Comparison of environmental effects and resource consumption for different wastewater and organic waste management systems in a new city area in Sweden

An analysis of the environmental effects and resource consumption by four systems for management of wastewater and organic household waste in a new city area have been performed, as follows: (1) conventional system complemented with advanced sludge treatment for phosphorus recovery, (2) blackwater system with urine diversion and food waste disposers, (3) blackwater system with food waste disposers and reverse osmosis, and (4) local wastewater treatment plant with nutrient recovery by using reverse osmosis. Substance-flow analysis and energy/exergy calculations were performed by using the software tool URWARE/ORWARE. Emissions were calculated and classified based on the impact categories global warming potential, acidification, and eutrophication, according to ISO 14042 (2000). The analysis also included nutrient recovery (i.e., the potential to use nutrients as a fertilizer). Depending on which aspects are prioritized, different systems can be considered to be the most advantageous.     

Product life-cycle implications for remanufacturing strategies

For remanufacturing to be successful, there is a need to gain information on future market needs of remanufactured products, and match this to information on the magnitude of return flows. One of the major issues impacting remanufacturing is in the difficulty of obtaining used products (cores) that are suitable for remanufacturing. The timing and quantity of product returns is dependent on the type of product. Factors such as the mean product lifetime, rate of technical innovation, and failure rate of components all influence the return rate of products from end-of-use and end-of-life. The balance between product returns and demand for remanufactured products is a function of many variables, where the rate of technological innovation and the expected life of a product are the major influencing characteristics. The main contribution of this paper is the support that is provided in different supply and demand situations. By using a product life-cycle perspective, the supply and demand situations can be foreseen, and support given regarding possible strategies in these situations.     

Evaluation of offshore emergency preparedness in view of rare accidents

The offshore industry in the North Sea has gone from a very high risk level for employees some 30–40 years ago, to a low level. The paper reviews the statistics briefly and discusses the implications of the low level. There has from the beginning of the operations been strong focus on emergency preparedness, due to the remoteness of the operations mostly far from shore. But there will always have to be a balance between the focus on preventative safety efforts and the extent of emergency preparedness provisions. This is discussed in detail, based on an extensive evaluation of the adequacy of emergency preparedness provisions recently performed. The main findings are presented, and the robustness and validity of the approach is discussed, together with implications of the rare major accidents.     

From safety culture to safety orientation: Validation and simplification of a safety orientation scale using a sample of seafarers working for Norwegian ship owners

Measuring safety performance is becoming increasingly important in many high-risk industries such as atomic power, the chemical industry, offshore oil production, air traffic control and construction. Much has been done to study the antecedents/factors that shape the safety culture and safety climate in these types of industries, but almost no research has been conducted into another high-risk industry – shipping. Based on the safety orientation model (SOM) and a review of items and scales used in surveys of safety climate and safety culture, a safety orientation scale (SOS) was developed and refined through the use of multivariate statistics. This study was conducted with a sample of seafarers sailing on Norwegian-owned vessels. A total of 2558 questionnaires were returned from 141 vessels and 16 shipping companies, giving a calculated response rate of 70%.The study showed that replicating previous studies on the sample of seafarers demonstrated a large degree of stability in scales and items across both industries and nations.Exploratory factor analysis (EFA) is the most commonly adopted approach to the development of scales of safety climate and culture scale reported in the literature, and factor retention seems to be the most important decision in EFA. In the present study several rules to determine the number of factors and items retained are applied, and a comparison is made of a short form of latent root criterion (SFLRC) and parallel criterion (PC). SFLRC is found to be the superior method for the present data set.Confirmatory factor analysis (CFA) did not support the preliminary SOM of 12 dimensions (13 dimensions, since one of the 12 dimensions was split during the CFA procedure); however, a re-specification of the model on the basis of the CFA for four different behavioural measures gave a simplified and well-defined model with seven factors and 22 items.     

A Bayesian framework for stable isotope mixing models

Stable isotope sourcing is used to estimate proportional contributions of sources to a mixture, such as in the analysis of animal diets and plant nutrient use. Statistical methods for inference on the diet proportions using stable isotopes have focused on the linear mixing model. Existing frequentist methods provide inferences when the diet proportion vector can be uniquely solved for in terms of the isotope ratios. Bayesian methods apply for arbitrary numbers of isotopes and diet sources but existing models are somewhat limited as they assume that trophic fractionation or discrimination is estimated without error or that isotope ratios are uncorrelated. We present a Bayesian model for the estimation of mean diet that accounts for uncertainty in source means and discrimination and allows correlated isotope ratios. This model is easily extended to allow the diet proportion vector to depend on covariates, such as time. Two data sets are used to illustrate the methodology. Code is available for selected analyses.     

Harnessing fertilizer potential of human urine in a mesocosm system: a novel test case for linking the loop between sanitation and aquaculture

Human urine (HU) is a biogenic fertilizer which has raised immense interest owing to its capacity of combining sanitation and nutrient recovery. In search of an alternative organic fertilizer for fish culture, the nutrient potential of HU was evaluated. Fries of Indian carps and larvae of freshwater prawn were reared for 120 days under six conditions: (a) aerated and (b) non-aerated fresh HU (0.01%), (c) cattle manure (CM; 1.8 kg tank⁻¹), mixed treatment with CM and HU under (d) iso-phosphorus and (e) iso-nitrogenous condition and (f) control. Monitoring of water quality and biological parameters revealed that total fish yield was the highest in CM (621.5 g tank⁻¹) followed by mixed treatments under iso-nitrogenous (428 g tank⁻¹) and iso-phosphorus (333 g tank⁻¹) conditions, aerated HU (321 g tank⁻¹) and HU (319 g tank⁻¹). The gross primary productivity (GPP) in HU was satisfactory (601.8 mg C m⁻² h⁻¹) and superior to all but CM treatment. The abundance of heterotrophic bacteria (HB) was highest in CM and lowest in HU. Both GPP and HB population were correlated positively with fish yield per tank. Although pH in all treatments remained high (pH 8.4–8.9), no ammonia toxicity was observed. No E. coli infestation in any fish muscle was encountered. The concentrations of cadmium and lead in fish muscle were within respective safe level. The study established that high fertilizer potential of HU could be exploited as an alternative organic fertilizer or as a candidate to be blended with cattle manure.

     

Transport of creosote compounds in a large, intact, macroporous clayey till column

The transport in macroporous clayey till of bromide and 25 organic compounds typical of creosote was studied using a large intact soil column. The organic compounds represented the following groups: polycyclic aromatic hydrocarbons (PAHs), phenolic compounds, monoaromatic hydrocarbons (BTEXs), and heterocyclic compounds containing oxygen, nitrogen or sulphur in the aromatic ring structure (NSO-compounds). The clayey till column (0.5 m in height and 0.5 m in diameter) was obtained from a depth of 1–1.5 m at an experimental site located on the island of Funen, Denmark. Sodium azide was added to the influent water of the column to prevent biodegradation of the studied organic compounds. For the first 24 days of the experiment, the flow rate was 219 ml day⁻¹ corresponding to an infiltration rate of 0.0011 m day⁻¹. At this flow rate, the effluent concentrations of bromide and the organic compounds increased very slowly. The transport of bromide and the organic compounds were successfully increased by increasing the flow rate to 1353 ml day⁻¹ corresponding to 0.0069 m day⁻¹. The experiment showed that the transport of low-molecular-weight organic compounds was not retarded relative to bromide. The high-molecular-weight organic compounds were retarded significantly. The influence of sorption on the transport of the organic compounds through the column was evaluated based on the observed breakthrough curves. The observed order in the column experiment was, with increasing retardation, the following: benzene=pyrrole=toluene=o-xylene=p-xylene=ethylbenzene=phenol=benzothiophene=benzofuran<naphthalene<1-methylpyrrole<1-methylnaphthalene=indole=o-cresol=quinoline<3,5-dimethylphenol=2,4-dimethylphenol<acridine<carbazole<2-methylquinoline<fluorene<dibenzofuran<phenanthrene=dibenzothiophene. This order could not be predicted from regularly characteristics as octanol/water-distribution coefficients of the organic compounds but only from experimentally determined data. The results indicate that a thin clayey till cover of the type described in this paper does not protect groundwater against contamination by low-molecular-weight organic compounds.     

Detection rates and residual risk for a postnatal diagnosis of an atypical chromosome aberration following combined first-trimester screening

Objectives

To determine the detection rates of all types of chromosome aberrations and the residual risk for postnatal diagnosis of an atypical chromosome aberration depending on the strategy for further investigation with either noninvasive prenatal testing (NIPT) or invasive testing in pregnancies with increased risk following combined first-trimester screening (cFTS).

Methods

A review of all pregnancies examined with cFTS during 2010 to 2017.

Results

The cohort consisted of 129 493 pregnancies. There were 852 (0.7%) clinically significant chromosome aberrations, including aberrations detected later on or after birth. A total of 12% were atypical chromosome aberrations. Considering that 40% were detected due to a miscarriage/intrauterine fetal death or a malformation on ultrasound there is a 0.05% (1:2000) background risk of a postnatal diagnosis of a liveborn child with an atypical chromosome aberration if no further invasive test is performed during pregnancy. If all women with an increased risk (≥1:200) had an invasive test and NIPT was performed up to a risk of 1:1000, 95% of common trisomies/sex chromosome aberrations and 55% of atypical aberrations would be detected.

Conclusions

If NIPT was offered to all women with an increased risk following cFTS it would imply that three times as many children would be born with an atypical chromosome aberration.