Search Results (4)

Population growth, urbanization, and changing consumption patterns are contributing to an increase in household waste production, particularly in sub-Saharan Africa. Composting of biowaste presents a sustainable solution by reducing the volume of waste sent to landfills while enriching the soil. The main objective of this study was to evaluate the suitability of solid household biowaste for composting in market garden crops in Dolisie (the Republic of Congo). Specifically, the study aimed to (i) assess the production and management practices of solid household waste in relation to socio-economic factors, (ii) analyze the chemical composition of solid household biowaste and its concentration of trace elements (TEs), and (iii) determine the potential phytotoxicity of solid household biowaste across different production seasons. In this study, wastes were collected from 40 households over a 60-day period, with daily sorting conducted during both the dry and wet seasons. Using a completely randomized design, various compost application rates were incorporated into the soil to conduct a germination test. The quality of the biowaste and compost was evaluated through physicochemical analyses. Results showed that approximately 90% of high-income households received regular waste collection services and practiced waste separation in contrast to middle- and low-income households. The composition of the biowaste was primarily composed of fruit and vegetable scraps, with slight contamination by chromium and cadmium. Temperature, pH, and humidity levels showed similar trends during compost formation in both the rainy and dry seasons. Germination rates were above 80% in all treatments across both seasons, indicating that the compost was mature. Overall, all physicochemical parameters of the compost met established quality standards, and trace element concentrations were below the recommended thresholds. The study concluded that biowaste, once converted into compost, can be safely applied to agricultural soils without posing any risk of phytotoxicity or contamination to crops. Full article

Anaerobic digestion (AD) is a promising biowaste valorization technology for sustainable energy, circular economy, local energy community growth, and supporting local authorities’ environmental goals. This paper presents a systematic review meta-analysis methodology for biomethane estimation, using over 600 values of volatile solids (VS) content and biochemical methane potential (BMP) of six different waste streams, collected from 240 scientific studies. The waste streams include cow manure (CM), sheep/goat manure (SGM), wheat straw (WS), household waste (HW), organic fraction of municipal solid waste (OFMSW), and sewage sludge (SS). The statistical analysis showed a mean VS content of 11.9% (CM), 37.3% (SGM), 83.1% (WS), 20.8% (HW), 19.4% (OFMSW), and 10.6% (SS), with BMP values of 204.6, 184.1, 305.1, 361.7, 308.3, and 273.1 L CH₄/kg VS, respectively. The case study of Kozani, Greece, demonstrated the methodology’s applicability, revealing a potential annual CH₄ production of 15,429,102 m³ (corresponding to 551 TJ of energy), with SGM, WS, and CM as key substrates. Kozani, aiming for climate neutrality by 2030, currently employs conventional waste management, like composting, while many local business residual streams remain unused. The proposed model facilitates the design and implementation of AD units for a sustainable, climate-neutral future. Full article

The main problems of the city of Nitra (Slovak Republic) in the field of municipal waste management include: 1. High production of municipal waste per capita; 2. Low rate of its separation; 3. High landfill rate; 4. No opportunity for composting; 5. Establishment of illegal landfills in the city; 6. Low waste prevention rate. To identify the attitudes and opinions of the respondents, and to evaluate certain behavioural practices of the inhabitants of Nitra in the management of municipal solid waste, we used a structured questionnaire (realized in 2020). The results of the questionnaire correspond to the behaviour of 4911 inhabitants of the city (6.46%). This paper evaluates the respondents’ answers, which could be utilised by the local government—not only for a more appropriate setting of municipal waste management and separation, but also in waste prevention and monitoring changes in the consumer behaviour of city residents. The degree of separation in individual housing construction (IHC) and complex housing construction (CHC) was statistically evaluated and compared separately. For paper and glass, a higher degree of separation was reflected in CHC; while conversely, households living in CHC avoided bio-waste and kitchen waste more than IHC households. The most common reason for not participating in the separate collection was the lack of collection containers, the distance of containers from their households, or the low frequency of their collection. The results of the questionnaire show the need for more rigorous education about waste generation, its proper separation, and its prevention. Full article

The increase in the amount of municipal solid waste (MSW) generated, among other places, in households is a result of the growing population, economic development, as well as the urbanisation of areas with accompanying insufficiently effective measures to minimise waste generation. There are many methods for treating municipal waste, with the common goal of minimising environmental degradation and maximising resource recovery. Biodegradable waste, including selectively collected biowaste (BW), also plays an essential role in the concept of the circular economy (CE), which maximises the proportion of waste that can be returned to the system through organic recycling and energy recovery. Methane fermentation is a waste treatment process that is an excellent fit for the CE, both technically, economically, and environmentally. This study aims to analyse and evaluate the problem of odour nuisance in municipal waste biogas plants (MWBPs) and the impact of the feedstock (organic fraction of MSW-OFMSW and BW) on this nuisance in the context of CE assumptions. A literature review on the subject was carried out, including the results of our own studies, showing the odour nuisance and emissions from MWBPs processing both mixed MSW and selectively collected BW. The odour nuisance of MWBPs varies greatly. Odour problems should be considered regarding particular stages of the technological line. They are especially seen at the stages of waste storage, fermentation preparation, and digestate dewatering. At examined Polish MWBPs c_od ranged from 4 to 78 ou/m³ for fermentation preparation and from 8 to 448 ou/m³ for digestate dewatering. The conclusions drawn from the literature review indicate both the difficulties and benefits that can be expected with the change in the operation of MWBPs because of the implementation of CE principles. Full article