Back to Search Start Over

Performance comparison between two equal stabilization ponds operating with and without sludge layer.

Authors :
Rodrigues VA
Possmoser-Nascimento TE
Dias DF
Passos RG
von Sperling M
Vasel JL
Source :
Water science and technology : a journal of the International Association on Water Pollution Research [Water Sci Technol] 2015; Vol. 71 (6), pp. 929-37.
Publication Year :
2015

Abstract

Stabilization ponds are a highly appropriate system for treating sewage in small to medium size communities. However, sludge accumulation at the pond bottom occurs with the passage of time, reducing the net pond volume, which, in principle, could affect its performance. The objective of this paper is to compare the behaviour of two equal ponds in parallel treating the same flow of municipal wastewater from an upflow anaerobic sludge blanket reactor in Brazil. Each pond treated a population equivalent of around 125 inhabitants. One pond had approximately 40% of its net volume occupied by sludge after 11 years of operation, while the other pond had previously undergone complete desludging. The study covers the removal of biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), nitrogen fractions and coliforms. Owing to the presence of a sludge layer, the theoretical hydraulic retention time (HRT) was lower in the pond without sludge. For BOD, COD, SS and Escherichia coli there were no significant differences (Wilcoxon matched-pairs test) between both ponds. The pond without sludge had significantly better removal efficiencies in terms of total Kjeldahl nitrogen and ammonia-N. The sludge layer probably allowed the occurrence of removal mechanisms that compensated for the reduction caused in the HRT.

Details

Language :
English
ISSN :
0273-1223
Volume :
71
Issue :
6
Database :
MEDLINE
Journal :
Water science and technology : a journal of the International Association on Water Pollution Research
Publication Type :
Academic Journal
Accession number :
25812104
Full Text :
https://doi.org/10.2166/wst.2015.014