Enhancement of performance and stability of anaerobic co-digestion of waste activated sludge and kitchen waste by using bentonite

PLoS One. 2019 Jul 10;14(7):e0218856. doi: 10.1371/journal.pone.0218856. eCollection 2019.

Abstract

There are large amounts of waste activated sludge (WAS) and kitchen waste (KW) produced every year in China. It has been confirmed that anaerobic co-digestion is an effective method to solve this problem. The targets of the present study were optimizing the digestive performances and clearing of the mechanism of bentonite addition by adding bentonite into digestive system. Group M (WAS: KW = 1:2, based on VS) presented higher cumulative methane yield (CMY), where the CMY increased from 19.8 to 36.3 mL/g VS with the bentonite dosage from 0 to 2 g/g VS. After bentonite addition, the lag phase of every digester presented an obvious decrease from 15.1 to 1.4 d. Furthermore, and the moderating effects on microbial community by bentonite. The addition of bentonite improved methane production, and it can also reduce the lag phase of methane production in co-digestion. What's more, bentonite addition increased the speed of pH recovery from 4.2-4.8 to normal level (7.0-8.0) and thus enhanced the system stability. The conclusion of this study can be used to guide practical engineering.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaerobiosis / physiology
  • Bentonite / pharmacology*
  • Biodegradation, Environmental
  • Bioreactors
  • Humans
  • Hydrogen-Ion Concentration
  • Methane / biosynthesis*
  • Microbiota / drug effects*
  • Microbiota / physiology
  • Sewage / microbiology*
  • Waste Disposal, Fluid / methods*

Substances

  • Sewage
  • Bentonite
  • Methane

Grants and funding

The authors would like to acknowledge the financial support for this work provided by the National Nature Science Foundation of China (NO. 51208531), National Key Technology Support Program (2014BAC29B001) and Chongqing science and Technology Commission Project (cstc2017jcyjAX0173). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.