Hydrothermal carbonization as an alternative sanitation technology: process optimization and development of low-cost reactor.

Background: The provision of safe sanitation services is essential for human well-being and environmental integrity, but it is often lacking in less developed communities with insufficient financial and technical resources. Hydrothermal carbonization (HTC) has been suggested as an alternative sanitation technology, producing value-added products from faecal waste. We evaluated the HTC technology for raw human waste treatment in terms of resource recovery. In addition, we constructed and tested a low-cost HTC reactor for its technical feasibility. Methods: Raw human faeces were hydrothermally treated in a mild severity range (≤ 200 °C and ≤ 1 hr). The total energy recovery was analysed from the energy input, higher heating value (HHV) of hydrochar and biomethane potential of process water. The nutrient contents were recovered through struvite precipitation employing process water and acid leachate from hydrochar ash. A bench-scale low-cost reactor (BLR) was developed using widely available materials and tested for human faeces treatment. Results: The hydrochar had HHVs (23.2 - 25.2 MJ/kg) comparable to bituminous coal. The calorific value of hydrochar accounted for more than 90% of the total energy recovery. Around 78% of phosphorus in feedstock was retained in hydrochar ash, while 15% was in process water. 72% of the initial phosphorus can be recovered as struvite when deficient Mg and NH 4 are supplemented. The experiments with BLR showed stable operation for faecal waste treatment with an energy efficiency comparable to a commercial reactor system. Conclusions: This research presents a proof of concept for the hydrothermal treatment of faecal waste as an alternative sanitation technology, by providing a quantitative evaluation of the resource recovery of energy and nutrients. The experiments with the BLR demonstrate the technical feasibility of the low-cost reactor and support its further development on a larger scale to reach practical implementation.

Characterization of a new heat dissipation matric potential sensor.

Soil moisture sensors can help to reduce the amount of water needed for irrigation. In this paper we describe the PlantCare soil moisture sensor as a new type of heat dissipation sensor, its calibration and the correction for temperature changes. With the PlantCare sensor it is possible to measure the matric potential indirectly to monitor or control irrigation. This sensor is based on thermal properties of a synthetic felt. After a defined heating phase the cooling time to a threshold temperature is a function of the water content in the synthetic felt. The water content in this porous matrix is controlled by the matric potential in the surrounding soil. Calibration measurements have shown that the sensor is most sensitive to -400 hPa and allows lower sensitivity measurements to -800 hPa. The disturbing effect of the temperature change during the measurement on the cooling time can be corrected by a linear function and the differences among sensors are minimized by a two point calibration.

Environmental exposure to lead, but not other neurotoxic metals, relates to core elements of ADHD in Romanian children: performance and questionnaire data.

Neurobehavioral measures of attention, and clinical features of the attention-deficit hyperactivity disorder (ADHD) have been studied in pediatric environmental lead research. However rarely, if ever, have performance measures of attention or executive functions and questionnaire-based quantitative ADHD-observations been studied in the same subjects. We examined associations between pediatric blood lead concentrations (PbB), as well as those of mercury (Hg), and aluminum (Al), and performance in four different attention tasks, as well as behavioral ratings from an ICD-10 (hyperactivity) and DSM-IV-coded (attention deficit) German questionnaire (FBB-ADHS). Asymptomatic, 8-12 year old children from two Romanian cities were studied, namely Bucharest and Pantelimon, a city near a metal-processing plant. Blood was analyzed for Pb, Al, and Hg. Data from 83 children were available for final analysis. We assessed attention performance by means of four tasks of the computer-based ADHD-taylored German KITAP-battery. We also received questionnaire ratings from parents and teachers covering three ADHD-dimensions. Multiple linear regression analysis was used to estimate associations between the three neurotoxic trace metals in blood and the different ADHD features. After adjusting for eleven potentially confounding variables we found consistent borderline to significant associations between Pb, but not other metals, in blood and various performance- and questionnaire data. False alarm responses (FAR) in the KITAP subtests rather than response latencies exhibited positive associations with PbB. Questionnaire ratings for ADHD dimensions also revealed PbB-related adversity. With any two-fold increase of PbB outcome changed markedly, namely up to 35%. Restriction to children with PbBs<10mug/dl had only a marginal influence on outcome.The converging evidence from performance- and questionnaire data confirms that core elements of ADHD are adversely affected by low environmental PbB even below 10mug/dl, but not by other neurotoxic trace metals. Observed effect-sizes are considerably larger than those typically found for lead-related IQ-deficit, thus suggesting that attention deficit could be the more basic adverse effect of lead in children. This is the first study from Central and Eastern Europe dealing with links between environmental exposure of children to neurotoxic metals and ADHD.

The influence of weathering and organic matter on heavy metals lability in silicatic, Alpine soils.

We investigated the effect of organic matter and weathering on the lability and solid phase speciation of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) in two contrasting subalpine regions in the Italian Alps. Cr, Ni and Cu could be linked to weathering. This was not the case for Pb. Since organic matter (OM) influences the solid phase speciation of heavy metals, the total organic C and N content, the C and N content of different density fractions of OM and also of the labile (oxidised by H(2)O(2)) and stable (H(2)O(2)-resistant) fractions were determined. Soil OM stocks were high and soils on north-facing slopes had more OM than the south-facing sites to which they were paired. Density measurements and the H(2)O(2) fractionation indicated that the higher OM content on north-facing sites was due to an accumulation of weakly degraded organic material. Due to higher weathering intensity on north-facing sites, the abundance of the EDTA-extractable heavy metals was higher than on south-facing sites. All EDTA-extractable heavy metals showed a good correlation to the water-soluble phenolic concentrations which indicates that the metals were probably translocated as metal-organic complexes. Pb and Cu correlate not only to the light (density < 1 g/cm(3)) and labile, organic fraction but also to the heavy (density > 2 g/cm(3)) and stable fraction. High-mountain ecosystems like the Alps are sensitive to changing environmental conditions such as global warming. A warmer climate and the more favourable conditions it brings for biological activity, especially at cooler sites, will probably lead in the short- to mid-term to an increased loss of accumulated, weakly degraded OM. As the Pb and Cu content is significantly related to the labile organic matter pools, the risk exists that an increase in OM mineralisation could affect the storage capacity and mobility of these metals in soils.

Heavy metal contamination in the vicinity of an industrial area near Bucharest.

BACKGROUND, AIM, AND SCOPE: Heavy metals such as lead are well known to cause harmful health effects. Especially children are particularly susceptible to increased levels of lead in their blood. It is also a fact that lead concentration is increasing in the environment due to increased anthropogenic activity. The risk of heavy metal contamination is pronounced in the environment adjacent to large industrial complexes. In a combined case study, the environmental pollution by heavy metals was related to children's health in the vicinity of an industrial area located 4 km south-east from Bucharest about 2 km east from the nearest town-Pantelimon. This site includes companies processing different, nonferrous solid wastes for recovery of heavy metals and producing different nonferrous alloys and lead batteries. In this paper, mainly the results of environmental sampling and analyses are summarized. MATERIALS AND METHODS: Water, soil, and atmospheric deposition samples were collected from different locations within 3 km from the industrial area. For comparison, samples were also taken from Bucharest. Water samples were filtered (<0.45 microm), extracted by salpetric acid, and quantified by ICP-OES and ICP-MS. Soil samples were dried, sieved (<2 mm), extracted by aqua regia and analyzed by AAS. In order to quantify the atmospheric deposition, three kinds of permanently open collecting pots were used on nine different sites between August and November 2006. RESULTS: At most sampling locations, the heavy metal concentrations in soil decrease with increasing distance to the presumably major source of pollution. Highest heavy metal concentrations were found in 10-20 cm soil depths. There were also decreasing heavy metal concentrations for atmospheric deposition with increasing distance to the industrial site. In surface and groundwater samples, traces of zinc, copper and lead were detected. DISCUSSION: The heavy metal concentrations in soil were increased in the study area, mostly under legal action limits in low-concern areas (e.g., 1,000 mg Pb/kg dry soil), but often above action limits for high-concern areas (100 mg Pb/kg dry soil) such as populated areas. The soluble lead concentrations in water samples indicate a need for monitoring and assessing water quality in more detail. The results for atmospheric deposition showed increased dust precipitation and heavy metal loads in the study area compared to Bucharest. However, based on mass flow balance calculations, the actual atmospheric deposition of heavy metals must be much lower than it was in the past decades. CONCLUSIONS: It was shown that highest lead values in water, soil and atmospheric deposition are rather to be found near the investigated industrial site than at the control sites in Bucharest. Our results correspond very well with results that show that children from Pantelimon have significantly increased lead concentrations in their blood compared to children in Bucharest. The increased lead contamination around the investigated industrial area is likely to have caused the increased exposure for children living in Pantelimon. RECOMMENDATIONS AND PERSPECTIVES: In high-concern areas, such as found in populated areas, further measures have to be taken to avoid health risks for people living in these areas. The measures already taken to reduce emissions from the industrial site will help to avoid further increases in heavy metal concentrations. In areas with exceeded action limits, measures have to be taken as required by law. Detailed risk assessments could help to take necessary actions to protect public health in this area. The public should be informed about the potential hazards of eating plants grown in that area. Educational programs for schools, informing children about the contamination, should lead to a better understanding of environmental problems and a more sustainable behavior in the future.

Safety of autologous bone marrow aspiration concentrate transplantation: initial experiences in 101 patients.

The clinical application of cellular based therapies with ex vivo cultivation for the treatment of diseases of the musculoskeletal system has until now been limited. In particular, the advanced laboratory and technical effort necessary, regulatory issues as well as high costs are major obstacles. On the other hand, newly developed cell therapy systems permit intra-operative enrichment and application of mesenchymal and progenitor stem cells from bone marrow aspirate concentrate (BMAC) in one single operative session. The objective of the present clinical surveillance study was to evaluate new bone formation after the application of BMAC as well as to record any possible therapy-specific complicationsFor this purpose, the clinical-radiological progress of a total of 101 patients with various bone healing disturbances was documented (surveillance study). The study included 37 necrosis of the head of the femur, 32 avascular necroses/bone marrow edema of other localization, 12 non-unions, 20 other defects. The application of BMAC was performed in the presence of osteonecrosis via a local injection as part of a core decompression (n=72) or by the local adsorption of intra-operative cellular bone substitution material (scaffold) incubated with BMAC during osteosynthesis (n=17) or in further surgery (n=12).After an average of 14 months (2-24 months), the patients were re-examined clinically and radiologically and interviewed. Further surgery was necessary in 2 patients within the follow-up period. These were due to a progression of a collapsed head of the femur with initial necrosis in ARCO Stage III, as well as inadequate new bone formation with secondary loss of correction after periprosthetic femoral fracture. The latter healed after repeated osteosynthesis plus BMAC application without any consequences. Other than these 2 patients, no further complications were observed. In particular, no infections, no excessive new bone formation, no induction of tumor formation, as well as no morbidity due to the bone marrow aspiration from the iliac crest were seen.There were no specific complications within the short follow-up period and a simple intra-operative use of the system for different forms of bone loss could be demonstrated. In the authors' opinion, the on-site preparation of the bone marrow cells within the operating theater eliminates the specific risk of ex vivo cell proliferation and has a safety advantage in the use of autologous cell therapy for bone regeneration. Additional studies should be completed to determine efficacy.

Removal of oxide nanoparticles in a model wastewater treatment plant: influence of agglomeration and surfactants on clearing efficiency.

The rapidly increasing production of engineered nanoparticles has created a demand for particle removal from industrial and communal wastewater streams. Efficient removal is particularly important in view of increasing long-term persistence and evidence for considerable ecotoxicity of specific nanoparticles. The present work investigates the use of a model wastewater treatment plant for removal of oxide nanoparticles. While a majority of the nanoparticles could be captured through adhesion to clearing sludge, a significant fraction of the engineered nanoparticles escaped the wastewater plant's clearing system, and up to 6 wt % of the model compound cerium oxide was found in the exit stream of the model plant. Our study demonstrates a significant influence of surface charge and the addition of dispersion stabilizing surfactants as routinely used in the preparation of nanoparticle derived products. A detailed investigation on the agglomeration of oxide nanoparticles in wastewater streams revealed a high stabilization of the particles against clearance (adsorption on the bacteria from the sludge). This unexpected finding suggests a need to investigate nanoparticle clearance in more detail and demonstrates the complex interactions between dissolved species and the nanoparticles within the continuously changing environment of the clearing sludge.