Compost Quality and Markets Are Pivotal for Sustainability in Circular Food-Nutrient Systems: A Case Study of Sri Lanka

Sustainable management of municipal solid waste (MSW) is a critical issue around the world, especially in South Asia where waste generation is expected to double by 2050. Closing the food-nutrient cycle through composting biodegradable MSW has the potential to meet human needs, including sanitation and food security, while protecting the environment. We use an interdisciplinary case study approach including systems thinking to assess Sri Lanka's national MSW composting system, which primarily receives residential and commercial food waste. We embed quantitative compost quality analysis and interviews at 20 composting facilities within a broader qualitative assessment informed by ~60 stakeholders in total. This approach yields insights on how institutional, economic, social, and biophysical aspects of the system are interrelated, and how challenges and solutions can create undesirable and desirable cascading effects, respectively. Such dynamics can create risks of composting facility failure and unintended consequences, diminishing the chances of achieving a sustainable circular food–nutrient system. Compost quality, which was variable, plays a pivotal role within the system—a function of program design and implementation, as well as a determinant of value capture in a circular economy. We make several recommendations to inform future efforts to sustainably manage biodegradable MSW using composting, drawing on our case study of Sri Lanka and prior case studies from other nations. Key among these is the need for increased emphasis on compost product quality and markets in policy and program design and implementation. Targeted measures are needed to improve waste separation, boost compost quality, effectively use compost standards, encourage compost market development, ringfence the revenues generated at municipal compost plants, and identify efficient modes of compost distribution. Such measures require adequate space and infrastructure for composting, resource investment, local expertise to guide effective system management, strong links with the agriculture sector, and continued political support.

Utilization of nyamplung industrial waste for compost and the response to nyamplung seedlings growth and nitrogen uptake

The solid waste (dregs seed) of nyamplung (Calophyllum inophyllum) industry from seed pressing processes could be more than 50% of the dry seed weight. Nyamplung oil industry in Bantul (Yogyakarta) has been produced nyamplung oil 4-5 ton/month that produced dregs seed around 50-60%/ton nyamplung dry seeds. The accumulated waste has been piled up and immediately important to utilize it. This study aimed to determine (i) the effect of bioactivators with ameliorant material application and the interactions among treatments on nyamplung dregs compost quality, and (ii) the growth response, seedling quality index and nitrogen uptake on nyamplung seedlings with nyamplung dregs compost application. The study was arranged in Completely Randomized Design (CRD) factorial. Two bioactivators Prouponic Gb#1 and cattle rumen bio starter were used in the study. The bioactivators were combined by ameliorants (no ameliorant, dolomite, and rice husk ash) with 3 replicates for each treatment. Analyses of soil chemical properties were carried out on nyamplung dregs before and after the treatments applied including: pH, DHL, N Total, C/N ratio, P Total, K Total. Those characters were compared to SNI No.19-7030-2004 on compost quality standards. DHL, C/N ratio, the total N, P, and K met the criteria on SNI. Seedling growth characters (height, diameter, number of leaves) and seedling quality index varied between nyamplung dregs compost treatments and control up to 16 weeks observation. Nyamplung dregs compost application showed the highest N uptake on nyamplung seedlings compared to the controls. Nyamplung seedling quality index was highly influenced by the uptake of N nutrients in the shoots and the roots than by height character and diameter.

Pengaruh Pemberian Limbah Batang Buah Naga Terhadap Kualitas Kompos Feses Sapi

This study aims to determine the best level of administration of dragon fruit stem waste on the quality of cow feces compost. The design used was a completely randomized design (CRD) with 5 treatments and 4 replications. The treatments consisted of P0 = cow feces 97.5% + EM4 2.5%, P1 = cow feces 77.5% + dragon fruit stem waste 20% + EM4 2.5%, P2 = cow feces 67.5% + waste dragon fruit stem 30% + EM4 2.5%, P3 = cow feces 57.5% + dragon fruit stem waste 40% + EM4 2.5, P4 = cow feces 47.5% + dragon fruit stem waste 50% + EM4 2.5%. The observed variables were color, odor, texture, temperature, pH, nitrogen, carbon, phosphorus, potassium and C/N ratio. The results showed that the colors produced in the treatment were P0 (100% black), P1 (100% black), P2 (100% black), P3 (50% black chocolate and 50% brown), P4 (100% chocolate). The odor produced in the treatment of P0 (100% soil), P1 (75% soil and 25% weathered), P2 (50% weathered and 50% weathered), P3 (100% weathered), P4 (100% weathered). The resulting texture in the treatment of P0 (100% crumb), P1 (100% crumb), P2 (100% crumb), P3 (50% crumb and 50% coarse), P4 (75% coarse and 25% crumb), pH value in treatment P0 (7.23%). The addition of dragon fruit stem waste had a very significant effect (P<0.01) on the content of nitrogen, phosphorus, potassium and C/N. The highest nitrogen content was at P2 (1.60%) and the lowest was at P0 (1.31%), the highest phosphorus content was at P4 (0.31%) and the lowest was at P0 (0.18%), the highest potassium content was found in at P3 (1.16%) and the lowest at P0 (0.44%), the highest C/N content was at P0 (22.25%) and the lowest was at P3 (16.75%). Meanwhile, the carbon content had no significant effect (P>0.05). From the results of this study, it can be concluded that the best compost quality results were obtained in treatment (P3), on the content of carbon, potassium and C/N. Because it is based on the standard range of compost quality (SNI 19-7030-2004).

Are the Enrichment Nutrient Feasible to the Vermicomposting Efficiency For Water Hyacinth (E. Crassipes)?

In eutrophic environments, aquatic weeds reproduce quickly and occupy large areas, preventing multiple uses of water resources. The use of the biomass of these plants in vermicomposting represents a sustainable alternative. The enrichment of macrophyte biomass during vermicomposting was tested using inorganic NPK solution (1.75% and 3.5%) and organic solution (0.25 g/L and 0.5 g/L) to improve the quality of the compound. Biomass consumption increased as the experiment progressed, reaching the highest values at the end. The experiment without worms remained stable. The influence of E. fetida individuals the vermicomposting process of water hyacinth will depend nutrient addition. The additions improved subtly the compost quality and the consumption of biomass, besides its low-cost, easily obtained and applicable treatment. It does not have the necessary requirements for its use as a fertilizer. However, we suggest the use in association with other fertilizers, adding moisture and structuring to the soil.

Evaluation of compost quality from municipal solid waste integrated with organic additive in Mizan–Aman town, Southwest Ethiopia

Background The present study evaluated the compost quality from municipal solid waste (MSW) and organic additives of coffee by-products and leaf of Millettia ferruginea. Compost sample (n = 30) was taken from fresh compost materials and MSW and different organic additive treatments (T1, T2, T3, T4, and T5). Compost treatments phytotoxicity test was conducted using lettuce seed (Lactuca Sativa L. var. crispa). Analysis of variance (ANOVA) was performed using SPSS (version 22) on major compost quality characteristics. Results The compost Physico-chemical characteristics like temperature (26.4 °C), moisture content (45.5%), electrical conductivity (4.6 mS/cm), pH (7.9), total nitrogen (1.2%) and phosphorous content (2918 ppm) in T4 and T5 were analogous but both are significantly different from T3, T2 and T1 compost treatments. Phytotoxicity test using 100% compost treatment media showed that T4 (101%) and T5 (102%) are phytonutrient for lettuce plant. While, T3 and T2; and T1 compost treatments are non-phytotoxic and moderately phytotoxic respectively to lettuce plant. Conclusion Therefore, compost from MSW + M. ferruginea (T4) and MSW + coffee pulp + M. ferruginea (T5) are important for improving the physico-chemical characteristics of compost and are phytonutrient for lettuce plant. Thus, for effectively management of the 75% of organic fraction of waste generated from households in the study area, recycling methods like composting with organic additives must be used at large.