0000000000396963
AUTHOR
Niina Koivula
Temporal perspective of humification of organic matter
Humustumisprosessissa kuollut orgaaninen aines hajoaa maaperässä. Osa tästä orgaanisesta aineesta mineralisoituu hiilidioksidiksi ja vedeksi lopun jäädessä maaperään ja muodostaa humusaineita, joita ovat humushappo, fulvohappo ja humiini. Humusaineilla, erityisesti humushappojakeella, on myönteisiä vaikutuksia maaperään sekä kasvien kasvuun. Huolimatta yli 200 vuoden tutkimuksista yksiselitteistä teoriaa humushappojen kemiallisesta rakenteesta tai niiden synteesistä ei vielä ole esitetty. Osa teorioista painottaa humushappojen rakenteen keskeisinä tekijöinä ligniiniä ja aromaattisuutta, osa teorioista taas korostaa hiilihydraattien ja alifaattisuuden merkitystä.Koivulan tutkimuksessa ns. hi…
Ash in composting of source-separated catering waste.
Our earlier experiments in small composters (220 l) indicated the favourable effect of ash from co-incineration of sorted dry waste on the composting of catering waste. The aim of this new study was to clarify further, at a scale of 10 m3, the feasibility of using similar ash as an additive in composting.Source-separated catering waste was mixed with bulking agent (peat and wood chips) and fuel ash from a small (4 MW) district heating power plant. Three compost mixes (CM) were obtained: CM I with 0%, CM II with 10% and CM III with 20 wt.% of fuel ash. These three different mixes were composted in a 10-m3 drum composter as three parallel experiments for 2 weeks each, from January to April 20…
Biodeterioration of cardboard-based liquid containers collected for fibre reuse.
Liquid packaging board (LPB) collected in Germany is processed in Finland as recycled fibre and as plastic reject for incineration. The chemical, biological and physical changes occurring in recycled LPB bales were monitored during storage of six and 18 months. The moisture content in the core of the bales ranged from 7% to 53%, and pH values varied from 6.0 to 8.5. The average amount of mesophilic bacteria per container was 1.5 x 10(7) - 5 x 10(8), which means that recycled LPB pulp cannot be recommended for sanitary use. The concentration of CO2 inside the bale is an indicator of the activity of aerobic microorganisms and might be suitable for identifying deteriorated bales and removing t…
Concentrations of monosaccharides in humic substances in the early stages of humification.
Deteriorated liquid packaging board (LPB) and biowaste compost are matrices, mainly consisting of cellulose, in the early stages of humification. Degradative studies on these matrices allow an examination of the role of carbohydrates in the synthesis of humic substances. Samples of different age were collected and divided by extraction into hot water extract (HWE), bitumen, humic acid (HA), fulvic acid (FA) and humin or residual fibre fractions. The following monosaccharides were identified in these fractions: L-arabinose, D-ribose, D-xylose, L-fucose, D-mannose, D-fructose, D-galactose, D-glucose, L-rhamnose and xylitol. The main component in all fractions was glucose. The concentrations o…