A review: factors affecting excess sludge anaerobic digestion for volatile fatty acids production.
This paper presents a review of methods that improve the production of volatile fatty acids (VFA) from excess sludge during the anaerobic digestion process. These methods are mainly divided into two approaches. The first approach is located in the pre-treatment methods, which change the properties of the substrates, such as thermal pre-treatment, alkaline pre-treatment, microwave pre-treatment and ultrasonic pre-treatment. The other approach is found in the fermentation process control methods, which influence the environment of anaerobic digestion for the production of VFA, such as pH, temperature, mixing, additives and solids retention time control. In the text recent research studies of each method are listed and analyzed in detail. Comparably, microwave and ultrasonic pre-treatment methods are considered emerging and promising technologies due to their efficiency and environmentally friendly characteristics. However, the microwave pre-treatment has high electricity demand, which might make the process economically unfeasible. In order to calculate optimal operation, further studies still need to be done.
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: daixiaohu@tongji.edu.cn.
Dong
D
Zhang
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: daixiaohu@tongji.edu.cn.
Xiaoshuai
X
Li
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: daixiaohu@tongji.edu.cn.
Shuting
S
Jia
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: daixiaohu@tongji.edu.cn.
Lingling
L
Dai
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: daixiaohu@tongji.edu.cn.
Jianfu
J
Zhao
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: daixiaohu@tongji.edu.cn.
Yinguang
Y
Chen
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: daixiaohu@tongji.edu.cn.
Xiaohu
X
Dai
D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D019149:Bioreactors; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D005285:Fermentation; D008872:Microwaves; D012722:Sewage / Q000382:microbiology*; D014465:Ultrasonics; D018505:Waste Management / Q000379:methods*
D005232:Fatty Acids, Volatile; D012722:Sewage