Instructions for using LIFE CYCLE COST MODEL
When starting the LCC model
it may ask to enable macros. Please enable macros and then proceed:
Major Components:
1)
INPUT SHEET:
Values for all the parameters are to be entered in this sheet. The columns colored Red are the entry column. Default values of each parameter are provided next to the entry column. The user can enter values as per their system requirements.
·
Total Population: The population at the beginning of the design study.
·
Percent of Population: Percentage of total population working with or
directly associated with various types of associations. This data is needed to
generate the base flow in the model.
·
Establishments: Number of housing, industrial, business, educational and recreational
establishments in the study area. The numbers of units are based on population
of the city/wastewater district. Note that the number of persons is an
important parameter and can be obtained from the U.S. census data.
·
Length of sewer per Unit: Length of sewer line added by each unit to the total
length of the main lines. Trunk sewer will be a percentage of main sewer
pipeline length.
·
Sewer pipe classification: Pipe sizes are classified in standard sizes. For
laterals pipe sizes ranges from 4,6 and 8 inch diameter while Main lines ranges
from 8, 10 and 12 inch diameter pipes and trunk sewer are 24,30,36,42 and
48-inch diameter. The laterals, main
and trunk are equally divided among the sizes. User can change the percentage
of various sewer pipe sizes according to the system to be designed.
·
Pipe Joint spacing: The joints in pipeline are classified in three categories.
Lateral-Main joints (joints at the intersection of lateral with main line
sewer), Mainline joints (joints between the pipes of the mainline sewer) trunk
line joints (joints between the pipes of the trunk sewer). The default spacing
is 20 feet. User can change the spacing as per their system.
·
Manhole spacing: Manholes at mainlines and trunk sewers are placed at a default distance
of 300 feet and 400 feet apart respectively.
·
Manhole sizes: Manhole sizes vary from 4 to 8 feet diameter based on the diameter of
the pipe where the manhole is placed.
·
Infiltration: Infiltration considered is the model is rain induced infiltration and
ground water infiltration. Infiltration takes place through manholes, pipeline
(cracks in main line and trunk line) and pipe joints (main-lateral joints, main
line joints, trunk line joints). The intensity of infiltration varies from day
to day; the user can determine the intensity of infiltration and number of days
associated with it. The default value is 0% infiltration for 250 days, 10% for
100 days and 30 % for 15 days. The percent infiltration and number of days are
on a sliding scale; infiltration increases every year with no maintenance
performed, so do the number of days associated with the infiltration.
·
Per capita Flow: Per capita flow is the individual discharge made by per person per day
on an average associated with various establishments. Default values are
provided.
·
Transportation cost: Transportation cost is the cost associated with the
collection and conveyance of waste water this includes the cost of minor sewer
repair, sewer maintenance, pumping station, Operation and
Maintenance and other miscellaneous expenses.
·
Treatment cost: Treatment cost is the cost of treating per gallon of wastewater.
Treatment cost depends on the capacity of the treatment plant and the capacity
utilized. Treatment plants are classified into three sizes small, mid size and
large treatment plants.
2)
BASIC MODEL SHEET:
This sheet provides the data
for a single event (one day) of occurrence of infiltration in the system.
Various parameters can be verifies from this sheet; the length of the sewer
system, number of manholes, per day sewer flow, treatment cost per 1000 gallons
etc; of the city/wastewater district under consideration. The model can be
further calibrated for a particular city by making corresponding changes in the
input sheet to achieve city specifications.
3)
CAPITAL COST:
The capital cost sheet shows
the cost associated with laying out a wastewater system of the size obtained in
the basic model sheet.
4)
MODEL SHEET 5, 10, 15, 20, 25, 30:
These model sheets incorporate the change in population every 5 years. Infiltration in the system is increased by one percent every year. Default Model values are provided in the Input sheet.
5)
CHECK FOR SSO (Sanitary Sewer Overflow):
This sheet helps to check
when the system flow exceeds the treatment plant capacity and the prescribed
regulations of EPA for excessive infiltration (average dry weather flow not
exceeding 120 gpcd-gallons per capita per day). Rehabilitation is performed at
the end of every 10 years period, when rehabilitation is performed the
infiltration is dropped by 50%.
6)
REHABILITATION COST :
Rehabilitation is performed
every 10 years cycle. Rehabilitation is performed on 10% of the system. The
cost calculation is done as per rehabilitation costs provided by the user
(default values are also provided). 30 years rehabilitation cost is calculated
based on two rehabilitation cycles.
7)
LIFE CYCLE COST:
The Life Cycle Cost sheet
gives us the cost of Wastewater treatment for 30 years period when
rehabilitation is performed every 10 years on the system.
8)
LIFE CYCLE COST(NO MAINTENANCE):
Alternate Life Cycle Cost is achieved for no rehabilitation on the system. The difference in the life cycle cost with maintenance and no maintenance is obtained.
----------------------------------------------------------