A novel dual circulating fluidized bed technology for thermal treatment of municipal sewage sludge with recovery of nutrients and energy.

Sewage sludge (SS), a by-product of the wastewater treatment process, should be viewed not as waste, but as a potential resource for renewable energy and nutrient recovery. However, SS contains various toxic and harmful pollutants, e.g., pathogens, pharmaceutical residues, and microplastics. Through organic recycling and reuse of SS on land, these contaminants may leak into the environment, creating potential hazards to the ecosystem and human health. To tackle this issue, an advanced SS treatment technique within circular economy principles was proposed. In this process, mechanically dewatered SS with 20-25 % total solids is first dried at 110 °C in a circulating fluidized bed dryer and then combusted at 850 °C in a circulating fluidized bed reactor. Consequently, all the unwanted organic compounds are eliminated, and the ash - relatively high in nutrients and sufficiently low in heavy metals - can be further processed into fertilizers and used in forestry or farming. Moreover, the process is self-sufficient in terms of energy, enabling standalone operation without supplementary fuels, and providing excess heat that can be utilized, e.g., as district heat. This paper describes the process in detail and reviews experiences and lessons learned from the commissioning and trial operation of a newly erected 1.5 MWth sludge combustion plant with a throughput of 10 000 t/a. The operational performance of the plant has been verified based on continuous processing of dewatered SS, and the main operating parameters were consistent with design values. Therefore, the scale-up of this technique was considered both feasible and successful.

Environmental performance of dewatered sewage sludge digestate utilization based on life cycle assessment.

Due to the global trend of urbanization, the amount of sewage water is increasing in cities. This calls for efficient treatment of the resulting sewage sludge. To date, in the 27 European Union member countries (EU-27), the prevailing treatment method is application on arable land. Anaerobic digestion is one of the treatment methods being increasingly used nowadays. However, the resulting digestate requires further utilization. Therefore, in this study, the environmental performance of composting, combustion, and pyrolysis options for dewatered sewage sludge digestate is evaluated based on a life cycle assessment. The results show that digestate combustion and composting performed better than pyrolysis for most of the selected impact categories. However, pyrolysis of sewage sludge is still under development, and there are, to some degree, uncertainties in the data related to this technology; thus, more information for the performance assessment of pyrolysis is still required.

Effects of 11-month interventions on oral cleanliness among the long-term hospitalised elderly.

OBJECTIVES: This trial studied the effects of interventions on the oral cleanliness of the long-term hospitalised elderly. BACKGROUND: Oral cleanliness is mostly poor in long-term facilities. While many agree on the importance of oral hygiene education for nursing personnel, little information and agreement exists on how to organise this education in geriatric institutions. MATERIALS AND METHODS: This is a longitudinal study with interventions. After a baseline clinical examination, the patient wards were divided into three groups (A, B and C) and the type of intervention was randomly assigned. In group A, dental hygienists provided oral hygiene measures for the subjects once every 3 weeks. In group B, the nursing staff first received hands-on instructions after which they assumed responsibility for the subjects' daily oral hygiene. Group C served as a control. Denture hygiene and dental hygiene were recorded at baseline and in the end of the 11-month study period. In total, 130 subjects completed the interventions; their mean age was 82.9 years. RESULTS: The best outcome in both denture and dental hygiene occurred when nursing staff at the wards took care of hygiene (group B). The increase in the proportion of those with good denture hygiene was the most prominent in group B (from 11% to 56%). The proportion of subjects with poor overall dental hygiene decreased from 61% at baseline to 57% in the end, for group B from 80% to 48%. CONCLUSIONS: Organised oral health education of the nursing staff should receive more attention.

Oral health-related well-being of the long-term hospitalised elderly.

OBJECTIVE: To investigate oral health-related well-being of the long-term hospitalised elderly as reported by their primary nurses in relation to subject's oral health assessed either by primary nurses or by a clinical dental examination. BACKGROUND DATA: Little is known about oral health-related well-being of the medically compromised, long-term hospitalised elderly, most of whom are unable to express their feelings and opinions. MATERIALS AND METHODS: A cross-sectional study using a questionnaire for primary nurses about oral health and oral health-related well-being regarding functional, pain/discomfort-related, and psychosocial limitations of the subjects (n = 255) and assessment of oral health by clinical examination. The total number of limitations and the number of limitations in each category was calculated. RESULTS: Most (77%) of our subjects were unable to eat normal food. Functional limitations dominated followed by psychosocial and pain/discomfort-related limitations. Overall assessment by each subject's primary nurse ranked oral health of as good for 9% of subjects, as moderate for 44%, and as poor for 47%. Clinical examination-based assessment ranked oral health as good for 19%, as moderate for 33%, and as poor for 48% of our subjects, with good oral health being ranked as good for more men than women (26% vs. 16%; p = 0.045). Fewer limitations were recorded for those with better oral health assessed both by primary nurse and by clinical examination. CONCLUSION: More efforts are called for to maintain the oral health of the long-term hospitalised elderly so as to improve their well-being.

Chewing ability of the long-term hospitalized elderly.

We investigated the chewing ability of 260 (25 percent men) long-term hospitalized elderly patients 60 years of age and older in Laakso hospital, Helsinki, Finland, in relation to their mastication capacity, sore mouth and degree of dependence. The subjects' (mean age 83.3 years, SD = 8.1 years) mastication capacity was determined by a specialist dentist by means of: (a) number of functioning teeth and dentures; (b) modified Eichner Index; and (c) the Eichner Score, based on the index. Based on the information given by the nursing staff, an indicator of chewing ability was created. The chewing ability was poor for 55 percent, limited for 17 percent, moderate for 14 percent and excellent for 14 percent. Excellent or moderate ability to chew was related to a subject's lesser degree of dependence (OR = 1.5; p = 0.02) and higher Eichner Score (OR = 1.3; p = 0.000). More attention should be focused on mastication capacity of the hospitalized elderly.

Oral health and treatment needs of the long-term hospitalised elderly.

OBJECTIVES: To determine the oral health and treatment needs of the long-term hospitalised elderly. SETTING: The Laakso long-term hospital, Helsinki, Finland. DESIGN: A cross-sectional study with clinical oral examinations. SUBJECTS: All long-term patients (n = 260) aged 60 and older. MAIN OUTCOME MEASURES: Edentulousness, presence and hygiene of dentures, mucosal findings, number of teeth, functioning teeth and tooth remnants, level of dental hygiene, and need for operative treatment. RESULTS: Subjects' mean age was 83.3 years (SD = 8.1); 42% were edentulous, 45% of women and 33% of men (p = 0.12). With no gender difference, 41% had removable dentures, but one in four were considered to be in need of repair or replacement. Denture hygiene was good in 19%, moderate in 44%, and poor in 37%, and for men worse than for women (p = 0.02). Stomatitis was found in 25%, and angular cheilitis in 28% of the denture wearers. The dentate subjects had on average 12.4 (SD = 8.6) teeth with a clear difference by age (p = 0.03), but no difference by gender. Dental hygiene was considered poor. Of the dentate subjects, 37% were in need of restorations, 51% of periodontal therapy and 42% of extractions. CONCLUSIONS: Oral cleanliness should be improved with regards to dentures and teeth. More attention should be focused on dental care of the long-term hospitalised elderly.