Alexander Szabo and Oscar Engle - Svenskt Vatten

Summary
Malaysia is developing fast and is striving to become a fully developed country by 2020. After
independence in 1957 from Great Britain, Malaysia has gradually set up goals for its waste water
management, which often goes together with economical development and growth. Most of the waste
water treatment facilities built so far have been made simple and in form of treatment ponds, septic tanks
and low flushing latrines. In this project a treatment pond at UTM in Johor Bahru has been analyzed. At
present, the management of UTM is not satisfied with the treatment efficiency and is looking for options
to upgrade the pond or replace it with an activated sludge system. The objective of this study is to propose
an upgraded waste water treatment facility to the current treatment pond.
The treatment pond consists today of two parallel lines, each line with a facultative pond followed by a
maturation pond. After treatment the water is discharged to a stream close to the treatment pond. At two
occasions in November 2009 and one occasion in January 2010 sampling and flow measurements were
performed at the treatment pond. During each occasion sampling and flow measurements were made
every second hour for 24 hours. This was made to get the characteristics and behavior of the waste water
quality and the waste water flow. The samples were analyzed and the amount of Chemical Oxygen
Demand (COD), Biological Oxygen Demand (BOD) and Total Suspended Solids (TSS) were measured.
The analysis of the data shows that the concentration of COD, BOD and TSS is low. It seems there is a
significant infiltration into the sewer network at UTM. This was confirmed by the flow measurements
done at the inlet into the treatment pond. During rain events the influent flow is more than doubled and
this is something that must be considered when dimensioning a new treatment facility. It seems there is a
possible misconnection between the stormwater network and the sewer network at UTM. During these
peaks, the concentration of COD is more than doubled compare to the average COD entering the
treatment pond. The high COD-values are confirmed by higher TSS values during these rain events. The
exact reason for this is unknown but one possible explanation could be that the increased flow in the
waste water pipes will catch and carry with it deposits from the sewage pipe. Another explanation could
be that somewhere a stormwater channel is connected to the sewer pipes and the stormwater is carrying
organic material from the ground into the pipes which ends up in the treatment pond.
At late night the COD value is low but there is still a significant influent flow. This leads to the
conclusion that the pipe is also taking in groundwater. Together with the increased influent flow during
rain events and the high flow at night, the total infiltration is estimated to 60-90% of the total influent
flow.
From the data collected and analyzed three different solutions for better treatment efficiency have been
proposed. One solution is an activated sludge system; another is upgrading the current pond by
rearranging the water flow so that it flows in a series through all four treatment ponds. The third
alternative is to add aeration to the upgraded treatment pond as calculations shows that the area is not
sufficient and therefore it is overloaded. A review of the sewer and stormwater network should also be
considered in order to find the possible misconnection between the stormwater and the sewer water.
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