TITLE:
Reed Beds for Sludge Dewatering and Stabilization
AUTHORS:
Manoj Kumar Pandey, Petter Deinboll Jenssen
KEYWORDS:
Sludge, Reeds, Dewatering, Evapotranspiration
JOURNAL NAME:
Journal of Environmental Protection,
Vol.6 No.4,
April
13,
2015
ABSTRACT: In urban
and peri-urban areas of developing countries decentralized wastewater treatment
using septic tanks as pretreatment is common. One challenge of decentralized
wastewater treatment systems (DEWATS) is handling and utilization of the
generated sludge. Sludge drying reed beds (SDRBs) are a robust method for
dewatering and stabilization of sludge. Constructed wetlands (CWs) and SDRBs
can be integrated to treat both wastewater and sludge. SDRBs require more area
than most other sludge treatment options, but have low operational cost and
energy requirements. The land area required for SDRB’s can be optimized by the
selection of an appropriate loading rate, sludge application frequency and
resting phase. This paper gives a review regarding the use of SDRB’s as well as
presenting a pilot scale experiment comparing planted and unplanted sludge
drying beds in Kathmandu. The planted beds showed a higher dewatering
capability and higher reduction of volatile solids (VS). A short-term
pilot-scale experiment can give valuable input to the design and operation of
full-scale systems and for sub-tropical climate as that of Kathmandu Nepal, an
initial sludge loading rate (SLR) of 100 kg total solids (TS)/m2/year
is suggested with a gradual increase to up to 250 kg TS/m2/year.