high TP inputs into waterbodies during dry or/and cold season with little or no agriculture runoff, and further microbial source tracking (MST) tests proved human contribution. There are considerable variations in retention of sediments and TP in the CW between the years, and the annual yearly retention was about 38 % and 16 %, respectively. During the study period, the average monthly retention of sediments and TP was 54 % and 32 %, respectively. E. coli concentrations were also reduced in water passing the CW. The study confirmed that runoff from agricultural areas is the main P source in watercourses, however, discharges from OWTS can also be of great importance for the water quality, especially during warm/dry- and cold/frosty periods. Small CWs treating catchment runoff contribute substantially to the reduction of sediments, TP and faecal indicator bacteria transport into water recipients.

Abstract

Norwegian constructed wetlands (CWs) that treat domestic wastewater are classified as horizontal subsurface flow constructed wetlands (HSFCWs). Over the years of continuous performance, the HSFCWs operating under cold climate conditions have shown a high and stable treatment efficiency with regard to the removal of organic matter (>90 % BOD), nutrients (>50 % N and >90 % P) and microbes (>99 % bacteria). The majority of Norwegian HSFCWs are categorised as small (<50 pe) on-site, decentralised wastewater treatment systems. The Norwegian systems consist of three fundamental elements: a septic tank, a pre-filter (i.e. an aerobic vertical flow biofilter) and a horizontal flow saturated filter/wetland bed. The first, primary treatment step begins in the septic tank from which effluents are pre-treated in the second step occurring in the pre-filter/biofilter section and further in the third, final step taking place in the filter bed/HSFCW. The first and third treatment steps are quite common in systems with CWs, but the pre-treatment in biofilter(s) is mainly known from Norway. The main purpose of using the pre-treatment phase is to supply air during the cold season, to enhance nitrification processes, and to reduce the load of organic matter before entering the filter/wetland bed. If constructed and maintained correctly, the biofilters alone can remove 90 % BOD and 40 % N. Various filter/CW beds have been introduced for treatment of domestic wastewater (as complete or source-separated streams) in Norway, but the most common feature is the use of specific filter media for high phosphorus (P) removal. A few Norwegian municipalities also have limits with respect to nitrogen (N) discharge, but the majority of municipalities use 1.0 mg P/l as the discharge limit for small wastewater treatment systems. This particular limit affects the P retention lifetime of the filter media, which varies from system to system depending on the filter media applied, the type of wastewater treated, and the system design and loading rates. An estimated lifetime of filter media with regard to P removal is approximately 15–18 years for a filter/CW bed of a single household. After completing the lifetime, the filter media is excavated and replaced with new/fresh materials, allowing the system to operate effectively for another lifespan. Since the exploited media are P-rich materials, the main intention is their reuse in a safe and hygienic way, in which P could be further utilised. Therefore, the Norwegian systems can represent a complex technology combining a sustainable technique of domestic wastewater treatment and a bio-economical option for filter media reuse. This is a quite challenging goal for reclamation and recycling of P from wastewater. Thus, there are some scenarios of reusing the P-rich filter media as a complementary P fertiliser, a soil amendment or a conditioner, provided the quality is acceptable for utilisation in agriculture. Alternatively, the filter media could be reused in some engineering projects, e.g. green roof technology, road screening or construction of embankments, if the quality allows application in the environment. The core aspect of the reuse options is the appropriate quality of the filter media. As for the theoretical assumption, it should not be risky to reuse the P-rich media in agriculture. In practice, however, the media must be proven safe for human and environmental health prior to introducing into the environment.

Abstract

Nutrients for food production are traditionally extracted from natural resources, most importantly as nitrogen from the air, and phosphorous from limited mineral resources. They can also be recovered and recycled from human waste products. There is generally a low P status in the world’s soils, while Norwegian soils are rich in phosphorous. Most recyclable P is in human and animal waste products as wastewater and manure, but also municipal solid waste and more recently, organic waste contain a considerable amount of P that ideally can be utilized.

Abstract

Polluted soil locations as well as solid waste landfills can be significant sources of potential pollution of the soil, biomass and both the surface and the groundwater. The management of the polluted soil sites in Norway is regulated according to the health risk related limits of target pollutants, focusing primarily on the presence of the eight key heavy metals and ten groups of organic pollutants in the top 1 m of soil, and to a risk based evaluation of the site leaching. The landfills are evaluated in a same way but the fate of the pollutants originating there is also supposed to be monitored using tracers. Tracing the sources and their effects can be complicated and expensive. Diffuse discharges of leachate from landfills are difficult to monitor since they typically originate under large volumes of waste. Typically, no adequate sampling or monitoring equipment is installed prior to when the landfilling operation begins. Groundwater flows are also hard to predict both in space and time and generally their scale asks for a very complex sampling strategy. The exact amount of water entering a landfill is also difficult to control and monitor due to typically large and heterogeneous areas involved, with differing evapotranspiration, infiltration and runoff characteristics. In this report we present cases of heavy metal pollution originating from a former oil production equipment scrapyard and case studies of complex pollution coming from traditional municipal solid waste landfills. Evaluation of tracers and the geostatistical modelling of their distribution and concentrations in order to evaluate the location of sources and the extent of pollution (plumes) was used. The analyses are cost reduction optimized. A total of 7 landfills were sampled over several years. The most effective tracer for the leachate description seems to be the carbon-13 isotope (13C). At some polluted sites the pollutants can be carried a great length due to wind erosion. Geostatistical methods and the software Grapher were applied. It became obvious that the public health focused risk assessments become difficult when the inflicted areas are large.

Abstract

The plant P uptake from sewage sludge and biochar was investigated in pot experiments after manipulating the waste pH by mixing with acidic compost leachate or high pH concrete waste at two levels. Available P was measured both wit passive DGT samplers and by P uptake in rye grass during three harvests. The treatment pH in waste was about 4 after waste was mixed with leachate, and 11.5 with concrete waste. The pH in the pot during grass production was approximately 6.5. The P uptake was significantly higher in the treated biochar pots, both after high and low pH treatment. The more extreme pH treatments gave the highest uptake. The DGT uptake gave the same broad picture for pots with biochar but not for pots with sludge. DGT uptake showed less diffenece between high and low pH treatments. The passive samplers correlated relatively well with the measured grass uptake.

Abstract

Municipal solid waste landfills are expected to be potentially important sources of gaseous mercury (Hg)(Lindberg et al. 2005). Such emissions can be difficult to locate and measure, since landfills can have diffuse, non-point emissions and the gas can also escape horizontally over large distances in unsaturated layers. The primary objective in this work was to investigate the possibility of depletion of gaseous mercury by means of moss transplants. The investigation was carried out at Solgård waste disposal site, an active landfill since its start-up in 1978, located in Moss, Norway. Today the landfill is licensed as a landfill for ordinary waste. The area of the landfill is estimated to be about 204 000 m2. Goodman and Roberts (1971) first introduced the “moss bag” technique, which was later modified by Little and Martin (1974). Hylocomium splendens, known for its capability as bio monitor since 1968 (Ruhling & Tyler 1968), was collected from an uncontaminated site, dried at room temperature and loaded in fine meshed nylon nets. Moss bags were made up of a frame of 10 x 10 cm square of thin wood sticks, filled with 1 gram of moss finely distributed and covered up by the nets. The moss bags were placed in two heights, about 40 and 100 cm above ground. A total of 130 moss bags were placed at suitable locations covering the landfill surface, with special attention to such places as gas vents and locations with suspicious odours. For comparison, moss bags were also placed a couple of kilometres north, south, west and east of the landfill. The exposure time was 6 months, lasting from primo October 2013 until the end of March 2014. About 0.2 g samples of air dried moss were subjected to acid digestion in a closed microwave system (260 0C) prior to analysis with inductively coupled plasma mass spectrometry, using an Agilent 8800 QQQ instrument. Results from ongoing work will be presented. References Goodman, G. T. & Roberts, T. M. (1971). Plants and soils as indicators of metals in the air. Nature, 231 (5301): 287-292. Lindberg, S., Southworth, G., Prestbo, E., Wallschläger, D., Bogle, M. & Price, J. (2005). Gaseous methyl-and inorganic mercury in landfill gas from landfills in Florida, Minnesota, Delaware, and California. Atmospheric Environment, 39 (2): 249-258. Little, P. & Martin, M. H. (1974). Biological Monitoring of Heavy metal pollution. Environmental Pollution, 6: 1-19. Ruhling, A., & Tyler, G. (1968). An ecological approach to lead problem. Botaniska Notiser, 121(3), 21.

Abstract

Large quantities of mercury (Hg) containing waste have been deposited on MSW landfills for half a century. Despite its known volatility, persistence, and toxicity in the environment, the fate of Hg in landfills has not been widely studied. However, the generation of methane by anaerobic bacteria suggests that landfills may act as bioreactors for methylated mercury (Me-Hg) (Lindberg et al. 2005). Studies conducted at operating landfills in the US identified and quantified both gaseous inorganic and Me-Hg species. Lindberg and co-workers (2005) estimated an average atmospheric Hg release in landfill gas (LFG) of about 300-400 mg/d, where the methylated forms of Hg were calculated to be 1- 10 mg/d. Industrial and commercial uses of Hg are regulated in many countries. The Norwegian government has introduced several resolutions with the intention to halting the Hg emissions by 2020 (Miljødirektoratet 2013). In an investigation by Øygard et al. (2004) it was found that less than 0.02% of the Hg deposited in a MSW landfill was discharged through the leachate, even without leachate treatment plants. Data on whether gas discharged from Norwegian MSW landfill sites contains any form of Hg are missing. As restrictions against the use of Hg in a number of products are adopted, most recently in 2008 (Miljødirektoratet 2013), there is every reason to believe that there are traces of Hg in discharged landfill gas. Discharged gas is sampled at Solgård waste disposal site in Moss, Norway, an active landfill established in 1978. Currently the landfill covers a surface area of approximately 204 000 m2. Different forms of mercury in LFG are sampled by means of a three pieces cassette packed with three selective adsorbents. In the first piece, an untreated cellulose support pad is used for trapping particles. For the determination of inorganic mercury (Hg0), cellulose support pads impregnated with palladium (Pd) is placed in the second piece. The last piece is filled with a CarbopackTM adsorbent for determination of organic Hg. The flow rate is set to 3 L/min for 3 hours. Subsequently, the adsorbents are subjected to acid digestion in a closed microwave system (260 0C) prior to analysis with ICP-MS. Use of CarbopackTM also allow us to simultaneously determine tin (Sn). Organic Sn is, like organic Hg, of interest in terms of hazardous pollutants, although it is not yet adopted restrictions for its use. Results from ongoing field and laboratory work will be presented. References Lindberg, S., Southworth, G., Prestbo, E., Wallschläger, D., Bogle, M. & Price, J. (2005). Gaseous methyl-and inorganic mercury in landfill gas from landfills in Florida, Minnesota, Delaware, and California. Atmospheric Environment, 39 (2): 249-258. Miljødirektoratet. (2013). Miljøstatus: Kvikksølv. Available at: http://www.miljostatus.no/Tema/Kjemikalier/Noen-farlige-kjemikalier/Kvikksolv/ (accessed: 09.01.2014). Øygard, J. K., Måge, A. & Gjengedal, E. (2004). Estimation of the mass-balance of selected metals in four sanitary landfills in Western Norway, with emphasis on the heavy metal content of the deposited waste and the leachate. Water research, 38 (12): 2851-2858.

Abstract

The concentrations of carbon monoxide (CO) and other gases were measured in the emissions from solid waste degradation under aerobic and anaerobic conditions during laboratory and field investigations. The emissions were measured as room temperature headspace gas concentrations in reactors of 1, 30, and 150 L, as well as sucked gas concentrations from windrow composting piles and a biocell, under field conditions. The aerobic composting laboratory experiments consisted of treatments with and without lime. The CO concentrations measured during anaerobic conditions varied from 0 to 3000 ppm, the average being 23 ppm, increasing to 133 ppm when methane (CH4) concentrations were low. The mean/maximum CO concentrations during the aerobic degradation in the 2-L reactor were 101/194 ppm without lime, 486/2022 ppm with lime, and 275/980 ppm in the 150-L reactors. The presence of CO during the aerobic composting followed a rapid decline in O2 concentrations Significantly higher CO concentrations were obtained when the aerobic degradation was amended with lime, probably because of a more extreme depletion of oxygen. The mean/maximum CO concentrations under field conditions during aerobic composting were 95/1000 ppm. The CO concentrations from the anaerobic biocell varied from 20 to 160 ppm. The hydrogen sulfide concentrations reached almost 1200 ppm during the anaerobic degradation and 67 ppm during the composting experiments. There is a positive correlation between the CO and hydrogen sulfide concentrations measured during the anaerobic degradation experiments.