Factors Associated with Composting of Solid Waste at Household Level in Masaka Municipality, Central Uganda.

The domestic solid waste stream composition of urban settings in many developing countries including Uganda is largely biodegradable in nature, and thus, composting provides the most suitable solid waste management option for these wastes. However, there is limited information about waste composting at the household level and associated determinants in Uganda. A cross-sectional study was employed to collect quantitative data from 368 residents of Masaka municipality, Central Uganda. A semistructured interviewer administered questionnaire was used which assessed knowledge, perceptions, and practices of composting. Data were analysed using STATA 13.0, and binary logistic regression was used to determine the factors that influence composting at the household level. Of the 368 participants, 11.4% were engaged in composting. Factors associated with household level composting were age of 46 years and above (aOR = 2.69, 95% CI = (1.06-6.80)), possession of a garden (aOR = 28.88, 95% CI = (3.85-216.72)), engagement in waste segregation (aOR = 5.56, 95% CI = (2.25-13.86)), and periurban residence (aOR = 3.81, 95% CI = (1.78-8.16)). The practice of composting at the household level was low. This therefore highlights the need for urban authorities to develop initiatives for promoting composting at the household level while considering the identified predictors associated with composting.

Developing a questionnaire to assess the health effects of bioaerosols.

BACKGROUND: Bioaerosol exposure occurs in several industries including green waste recycling, poultry farming, grain, animal feed and cotton production. Whilst several studies have investigated exposure and health effects in compost workers, the best questions to ask about health are uncertain. AIMS: This study aimed to develop a questionnaire to assess health symptoms in compost workers. METHODS: A 46-item questionnaire to ascertain possible symptoms of occupational illness related to bioaerosol exposure in a cohort of UK industrial compost workers and delivery in an interviewer-led format. The reliability of the questionnaire was assessed using Cronbach's α. A principal component analysis (PCA) was conducted to condense the questionnaire for practical purposes. RESULTS: One hundred and eleven (89%) workers completed the questionnaire. All items showed very good reliability (Cronbach's α = 0.83). After removing perfectly correlated questions from the data set, the PCA was conducted on a reduced data set of 28 items to explore underlying themes. Nine components were identified that explained 77% of the total variation. Nine of the questions removed prior to PCA due to perfect correlation were reintroduced because they added clinical value. The final questionnaire therefore consisted of 37 items and retained very adequate reliability (Cronbach's α = 0.76). CONCLUSIONS: Our health questionnaire has demonstrated adequate reliability when used within this industrial composting workforce. Further applications may include health surveillance, investigating outbreaks of occupational disease or research. Future work should examine the predictive validity of the questionnaire in these settings.

Emission of bacterial bioaerosols from a composting facility in Maharashtra, India.

This study was undertaken to quantify and characterize size-segregated bacterial bioaerosols both on-site and off-site of a waste treatment facility (WTF) in Maharashtra employing windrow composting. Viable bacterial bioaerosols on nutrient agar (NA) and actinomycetes isolation agar (AIA) were quantified after sampling using Anderson-six stage impactor. Viable bacterial bioaerosols were identified based on 16S rDNA sequencing. Approximately, 16-34% of the total viable bacteria collected at the WTF were in the size range 0.65-2.1µm that can penetrate deep into the respiratory tract and also represents bacteria present in free form. Thus, 66-84% of bacterial bioaerosols were associated with coarse airborne particles greater than 2.1µm. A total of 24 bacterial species were isolated and characterized through gram staining. Among these 25% were gram negative and 75% were gram positive. The predominant bacterial genera were Bacillus, Streptococcus, Staphylococcus, Acinetobacter and Kocuria. The mean on-site concentration of total viable bacteria on NA and AIA and airborne particles (PM2.5 and PM10) were higher than the corresponding off-site values. The mean on-site concentration of viable bacteria on NA and AIA were in the range of 3.8×10(3) to 5.4×10(4)CFU/m(3) and 9.8×10(3) to 1.2×10(5)CFU/m(3), respectively, during activity period. Good correlation (R(2)=0.999) was observed between total bioaerosols and aerosols (PM10) collected using Anderson impactor and High volume sampler, respectively. Sampling size segregated aerosols using the Siotus personal cascade impactor indicated higher association of bacteria with the coarse fraction (greater than 2.5µm).

Microbiological consequences of indoor composting.

Recycling of organic waste appeals to more and more people. The aim of this study was to evaluate the microbiological contamination around organic waste bins at three distances over a 12-month period. Contamination near the customary trash of control households was evaluated at the beginning to ensure that there is no recruitment bias. Air samples using the MAS 100 impactor were carried out in 38 dwellings that do household waste composting and in 10 dwellings of controls. Collection of particles by CIP 10 rotating cup sampler and dust samples collected by electrostatic dust collector cloths were acquired in dwellings that do household waste composting. Samples were analyzed by culture and by real-time quantitative PCR. Information about dwelling characteristics and inhabitant practices was obtained by a standardized questionnaire. The genera most often isolated were Penicillium, Aspergillus, Cladosporium and Streptomyces. Near the organic waste bins, bioaerosol samples showed an increase of Acarus siro (P = 0.001). Sedimented dust analyses highlighted an increase of A. siro, Wallemia sebi, Aspergillus versicolor, and Cladosporium sphaerospermum concentrations after a 12-month survey compared to the beginning. Composting favors microorganism development over time, but does not seem to have an effect on the bioaerosol levels and the surface microbiota beyond 0.5 m from the waste bin.