IWC 13‐37

Recovering Valuable Byproducts from 

Oil and Gas Wastes 

Russell Huffmyer 

Heckmann Water Resources 

Coraopolis, PA 

John Van Gehuchten 

HDR Engineering Inc. 

Pittsburgh, PA 

 
IWC 13‐37

Keywords: Shale Gas, Hydro fracturing, Crude Oil, Hydrocarbons, Drilling Mud, Drilling 

Fluids, Oil and Gas wastes. 

ABSTRACT 

An oft-neglected component of wastes generated during drilling and completion of oil and gas 

wells in shale plays are the drilling fluids, drilling wastes, and assorted liquids that are captured 

and require disposition. These streams contain substantial amounts of suspended solids and 

contamination from the formation being accessed, as well as potential valuable recoverable 

components such as crude oil and other valuable hydrocarbons. Treatment is required for 

these streams prior to either reuse or deep well disposal. In addition, significant revenue can be 

generated by recovering the valuable byproducts. 

 
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INTRODUCTION 

The act of drilling oil and gas wells, 

conventionally or for hydro-fracturing 

requires the use of water based and/or 

hydrocarbon based drilling mud. These 

materials are typically defined as drilling 

fluids. This material lubricates drilling 

operations, cools the drill head, and 

transports drill cuttings to the surface. 

Various products are combined in precise 

quantities in order to optimize the drilling 

operation. This drilling mud is then recycled 

as much as possible before being hauled to 

disposal. 

In the process of drilling the well, or during 

well completions, the treatment or disposal 

of wasted drilling mud and flow-back water 

is required. While some components of the 

flow-back water and drilling mud must be 

disposed of, there is a significant financial 

and environmental benefit to isolating some 

of the more valuable mud and wastewater 

components for sale and reuse. 

DRILLING FLUID COMPOSITION 

The drilling fluid chemistry is created 

specifically for each drilling operation. Not 

only is the chemistry specific to each drill 

operation, but it is changed during the 

operation due to bore hole depth and/or 

observed conditions. There are three 

primary classifications to these fluids; waterbased, oil-based, and synthetic-based 

(Rehm, 2012). 

Water-based mud (WBM): At its most 

basic, water-based mud system begins with 

water followed by the incorporation of clays 

and other chemicals to create a 

homogenous blend resembling something 

between chocolate milk and a malt 

(depending on viscosity). The clay (called 

"shale" in its rock form) is usually a 

combination of native clays that are 

suspended in the fluid while drilling or 

specific types of clay that are processed 

and sold as additives for the WBM system. 

The most common of these is bentonite, 

frequently referred to in the oilfield as "gel". 

Gel likely makes reference to the fact that 

while the fluid is being pumped, it can be 

very thin and free-flowing (like chocolate 

milk). However when pumping is stopped 

the static fluid builds a "gel" structure that 

resists flow. Sufficient pumping force is 

applied to "break the gel" and resume flow. 

At this point the fluid returns to its previously 

free-flowing state. Many other chemicals 

(e.g. potassium formate) are added to a 

WBM system to achieve various effects. 

These include controlling viscosity, 

improving shale stability, enhancing drill rate 

of penetration, and cooling and lubricating 

equipment. Water-based fluids are 

considered the most environmentally and 

operator friendly (Rehm, 2012). In offshore 

locations these fluids are typically 

discharged after solids removal. 

Oil-based mud (OBM): Oil-based mud can 

be a mud where the base fluid is a 

petroleum product such as diesel fuel. Oilbased muds are used for many reasons, 

some being increased lubricity, enhanced 

shale inhibition, greater cleaning abilities, 

and reduced fluid viscosity. Oil-based muds 

also withstand greater heat without breaking 

down. Oil based fluids drill a cleaner hole 

that than water based fluids as well as 

creating less sloughing and a smaller 

volume of drill cuttings (Rehm, 2012). 
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Synthetic-based fluid or mud (SBM): 

Synthetic-based fluid is a material where the 

base fluid is a syntheticsynthetic oil. 

Synthetic based oils include vegetable 

esters, olefins, ethers, and other similar type 

products. These products are used much in 

the same way as oil-based fluids in the use 

of weighing agents. Synthetic-based fluids 

also cut cleaner holes with all the same 

benefits of oil based fluids. However 

synthetic based muds can be more 

expensive (Rehm, 2012). 

Universal Additives: Drilling fluids can 

contain some form of biocides, surfactants, 

de-foamers, corrosion inhibitors, scale 

inhibitors, polymers, and clays. The 

reclaimed drilling fluids also contain 

inorganic, organic, dissolved and 

suspended material that is picked up from 

the formation during the drilling operation 

(Rehm, 2012). 

WELL HEAD DRILLING FLUID 

TREATMENT 

Due to the volume of drilling fluids required 

it is most economical to reuse drilling fluids 

to the greatest extent possible. Drilling fluid 

treatment focuses on the four primary 

components of recovered drilling fluid. 

Those being drill cuttings, drilling mud, 

water, and hydro-carbons (oils) (Pharis 

1991). 

Most drilling operations include a drill rig 

“backyard” setup that includes facilities to 

reclaim the drilling mud. 

Figure 1 – Backyard Drill Rig Process Flow 

Diagram 

The first step in treating drilling fluids at the 

rig is to run the fluid recovered from the hole 

through a vibrating screen known as a 

shaker screen or shale shaker. This screen 

separates most drill cuttings, which are then 

stored for disposal or to be treated for 

reuse. 

Photograph 1 – Backyard Drill Rig 

The fluid passing through the screen can 

still contains a large amountslarge amounts

of solids. This fluid is typically run through 

one or more hydro-cyclones or centrifuges 

for additional solids removal. The higher 

solids fraction or the mud from the 

equipment is then sent to the source tank or 

pit to create the reclaimed drilling fluid 

(Pharis 1991). 

The amount to which drilling mud is reused 

is limited. As the clay solids are passed 

through the hydro-cyclone the particles are 

sheared into smaller particles. When the 
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clay particle size shrinks then the amount of 

chemicals required increases due to the 

larger surface area of the aggregate 

particles (see Table 1). This means that 

mud must be wasted at such a rate to 

maintain a satisfactory large particle 

distribution, observed by chemical usage, in 

the drilling fluid. Wasted drilling mud is then 

stored for offsite treatment and/or disposal 

(Pharis 1991). 

 Mud 

entering 

system 

Mud 

returning 

to system 

Solids 

Content % 

6.0 4.0 

Avg Particle 

Size (μm) 

50 10 

Surface Area 

(acre/bbl) 

5 16 

Table 1 - Particle Size of Drilling Mud 

(Pharis, 1991) 

The clean water from the hydro-cyclones or 

centrifuges is either recycled in the drilling 

operation or stored for treatment and/or 

reuse offsite. It should be noted that clean 

drilling fluid water is significantly different in 

characteristics from flowback or produced 

water that is generated from oil/gas well 

development and oftentimes reused during 

hydraulic fracturing. The drilling fluid is 

typically lower in volume and dissolved 

solids, but higher in suspended solids and 

drilling chemicals (Pharis 1991). 

Oils and other hydrocarbons in the water 

following the shaker screen are removed by 

a skimmer or in an oil/water separator. 

These oils can be of good quality for 

immediate reuse or may become emulsified 

with the water and solids. Emulsified oils 

must be treated, typically offsite, before they 

can be reused. 

 

Photograph 2 – Emulsified Oil 

DRILL CUTTINGS TREATMENT 

Treatment of drilling fluids during drilling at 

the rig location is based on optimizing 

usage of drilling fluid for the creation of the 

borehole and minimizing the need to 

transport waste materials. The waste 

cuttings removed by the shaker screens 

require treatment before the materials are of 

a suitable quality for disposal in a landfill of 

for their reuse. In addition, there is typically 

a “high suspended solids” wastewater 

volume that can be treated for reuse. 

Drill cuttings can be reclaimed with proper 

treatment. If hydro-carbons such as diesel 

are used during drill operations then the drill 

cuttings can be blended with coal and burnt 

for energy recovery. Alternately the drill 

cuttings can be heated in an anoxic 

environment which vaporizes the hydrocarbons removing them from the drill 

cuttings. One such system manufactured by 

Thermtech is a thermo-mechanical cuttings 

cleaner (TCC), The TCC is based on the 

basic principle of thermal separation. The oil 

based mud (OBM) cuttings are heated to a 
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temperature sufficiently high to evaporate 

the oil (and water) from the mineral solids. 

By heating the waste to a temperature 

higher than the evaporation point of the 

base oil in the OBM. The oil and water will 

be condensed back to liquids in later 

process steps. A common name for such 

technologies is “thermal desorption” 

technologies (Therma-Flite 2013). 

There are different ways of heating the 

waste. In a TCC the heat is created by 

friction as opposite to indirect heating. 

The TCC is based on a completely different 

principle than the indirect thermal 

technologies. The TCC converts kinetic 

energy to thermal energy by creating friction 

in the waste. A drive unit sets a series of 

shaft mounted hammer arms in motion 

inside a barrel shaped process chamber 

(also referred to as the hammermill or just 

the mill). The solid particles are forced 

towards the inner wall of the process 

chamber where the kinetic energy from the 

rotating arms will be transformed to heat by 

friction. The unit can run continuously, 

automatically controlled by an advanced 

Programmable Logic Controller (PLC) 

system. Frictional heat is constantly created 

by the hammering and motions (ThermaFlite 2013). 

The liquids evaporate and leave the 

chamber, new waste is pumped in, and 

solids are discharged through a cell valve. 

The hottest spot in the process is the waste 

itself. The base oil is under influence of 

high temperature for maximum a few 

seconds. The oil is re-used by mud 

companies as a component in new OBM 

(Therma-Flite 2013). 

Compared to other thermal desorption 

technologies most of the TCC benefits are 

related to the way the TCC is heating the 

waste (Therma-Flite 2013). 

An alternative thermal desorption 

technology is the Therma-Flite Holo-Scru® 

thermal desorption systems which volatilize 

and recover 99.5% of hydrocarbons from 

drilling mud. Holo-Scru® processes can 

accept feed stock with hydrocarbon 

percentages greater than 70%, effectively 

collecting and condensing water, diesel and 

other hydrocarbon vapors. In applications 

such as natural gas drilling where diesel 

and water constitute the liquid phase diesel 

is typically filtered and then resold or reused 

as a lubricant for future drilling (ThermaFlite 2013). 

Therma-Flite units in operation in the U.S. 

process drill cuttings from shale drilling. 

This feed stock is generally 10% to 30% 

diesel, and 20% water. Recovery rates for 

diesel typically range from 97% to 99.5% 

(Therma-Flite 2013). 

The standard Therma-Flite system includes 

a feed screw with loading trough, or for 

applications when feed storage is required, 

a feed hopper with integrated live bottom. 

For low viscosity drill cuttings containing 

diesel and water a positive displacement 

pump is used to feed the unit. Feed stock is 

discharged from the feed screw into a 

double knife-gate airlock. The airlock cycles 

to allow feed to enter the airlock chamber 

while maintaining a seal to the desorption 

chamber. For added safety the airlock 

includes optional fittings for a nitrogen or 

CO2 purge which can be used to insure any 

air remaining in the airlock is displaced prior 

to the airlock cycling, and discharging the 

feedstock into the desorption chamber 

(Therma-Flite 2013). 
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The heart of the system, the desorption unit, 

includes intermeshed Holo-Scru® rotors. In 

this chamber feed stock is heated under a 

slight negative pressure in a sealed, anoxic 

environment. Heating in this system is 

indirect. Thermal fluid is circulated 

throughout the Holo-Scru® rotors and outer 

jacket of the desorption chamber. The 

proprietary Holo-Scru® dual rotor design is 

self-clearing and feed stock which might 

otherwise bake on to the rotors and is easily 

removed. Different mixing programs may 

be set in the PLC which will increase the 

heat transfer into the feed stock (ThermaFlite 2013). 

A variety of heat transfer fluids may be used 

to heat product up to 850-degrees 

Fahrenheit. A second stage system can be 

incorporate to heat the product to above 

1,200-degrees Fahrenheit. Most feed stocks 

may be de-volatilized to less than 0.05% 

remaining hydrocarbons. As the heated 

solids exit the desorption chamber they 

pass through a second airlock and into a 

cooling screw conveyor. In the cooling 

screw solids are indirectly cooled by 

circulating water through the jacketed wall 

of the screw. The temperature is further 

reduced by direct-contact quench cooling 

via atomizing sprays along the top of the 

cooling screw housing. The vapors exit the 

unit into a Venturi-effect, multi-stage 

condenser. Cooled and filtered condensate 

is used as the condensing fluid. The 

Venturi-effect condenser is highly-efficient 

with less than 0.01% hydrocarbons 

remaining in the non-condensable stream. 

The non-condensable stream is released 

through a duct to the air intake on the diesel 

generator providing power. The drill 

cuttings after these processes are clean and 

can be disposed of or reused. Typical 

reuse applications can be in asphalt or 

concrete aggregate or for road base 

construction (Therma-Flite 2013). 

Photograph 3 – Thermal Treatment System 

(Image courtesy Therma-Flite 2013) 

DRILLING MUD TREATMENT 

The waste drilling mud and other highsuspended solids wastewater must be 

treated for the removal of the large amount 

of suspended solids. The treatment 

process typically begins with chemical 

addition of an oxidant to break down any 

surfactants or de-foamers which would 

negatively impact the downstream treatment 

process. The pH is then adjusted to 

optimize coagulation and solids removal. 

Coagulants used can be iron, aluminum, or 

carbonate based. Carbonate based 

coagulants can serve a dual purpose of 

adsorbing oils and other hydro-carbons from 

the drilling mud. 

The removed solids at this point are usually 

of sufficient concentration that they can be 

dewatered in a filter press, centrifuge, or 

similar treatment process. The filtrate from 

dewatering operations can then be sent to a 
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treatment facility that handles drilling fluid 

water. While the mud solids can be 

disposed of in a landfill they can also be 

reused in various applications. Favorable 

data has shown that drilling mud could be 

used to line landfills, be land farmed, or 

mixed with organic mater to aid in wetland 

restoration. However regulatory approval 

for some of these options is still an obstacle 

(Stewart 2012). 

DRILLING WASTWATER TREATMENT 

Wastewater from drilling operations 

undergoes a similar chemical treatment 

regiment as mud processing. Oxidants, pH 

adjustment, and coagulants are added in a 

staged series of treatment vessels. 

Biocides may need to be added as well. 

Gravity separation can then be used to 

remove solids. A skimmer on the gravity 

separation process can serve to remove 

any oils in the wastewater. Alternatively a 

dissolved air floatation (DAF) process can 

be used instead of gravity separation. Since 

the oils and solids will be combined in the 

solids from the DAF it will not be possible to 

reuse any oil. 

Following gravity or DAF solids removal the 

wastewater is filtered either through sand, 

mixed media, or bag filters. The filtered 

water can then be re-used for drilling water 

makeup or for hydro-fracturing. 

Oil treatment is only typically necessary if 

the oil recovered from drilling operations 

has become emulsified. Emulsion breaking 

is typically done in a batch process where 

acid is added to the rag oil before it is 

heated. This breaks the hydro-carbons and 

oil from water and solids. The oil and 

hydro-carbons can then be skimmed off for 

reuse. The solids-laden wastewater is then 

sent to the head of the wastewater 

treatment process, typical of that described 

above, for treatment and reuse. 

EXAMPLE TREATMENT FACILITY AND 

DATA 

The Marcellus shale region has led the 

industry in treating and reusing water and 

wastes generated during the drilling, 

completion, and production phases of well 

development. One commercial facility has 

been operating in Masontown PA, since 

2010, servicing the industry within a 150 

mile radius. When customers determine 

that their water or wastes cannot be reused 

on the well location they transport the 

drilling wastes, flowback water and 

production water to the plant via vacuum 

tanker trucks. Plant personnel pre-screen 

the incoming material for various 

contaminants prior to entry into the system 

to determine if the material can be 

adequately treated, and if so, the 

appropriate treatment regime. 

Typical contaminant levels are provided 

below for the incoming waste water. As can 

be seen from the data, the influent waters to 

be treated are extremely variable, which 

poses operational challenges in treatment. 

Parameter Influent Range (mg/L) 

Calcium 150 - 7,000 

Strontium 10 - 1,500 

Sulfate 0 - 1,500 

Barium 25 - 2,000 

TSS 200 - 2,000 

TDS 3,000 – 80,0000 

Table 2 – Typical Influent Wastewater 

Characteristics 
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The plant has a hydraulic capacity of 1 

MGD. The facility consists of chemical mix 

tanks, clarifiers, oil skimming, finished water 

storage, sludge preparation tank, and 

sludge dewatering equipment. The 

incoming material is fed into one of three 

chemical mixing tanks where its pH is 

adjusted with sulfuric acid, hydrochloric acid 

or sodium hydroxide to be near neutral. 

The treatment process for most 

wastewaters into the system begins with 

adding potassium permanganate in the mix 

tanks oxidize metals to a higher valence 

state and to increase the ORP to create an 

oxidizing environment. Produced water, 

containing barium, may be added to the 

other wastewater stream so that barium 

sulfate can be precipitated in the clarifiers. 

After the mix tanks the wastewater is 

pumped to a primary clarifier for settling of 

heavier solids. Coagulant aid and emulsion 

polymer is added to assist in proper settling. 

The effluent from the clarifier is then 

pumped into a second mixing tank where 

soda ash is added. This will help precipitate 

calcium and remove it from the return water. 

The wastewater then flows by gravity to a 

secondary clarifier where emulsion 

polymers are added to aid in the removal of 

additional solids. 

Effluent from the secondary clarifier flows by 

gravity through a trough that is quiescent 

enough to allow oil and other hydrocarbons 

to float to the surface and be skimmed off 

using a belt skimmer. In the hotter summer 

months, bleach may be added at this point 

to prevent biological growth. If required, 

the pH may be adjusted following the 

removal of oil. The trough flows into a 

finished water tank, where it is temporarily 

stored prior to sale. 

Settled solids from each of the two clarifiers 

are pumped to a sludge storage tank. This 

sludge is then pumped through a plate and 

frame filter press which produces a solid 

cake. This cake passes the paint filter test 

prior to disposal at an approved landfill. 

The primary contaminants removed in the 

process are sulfate, iron, barium, calcium, 

strontium and various other suspended 

solids. Oil is recovered from the clarifiers 

and skimming trough it is transported for 

reuse at other wells. Currently additional 

facilities are being added to enhance the 

removal and recovery of natural gas liquids 

from the water generated from the 

Marcellus gas production. 

Waste 

Material 

Recovery 

Process 

Recyclable 

Product 

Drill Cuttings Shaker, 

Thermal 

recovery 

Fill material 

Drilling Mud Oxidation, 

Precipitation, 

centrifugation 

Brine, Mud 

reuse 

Drilling Oil Skimming/ 

Thermal 

Diesel, drill 

oil 

Table 3 – Material Recycling Summary 
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Pharis, B; West, G (1991). Dewatering cuts drilling mud and disposal costs, The Oil and Gas 

Journal, 89.39, 84. 

Rehm, B; Haghshenas, A; Paknejad, A; Al-Yami, A; Hughes, J; Schubert, J (2012). 

Underbalanced Drilling - Limits and Extremes, Gulf Publishing Company, 198-230. 

Ball, S; Stewart, R; Schliephake, K (2012). A review of the current options for the treatment and 

safe disposal of drill cuttings, Waste Management and Research, 30[5], 457-473. 

Marie-Pierre, C; Craig, B; Menzies, L; Menzies, T (2007). Assessment of two thermally treated 

drill mud wastes for landfill contaminant application, Waste Management Res, 25, 394-

401. 

Wang, F; Zou, J; Zhu, H; Han, K; Fan, J (2010). Preparation of High Effective Flocculant for 

High Density Drilling Mud, Journal of Environmental Protection, 1, 179-182. 

Bråtveit, M; Steinsvåg, K; Atle Lie, S; Moen, B (2009). Modeling of Oil Mist and Oil Vapor 

Concentration in the Shale Shaker Area on Offshore Drilling Installations, Journal of 

Occupational and Environmental Hygiene, 6, 679-686. 

Jixiang, G; Yongjie, C; Jingjing, C (2013). Treatment of drilling wastewater from a sulfonated 

mud system, China University of Petroleum (Beijing) and Springer-Verlag Berlin 

Heidelberg, 10, 106-111. 

Therma-Flite Indirect Thermal Desorption System (2013). Therma-Flite, Inc. Retrieved from 

http://www.therma-flite.com/literature.php, Therma-Flite 53012.pdf, publication TFIDTDS 053012.