Andrew Choie
WRIT 340
Why Don’t I See My Poo in the Ocean? Because Your Poo is Not Sanitary.
Bodily waste is an inevitable part of life. Unfortunately, people today take proper
disposal of waste for granted. Because human waste is not compatible with the environment, to
lessen the inevitable contact, proper disposal and treatment is necessary. Treatment plants and
modern procedures were thus established to provide a solution. Although modern processes are
continuing to be developed with new discoveries, current procedures include filtration and
chemical treatment of wastewater. Los Angeles is one prime example of a city incorporating
modern wastewater treatment processes.
Updated Sanitation Means Safer Living
Wastewater treatment has been a necessary advancement in the urban society. History
has shown diseases and viruses to cause epidemics originating from mishandled human and
animal excretion. Previous common practices lacked sanitation regulations and mainly
consisted of dumping waste into the streets or nearby bodies of water [1]. Enhancement
through innovative sewer systems and wastewater treatment plants helped improve the messy
sanitation situation. While the function of sewers – the transporting of waste – may be simple,
treatment of wastewater consists of a progression of steps that separate solids from liquids to
rid both effluents of harmful elements so they can seamlessly be released back into the
environment. While most treated wastewater is dumped into the ocean, some of it is reclaimed
and reused to provide irrigation and fertilization.
A History of Cleaning Up
The excretion of human waste has been constant throughout history, but the process of
disposing of it has changed drastically. The earliest forms of discarding human waste included
allowing the earth to directly consume it, throwing refuse into the streets, dumping the waste
at a designated spot, and transporting the waste to bodies of water. These unsanitary practices
infected drinking water sources, ultimately causing epidemics and diseases. But these barbaric
methods were replaced with more sanitary solutions developed through the innovation of
various civilizations. The Greeks and Romans, two thriving empires that studied human health
extensively, took steps in advancing technologies to dispose of waste. By 300 B.C. the Greeks
had passed a law prohibiting the dumping of refuse in the streets and delegated responsibilities
of removing waste from the streets. The Romans, like the Greeks, also recognized the direct
correlation between clean water and public health. They expanded water resources through
resourceful aqueducts and built open and underground sewers by 300 A.D. These advances,
however, still did not treat the problem; they merely transported waste from the city to rivers
[1], [2].
Wastewater treatment practices began developing in the 19th century. For example, in
1860, Louis Moureas invented the septic tank – a large tank that removed solid waste before
discarding the remaining water. Various filters were also developed and tested, but not widely
used [1]. Eventually sewage treatment became a necessary weapon in the battle against
wastewater. Along with sewers, innovative treatment plants were constructed to further clean
the wastewater before discharging it into open waters.
The Present Process of Wastewater Treatment: In the Ideal Location of Los Angeles
Los Angeles is located next to the ocean, prime real estate for dumping treated
wastewater. There are two main groups who manage the wastewater treatment systems in Los
Angeles County. These are the Sanitation Districts and the sewerage system run by the City of
Los Angeles. Within the Sanitation Districts are eleven valuable wastewater treatment plants
that serve twenty three districts of about five and a half million people. Within the Los Angeles
sewerage system are four important treatment and water reclamation plants that provide for
over four million people [3]. Both agencies clean and manage unclean wastewater to be
recycled or dumped through various steps, as shown in Figure 1.
Figure 1 – The general process of
wastewater treatment.
http://www.biosolids.com.au/whatare-biosolids.php
Modern methods of revolutionary wastewater treatment start with transporting waste
through underground sewers. There must be a driving force in order to move waste through
them, and in Los Angeles, sewers were cleverly built in valleys to maximize the use of gravity
and minimize the expensive costs of pumping. Diameters of these sewers range from five to
twelve feet and accumulate waste from a vast network of six thousand five hundred miles of
sewage systems. Although sewers require cleaning and inspections, the average life of sewers is
only about fifty years, due to the corrosive nature of wastewater. They are not perfect in
solving the dilemma. One major problem is an atrocious odor – caused by hydrogen sulfide, a
chemical byproduct of bacteria [4].
Primary treatment begins once the wastewater reaches the treatment plant as various
objects are filtered out. The effortless process takes place as these solid particles sink to the
bottom and lighter substances, such as plastic and grease, float to the top of the flowing
wastewater. This separation allows for an easy filtration of removing the top and bottom sludge
while leaving the remaining wastewater to move on to the crucial secondary treatment. What is
left of the remaining wastewater is dissolved and suspended substances that are mostly organic
[5].
The mixture then moves into the revolutionary secondary treatment. The secondary
treatment is a ground-breaking biological treatment that deals with microorganisms. These
naturally occurring microorganisms and bacteria are not filtered out by the primary treatment
and consume the leftover dissolved organic materials. The consumption of organic materials is
complemented by the addition of oxygen, which helps decompose the organic matter. In most
world-wide cases, oxygen is added simply through the atmosphere with open tanks, but in such
land-restricted cases like Los Angeles, the process requires concentrated oxygen to be pumped
into closed containers, so that minimal oxygen is wasted. To supply adequate oxygen, a
cryogenic air separation facility that liquefies and provides oxygen is used. Sometimes pure
oxygen is used through a High Purity Oxygen Process, which helps maximize the quantity of
treated wastewater while minimizing the plant’s square footage. The general chemical process
taking place in these amazing containers can be simply shown as: Organic Matter + O₂ → H₂O +
CO₂, which shows how oxygen helps decompose the organic matter. After the bacteria and
microorganisms consume the organic materials, they settle at the bottom of the remarkable
tanks to be recycled back into the innovative treatment process as activated sludge – another
term for wastewater containing microorganisms or “any solid, semisolid, or liquid waste that
settles to the bottom of sedimentation tanks or septic tanks” [5], [6]. The rest of the
wastewater, everything except sludge, now meets wastewater discarding standards.
With the solid and liquid effluents that have been ingeniously treated, several actions
may take place to completely rid of these waste byproducts. Once again, most liquid effluent is
transported through sewers and dumped in the ocean. This discharge is essentially harmless to
the environment and technology continues to develop to ensure this [4]. The remainder of the
liquid effluent is sent to advanced water reclamation plants and is purified more to provide
recyclable byproducts, such as water for irrigation. Some of this liquid effluent is further filtered
and treated, with cutting-edge chemical processes, to create potable water. While these steps
treat the liquid effluent, the solid effluent is treated in a different manner. In some crafty
treatment plants, thermophilic digestion is used to process primary and secondary sludge.
Thermophilic digestion is anaerobic digestion, or digestion done without oxygen, completed at
very high temperatures. Primary sludge, which is mostly solid waste and black in color, is mixed
with secondary sludge, which is liquid and brown in color, and processed in the resourceful
thermophilic digester. Digestion of the combined sludge forms an effluent that is ready to be
recycled as fertilizer or disposed of at landfills. This handy process results in large amounts of
methane gas being excreted, which is then used to generate electricity for plants and sold to
increase revenue [6]. With this, the contemporary wastewater treatment method in Los
Angeles is completed.
The Hyperion Treatment Plant: A Prime Example of Treated Wastewater Disposal
Instead of giving an overview of every amazing wastewater treatment plant in Los
Angeles County, the focus will be placed on the leading-edge Hyperion Treatment Plant, which
is the largest facility [7]. The Hyperion Treatment Plant is located in Playa Del Rey, California, as
shown in Figure 2, and began operating in 1925 as a screening plant and upgraded into a full
secondary treatment plant in 1950. Inventive treatment processes here include primary
treatment, full secondary treatment, biosolids handling, and biogas generation. The full
secondary system was rebuilt in 1998 and is the fundamental aspect of the improved treatment
plant [7]. The process of treating wastewater through the Hyperion Treatment Plant starts with
wastewater imported through a vast network of sewers and concludes with the export of clean
liquid effluent, reclaimed water, and biosolids.
Figure 2 – A map of sewer lines and the Hyperion Treatment
Plant.
http://www.lasewers.org/treatment_plants/about/map.htm
Wastewater is brought to the plant by four major sewer lines, bringing in about three
hundred fifty million gallons a day. The first stop at the plant is the prolific headworks, a
preliminary treatment that filters out larger solids, ranging from branches to sand. Continuing
by gravity, the modern primary treatment section is reached. Here sludge is removed as it sinks
and is pumped to the digesters from underground tanks. Next an advanced intermediate pump
station is used to push up the primary treated wastewater in order to allow for it to flow by
gravity throughout the rest of its treatment. At the top of the flow is the imperative secondary
treatment stage. This is the most recent and significant update to the Hyperion Plant because
this is where wastewater is transformed the most, and treatment here occurs in two steps. In
the first step bacteria consume remaining organic particles in enclosed, oxygen rich reactor
tanks and settle at the bottom of the tanks. Step two of the proficient secondary treatment
deals with the separation of bacteria and wastewater to make a final product clean enough to
be circulated back into nature. These processes take place in one location, shown in Figure 3.
Most of this acceptable effluent is then transported by a five mile long pipe to be dumped into
the Santa Monica Bay. Some of it is pumped to the West Basin Water Recycling Plant to be
reclaimed and reused for landscape irrigation and industrial applications. This completes the
innovative wastewater treatment for the liquid effluent, but solid wastes, or biosolids, are
processed further and used to provide energy, fertilizer, and non-food agricultural applications
[7].
Figure 3 – An aerial view of the Hyperion Treatment Plant
Conclusion:
Meeting Supply of Waste with Progress in Treatment
http://www.lasewers.org/treatment_plants/hyperion/tour/sewers.htm
Although not all of it is completed at the remarkable Hyperion Plant, through this
procedure, all of Los Angeles’ wastewater is purified enough to be discarded or recycled.
Modern practices of treatment are currently sufficient for handling the capacity of wastewater
in Los Angeles, but advances in technology are constantly necessary to manage an everincreasing quantity of wastewater. The Hyperion Plant is a pioneer in advancing itself to meet
this rising demand for wastewater treatment [7]. Because of incredible treatment plants, we
are able to experience sanitary living conditions where our feces do not accompany us on the
streets and in the oceans.
References
[1] S. Hoban. (2013, September 12). Onsite Wastewater Demonstration Project [Online].
Available: http://www.cefns.nau.edu/Projects/WDP/resources/History/History.htm
[2] S. Channel. (2013, September 12). Pollution [Online]. Available:
http://curiosity.discovery.com/question/what-history-sewage-treatment-systems
[3] (2013, September 12). Sanitation Districts of Los Angeles County [Online]. Available:
http://www.clearwaterprogram.org/clearwater/sanitationdistricts.asp
[4] J. A. Wilson, “Decade of Progress: Wastewater Program City of Los Angeles,” Department of
Public Works, City of Los Angeles, CA, Bureau of Sanitation, 2011.
[5] C. C. C. Texas, “Wastewater Treatment,” unpublished.
[6] W. Song Ph.D., P.E., “Interview,” Civil Engineer, Sanitation Districts of Los Angeles County,
City of Los Angeles, CA, Wastewater and Solid Waste Design Section, September 18, 2013.
[7] (2013, September 12). Treatment Plants [Online]. Available:
http://www.lasewers.org/treatment_plants/about/index.htm