Biotechnology for aerobic conversion of food waste into organic fertilizer

Abstract

A biotechnology for aerobic conversion of food waste into organic fertilizer under controlled aeration, stirring, pH and temperature at 55-65 degrees C, is proposed. To maintain neutral pH at the beginning of the bioconversion 5% CaCO3 was added to the total solids of the food waste. The addition of 20% horticultural waste compost as a bulking agent to the food wastes (w.w./w.w.), improved the bioconversion and increased the stability of the final product. No starter culture was needed for aerobic bioconversion of food waste into organic fertilizer for 10 days. The low contents of heavy metals in the raw materials used in the bioconversions ensured the safety of fertilizer from food waste for application in agriculture. The addition of 4% organic fertilizer to the subsoil increased the yield and growth of Ipomoea aquatica (Kang Kong) by 1.5 to 2 times. The addition of phosphorus is required to enhance the positive effect of organic fertilizer on plant growth.

Physico-Chemical and Biological Changes During Co-Composting of Model Kitchen Waste, Rice Bran and Dried Leaves With Different Microbial Inoculants

“…Some of them stated that MI is able to increase enzymatic activities [2,3], promote biodegradation of organic matter [4,5] and accelerate the process [4,6]. In contrast, part of them suggests that microbial community naturally present in the waste is able to carry out the degradation satisfactorily when optimum environmental conditions were given [7,8,9]. In this study, co-composting of model kitchen waste, rice bran and dried leaves in the total size of 4 kg under five different treatments were used to study the necessity and effect of MI for composting.…”

New Steady-State Microbial Community Compositions and Process Performances in Biogas Reactors Induced by Temperature Disturbances

“…Its use is not a new practice for composting, where Wang et al (2003) added a starter bacterial culture of Bacillus thermoamylovorans SW25 in composting mixtures of anaerobic dewatered sewage sludge and vegetable food waste. Although Fang et al (2001) suggested that starter culture might assist in the composting process, Stabnikova et al (2005) found that starter cultures are useless in food waste aerobic thermophilic bioconversion as sufficient air and thermophilic temperature ensure a quick composting process. The starter culture governs the process by reducing the accumulation of actinomycetes and fungi, which discharge allergenic spores into the air, and lowering the risk of harmful microorganism growth in the end product (Wang et al 2003).…”

“…The starter culture governs the process by reducing the accumulation of actinomycetes and fungi, which discharge allergenic spores into the air, and lowering the risk of harmful microorganism growth in the end product (Wang et al 2003). Previous researchers have used B. thermoamylovorans SW25 (Wang et al 2003;Stabnikova et al 2005), cultures of three Bacillus species (such as B. brevis, B. coagulans and B. licheniformis (Fang et al 2001)), and a specially developed association of microorganism (Volchatova et al 2002) in their composting studies.…”

“…Recognised bulking agents used for composting include sawdust (Sundberg and Jönsson 2005;Kalamdhad et al 2008), rice hulls and chips of tree cuttings (Chikae et al 2006), horticultural waste compost (Stabnikova et al 2005) and mulch hay and wood shavings (Cekmecelioglu et al 2005). Newspaper contains 9% of moisture content (MC) (Wayman et al 1992) and 94% of volatile solids with lignin content of the volatile solids ranging from 16% to 22% (Sun and Cheng 2002), while the onion peels contain about 54% of volatile solids (Lubberding et al 1988) with 1.5% dry weight of lignin (Suutarinen et al 2003).…”

“…As kitchen waste is produced everyday and everywhere from processed and unprocessed food for human consumption, its composition is quite variable. An optimised kitchen waste formulation and composition involving the use of bulking materials, waste load size and presence of microbes are important in ensuring the commencement of an effective composting process (Fang et al 2001;Ishii and Takii 2003;Cekmecelioglu et al 2005;Stabnikova et al 2005;Cayuela et al 2006;Chang and Hsu 2008).…”