Vermicomposting of anaerobically digested sewage sludge with hazelnut husk and cow manure by earthworm Eisenia foetida

Abstract

Article InfoVermicomposting of organic waste has an important part to play in an integrated waste management strategy. The aim of the present study was to investigate the ability of an epigeic earthworm Eisenia foetida to transform anaerobically digested sewage sludge (SS) amended with hazelnut husk (HH) and cow manure (CM) in different proportions under laboratory condition (in darkness at 25°C0,5 0 C). Two approaches investigated in the study were: (1) to find the best medium for growth and reproduction of E. foetida in different feed mixtures, (2) to analyze the heavy metal concentrations in different feed mixtures of SS-HH-CM before and after vermicomposting, and (3) to explore heavy metals accumulation of earthworms in sewage sludge with different feed mixtures. Number and biomass of earthworms and heavy metal contents in feed mixtures and earthworms were periodically monitored. The results indicated that maximum earthworm biomass was attained in feed mixture of 20% SS + 40% CM + 40% HH while the earthworm number was highest in feed mixture of 30% SS + 35% CM + 35% HH during the vermicomposting period. Heavy metals concentration (Zn, Cu, Cd, Pb, Ni and Cr) in all feed mixtures decreased associated with the increasing vermicomposting time. The heavy metals' content in the feed mixtures was lower than that of initial mixtures. Metal analysis of earthworms revealed considerable bioaccumulation of heavy metals in their bodies' tissue. Heavy metal analysis of earthworm body showed that increasing proportion of SS in the feed mixtures promoted the heavy metal content of earthworm body.

Heat pre-treatment as an initial step in vermicomposting significantly influences worm population and cocoon production

“…This method offers an alternative to traditional composting techniques for recycling organic material. During vermicomposting, organic materials are rapidly humified, detoxified, and disinfected, aided by beneficial microorganisms and earthworms (Kızılkaya and Hepşen, 2014;Rakıcıoğlu and Kızılkaya, 2021). The epigeic earthworm species, Eisenia foetida 103 Vermicompost is a finely divided, peat-like substance with a low C: N ratio, superior structure, porosity, aeration, drainage, and water-holding capacity (Demir, 2019;2020;Yılmaz and Uğur, 2022).…”

Influence of inoculating microbes on municipal sewage sludge composting

“…Currently, with the development of industrialization and urbanization, the yield of sewage sludge (SS) in Kazakhstan sharply increases every year (Ospanov et al, 2022). SS is a by product of waste water treatment process, which contains lots of organic matter, plant nutrients (N, P, K, Ca, Mg, etc) and harmful components such as potential toxic heavy metals and pathogenic microorganisms (Delibacak et al, 2020;Kızılkaya et al, 2021). The use of SS in agriculture includes several operations that improve its efficiency in crop production, as compared to mineral fertilizers, which are related to the stabilising process before spreading (Shashoug et al, 2017;Jatav et al, 2021).…”

Comparison of different types of fertilizers on growth, yield and quality properties of watermelon (Citrullus lanatus) in the Southeast of Kazakhstan

“…Goss et al (2013) are of the same opinion. Several studies have been done related to organic amendments on improving soil physical, chemical, and biological properties, providing essential plant nutrients to stimulate plant growth and yield Hepşen, 2004, 2007;Candemir and Gülser, 2010;Gülser et al, 2017;Kızılkaya et al, 2021). Rodriguez-Vila et al (2016) found that organic amendments sustain soil properties by increasing organic matter, nutrient content, microbial activity and thus increase crop growth and yield.…”