Water Efficiency and Sustainability - University of Toledo · Web viewIdentification of the Most Sustainable Alternative System to be used for Toilets in North Engineering Building

Identification of Sustainable Alternative Applicable to North Engineering Toilets

Identification of the Most Sustainable Alternative

System to be used for Toilets in North Engineering

Building of University of Toledo: A Comparative Study

of Implementation of Rain Water Harvesting, Grey

Water Recycling and Composting Toilets

ByAkhil Kadiyala

Zheng XueAndrew E. Wright, LEED A.P.

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Table of Contents

1. Abstract ............................................................................................ 5 2. Introduction .................................................................................... 5

2.1 Economic Input output Life Cycle Assessment (EIOLCA)......................................72.2 Indicators...................................................................................................................82.3 Sustainability Index and Performance Percentage....................................................92.4 LEED Requirements................................................................................................10

3. Data Collection ............................................................................ 10 3.1 Data collected from Maintenance Department and Survey.....................................113.2 Data collected for Life Cycle Inventory of Life Cycle Assessment........................13

4. Design of Alternative Systems ................................................ 13 4.1 Rainwater Harvesting..............................................................................................144.2 Grey Water Recycling.............................................................................................174.3 Composting Toilets..................................................................................................22

5. Results ........................................................................................... 25 5.1 LCA Results.............................................................................................................265.2 Indicator Analysis Results.......................................................................................27

5.2.1 Environmental Pollution Indicator...................................................................285.2.2 Natural Resource Consumption Indicator........................................................295.2.3 Economic Indicator...........................................................................................30

6. Sustainability Index and Performance Percentage ......... 32 7. LEED Credits ................................................................................. 32 8. Conclusion ..................................................................................... 33 9. References ..................................................................................... 34 Appendix A ........................................................................................ 37 Appendix B ..................................................................................................... 44

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List of Figures

Figure 2.1.1: System Boundary of LCA..............................................................................7

Figure 2.1.2: Inputs-Outputs of construction and O&M phases..........................................8

Figure 4.1 - Graph of present water consumption in restrooms........................................14

Figure 4.1.1: Concept of Rainwater collection system .....................................................15

Figure 4.2.1: Concept of Living Machine System to be used at UT.................................21

Figure 4.3.1 - Clivus Multrum M18..................................................................................24

Figure 4.3.2 – Schematic of composting system...............................................................24

Figure 5.1: Water use Consumption and Waste Water Effluent.......................................26

Figure 5.1.1: Greenhouse gases for “Construction” and “O&M” Stages of a Life Cycle.27

Figure 5.1.2: Energy for “Construction” and “O&M” Stages of a Life Cycle..................27

Figure 5.2.2.1: Average daily water savings (gal/day) for different systems....................29

Figure 5.2.3.1: Economical Choice Comparison based on Cost of Construction and O&M

...........................................................................................................................................30

Fiigure 5.2.3.2: Economical Choice based on Cost/gal of water saved/day......................31

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List of Tables

Table 2.2.1: Indicators used for comparing the three systems............................................9

Table 3.1.1: Details of Restroom Fixtures in North Engineering Building.......................12

Table 4.1.1 – Rainwater Harvesting Estimate1..................................................................16

Table 4.1.2 – Rainwater Harvesting O&M........................................................................16

Table 4.2.1: Effluent characteristics as observed in universities.......................................18

Table 4.2.2: Estimated Costs for Construction of Grey Water..........................................22

Table 4.2.3: Annual Costs for Operation and Maintenance of Grey Water......................22

Table 4.3.1 – Proposed Composting System for NE.........................................................25

Tables 5.2.1 – Water Consumption Analysis from EIO-LCA...........................................28

Table 6.1: Sustainability Index and Performance Percentage Values...............................32

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1. Abstract

This study compares the degree of sustainability and performance across three

different systems that could be practically adopted by The University of Toledo (UT) to

help conserve water for future generations. The systems considered were rainwater

harvesting, greywater recycling and composting toilets. Over the last decade, the role of

these three systems in reducing water consumption had been widely recognized across

the world and many buildings are currently using these systems either individually or in

combinations. While all three systems are capable of reducing the potable water usage in

toilet flushing in North Engineering (NE) building of UT, each system has its own

method of water conservation. Rainwater harvesting uses the collected rainwater as an

additional source of supply for toilet flushing while greywater treatment enables the reuse

of treated greywater from university for toilet flushing. Composting toilets reduce the

water consumption as they consume minimum amount of water per flush and no water in

some cases. None of the studies so far have compared these three systems that have

different ways of conserving water from a sustainability point of view and this study aims

at filling this knowledge gap.

This study provides two approaches of comparing these systems. Based on the

LCA and indicator analysis performed by the group, it was inferred that composting

toilets were found to be the most sustainable alternative system to reduce water

consumption at UT. However, it is also preferable to have greywater recycling for

maximum water conservation as the grey water produced by the university accounts for

almost 35% total water consumed by university.

2. Introduction

The College of Engineering at The University of Toledo has proposed to renovate

the North Engineering building in order to facilitate bringing all the students, faculty and

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administrative services within the main campus. The College of Engineering has heavily

emphasized on the need to use sustainable alternatives during the renovation work. This

project is being performed as part of evaluating the sustainable options of water use

consumption for toilets and urinals in the North Engineering building that include the use

of rain water harvesting, grey water recycling and composting toilets.

Rainwater harvesting has been used mainly for agricultural usage and landscape

irrigation. It was found that rainwater harvesting has not been thoroughly studied in a

sustainable aspect for its uses for water to be recycled through toilet and urinal flushing.

Over the years, the number of studies that have focused on using recycled grey water for

toilet flushing has been increasing and the standards for recycled grey water vary from

one country to another. Lazarova et al. (2003) provided a comprehensive review of the

various studies that have used recycled grey water for toilet flushing and documented the

grey water quality criteria that needs to be adopted across different countries. The use of

composting toilets has shown to reduce the amount of water needed and therefore

reducing the amount of effluent going to waste water treatment plants (WWTP). There

were no studies found that have focused on comparing the performance of these systems

with respect to sustainability.

The overall objective of the study is to determine the most sustainable alternative

system that can be applied to NE building at UT to reduce the water consumption,

thereby identifying the possibility of obtaining LEED points for better management

practices. The approaches used by the researchers in meeting the objectives are listed

below and discussed in detail in subsequent sections 2.1-2.4.

1. Use ‘EIOLCA’ to determine the most suitable system by considering

‘construction’ and ‘operation and maintenance’ phases in a life cycle across

the impact categories of greenhouse gases and energy.

2. Use different sustainable indicators as listed in Table 2.1.1 to analyze the

performance of the systems.

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3. Choose the most sustainable alternative system that could be adopted in toilets

at the NE building based on sustainability index and performance percentage

values.

4. Identify the possibility of obtaining LEED points for better management

practices.

2.1 Economic Input output Life Cycle Assessment (EIOLCA)

EIOLCA was used to compare the three systems based on the economic inputs for

each system obtained by designing of individual components for the systems and

obtaining cost estimates for each component in the system. EIOLCA was used to

identify the most sustainable alternative system from rainwater harvesting, grey water

recycling, and composting toilets to reduce water consumption by toilets in NE block at

UT using the phases of “Construction” and “Operation and Maintenance” across impact

categories of greenhouse gases and energy.

Figure 2.1.1: System Boundary of LCA

Figure 2.1.1 presents the boundaries of the system adopted by the research group

that is similar to the system boundary concept discussed by Memon et al. (2007). Only

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the construction and O&M phases are considered while transportation and energy

required in material manufacturing and transport are neglected. To compare the three

technologies we use the savings per life cycle of each system ($/life cycle) as a functional

unit. It should be noted that only the raw materials for construction phase products will be

considered but not the raw material extraction at manufacturing phase.

Figure 2.1.2 shows that the construction and O&M phases require the

manufactured material and energy (electricity) as inputs for the three systems. The

resulting outputs from these operations are atmospheric emissions, energy, and savings

due to adoption of any of the systems. The life cycle assessment for these operations is

performed using EIOLCA tool. Costs for manufactured materials for the different

systems were obtained from online websites or open literature and are cited in the design

sections. The energy consumption included electricity and the cost of electricity per kWh

is taken as 5.6 cents that was taken from an electricity bill in Toledo.

Figure 2.1.2: Inputs-Outputs of construction and O&M phases

2.2 Indicators

Table 2.2.1 summarizes the type of indicators and their corresponding points used

for comparing the three systems. Three different types of indicators namely economic

indicator, natural resource consumption indicator and environmental pollution indicator

are used to identify the most sustainable system from their perspectives.

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Table 2.2.1: Indicators used for comparing the three systems

Type of Indicator Points for comparison

EconomicDetermine economical choice for construction and O&M

phases and calculate payback period for each system

Natural Resource

ConsumptionCompare the quantity of water saved by each system per day

Environmental

PollutionDetermine the amount of greenhouse gases released and

energy requirements for each system.

2.3 Sustainability Index and Performance Percentage

In order to compare the three systems, the points for comparison listed in Table

2.2.1 are used as a series of questions that were classified under economic, environmental

and natural resource consumption indices. Points are allotted (‘3’ for best alternative, ‘2’

for intermediate alternative, and ‘1’ for last alternative) for each system for each

question. If two systems have no relative advantages then both of the systems are given

equal points for that particular question considered. The points are allotted based on the

relativity rather than on absolute basis. The points are summed up in the end to provide a

sustainable score to each of the systems considered. The best sustainable alternative

system is then identified based on ‘Sustainability Index’ and ‘Performance Percentage’

calculated using equations 2.3.1 and 2.3.2 respectively.

….2.3.1

….2.3.2

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where,

Performance percentage = Maximum Score of indicator × ∑Sustainable Score.

2.4 LEED Requirements

The U.S. Green Building Council's LEED Green Building Rating System

establishes “best practice” criteria for water and energy usage that can be applied to any

type of construction, even if certification is not the goal. The Water Use Reduction

section of LEED-NC identifies a baseline for water use and awards one or two credits for

surpassing requirements, in aggregate by 20 percent or 30 percent, respectively, beyond

the Energy Policy Act of 1992 fixture performance requirements.

The categories that the research group analyzed for obtaining points in water

conservation are listed below.

WE 2: Innovative Wastewater Technologies. The intent is to reduce generation of

wastewater and potable water demand, while increasing the local aquifer

recharge.

WE 3.1: Water Use Reduction 20%. The intent is to maximize water efficiency

within buildings to reduce the burden on municipal water supply and wastewater

systems.

WE 3.2: Water Use Reduction 30% has same intent as 3.1.

3. Data Collection

The data collected for the project can be divided into two categories. The first set

of data was collected from the maintenance department, and also a survey of utilities in

existing restrooms. This data helped to determine the existing water usage, and to predict

water savings by adoption of alternative techniques. The second set of data was collected

from various websites and open literature to estimate the quantity and costs of materials

that would be used in the life cycle assessment.

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3.1 Data collected from Maintenance Department and Survey

Preliminary information on water source and drainage systems was obtained from

the maintenance department at UT. It was confirmed that only potable water obtained

from Lake Erie provided by ‘The City of Toledo Water Treatment Plant’ is being used

for all purposes including toilets at UT and there have been no recycling systems on

campus. A monthly water bill for north engineering building revealed that the university

was paying about $4277.00 for 1048 ccf (783,904 gallons). All of the waste water from

toilets, sinks, sinks in labs, maintenance sinks and floor drains, and urinals are combined

together before discharge and there are no provisions for separate discharges from sinks

and toilets. In this study, we assume that 90% of this water is being released into the

city’s sanitary system. An in depth comparison of each system is presented for its water

reduction benefits and sustainability.

An initial survey was performed to find out the makes and model fixtures used in

the restrooms of the north engineering building. The maintenance department could only

provide information on the number of toilets in north engineering building and their floor

plans. A walk through of existing facilities provided information on the number of

fixtures and manufacturing company of the fixtures. The flow rates were obtained from

online web search after getting the company and model numbers for the different fixtures.

A summary of the restroom fixtures used in the North Engineering building are given in

Table 3.1.1.

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Table 3.1.1: Details of Restroom Fixtures in North Engineering Building

Room No Type of Utility No. of facilities in the room

Company / Manufacturer

Flow rate

1262 Faucets 3 Crane Plumbing NAUrinals 2 Zurn 3.0 g/fToilets 3 Zurn 1.6 g/f

1260 Faucets 2 Crane Plumbing NAToilets 3 Zurn 1.6 g/f

2014 Faucets 3 Kohler NAUrinals 2 Sloan 1.6 g/fToilets 3 Sloan 1.6 g/f

2013 Faucets 3 Kohler NAToilets 5 Sloan 1.6 g/f







0520A Faucets 3 Kohler NAUrinals 2 Sloan 1.6 g/fToilets 3 Sloan 1.6 g/f


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3.2 Data collected for Life Cycle Inventory of Life Cycle Assessment

The data collected for use in the EIOLCA that included parameters such as

materials, quantities, and their respective costs were obtained from various websites and

available open literature. Once the cost of construction and O&M were determined after a

careful design of the individual systems, EIOLCA was used to perform the life cycle

assessment.

4. Design of Alternative Systems

The design of alternative systems is based on the water requirement for toilet

utilities in NE block of UT. The amount of water required for toilet utilities in NE block

can be seen in Figure 4.1 It is assumed that there will be 2370 people in the building per

day based on the size of the classrooms and staff offices. The number of people is based

on the maximum seating in the laboratories, classrooms and offices. It is also assumed

that all persons in the building will use the restroom 1.5 times a day on average. It is

assumed that the students are 75% male and 25% female and that the males will use the

urinals and toilets in equal portions of their 1.5 times per day. This equates to 237,420

gallons per month used by the restrooms or 30% of the total water used in the building at

a cost per month of $1,283. The annual estimate is then $15,480 for 2,849,040 gallons of

water used by the restrooms only.

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Figure 4.1 - Graph of present water consumption in restrooms

4.1 Rainwater Harvesting

Rainwater harvesting is the process of intercepting storm-water runoff and putting

it to beneficial use. Rainwater is usually collected or harvested from rooftops, concrete

patios, driveways and other impervious surfaces. Buildings and landscapes can be

designed to maximize the amount of catchment area, thereby increasing rainwater

harvesting possibilities. Intercepted water can be collected, detained, retained and routed

for use in toilet and urinal flushing.

Rainwater harvesting systems vary from the simple and inexpensive to the

complex and very costly. Typically, these systems are simple, consisting of gutters,

downspouts, and storage containers. Directing rainfall to plants located at low points is

the simplest rainwater harvesting system. Figure 4.1.1 presents a proposed system that

the north engineering building would utilize for the use of flushing toilets and would

include the following design criteria:

All the roof rainwater is collected at a general point and distributed to

the collection tank

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Prior to the rainwater entering the collection tank it is filtered via a ground filter.

The rainwater is then pumped to a header tank located on the roof

Prior to reaching the header tank it is disinfected via the ultra violet process

The rainwater is distributed to the WCs via the header tank which incorporates the

main water back up, riser connection and overflow.

This system virtually reduces the water needed for toilet flushing as long as the

tank(s) are sized to handle the daily flushing needs. Design considerations take into

account any drought conditions during summer months, given the fact that peak usage is

during the months August through May during college semesters.

Figure 4.1.1: Concept of Rainwater collection system [Greywater Reuse and

Rainwater Harvesting]

It was found that a rainwater harvesting system designed for the NE building

would cost approximately $262,757.17 as shown in Table 4.1.1. Table 4.1.1 presents an

estimate for the costs of installing a rainwater collection system and using the water for

flushing toilets and urinals. The tanks would be located outside of the building and could

range in any size depending on area designated for storage. The total volume needed for

the rain water tank(s) would need to be 240,000 gallons based on a maximum dry season

of 1 month in this area, multiplied by days, multiplied by required amount of water

needed (5691×30 = 170,730 gallons). In this study we are using 2 tanks at the size of

90,000 gallons each. The system would pump water to a header tank located on top of

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the roof. The size of the header tank would need to be approximately 6,000 gallons based

on the daily usage requirements of 5691 Gpd. Each tank would have a Self Cleaning

Inlet Filter and a floating tank filter. The system would need to use 6” PVC pipes to

direct the rainwater from the roof downspouts to the holding tanks. There will also be 2”

PVC pipes installed from holding tanks to the Header tank and 4” PVC pipes from the

header tank to existing piping inside of the building to toilets and urinals. For practicality

of this study prices include installation and do not include unforeseen factors not

designed for and are not in the estimate. It is assumed by the group that at a minimum

the rainwater harvesting system would require the items as mentioned.

Table 4.1.1 – Rainwater Harvesting Estimate1

Rainwater Harvesting Estimate Quantity Unit $ TotalHolding Tanks 2 ea $113,783.00 $227,566.00Pipe from downspouts to holding tank 300 lf $14.50 $4,350.00Pump-2 hp, 100 gpm 1 ea $965.00 $965.00Self Cleaning Tank inlet Filter 2 ea $750.00 $1,500.00Floating tank filter 2 ea $220.00 $440.006000 Gallon Header tank 1 ea $4,611.17 $4,611.172" pipe from holding tank to header tank 50 lf $11.50 $575.004" pipe back to toilets piping 700 lf $32.50 $22,750.00 $262,757.17

1. Estimate pricing was obtained from internet searches at http://www.watertanks.com/products/0035-220.asp for the tanks and at http://stores.floridarainwaterharvesting.com/-strse-Rainwater-Harvesting-Products-cln-Filters/Categories.bok for the filters and from RS Means Building Construction Cost Data 2008 copyright 2008.

Table 4.1.2 – Rainwater Harvesting O&MActivity CostLabor Charges $80 Power Consumption by Pumps $42.34 Spare parts and Repairs $800 Total O&M Charges $922.34

The benefit of this system is the use of collected rain water instead of using

potable water for flushing toilets and urinals. The use of rainwater collection would also

slow down the amount of water entering the municipal storm water system. The only

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http://stores.floridarainwaterharvesting.com/-strse-Rainwater-Harvesting-Products-cln-Filters/Categories.bok

http://stores.floridarainwaterharvesting.com/-strse-Rainwater-Harvesting-Products-cln-Filters/Categories.bok

http://www.watertanks.com/products/0035-220.asp


disadvantage of a system such as this would be the maintenance. Depending on the life

of the equipment, location of equipment, and ease of installation would mandate the

amount of maintenance needed. It was calculated that the operation and maintenance for

a system such as this would be approximately $922.34 per year as shown in Table 4.1.2.

This was based on the need to replace and/or clean filters in the system twice a year. The

cost of operation for the system is based on a 2 Hp Pump at 100 gpm running everyday

for 80 minutes. This is equivalent to 1.5 kW per hour which is a total of 2 kWh per day

or a maximum total of 730 kWh per year. The cost for operation is then 730 kWh ×

$0.056 = $42.34 per year.

4.2 Grey Water Recycling

Grey water is the waste water resulting from the performance of various activities,

which involves using bathroom sinks, tubs, showers, laundry, kitchen sinks, dishwaters,

etc. and doesn’t involve any hazardous waste discharge or drainage from toilets and

urinals. Grey water, with proper treatment can be used for various water reuse

applications like irrigating lawns and flushing of toilets. Sunderan and Wheatley (1998)

observed that lavatories account for nearly 65% of water consumption in universities

which shows that adopting recycled grey water can decrease considerable amounts of

water consumption. The characteristics of effluent grey water coming out from the UT

can be assumed to be similar to the findings of Holden and Ward (1999) and Surendan

and Wheatley (1999) and are tabulated in Table 4.2.1.

Table 4.2.1: Effluent characteristics as observed in universities

Source BOD5 (mg/l)

COD (mg/l)

Turbidity (NTU)

NH3 (mg/l)

P (mg/l)

Total Coliforms

College 80 146 59 10 - -

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Large College 96 168 57 0.8 2.4 5.2×106

It is important to treat grey water to meet the U.S EPA guidelines of having a

BOD5 of 10mg/l, E.Coli of 1CFU/100ml, turbidity of 2NTU, pH of 6-9, and chlorine

residuals of 1mg/l before using it for toilet flushing. There are different types of grey

water treatment systems that help in meeting the required standards. Any grey water

recycling system will have the following components.

Greywater Source

Collection through plumbing

Treatment System

Storage

Greywater Reuse

Sinks act as the main source of grey water in the NE building. All of the water

coming from the sinks would be collected using a 6˝ PVC pipe and transported to the

equalization tank where the collected grey water is treated using a suitable treatment

system and then the treated effluent is pumped back to the toilets.

A review of literature helped identify the various treatment methods currently

being used for many buildings around the world. Some of the well-known grey water

recycling systems currently being used are:

1. Basic Two-Stage System.

2. Physical and Physiochemical System.

3. Biological Treatment System (MBR, BAF, RBC).

4. Constructed Wetlands (Living Machines).

5. Chemical Treatment System (MCR).

6. Green Roof Water Recycling System (GROW).

A basic two-stage system involves coarse filtration using a metal strainer and

disinfection using either chlorine or bromine applied regularly. This process was used in

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a study by March et al. (2004) where a hotel used filtration, sedimentation and

disinfection to recycle grey water for toilet flushing. This type of system however needs

to be considered only when lower treatment standards are sufficient as in some cases it

failed to maintain the coliform levels within the required standards regularly. The

physical process includes the use of sand and/or membrane filters with pre-treatment for

membrane filters while physiochemical systems work using coagulation and advanced

oxidation. This type of system imparts higher process costs due to higher energy

requirements. The application of this process for on-site greywater treatment and reuse in

multi-storeyed buildings is discussed by Friedler et al. (2005). The biological treatment

system is mainly used to remove the biodegradable material and is widely used in hotels

or places where the systems are large and the effluent is of a high quality [Merz et al.

(2007), Nolde (1999), Friedler and Hadari (2006), Atasoy et al. (2007)]. Membrane

bioreactors (MBR), biologically aerated filters (BAF), and rotary biological contractor

(RBC) are generally used to assist in biological treatment. The working of a chemical

treatment system (MCR) is similar to that of an MBR. Wetlands and green roof water

recycling systems are environmentally friendly [Memon, 2007] and also have a better

treatment efficiency as compared to other treatment systems.

The treatment system adopted for design of grey water recycling for the NE

building is a tidal wetland living machine system. This system was selected because it is

environmentally friendly, has higher treatment efficiency, and treats large quantities of

grey water. The hydraulic and organic loading rates are calculated using the equations

4.2.1, 4.2.2 and 4.2.3.

……….4.2.1

……….4.2.2

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….4.2.3

In general, hydraulic flow rates of 0.25 to 1 gal/ft2/day and 3 to 10 gal/ft2/day are

used for fixed fine media and recirculating in fine media several times while organic

loading rates may vary from 0.00025lbs BOD5/ft2/day to 0.0012 lbs BOD5/ft2/day for fine

media fixed films [The Ohio State University Report, 2007]. The OSU report, 2007 also

states that the problem of clogging can be reduced by having lower dosage of the order of

up to 3 doses per hour and helps to facilitate higher organic and hydraulic loading rates.

Figure 4.2.1 provides a layout of a living machine at Port of Portland where the

treated domestic waste water is used for toilet flushing. The group used a similar design

to be adopted by Worrell Water Technologies, LLC for treating grey water at UT. The

grey water collected from different sources is first transferred to the equalization tank

through a series of horizontal and vertical pipes. After studying the plumbing system for

NE block, it was observed that rather than completely changing the piping system

(vertical and horizontal piping), it would be economical if only a 6" PVC pipe is provided

along the circumference of NE block at level 1 to collect grey water from vertical pipes

located at different positions in the building. The primary/equalization tank helps reduce

the fluctuations in flow through wetlands where simultaneous nitrification,

denitrification, and BOD removal occur as a result of “drain and fill” operation. The

effluent from tidal wetlands is disinfected and stored in a storage tank placed on the roof

of the NE block and the reclaimed water is sent back to the toilets for flushing through

the plumbing system under the force of gravity.

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Figure 4.2.1: Concept of Living Machine System to be used at UT [21].

The design of the grey water recycling system also includes provisions for screens

along with an equalization tank, plumbing system with PVC pipes, suitable filter media

that includes gravel and sand, and reed bed plants. The calculations associated with

design flow, hydraulic & organic loading rates and energy consumption are shown

below:

Assuming that about 35 percent of the water consumed by the north engineering

building is grey water [Sunderan and Wheatley, 1998]; the design flow obtained is

274,366.4 gal/month ≈ 9,145.55 gal/day. Tidal wetlands requires about 150 ft2 for every

1000 gallons treated per day. Hence, considering 12,000 gal/day (including a margin of

safety) the area required for tidal wetlands is 1800 ft2. The hydraulic loading rate as

calculated from equation 3.2.1 is 6.67 gal/day/ft2 [12,000 Gpd/1800 sq.ft] that is good to

maintain medium hydraulic rate for recirculation. Considering the effluent BOD to be

a maximum of 10mg/l according to U.S norms and tidal wetland treatment efficiency

the organic loading rate calculated using equations 4.2.2 and 4.2.3 is 0.00055 lbs

BOD5/ft2/day which is also good as it is within the limits of 0.00025lbs BOD5/ft2/day to

0.0012 lbs BOD5/ft2/day. The designed system treats all of the grey water coming from

NE building and any excess water can be diverted to maintaining lawns and grass areas at

Carter field.

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The components/activities and costs associated with construction and O&M for

the designed tidal wetland living machine can be observed in Table 4.2.2 and table 4.2.3

respectively. (Refer to Appendix-A for detailed calculations).

Table 4.2.2: Estimated Costs for Construction of Grey Water

Components CostPiping $1,101.60Equalization Tank $11,108.12Living Machine $650,000Disinfection System $244,000Pumps $965Storage Tanks $ 4,939.04Additional Charges $39,172.34Total Construction Charges $950,321.10

Table 4.2.3: Annual Costs for Operation and Maintenance of Grey Water

Activity CostLabor Charges $1,040Power Consumption by Living Machines $205Power Consumption by pump to lift water to storage tank $4038.94Spare parts and Repairs $5,222.98

Total O&M Charges$10,506.92

4.3 Composting Toilets

Composting toilets are one of the most direct ways to avoid pollution and

conserve water and resources. Composting toilets can be waterless or consume a

minimum amount of flushing water, thereby reducing the water consumption rate. The

working principle of composting toilet is that human waste is converted into an organic

compost and usable soil by microorganisms that help in natural breakdown to essential

nutrients. Typically, the waste breaks down to 10% of its original volume [Del Porto and

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Steinfield, 1998]. The resulting end product is a stable soil like material called humus,

which can be either buried or used as a soil conditioner.

The research group took into consideration the following factors when deciding

on the type of composting toilet system needed for the NE building: local regulation,

performance, lifestyle consideration, and installation constraints. Commercially used

composting toilets are of two types, manufactured composting toilet systems and site-

built composting toilet systems. Due to lack of precise performance data for site-built

systems or lack of guarantee by any standard organization, the design chosen would need

to be an approved NSF International manufactured composting toilet system.

The proposed system will have adequate ability to safely manage the excrement

for the amount of people who will use the system. There are a total of 46 toilets in NE

building. Assuming the average number of people in NE block being 2,370 (refer to

Appendix-A for a list of assumptions made) with their usage of toilet at 1.5 times per

person per day, number of times the toilets are used daily = 2,370 × 1.5 = 3,555 times.

Average no. of times toilets are being used daily = 3,555 / 46 = 77.28.

The capacity of a composting toilet is mainly related with the amount of

excrement, and not confined by the amount of urine. It is also assumed that the frequency

of defecating and urinating are in equal portion. In this case the actual daily use for each

toilet is nearly half cut. However, a margin of safety needs to be adopted to ensure that

the system is capable of handling any increase in the number of people at NE.

Composting toilet systems come either as self-contained system or central system.

A central system is preferable over self-contained system due to its advantages for ease in

construction and maintenance. The important aspect of a composting toilet system

installation is the location of the composting tank and air ventilation systems. Systems

with simple ventilation and a compact composting tank are preferable. With respect to

the above mentioned factors, the group chose to use the Clivus Multrum M18 model

manufactured by Clivus Multrum, Inc. This system has a capacity of 120 uses per day

and is applicable for public facilities. The advantages of this model are convenient

installation, long-term retention and infrequent handling of the end-product. An example

of the Clivus Multrum M18 model is shown in Fig 4.3.1.

Page 23 of 47


Figure 4.3.1 - Clivus Multrum M18 [Clivus Spec Sheets]

Figure 4.3.2 shows a schematic diagram of the composting toilet system layout.

One can see that both the toilets in the first floor and the second floor share a single

composting tank towards the west part of the NE building. The proposed changes are

using foam flushing toilets in the second floor due to the convenience in setting up the

drain line, while using waterless toilets in the first floor as it can be connected to the

composting tank with a 14" straight chute for the standard model. The two restrooms on

floor 1 towards the eastern part of the building are also modified using foam flushing

toilets and collecting excrement in one composting tank for each restroom. Details of

replacements for existing toilets can be seen in Table 4.3.1.

Figure 4.3.2 – Schematic of composting system [Clivus Multrum, Inc.]

Page 24 of 47


Table 4.3.1 – Proposed Composting System for NE

Room Type of toilet Number of toilets Number of composting tank(s)

1262 Foam flushing 3 11260 Foam flushing 3 11014 Waterless 5 52013 Foam flushing 51015 Waterless 3 32014 Foam flushing 31057 Waterless 3 32053 Foam flushing 31058 Waterless 5 52056 Foam flushing 5

It is recommended that about 30 foam flushing toilets, 16 waterless toilets and 20

sets of composting tanks be installed in NE building. Adopting these recommendations

would reduce the water usage by toilets in NE as much as 72.3% with an investment of

$105,180 for construction purpose while the maintenance and operating phase accounted

for $5,268. (Refer Appendix-A for detailed calculations). About 115 gallons of water will

be used for the composting system and 2223 gallons for sinks after adopting composting

toilets. So the daily water savings is 7914 – 115 – 2223 = 5576 gallons.

5. Results

The existing restroom facilities water consumption and the amount of waste water

effluent are summarized in Figure 5.1.1. This graph shows the required potable water

needed in the restrooms in gallons per day and the amount of waste water effluent in

gallons per day for existing conditions and the proposed conditions with rainwater (RW)

harvesting, grey water (GW) recycling, or composting toilets installed in the building.

Based on these conditions one can easily see that a modification to the existing system

using one of the proposed systems has significant results in the amount of water needed

on a daily basis. The following LCA and indicator results describe more detail on the

benefits for these systems.

Page 25 of 47


Figure 5.1: Water use Consumption and Waste Water Effluent

5.1 LCA Results

The research group chose to use Mining and Utilities as the industry group list

with the industry sector #221300: Water, sewage and other systems to run the EIOLCA.

Figures 5.1.1 and 5.1.2 presents the variation of ‘construction’ and ‘O&M’ phases of life

cycle across impact categories of greenhouse gases and energy. It was observed that the

grey water recycling had significant environmental impacts as compared to rain water

harvesting and composting toilets and also is the leading energy consumer among the

three. The group also checked the cost of construction per quantity of water saved per day

for each system to account for the possibility of having higher environmental impacts and

energy for varying quantity of water treated by the three systems. The current scenario

suggests that composting toilets is the best sustainable alternative that can be adopted at

the north engineering building at UT.

Page 26 of 47


Figure 5.1.1: Greenhouse gases for “Construction” and “O&M” Stages of a Life

Cycle

Figure 5.1.2: Energy for “Construction” and “O&M” Stages of a Life Cycle

5.2 Indicator Analysis Results

Page 27 of 47


5.2.1 Environmental Pollution Indicator

Environmental indicators for each system shown previously in the LCA certainly

have different impacts. Utilizing the EIO-LCA for pollution reduction as it pertains to

water consumption; one can see the effect that water use reduction has on pollution.

Because the information obtained was an average month basis for costs and amount of

water used, this study assumed an average water use per day of 2,888,610 gallons per

year at a cost of $15,480.

The need for potable water use for toilet flushing would be the same for rainwater

harvesting and grey water recycling with 811,950 gallons per year at a cost of $4,348. If

using composting of toilets then the need for potable water would be 853,370 gallons

with a cost of $4,608. The environmental impact from the water savings is shown in

Table 5.2.1. and compares the LCA pollution amounts from the initial conditions with the

proposed conditions. Gallons used per year were used for use of the LCA data as the

gallons per day the units were too small to compare.

Tables 5.2.1 – Water Consumption Analysis from EIO-LCA

Conventional Air Pollutants

Water Consumption

Cost/year SO2 CO Nox VOC LEADPM 10

$ mt mt mt mt mt MtPre - Design RW & GW $15,480 0.020 0.034 0.016 0.059 0 0.002Post - Design $4,348 0.006 0.009 0.005 0.017 0 0Composting $4,608 0.006 0.010 0.005 0.018 0 0

Green House Gases

Water Consumption

Cost GWP CO2 CH4 N20 CFC

$MTCO2

EMTCO2

EMTCO2

EMTCO2

EMTCO2

EPre - Design RW & GW $15,480 121 10.9 72.2 37.8 0.106Post - Design $4,348 34 3.07 20.3 10.6 0.030Composting $4,608 36 3.25 21.5 11.3 0.032

Page 28 of 47


5.2.2 Natural Resource Consumption Indicator

We consider the amount of water saved as a benchmark for the natural resource

consumption indicator. The quantity of water consumed on an average daily basis used

by toilets in NE building is 7914 gallon (refer Appendix-A), of which 5691 gallons are

used for flushing toilets and urinals while 2223 gallons are used for sinks. Figure 5.2.2.1

shows that the daily savings in water consumption on adopting rainwater harvesting,

greywater recycling and composting toilets are 5691 gal/day, 12000 gal/day and 5676

gal/day respectively. It can be observed that adoption of proposed greywater recycling

reduces the water consumption usage by NE buildings to as much as 45.92% (12000

Gpd×100/26130 Gpd) while rainwater harvesting and composting toilets reduce water

consumption by 21.77% (5691 Gpd×100/26130 Gpd) and 21.72% (5576 Gpd×100/26130

Gpd). Comparing the quantity of water saved by each system per day, greywater

recycling is considered to be the most efficient in potable water savings.

Figure 5.2.2.1: Average daily water savings (gal/day) for different systems

Page 29 of 47


5.2.3 Economic Indicator

Figure 5.2.3.1 shows the comparison of three systems adopted from an

economical point of view. We considered the summation of cost of construction

and one years operation and maintenance charges to compare the economical

choice of investment. Figure 5.2.3.1 presented below shows that the order of

economical choice would be adopting the composting toilets followed by rain

water harvesting and greywater recycling. Since greywater recycling saved more

amount of water as compared to rainwater harvesting and composting toilets, the

group also compared the cost per gallon of water saved per day and similar

observations were made with regard to economical choice as illustrated in Figure

5.2.3.2.

Figure 5.2.3.1: Economical Choice Comparison based on Cost of Construction

and O&M

Page 30 of 47


Fiigure 5.2.3.2: Economical Choice based on Cost/gal of water saved/day

Payback period is calculated based on the annual water savings to regain the cost

of investment.

Cost of water from monthly utility bill = $0.0054/gal

Annual amount saved by using these three techniques = (Water Cost × Water savings/day

× 365 days)

Annual amount saved using rainwater harvesting, greywater recycling and composting

toilets are ($0.0054/gal × 5691 gal/day × 365days) $11,216.91, ($0.0054/gal × 12000

gal/day × 365days) $23,652, and ($0.0054/gal × 5576 gal/day × 365days) $10,990.30

Payback period is calculated using the equation given below.

Hence, payback periods for rainewater harvesting, greywater recycling and composting

toilets are ($262,800/$11,216.91) 23.42 years, ($950,321.10/$23,652) 40.18 years, and

($105,180/$10,990.30) 9.5 years respectively. Since composting toilets have less

Page 31 of 47


investment cost and quicker payback period, it is better to adopt composting toilets from

an economic perspective followed by rainwater harvesting and then greywater recycling.

6. Sustainability Index and Performance Percentage

The sustainable scores, sustainability index and performance percentage achieved

based on the points of comparison are tabulated in table 6.1.

Table 6.1: Sustainability Index and Performance Percentage Values

S.No Points of Comparison Rainwater Harvesting

Greywater Recycling

Composting Toilets

1Economical choice of cost of construction per gallon of water saved per day

2 1 3

2. Quantity of water saved per day 2 3 1

3. Environmental Pollution 2 1 3

Maximum Achievable Score 9 9 9

Sustainable Score Achieved 2+2+2 = 6 1+3+1 = 5 3+1+3 = 7

Sustainability Index 66.67 55.55 77.78

Performance Percentage 12 15 21

7. LEED Credits

Considering the reduction in water consumption based on toilet usage all three

systems are capable of obtaining a credit for WE 3.1. Greywater recycling, rainwater

harvesting and composting toilets would reduce the potable water usage by 21.77%,

21.77% and 21.72% respectively. This study only took into account the restroom

facilities and to achieve the LEED credits through water efficiency one would need to

Page 32 of 47


consider the building as a whole. Using a combination of systems, fixtures and other

criteria one would be able to obtain further credits.

8. Conclusion

The life cycle assessment and sustainability index values showed that the

composting toilet system is the most sustainable alternative recommended for water

conservation with respect to toilets in NE. However, there might be differences in

person’s perspective during design part that could change the choice of the systems. This

study did not take into account for complete life cycles of all materials and systems that

could have resulted in different selection. Even thought the rain water harvesting and

grey water recycling, for this study, only took into account the benefits of using the water

for flushing of toilets and urinals; the systems could also benefit the University in the use

of irrigation, diverting storm water, and possible laboratory uses. The use of composting

toilets in the NE building would benefit not only on the costs of water consumption but

would also benefit the environment by reducing greenhouse gases and energy required

for their existing systems. Greywater Recycling can be adopted by the university only on

a long term scale as the university produces significant amounts of grey water daily

(nearly 35% of total water consumed based on a study by Sunderan) that can reduce

potable water needs in other areas also where it is not required. Rain water harvesting can

also be used similarly but the source of supply to this system is dependent on rainfall and

seasons.

Page 33 of 47


9. References

1. Agriclean technology Report, 2006. Available at

http://www.cals.ncsu.edu/waste_mgt/smithfield_projects/phase3report06/pdfs/

B.1.pdf, accessed November 22,2008.

2. Atasoy, E. et al. 2007. Membrane bioreactor (MBR) Treatment of Segregated

Household Wastewater for Reuse, Clean 2007, 35, 465 – 472.

3. BC greenbuilding code. Background Research - Greywater Recycling, October

2007. <http://www.housing.gov.bc.ca/building/green/Lighthouse%20Research

%20on%20Greywater%20Recycling%20Oct%2022%2007%20_2_.pdf>

4. Carnegie Mellon University Green Design Institute. (2008) Economic Input-

Output Life Cycle Assessment (EIO-LCA), US 1997 Industry Benchmark model

[Internet], Available from:<http://www.eiolca.net> Accessed 22 November, 2008.

5. C. K. Choi Building for the Institute of Asian Research

6. Clivus Multrum. Inc, Available at

http://www.clivusmultrum.com/products_basic.shtml, accessed on November 22,

2008.

7. Clivus Spec Sheets, Available at http://www.thenaturalhome.com/clivusm10.htm,

accessed on November 22, 2008.

8. Del Porto, D., Steinfeld, C. 1998. The Composting Toilet System Book. p15.

9. Environmental Sanitation, S.A. Esrey, U. Winblad et. al. 1999 SIDA. Sweden.

10. FEMP “Domestic Water Conservation Technologies.” 18 Mar. 2008 accessed at

<http://www1.eere.energy.gov/femp/pdfs/22799.pdf>.

11. Friedler, E., and Hadari, M. 2006. Economic feasibility of on-site grey water

reuse in multi storey buildings. Desalination, 190, 221-234.

12. Holden, B., & Ward, M. 1999. An overview of domestic and commercial re-use

of water. Presented at the IQPC conference on water recycling and effluent reuse,

16 December, Copthorne Effingham Park, London, UK.

Page 34 of 47

http://www.thenaturalhome.com/clivusm10.htm

http://www.clivusmultrum.com/products_basic.shtml

http://www.housing.gov.bc.ca/building/green/Lighthouse%20Research%20on%20Greywater%20Recycling%20Oct%2022%2007%20_2_.pdf

http://www.housing.gov.bc.ca/building/green/Lighthouse%20Research%20on%20Greywater%20Recycling%20Oct%2022%2007%20_2_.pdf

http://www.cals.ncsu.edu/waste_mgt/smithfield_projects/phase3report06/pdfs/B.1.pdf

http://www.cals.ncsu.edu/waste_mgt/smithfield_projects/phase3report06/pdfs/B.1.pdf


13. Joseph Jenkins, Humanure Compost Toilet System

Instruction Manual, 2006.

14. Lazarova, V., Hills, S., Birks, R. 2003. Using recycled water for non-potable,

urban uses: a review with particular reference to toilet flushing, Water Science

and Technology: Water Supply, 3, 69–77.

15. Living Machines Presentation, Available at http://www.edc-cu.org/ppt/Living

%20Machines.pdf, accessed November 22, 2008.

16. March, J.G. et al. 2004. Experiences on greywater re-use for toilet flushing in a

hotel, Desalination, 164, 241-247.

17. Memon, F. A. et al., 2007. Life Cycle Impact Assessment of Greywater Recycling

Technologies for New Developments, Environ Monit Assess, 129, 27–35.

18. Merz, C., Scheumann, R., El Hamouri, B., Kraume, M. Membrane bioreactor

technology for the treatment of greywater from a sports and leisure club,

Desalination, 2007, 215, 37-43.

19. Mikkelsen P.S., Adeler O.F. “Collected Rainfall as a water source in Danish

Households – What is the potential and what are the costs.” Water Science Tech.

Vol. 39 NO. 5, pp 49-56, 1999.

20. Nolde, E. 1999. Greywater reuse systems for toilet flushing in multi-storey

buildings – Over ten years experience in Berlin, Urban Water, 1, 275-284.

21. NEW FREIGHT RATES HIT STEEL TRADE, Special to The New York Times.

Jun 2, 2008, Sunday Section: Editorial, Page 30.

22. Port of Portland Case Study. Available at

http://www.livingmachines.com/docs/port_of_portland_case_study_final.pdf,

accessed November 22, 2008.

23. Sunderan, S., and Wheatley, A.D. 1998. Grey-Water Reclamation for Non-

Potable Re-Use, J.CIWEM, 12, 406-413.

24. The Ohio State University Report, 2007. Available at http://ohioline.osu.edu/aex-

fact/pdf/0756.pdf, accessed November 22, 2008.

25. United States Plastic Corporation (USPC), Available at

http://www.usplastic.com/catalog/product.asp?

Page 35 of 47

http://www.usplastic.com/catalog/product.asp?catalog_name=USPlastic&category_name=13669&product_id=16587

http://ohioline.osu.edu/aex-fact/pdf/0756.pdf

http://ohioline.osu.edu/aex-fact/pdf/0756.pdf

http://www.livingmachines.com/docs/port_of_portland_case_study_final.pdf

http://www.edc-cu.org/ppt/Living%20Machines.pdf

http://www.edc-cu.org/ppt/Living%20Machines.pdf


catalog_name=USPlastic&category_name=13669&product_id=16587, accessed

November 22, 2008.

26. Waskom, R. Colorado State University Extension water resources “Graywater

Reuse and Rainwater Harvesting.” Colorado State University. 15 Feb. 2008

accessed at <http://www.ext.colostate.edu/pubs/natres/06702.html>.

Page 36 of 47

http://www.ext.colostate.edu/pubs/natres/06702.html

http://www.usplastic.com/catalog/product.asp?catalog_name=USPlastic&category_name=13669&product_id=16587


Appendix A

Design Calculations and Cost Estimations

Page 37 of 47


Calculations for Total Water Usage by Toilets and Urinals

Men

Toilets = 1778 people x .75 uses/day x 1.6 gal/use = 2134 gal/day

Urinal = 1778 people x .75 uses/day x 1.6 gal/use = 2134 gal/day

Sink = 2370 people x 1.5 uses/day x ½ gal/use = 1778 gal/day

Women

Toilets = 593 people x 1.5 uses/day x 1.6 gal/use = 1423 gal/day

Sink = 593 people x 1.5 uses/day x ½ gal/use = 445 gal/day

Total = 7914 gallons / day

Also given in section 4

Rain Water Harvesting Design Calculations and Cost Estimations

Rainwater Harvesting Estimate Quantity Unit $ Total

Holding Tanks 2 ea $113,783.00 $227,566.00Pipe from downspouts to holding tank 300 lf $14.50 $4,350.00

Pump 1 ea $965.00 $965.00Self Cleaning Tank inlet Filter 2 ea $750.00 $1,500.00

Floating tank filter 2 ea $220.00 $440.008000 Gallon Header tank 1 ea $4,611.17 $4,611.17

2" pipe from holding tank to header tank 50 lf $11.50 $575.004" pipe back to toilets piping 700 lf $32.50 $22,750.00

$262,757.17

Use d $262,800.00

Page 38 of 47


Grey Water Design Calculations and Cost Estimations

1. Estimating costs from purchases:

a. Construction Charges

Equalization Tank:

Total average daily flow = 12,000 gallons per day.

Total average hourly flow = 500 gallons per hour.

Since there is no data monitoring system available at UT, a worst case scenario of 1400

gal/hr is assumed as flow rate and an equalization tank is designed for this flow rate

assuming a retention time of 4 hrs.

Equalization tank Size = Flow × Retention Time

= 1400 gallons/hour × 4 hours = 5600 gallons.

The cost estimate for construction of this equalization tank is assumed to be similar to

that provided by Agriclean Technology Report (2006), where the equalization tank was

designed for 6000 gallons

Hence, cost of equalization tank (includes a tank, pump and control panel) = $11,108.12

Piping Cost

Direct purchase of 6"PVC pipes from United States Plastic Corporation (USPC) for a

circumference of 68 ft = $1,101.60

Living Machine Costing:

Since, Ohio has a cold climate the estimated cost of building a living machine with green

house is considered to be approximately $650,000 ($1,077,777 for 40,000 GPD as stated

in Living Machines Presentation).

Storage Tank Costing

Page 39 of 47


The storage tank is designed to meet the requirements of toilets and the excess water is

diverted to be used for watering Carter field which the maintenance department identified

as one of the major water consuming area at UT.

Total water used by toilets at NE block in UT = (2134+2134+1423) GPD = 5691 GPD.

Hence, required size of storage tank for toilet utilities ≈ 7800 gallons.

Cost of a 7800 gallon heavy duty vertical poly storage tank as observed in WaterTanks =

$ 4,939.04

Disinfection Unit:

Cost of UV disinfection unit based on EPA’s Waste Water Technology Factsheet =

244,000 (Capital Cost) + 19,190 (O&M) = $263,190

Additional Expenses:

Some miscellaneous charges of about 15% of the (Total Cost-Cost of Living Machine)

are incorporated to facilitate purchase of valves, fittings, etc.

Additional Expenses = 0.15×261,148.76 = $39,172.34

Hence,

Total Construction Cost

= 11,108.12 + 1,101.60 + 650,000 + 4,939.04 + 244,000 + 39, 172.34

= $950,321.1

b. Operation and Maintenance Charges:

Labour Charges:

A labour charge of $20/hr is taken to facilitate maintenance as used by Friedler and

Hadari (2006).

Page 40 of 47


Annual Labour charge = 20 ×52 = $1,040

Power Consumption by Living machines:

The energy consumed for running a living machine is 0.5 kWh/1000 gal/day.

Hence the average daily energy consumption for living machine = 0.5 kWh/1000 gal/day

× 12,000 gal/day = 6 kWh.

At 5.6 cents per kWh, Annual cost to treat 12,000 GPD = 6 ×5.6 × 365/100

= $122.64

Power Consumption by Pump:

Assuming a pump that uses 2hp, 100gpm

Time required to transfer 7800 gallons = 7800/100 = 78 min = 1.3hr

Power used = 1.3 × (2 × 76) × 5.6 ×365/100 = $4,038.94

Spare parts and Repairs:

These are calculated using 2%of total investment excluding living machine and

additional expenses = 0.02×261,148.76 = $5,222.98

Page 41 of 47


Composting Toilets Design Calculations and Cost Estimations

Calculation of Water Consumption After Replacements:

Waterless toilet: No water is needed for flushing.

Foam flushing toilet: 3 oz. of clean water each flush

Moistening system: 3 gallons clean water per day

Total water consumption: 3 × 20 +3 × 30 × 77.28 × 0.0078= 114.25 gallon/ day

Yearly water consumption of toilets is 41,702 gallons. Adding water used for sinks,

yearly water consumption is: 41702 + 2223 × 365 = 853,097 gallons at the cost of

$4,265. That is 72.3% reduction compared with $15,397 cost for 2,849,040 gallons of

water for the existing toilet system.

Calculation of Energy Consumption After Replacements:

Ventilation: 93 W

Automatic moistening system: 10 W (spray time is preset, and approximately half time

working)

Liquid removal pump: 575 W

Total energy consumption of the composting toilet system in NE: 13,460 W

Yearly energy consumption is 13460 × 10-3 × 24 × 365 = 17,909.6 kWh

According to Average Retail Price of Electricity to Ultimate Customers by End-Use

Sector from energy information administration of official energy statistics from the US

government, the retail electricity price in Toledo is 5.6 cents per kWh. Yearly electricity

cost of the proposed system is $1,003.

Cost of Clivus Multrum M18:

Considering the cost per set to be at $ 4,995, cost for 20 sets = $ 4,995 × 20 = $99,900

Page 42 of 47


Cost of Pipeline

diameter materialLength

(ft)

Price per

unit ($)

Total

($)

air ventilation duct 4’’ PVC 720 5.50 3960

drain line from foam flushing

toilet to composting tank4’’ PVC 240 5.50 1320

Total = $5,280

The total cost for construction is $105,180. The yearly operation cost of composting toilet

system is $2,024.

Page 43 of 47


Appendix B

EIOLCA Results

Page 44 of 47


LCA - Using EIOLCA Website

Water Use Consumption


Water Consumptio

n Cost SO2 CO Nox VOC LEADPM 10

$ mt mt mt mt mt mtPre - Design RW & GW $51,600.00 0.034 0.116 0.034 0.023 0 0.008Post - Design $11,072 0.003 0.01 0.01 0.003 0.002 0Composting $6,403 0.002 0.008 0.008 0.002 0.001 0

Green House Gases

Water Consumptio

n Cost GWP CO2 CH4 N20 CFC

$MTCO2

EMTCO2

EMTCO2

EMTCO2

EMTCO2

EPre - Design RW & GW $51,600.00 14.8 12.5 1.74 0.235 0.237Post - Design $11,072 6.2 4.4 3.74 0.035 0.07Composting $6,403 1.24 1.05 0.146 0.02 0.02


Manufacturing/Const.

Cost SO2 CO Nox VOCLEAD

PM 10

$ mt mt mt mt mt mtRainwater Harvesting

$262,800.00

0.346

0.571

0.275

0.996 0

0.034

Greywater Recycling $950,321 1.25 2.06

0.995 3.6 0

0.122

Composting $95,190

0.122

0.476

0.114

0.109 0

0.024

Green House Gases


CostGWP CO2 CH4 N20 CFC

Page 45 of 47


$MTCO2E

MTCO2E

MTCO2E

MTCO2E

MTCO2E

Rainwater Harvesting

$262,800.00

2060 186

1230 642 1.8

Greywater Recycling $950,321

7430 671

4430

2320 6.51

Composting $95,190

58.56

48.59

5.906

2.553

1.493

Energy


CostTotal elec coal

natural gas LPG

MOTO GAS

DISTILATE

KERO

JET FUEL

RESIDUAL

$ TJMkWh TJ TJ TJ TJ TJ TJ TJ TJ


$262,800.00 2.98

0.126

0.559 1.22

0.132

0.107

0.747 0

0.04

0.033

Greywater Recycling $950,321 10.8

0.457 2.02 4.41

0.478

0.388 2.7 0

0.144

0.119

Composting $95,190

0.767

0.037

0.178

0.372

0.043

0.033

0.061 0

0.016

0.022


Operation & Maint. Cost SO2 CO Nox VOC LEAD

PM 10

$ mt mt mt mt mt mtRainwater Harvesting

$922.34

0.001

0.002

0.001

0.003 0 0

Greywater Recycling

$10,506.00

0.014

0.023

0.011 0.04 0

0.001

Composting$10,6

71 0.569

0.058 0.27

0.009 0

0.014

Green House Gases

Operation & Maint. Cost GWP CO2 CH4 N20 CFC

Page 46 of 47


$MTCO2E

MTCO2E

MTCO2E

MTCO2E

MTCO2E


$922.34 7.21

0.651 4.3 2.25

0.006

Greywater Recycling

$10,506.00 82.2 7.42 49 25.7

0.072

Composting$10,6

71 110 105 3.950.053 1.29

Energy

Operation & Maint. Cost Total elec coal

natural gas LPG

MOTO GAS

DISTILATE

KERO

JET FUEL

RESIDUAL

$ TJMkWh TJ TJ TJ TJ TJ TJ TJ TJ


$922.34 0.01 0

0.002

0.004 0 0 0.003 0 0 0

Greywater Recycling

$10,506.00

0.119

0.005

0.022

0.049

0.005

0.004 0.03 0

0.002 0.001

Composting$10,6

71 1.270.002 0.98

0.237

0.002

0.002 0.01 0

0.001 0.039

Table for Figure 5.1.1

Rainwater Harvesting Greywater Recycling Composting ToiletsConstruction Costs ($) 262800 950321.1 105180Construction GHG (MTCO2E) 2060 7200 823O&M (MTCO2E) 7.21 82.2 41.2O&M Costs ($) 922.34 10506.92 5268

Table for Figure 5.1.2

Rainwater Harvesting Greywater Recycling Composting ToiletsConstruction 262800 950321.1 105180Construction 2.98 10.8 1.19O&M 0.011 0.119 0.06O&M 922.34 10506.92 5268

$

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Documents

Water Efficiency and Sustainability - University of Toledo · Web viewIdentification of the Most Sustainable Alternative System to be used for Toilets in North Engineering Building