NOT Final Senior Design Project

Utilization of Biosolids:
Soil Fertilization & Energy Production
Devon Beesley, Patrick Cusack, Parker Raymond & Graham Walker
Clemson University, Clemson, SC - November 19, 2019

● Introduction
○ Background
○ Rationale
○ Objectives
○ Approaches
● Literature review
● Materials and methods
● Results
○ Land application
○ Gasification
● Take home messages
● Acknowledgements
Outline

Introduction
● Human waste will always be produced
● Typical treatment processes
○ Primary treatment: solid separation by sedimentation and
filtration
○ Secondary treatment: reduction of BOD by microorganisms
○ Tertiary treatment: removal of excess pollutants and nutrients
● Main products
○ Treated water
○ Biosolids
● Definitions
○ Sewage sludge: pre-treated solid waste
○ Biosolids: post-treated solid waste
Sewage Treatment Plants

Clemson University WWTP
Introduction

Clemson University WWTP
● Biosolids
○ Exit secondary digester as 2-3% solid
○ Exit dewatering press at 18% solid
○ Sent to the Anderson County landfill
(Subtitle-D, Class III)
● Historical masses produced
○ 2017: 745.08 tons
○ 2018: 871.49 tons
○ 2019: 646.98 tons (as of 9/13/19)
● Future
○ Amount produced is projected to
increase in the coming years, as the
university plans to increase enrollment
and open the new College of Business
Aerial View of Clemson University Wastewater Treatment
Plant
Introduction

Biosolids
● Beneficial components
○ Organic compounds (C)
○ Macronutrients
○ Micronutrients (B, Cu, Fe, Mn, Mo, Zn)
● Negative components
○ Praestol Polymer
○ Excess nutrients (C, N, P)
○ Heavy metals (As, Cd, Cu, Pb, Hg, Mo, Ni, Se, Zn)
○ Endocrine disruptors (e.g., androgens, estrogens)
○ Pathogens (e.g., E. coli, C. jejuni, V. cholerae)
○ Pesticides (e.g., organophosphates, organochlorines)
○ Toxic organic compounds
○ Detergents
○ Salts
○ Polyfluoroalkyl Substances (PFAs)
● Potential Uses
○ Land application
○ Gasification
○ Incineration
○ Composting
○ Landfill
Introduction
Biosolids

Polymer
Introduction
● PraestolTM K 274 FLX FLOCCULANT
○ Created by Solenis
○ Harmful to aquatic life with
long lasting effects
○ Cannot be inhaled
○ Should not be allowed to
enter drains, water courses or
soil

Rationale
The CU WWTP currently produces more than 700 tons of dewatered biosolids per year.
Unfortunately, these nutrient-dense materials are currently being sent to the Anderson
county landfill. Alternative uses of the biosolids produced from the CU WWTP must be
developed to make Clemson University more environmentally, economically, and
socially sustainable.
Introduction

Objective
The objective of this project is to design a viable pathway to utilize all of the biosolids
coming from the Clemson University wastewater treatment facility.
Introduction

Approaches
Task 1. To review information regarding land application, gasification and the related regulations
Task 2. To determine fecal coliform concentrations by sampling the biosolids produced at the CU WWTP
Task 3. To reduce the fecal coliform concentration with a process to significantly reduce pathogens (PSRP)
Task 4. To use an environmentally friendly starch based polymer
Task 5. To determine land(s) on which biosolids can be applied, type(s) of vegetation grown on that land,
and area of that land
Task 6. To calculate the volume of biosolids that will be applied to the land(s).
Task 7. To design a gasification process for Clemson University for energy utilization.
Task 8. To model gasification of biosolids with SuperPro.
Task 9. To perform a cost analysis of land application and gasification
Introduction

Introduction
Sustainability
Capstone
Design
LawsResearch
Education

Literature Review
Carbon Cycle Hydrolysis
Complex organic C→
C6H12O6
Aerobic respiration
C6H12O6 + O2→CO2
Carbon fixation
CO2→ C6H12O6
Carbon assimilation
C6H12O6→ complex organic
C
Anaerobic respiration
C6H12O6 + NO3- →CO2
Fermentation
C H O → reduced

Literature Review
Microbial Nitrogen Cycle
Nitrogen fixation
N2→ NH3 / NH4
+
Nitrification
NH4
+ → NO3
-
Assimilative reduction
NO3
- → NH4
+
Denitrification
Glucose + NO3
- → N2 + CO2
Hydrolysis (ammonification, mineralization)
Organic N → NH4
+ / NH3
Nitrogen assimilation
Amino acids → protein → cell
mass
NH4
+ → C5H7O2N

Literature Review
Phosphorus Cycle
Mineralization
Organic P→ PO4 3-
Assimilation
PO43- → Organic P

Literature
Review
Elemental Cycles
● Naturally each cycle is a closed
loop system
○ Elements recycled efficiently
● Landfilling causes process to
operate as an open loop system
○ Prevents the elements from
recycling efficiently

Literature Review: Land Application

Permitting
● National Pollutant Discharge Elimination System (NPDES) permit
○ Required for wastewater treatment facilities
○ Basic requirements
■ Topographical map of wastewater treatment plant
■ Population of humans who contribute to the wastewater
■ Facility’s design maximum flow
■ Process flow diagram
■ Location and flow rate of effluent wastewater

Permitting
● SC Department of Health and Environmental Control (SCDHEC) permit
○ Required to land apply biosolids in South Carolina
○ Requirements
■ Qualitative
● Continuous or intermittent application
● Location of application size
■ Quantitative
● Biosolid concentrations of Kjeldahl N, inorganic N, ammonia N, P and K
● Biosolid pollutant concentrations: As, Cd, Cu, Pb, Hg, Mo, Ni, Se, Zn
● Effluent pH, temperature, cyanide concentration, total phenols, residual chlorine, oil & grease
concentrations, and fecal coliform levels
● Average daily volume (gpd) applied to site
● Area of the application site
● Design TSS removal (percent)
● 5-day BOD test

Regulations
● Maximum allowable heavy metal concentrations for land applied biosolids

Regulations
● Regulation 61-9: Water Pollution Control Limits
○ Biosolids cannot be applied to land…
■ If likely negatively affect threatened/endangered species under section 4 of Endangered Species Act
■ If runoff into a wetland or other waters of SC
■ Within 10 meters of a body of water of SC
■ At a rate larger than agronomic rate for the biosolids (for agricultural fields)

● Part 503 of the Clean Water Act (CWA)
● Pathogens
○ Classification of biosolids: Class A or Class B
■ Class A: contain pathogen concentrations below detectable limits
■ Class B: contain maximum of 1-2 million MPN per 4 gram per dry weight, or 100 mL per wet
weight basis, of fecal coliforms
● Pathogen concentration must be reduced before land application
○ Processes to significantly reduce pathogens (PSRPs)
■ Aerobic digestion, anaerobic digestion, air drying, composting, lime
stabilization
○ Processes to further reduce pathogens (PFRPs)
■ Composting, heat drying, heat treatment, thermophilic aerobic digestion,
beta ray irradiation, gamma ray irradiation, pasteurization
Regulations

Regulations
● Indicator species according to Part 503 of CWA
Fecal coliforms (ex. E. coli) Salmonella sp.
Enteric viruses (ex. Poliovirus sp.) Viable helminth ova (ex. Ascaris lumbricoides)

● 40 CFR Part 503 of CWA
● Vectors: organisms or objects that transfer pathogens
○ Required to accomplish one of ten options mentioned in Part 503 to
achieve vector attraction reduction (VAR)
○ Preventative strategies
■ Reduce mass of volatile solids by a minimum of 38%
■ Additional anaerobic or aerobic digestion in a bench-scale unit
■ Meet specific oxygen uptake rate for aerobically treated biosolids
■ Use aerobic processes at greater than 40℃ for 14 days or longer
■ Add alkaline materials to raise the pH under specified conditions
■ Reduce moisture content of biosolids with unstabilized solids to at
least 90%
Regulations

Additional Constraints
● No regulations to control the application of these compounds
○ Pharmaceuticals
○ Hormone disruptors
○ Microplastics
○ PFAS
○ Patented polymer flocculant
● Site restrictions
○ Animals can not be grazed on the land until 30 days after land application
○ Humans cannot access site for 30 days

Literature Review: Gasification

● Input
○ Biomass
○ Air
● Outputs
○ Producer gas
○ Ash and high temp biochar
○ Impurities
● Processes
○ Drying
○ Pyrolysis
○ Combustion/Cracking
○ Reduction
● Partial combustion
Process Overview

Process Overview

Reduction

● Updraft gasification
○ Counter-current flow
○ Low particulate content of outgoing gas
● Downdraft gasification
○ Co-current flow
○ Possibly carbon negative
● Fluidized gasification
○ Higher fuel throughput than fixed bed
but less than entrained flow
○ Fuel must be highly reactive
● Entrained flow gasification
○ Fuel slurry
○ More slag and no tars in gas production
Types of Gasification

Feedstocks
Wood chips
Coke
Biosolids Pellets
CoalSlurry

● Outlet Gas
○ Fine particulates
○ Aromatics
○ Nitrogen gas & carbon dioxide
○ Combustible gases
■ Carbon monoxide, hydrogen
gas, methane, ethane,
ethene, propane, propene
○ High CO and N2 content
Products
● Solids
○ Char
○ Biochar
○ Activated carbon
○ Ash
● Impurities
○ Tars
○ Sulfur and nitrogen
compounds
○ Hydrogen halides
○ Trace metals

Solid Production
● Biochar (High Heat)
○ Low porosity
■ Crystalline structure
■ Stores carbon if
added to soil
● Ash
○ Created from high heat
○ Powder form
○ C, H, O, and N completely
removed
○ Minerals remain
■ Na, Ca, K, e.g.

● Easy and cost effective
● Energy dense and consistent compounds
● Pretreatment
○ Select Feedstock
○ Filtrate
○ Store
○ Dry to 10-15% water content
○ Crush to consistency
● Pelletization
○ Die and roller compress
○ Lignin and resins act as binding agent
○ Binding agent addition
● Post treatment
○ Cooled and stored
Pelletization

● Systems that produce electricity
○ Internal combustion engines
■ Cars and other motor vehicles
○ Diesel engines
■ Two stage combustion with
Hydrogen gas
○ Dual fuel mode
■ Hybrid vehicles
○ Combined heat and power systems
■ Gasification
■ Gas turbines
Energy Production

Dewatering & Drying of Biosolids

● Environmental Impact
○ Friendly
Starch Polymer
Materials and Methods

Solar Dryer form Huber
Materials and Methods
● Greenhouse set up
● Utilizes solar heat
● Dimensions: 40ft by 60ft

Overview
Materials
● Biosolid storage tanks
● Simpson farm pasturelands
● Terragator or other equipment capable of spreading
● Dryer (add specific name)
● Starch based polymer
Methods
● Determine acceptable lands based on SC DHEC regulations
● Take soil samples of land to determine nutrient concentrations
● Calculate acceptable biosolid volume to be land applied based on
nutrient concentrations in the soil & biosolids, size of land, and
agronomic rate of crop
● Heat the biosolids to ____ ℃ for ____ days
Materials and Methods: Land
Application

Options for PSRP/PFRP
Application
● Lime stabilization
○ Class B
○ Con: socially unsustainable because it adds a smell
● Anaerobic Digestion
○ Class B
○ Con: reverting to a previous process
■ Revision of entire system would be required
● Drying
○ Class A
○ Con: energy intensive

Gasification of Biosolids
for Energy Production

● Clemson University Pelletizer
○ California Pellet Mill CL Type 3
○ Creates cylindrical pellets
■ Length is 2.5 times the diameter
○ Produces 30-200 pounds of pellets per hour
○ Energy input
■ 3-phase
■ 60 Hz
■ 230-460 volt current
Clemson University Pelletizer
Materials and Methods: Gasification

● All Power Labs
● PP20 Power Pallet
○ Feedstock holding tank
■ Feedstock is 15-30% moisture on dry basis
○ Pyrolysis chamber
○ Combustion, cracking, and reduction zone
○ Ash collector
○ Cyclone (fine particles)
○ Filter (tar gases)
○ Internal combustion engine
○ Generator
○ Automatization of system
● Produces 1 kWh from 1.2 kg feedstocks
Clemson University Gasifier

Governing Equations
We don’t use two of
these equations

Design Equations
● mG= mass of pellet before gasification
● mp= mass of solid before pelletization
● mb= mass of biosolids
● mwc= mass of woodchips
● mwater= mass of water
● ⍴T= total density
● ⍴water= density of water
● ⍴wc= density of woodchips

Results
Process
Flow
Diagram
Update PFD to include
the other considerations
for PSRP/PFRPs

Results: Land Application
Initial Testing Monitoring
Microbes
Update the decision
making process to have
two different processes
instead of a sequential
single process

Fecal Coliform Tests
● Two replicates of biosolid samples
Dewatered Sludge
Secondary Sludge
Primary Sludge
Fecal Coliform (MPN/g dry wt)
Primary Digester 597,000,000
Secondary Digester 1,720,000
Dewatered Sludge 10,600,000
● Do not meet Class B classification
○ 10.6 million MPN > 0.5 million MPN

Soil Sampling Area
Application
Simpson Farm
Pendleton, SC
Lot 29 (fertilizer)
Lot 23 (no fertilizer)

Soil Testing
Soil
pH
P
(lbs/A)
K
(lbs/A)
Ca
(lbs/A)
Mg
(lbs/A)
Zn
(lbs/A)
Mn
(lbs/A)
Cu
(lbs/A)
B
(lbs/A)
Na
(lbs/A)
NO3-N
(lbs/A)
Lot 23
(no
fertilizer)
5.76 3.67 302 920 279 3.50 32 0.467 0.60 10 1.67
Lot 29
(fertilizer) 5.98 24.6 125 1454 373 5.31 39.8 1.68 0.456 16.4 32.9

Step 2: Dryer and Pelletizer

Drying System
● Incoming biosolids at 872 tons of 18% dry weight
● Solar dryer used a combination of convection, conduction, and radiation to heat
○ Greenhouse effect allows for heat to be retained
○ Dries the solids from 18% to 65% dry weight
● Conventional dryer then uses electrical energy to produce heat
○ Dries the solids from 65% to 95% dry weight
● Products
○ 165 tons of solids
○ 706 tons of water
Take into account water
recycled from press.
Entering Water
Mass (Tons)
Retained Water
Mass (Tons)
Lost Water
Mass (Tons)
Press 7848.00 715.04 7132.96
Solar Dryer 715.04 84.52 630.52
Conventional
Dryer 84.52 8.26 76.26

Model: Dryer
Change screenshot

Pelletizer
● Inputs based on 2018 numbers
○ Solids: 165 tons with 10% lignin content
○ Wood chips: 83 tons with 25% lignin content
● Product
○ Pellets with density of 651 kg/m3 with 15% lignin content and 83% solid
Put in the results of the
wood chips

Model: Pelletizer
Place composition of
wood chips and
biosolids. Change
screenshot.

Applying Biosolids

Storage Tank
Calculations for storage tank dimensions
● Amount of biosolids produced in 2018 = 1,742,980 lb
● Density of biosolids = 45.01 lb/ft3
● Volume of biosolids produced per year
Choose mass of biosolids produced = 1,000,000 lbs
V = m / ρ
V = (1,000,000 lbs) / (45.01 lb/ft3)
V = 22,217.29 ft3
● Storage tank dimensions
Choose radius = 25 ft
V = π * r2 * h
22,217.29 ft3 = π * (25 ft)2 * h
h = 11.32 ft
V = 23,561.9 ft3
r = 25 ft
h = 12 ft
Tank
Aerial view of CU WWTP
Need to revise
these calculations

Calculation for amount of biosolids land applied
● 103.65 acres of rotational cropping further than 10 m of body of water)
● Biosolids application (app.) rate on hay: 2-5 dry tons of biosolids/acre
Rate of Application
(103.65 acres) / (4 rotational fields) = 25.9 acres/field
Acreage Biosolids application
rate (dry tons/acre)
Number of
applications per year
Tons of biosolids
25.9 7.5 1 194.25
25.9 12.5 1 323.75
25.9 31 1 802.90
25.9 3.5 3 90.65
1,411.55

Take Home Messages
Pros & Cons of Land Application
● Pros
○ Addition of organic matter
○ Increase in macro and microporosity
■ Increases infiltration rate
■ Increases water holding capacity
■ Decreases rate of runoff
○ Addition of vital nutrients
■ Phosphorus
■ Nitrogen
● Cons
○ Nutrients could leach into groundwater or
runoff into bodies of water after extreme
weather events
○ Addition of pharmaceuticals, hormones,
and microplastics into soil

Gasification Flow model
Results: Gasification

Gasifier
● Feedstock
○ Density of feedstock: 651 kg/m3
○ Volume of feedstock: 345 m3
● Batches
○ Volume of vessel: 0.33 m3
○ Number of batches: 1046 cycles
○ Batches per day: 3 cycles/day
● Recycling waste
○ Solar dryer
■ Water vapor inlet to pyrolysis chamber
○ Heat to secondary dryer
■ High moisture content fuel
○ Electricity to power dryer and pelletizer

Gasifier
This is not the final
screenshot for this

Model: Gasifier
Change the screenshot

Gasification: Engine
● Incoming producer gases: TABLE
○ 10.5% H2 with enthalpy of combustion 141,584 kJ/kg
○ 8.7% CO with enthalpy of combustion 10,100 kJ/kg
○ 1.6% CH4 with enthalpy of combustion 55,514 kJ/kg
○ 0.7% C2H4 with enthalpy of combustion 50,285 kJ/kg
○ 0.2% C2H6. with enthalpy of combustion 51,895 kJ/kg
Include Screenshot for
this and the generator?

Gasification: Generator
● Energy is produced 187,000 kWh TABLE
○ H2 39.33 kWh/kg
○ CO 2.81 kWh/kg
○ CH4 15.42 kWh/kg
○ C2H4 13.97 kWh/kg
○ C2H6. 14.42 kWh/kg
● Enough energy for 14 houses in South Carolina a
year
If we can get $0.08 for 1
kWh, then its 11,490
money dollars

Take Home Messages
Pros & Cons of Gasification
● Pros
○ Contributes to a closed loop system
■ A carbon negative process
○ Successfully turns a waste material into
an energy source
■ 187,000 kWh
■ Creates a clean gas
■ Create electricity from an item
currently discarded
○ Production of high heat biochar
■ Soil remediation
● PFAS reduction
■ Carbon storage
○ Production of ash
● Cons
○ Increased workload
■ Biochar, ash, additional personnel
○ Production of impurities
■ Tar gas
○ High levels of waste heat
■ Thermodynamically unfavorable
○ Inconsistent biosolids flow
■ Unable to utilize all biosolids at peak flow
● Would need to use additional
processes
○ Regulations and handling
■ EPA Emissions permitting
■ Record keeping
■ OSHA worker health safety

● Cost
○ Solar dryer capital cost
○ Solar dryer operating cost
○ Conventional dryer capital cost
○ Conventional dryer operating cost
○ 2 paid operators
○ Gasification operating cost
○ Pelletizer operating cost
○ Mixing before pelletization
operating cost
Results
Economic Analysis
● Money Gained
○ $11,490 from gasifier
○ $20,000 for no more landfill
● Money payback time
Make this look pretty
and finish numbers
Estimate the costs of the drying
system if the company does not
respond

Take Home Messages
Recommendation
● Replace current polymer for starch polymer
● Look at the system from an overall perspective
What do we put here?
Do we even have a
recomendation?

Sustainability
Capstone
Design
LawsResearch
Education
● Reduces landfill space
● Produces electricity
● Produces natural fertilizers
pharmaceuticals
microplastics
hormone
disruptors
governmental
regulations
presentation
● Humans excrete waste
● Proper disposal and
treatment of human
wastewater is necessary
for public and
environmental health
● Gasification
● Land application
● Pelletization
Take Home Messages

● Clemson University
● Dr. Christophe Darnault, Associate Professor
● Ms. Jazmine Taylor, Lecturer
● Dr. Tom O. Owino, Associate Professor
● Dr. Caye Drapcho, Associate Professor
● Tony Putnam, Clemson University Executive Director of Utility Services and Energy Management
● Matthew Garrison, Clemson University Waste Treatment Superintendent
● Harry Kirby, Clemson University Environmental ComplianceEngineer
● David “Buddy” Haines, Project Assistant and Composting Operations Manager
● Billy Bolger, Project Engineer
● Holly Elmore, CEO and Founder of Elemental Impact
● Doris Wilson, Chief Operator of City of ClemsonWWTP on Cochran Rd.
● Russell A. Hardy, CF, Forest Manager at Clemson Experimental Forest
● Garland M. Veasey, Director Research Farm Service, USDA NIFA Screener
● Matthew J. Fisher, Manager, Simpson Station
● Wayne King, ERTH Products CEO, Advisory Board Member of Elemental Impact, & former President of the U.S. Composting Council
● Kathy Kellogg Johnson, Kellogg Garden Products Chair and Chief Sustainability Officer
● Dr. Thomas Dodd, Exam Development Engineer & previous Senior Application Engineer
● Dr. Terry Walker, Professor
● Dr. Rui Xiao, Lecturer
Acknowledgments

NOT Final Senior Design Project

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to NOT Final Senior Design Project

Similar to NOT Final Senior Design Project (20)

Recently uploaded

Recently uploaded (20)

NOT Final Senior Design Project

Editor's Notes