Municipal Sewage Sludge Composting in the Two-Stage System: The Role of Different Bulking Agents and Amendments

Dorota Kulikowska, Katarzyna Bernat, Magdalena Zaborowska and Magdalena Zielińska
Additional contact information
Dorota Kulikowska: Department of Environmental Biotechnology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, 10-709 Olsztyn, Poland
Katarzyna Bernat: Department of Environmental Biotechnology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, 10-709 Olsztyn, Poland
Magdalena Zaborowska: Department of Environmental Biotechnology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, 10-709 Olsztyn, Poland
Magdalena Zielińska: Department of Environmental Biotechnology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, 10-709 Olsztyn, Poland

Energies, 2022, vol. 15, issue 14, 1-14

Abstract: This study assessed the effect of different lignocellulosic amendments and bulking agents on compost stability (based on a 4 day respiration activity test, AT4, and self-heating factor, SH F ) and maturity (based on the nitrification index I nitr and the ratio of C in humic acids, HA, to total organic carbon, TOC, in compost, C HA /TOC). With all feedstock compositions (FCs), the share of sewage sludge was 79% (wet mass). For FC 1 , wood chips (13.5%) and wheat straw (7.5%) were used as bulking agents and amendments; for FC 2 , instead of wood chips, energy willow was added; for FC 3 , pine bark (13.5%) and conifer sawdust (7.5%) were used. All FCs produced stable and mature compost; however, with FC 2 , the thermophilic phase last 3 days longer than with the other FCs. Moreover, an AT4 value below 10 g O 2 /kg dry mass (d.m.) was obtained the earliest with FC 2 (after 45 days, ca. 15–20 days earlier than with other FCs). With FC 2 , I nitr below 0.5 was obtained in ca. 60 days, 10 days earlier than with FC 3 and 30 days earlier than with FC 1 . The highest net increases in HS (86.0 mg C/g organic matter (OM)) and HA (56.3 mg C/g OM) were also noted with FC 2 ; with other FCs, the concentrations of these compounds were from 1.3- to 1.5-fold (HS) and from 1.4- to 1.9-fold (HA) lower. With FC 2 , the highest C HA /TOC (15.5%) was also noted, indicating that this compost contained the largest share of the most stable form of organic carbon. The rates of OM removal in the bioreactor ranged from 7.8 to 10.1 g/(kg d.m.·day). The rates of SH and HA formation ranged from 1.63 to 4.83 mg C/(g OM·day) and from 1.23 to 1.80 mg C/(g OM·day), respectively. This means that, through the choice of the amendments and bulking agents, the length of the composting time needed to obtain a stable and mature product can be controlled.

Keywords: sewage sludge; compost stability; humic substances and humic acids; nitrification index; nutrients; heavy metals (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.mdpi.com/1996-1073/15/14/5014/pdf (application/pdf)
https://www.mdpi.com/1996-1073/15/14/5014/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:15:y:2022:i:14:p:5014-:d:858962

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().