Gaseous pollutants emitted from a mechanical biological treatment plant for municipal solid waste: Odor assessment and photochemical reactivity

The concentrations and chromatographic profiles of gaseous pollutants emitted from a municipal solid waste (MSW) biological treatment plant were investigated to identify the major odor substances and atmospheric photochemical reactive species (PRS). Four methods were used to measure different gaseous pollutants in this study, including colorimetric tubes, gas chromatography with mass spectrometry/flame ionization detection/pulsed flame photometric detection (GC-MS/FID/PFPD) preceded by cold trap concentration, GC-FID preceded by solid-phase microextraction (SPME), and high-performance liquid chromatography (HPLC) after derivation by 2,4-dinitrophenylhydrazine (DNPH). Seventy-five gaseous compounds belonging to nine groups (nitrogen compounds, sulfur compounds, alkanes, alkenes, aromatics, terpenes, alcohols, carbonyls, and volatile fatty acids [VFAs]) were identified. In the pre-biotreatment facility, the total concentration of the gaseous pollutants reached the maximum value on day 7 (317 ppm). During the post-biotreatment process, the total concentration of gaseous pollutants decreased from 331 ppm at the beginning to 162 ppm in the end. The group with the greatest decrease was carbonyls, from 64 to 7.4 ppm, followed by alcohols, from 40 to 4.5 ppm, which were both oxygenated compounds. The proportion of aromatics was notably high in the pre-mechanical treatment facility, accounting for 50.6% of the total, revealing the xenobiotic compounds disseminated by stirring and agitating the waste in the initial stage. The proportions of nitrogen compounds were lower in the pre- and post-mechanical treatment facilities (1.5% and 6.9%) than in the pre- and post-biotreatment facilities (11.9% and 13.8%), suggesting that their generation was closely associated with waste degradation. The major odor compounds in the facilities were acetic acid, butyric acid, valeric acid, isovaleric acid, and dimethyl sulfide. The major PRS in the facilities were aromatics, acetaldehyde, butyraldehyde, hexanal, isopentyl aldehyde, alcohol, α-pinene, limonene, and terpinene. Outside the facilities, VFAs and aromatics were the most important compounds causing an environmental impact.

Implications: The aim of this work is to assess the gaseous environmental impacts of mechanical biological treatment technology. The emission of gaseous pollutants greatly affects the living quality of nearby residents and odor complaints are becoming a major problem now. In this study, the authors utilized various pretreatment and analytical methods to obtain integrated emission information of gaseous pollutants. The results showed the transformation and fate of the gas pollutants during the treatment processes, which would help to improve the processes and to mitigate gaseous pollution.

Supplemental Materials: Supplemental materials are available for this paper. Go to the publisher's online edition of the Journal of the Air & Waste Management Association for information on the concentrations of the nine compound families at different sampling locations in the plant.     

Non-destructive pollution exposure assessment by means of wood mice hair

Concentrations of cadmium, copper, lead and zinc were measured in hair, kidney, liver, lung and muscle tissue of wood mice captured along a pollution gradient. We found positive relationships between cadmium concentrations in hair and all internal tissues. Hair lead concentrations were positively correlated with lead contents in kidney and liver. Age had a significant effect on cadmium accumulation in all tissues and hair. Apart from a very weak relationship between zinc concentrations in hair and liver, no significant relation between copper or zinc content in hair and any of the internal organs was observed. In summary, our observations suggest that hair of wood mice can be used for monitoring exposure to non-essential metals like cadmium and lead, but not to homeostatically regulated metals such as copper or zinc.     

Monitoring, modelling and environmental exposure assessment of industrial chemicals in the aquatic environment

Monitoring and laboratory data play integral roles alongside fate and exposure models in comprehensive risk assessments. The principle in the European Union Technical Guidance Documents for risk assessment is that measured data may take precedence over model results but only after they are judged to be of adequate reliability and to be representative of the particular environmental compartments to which they are applied. In practice, laboratory and field data are used to provide parameters for the models, while monitoring data are used to validate the models' predictions. Thus, comprehensive risk assessments require the integration of laboratory and monitoring data with the model predictions. However, this interplay is often overlooked. Discrepancies between the results of models and monitoring should be investigated in terms of the representativeness of both. Certainly, in the context of the EU risk assessment of existing chemicals, the specific requirements for monitoring data have not been adequately addressed. The resources required for environmental monitoring, both in terms of manpower and equipment, can be very significant. The design of monitoring programmes to optimise the use of resources and the use of models as a cost-effective alternative are increasing in importance. Generic considerations and criteria for the design of new monitoring programmes to generate representative quality data for the aquatic compartment are outlined and the criteria for the use of existing data are discussed. In particular, there is a need to improve the accessibility to data sets, to standardise the data sets, to promote communication and harmonisation of programmes and to incorporate the flexibility to change monitoring protocols to amend the chemicals under investigation in line with changing needs and priorities.     

Characterizing exposure to chemicals from soil vapor intrusion using a two-compartment model

Though several different models have been developed for sub-surface migration, little attention has been given to the effect of subsurface transport on the indoor environment. Existing methods generally assume that a house is one well-mixed compartment. A two-compartment model was developed to better characterize this exposure pathway; the model treats the house as two well-mixed compartments, one for the basement and one for the remainder of the house. A field study was completed to quantify parameters associated with the two-compartment model, such as soil gas intrusion rates and basement to ground floor air exchange rates. Two residential test houses in Paulsboro, New Jersey were selected for this study. All experiments were completed using sulfur hexafluoride (SF₆) as a tracer gas. Soil gas intrusion rates were found to be highly dependent on the soil gas to basement pressure difference, varying from 0.001 m³ m⁻² h⁻¹ for a pressure drop of –0.2 Pa to 0.011 m³ m⁻² h⁻¹ for a pressure drop of –6.0 Pa. Basement ventilation rates ranged from 0.17 to 0.75 air changes per hour (ACH) for basement to ambient pressure differences ranging from –1.1 to –7.6 Pa (relative to ambient). Application of experimental results in conjunction with the two-compartment model indicate that exposures are highly dependent on gas intrusion rates, basement ventilation rate, and fraction of time spent in the basement. These results can also be significantly different when compared with the simple well-mixed house assumption.     

Ecochemical assessment of environmental chemicals Part I: Standard screening procedure to evaluate chemicals in plant cell cultures

A standard screening procedure using sterile soybean and wheat cell suspension cultures has been developed to study the metabolic profiles of established xenobiotics as well as new synthesized compounds. This short term test provides quantitative data on the distribution of metabolites and the parent compound between the nutrient medium and the plant cells, on the amount of more and less polare metabolite fractions in comparison to the parent compound and the amount of substance bound or irreversibly absorbed to the extracted cell fragments. From this data turnover rates are calculated for ranking purpose. Results obtained for 2,4-D, PCP, DEHP and monolinuron as model substances are presented and compared with data from other environmental tests.     

Heavy metals in untreated/treated urban effluent and sludge from a biological wastewater treatment plant

Background, Aim and Scope

The presence of heavy metals in wastewater is one of the main causes of water and soil pollution. The aim of the present study was to investigate the removal of Cd, Cu, Pb, Hg, Mn, Cr and Zn in urban effluent by a biological wastewater treatment, as well as to quantify the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sn, Tl, V and Zn in dewatering sludge from the Biological Wastewater Treatment Plant to Ribeirão Preto (RP-BWTP), Brazil.

Materials and Methods

Concentrations of Cd, Cr, Cu, Mn and Pb in wastewater and those of Ni in sludge were determined by atomic absorption spectrophotometry with graphite furnace atomization. Mercury concentrations in wastewater were measured by hydride generation atomic spectrophotometry, and Zn levels were determined by atomic absorption spectrophotometry using acetylene flame. In sludge, the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Sn, Tl, V and Zn were determined by inductively coupled plasma-mass spectrometry.

Results

The percentages of removal efficiency (RE) were the following: Hg 61.5%, Cd 60.0%, Zn 44.9%, Cu 44.2%, PB 39.7%, Cr 16,5% and Mn 10.4%. In turn, the mean concentrations (mg/kg) of metals in dewatering sludge followed this increasing order: Tl (<0.03), Hg (0.31), Be (0.43), As (1.14), Cd (1.34), V (59.2), Pb (132.1), Sn (166.1), Cr (195.0), Mn (208.1), Ni (239.4), Cu (391.7), Zn (864.4) and Fe (20537).

Discussion

The relationship between metal levels in untreated wastewater, as well as the removal efficiency are in agreement with previous data from various investigators, It is important to note that metal removal efficiency is not only affected by metal ion species and concentration, but also by other conditions such as operating parameters, physical, chemical, and biological factors.

Conclusions

Metal values recorded for treated wastewater and sludge were within the maximum permitted levels established by the Environmental Sanitation Company (CETESB), São Paulo, Brazil.

Recommendations

There is an urgent need for the authorities who are responsible for legislation on sludge uses in agriculture of establishing safety levels for As, Be, Hg, Sn, Tl and V.

Perspectives

According to the current metal levels, RP-BWTP sludge might be used for agriculture purposes. However, for an environmentally safe use of sewage sludge, further studies including systematic monitoring are recommended. Annual metal concentrations and predicted variations of those elements in the sludge should be monitored.

     

Ecochemical assessment of environmental chemicals: Draft guideline of the test procedure to evaluate metabolism and degradationof chemicals by plant cell cultures

A guideline is drafted describing the screening procedure in detail. The aim for this is to facilitate an adoption of this test by bodies supervising environmental chemicals. Successful introduction of this method into the respective laboratories will cause no problems, as the procedure has been collaboratively established and improved.     

A2O工艺城市污水处理厂恶臭物质逸散特征及风险评估

污水处理过程释放的大量恶臭气体对人体感官和健康产生不利影响。本研究在城市污水处理厂设置采样点,研究主要污水处理单元恶臭物质的逸散特征。结果表明,恶臭物质的排放主要集中在进水区,硫化氢、氨、二硫化碳、磷化氢的平均浓度分别为1.07、0.19、44.32和0.58 mg·m⁻³。污泥脱水间也是恶臭物质氨的主要释放源。硫化氢是主要的致臭物质,其在各工艺段的异味贡献率超过75%。二硫化碳和磷化氢的慢性致病风险较高,有必要采取相应的措施削减和控制其在污水处理厂内的影响。在厂界外300 m处,二硫化碳和磷化氢的慢性致病风险值可忽略,同时,硫化氢、氨、以及二硫化碳的厂界浓度均远远低于《恶臭污染物排放标准》(GB 14554-93)规定的相关限值。     

Life cycle assessment of a large water treatment plant in Turkey

Environmental Science and Pollution Research - The objective of this study is to assess the environmental sustainability of a large water treatment plant through life cycle assessment (LCA)...     

Integrated physicochemical and biological treatment process for fluoride and phosphorus removal from fertilizer plant wastewater

The phosphate fertilizer industry produces highly hazardous and acidic wastewaters. This study was undertaken to develop an integrated approach for the treatment of wastewaters from the phosphate industry. Effluent samples were collected from a local phosphate fertilizer producer and were characterized by their high fluoride and phosphate content. First, the samples were pretreated by precipitation of phosphate and fluoride ions using hydrated lime. The resulting low- fluoride and phosphorus effluent was then treated with the enhanced biological phosphorus removal (EBPR) process to monitor the simultaneous removal of carbon, nitrogen, and phosphorus. Phosphorus removal included a two-stage anaerobic/aerobic system operating under continuous flow. Pretreated wastewater was added to the activated sludge and operated for 160 days in the reactor. The operating strategy included increasing the organic loading rate (OLR) from 0.3 to 1.2 g chemical oxygen demand (COD)/L.d. The stable and high removal rates of COD, NH4(+)-N, and PO4(3-)-P were then recorded. The mean concentrations of the influent were approximately 3600 mg COD/L, 60 mg N/L, and 14 mg P/L, which corresponded to removal efficiencies of approximately 98%, 86%, and 92%, respectively.     

Risk assessment of environmental chemicals

This article is a summary from eleven important symposia. In these meetings, critical facts were discussed which are the necessary basis for the important legislation about toxic substances in Europe, in the U.S.A. and in Japan. This review article should also be of some help to the readers of “Chemosphere” for direct contacts with the experts mentioned. It is therefore an informative and coordinative survey, in which chemical and ecotoxicological details are largely omited.     

炼焦废水生化处理技术研究进展

综述了近几年来炼焦废水及炼焦废水中主要成分(酚类、氨类物质、氰化物)的生化处理方法.其中废水中酚类物质的去除方法有投加有效菌、超滤法等;去除氨类物质的方法有A2/O法、纳滤法和反渗透法等;去除氰化物的方法有生物法和化学法等.综合处理炼焦废水的方法有双层生物膜法、生物脱氮法和含铁活性污泥处理技术等.     

Ecochemical assessment of environmental chemicals Part 2: Standard supplementary screening procedure to evaluate more volatile and less persistent chemicals in plant cell cultures

The described methodology allows the determination of metabolic turnover, biomineralization and volatilization of organic environmental chemicals. The overall accountability of radiolabelled chemicals with standardized soybean and wheat cell cultures determined is nearly quantitative. The total balance of the radiolabelled dichlofluanid, 2,4-dichlorophenoxyacetic acid, monolinuron, lindane, parathion and pentachlorophenol recovered by this method are reported.     

Lung-deposited dose of particulate matter from residential exposure to smoke from wood burning

Environmental Science and Pollution Research - Residential settings are of utmost importance for human exposure, as it is where people spend most of their time. Residential wood combustion is a...     

Environmental risk assessment of existing chemicals

Most of the existing chemicals of high priority have been released into the environment for many years. Risk assessments for existing chemicals are now conducted within the framework of the German Existing Chemicals Program and by the EC Regulation on Existing Substances. The environmental assessment of a chemical involves:

1. exposure assessment leading to the derivation of a predicted environmental concentration (PEC) of a chemical from releases due to its production, processing, use, and disposal. The calculation of a PEC takes into account the dispersion of a chemical into different environmental compartments, elimination and dilution processes, as well as degradation. Monitoring data are also considered.
2. effects assessment. Data obtained from acute or long-term toxicity tests are used for extrapolation on environmental conditions. In order to calculate the concentration with expectedly no adverse effect on organisms (Predicted No Effect Concentration, PNEC) the effect values are divided by an assessment factor. This assessment factor depends on the quantity and quality of toxicity data available.

In the last step of the initial risk assessment, the measured or estimated PEC is compared with the PNEC. This “risk characterization” is conducted for each compartment separately (water, sediment, soil, and atmosphere). In case PEC > PNEC an attempt should be made to revise data of exposure and/or effects to conduct a refined risk characterization. In case PEC is again larger than PNEC risk reduction measures have to be considered.     

Hazard assessment of chemicals in soil

Based on a stepwise (tiered) approach, degradation, adsorption and leaching tests as well as various effect tests (using plants, microorganisms and animals) are recommended for the testing of environmental chemicals. If, after the tests of tiers 1 and 2, the results of a monospecies-effect-test (including a safety factor) are within the range of the predicted exposure, the ecotoxicological hazard should be determined using a terrestrial model ecosystem. Some of the tests for the proposed strategy were selected from practical experience in testing environmental chemicals in the laboratory, and some on the basis of a comprehensive literature review.     

Environmental and biological monitoring of endocrine disrupting chemicals.

Trends toward an increase of adverse health effects on reproductive organs have been reviewed. An urgent need has been recognised to establish validated in vivo and in vitro screening assays to test for hormonal activities of chemicals. Relevant existing OECD guidelines have been reviewed and enhancements of some of these have been identified, mainly to test for estrogenic and androgenic activity of chemicals. The problems connected to monitoring activities are outlined, particularly for ambient and biological monitoring. Indeed, the problem of assessing human exposure to endocrine disrupting chemicals through environmental chemical analysis tends to a very high level of complexity. This has been illustrated through the example of one single subclass of endocrine disrupting compounds (EDCs), the organohalogen compounds. Valid biological markers are also needed to be effectively used in epidemiological studies and risk assessment. A multidisciplinary approach and the collaboration among experts in the field of clinical biochemistry, toxicology, and epidemiology is required.     

Chemical and biological characterization of emissions from small residential stoves burning wood and charcoal

Emissions from a small residential wood stove and a newly developed residential stove burning charcoal have been characterized by chemical analysis and mutagenicity testing (Ames Salmonella test). For wood burning the samples were taken under normal and starved air conditions burning birch and spruce separately. The burning conditions in the stove seemed to influence the emissions to a larger extent than the type of wood.The emissions of aldehydes, benzene and polycyclic aromatic hydrocarbons from the charcoal-burning stove are lower by a factor of 25–1000 as compared to the wood stove. The mutagenicity of the emissions showed a similar trend.