Western Treatment Plant (Warribee) and Eastern Treatment Plant (Carrum)
|Topics:||♻️ Recycling, Environmental Issues, Waste Management, Water Pollution|
Table of Contents
The Warribee Treatment Plant on Western Melbourne and the Carrum Treatment Plant also known as the Eastern Treatment Plant, are two world-class water/sewage treatment plants. While the Eastern Plant was started in the late twentieth century, the plant at Werribee has been around as far as the 1800s. Back in the late nineteenth and the early twentieth centuries, the treatment plant at Werribee processed sewage using various traditional methods of treatments such as land and grass filtration. Today, the Werribee Plant treats its sewage by the use of Treatment Lagoons, a technique which has been greatly upgraded in the modern day. The Carrum Plant, on the other hand, constructed in 1975, uses a different approach of treatment which takes quite a short time as compared to the Werribee Plant. The treatment at Carrum involves a primary and a secondary treatment stage followed by a final tertiary stage, which has been introduced in the current times. While the processes are aimed at making the environment safer, some problems and hazards also arise from the treatment plants. More improvements and policies are being considered to suppress these arising problems and hazards. This paper aims to provide a report on the two water treatment plants and their operations by answering the questions bellow.
Discuss the nature of the sewage inputs at Waribee and Carrum and how it is transferred from Melbourne
The wastewater from different places such as kitchens, laundry, flashed water from toilets, and bathroom sinks forms the sewage at the Western Treatment Plant. The same can be said for the sewage composition at the Eastern Treatment Plant. Wastewater from houses in Melbourne are directed down to the sewers through pipes (Water, 2010). The sewers in the western region are directed to the Werribee Plant while most of the Eastern sewers are directed to the Carrum Plant. While the treatment plant at Carrum is smaller as compared to the one at Werribee, it is very efficient and treats wastewater in a very short time. It is therefore, just as suitable to treat sewage from the vast Eastern region. The Werribee Plant, on the other hand, is quite enormous and has the capacity to handle large volumes of sewage content (Bishop and Cross, 2015).
Describe the three traditional types of the treatment originally used at Warribee, using appropriate diagrams and also describe the conditions under which each method is used. Include your response and explanation of how the treatment operation works and any pre-treatment procedures used.
The Werribee plant’s sewage management approaches today are not the same as the initial or traditional treatment methods. Previously, the treatment methods at the Western Treatment Plant included land filtration (as shown in figure 1 bellow), grass filtration and lagoon treatment. The use of land filtration dates back to the late 1890s, where it majorly used in the summer. The whole process of treating water using land filtration tales approximately three weeks and was done in sequences. In the first phase, an open enclosure is flooded with sewage, ten centimeters deep. Land filters out solids while bacteria in the soil break down pollutants (Bishop and Cross, 2015). Filtered sewage is seeped down through the soil, a process which takes about five days. The treated effluent then flows out through the lower end of the paddocks into a drain, which then carries it to port Philip Bay. Cattle and sheep are allowed to graze on the paddocks for two to three weeks before it’s flooded again with sewage.
Figure 1: Land Filtration
Source: adapted from Bishop and Cross (2015)
On the other hand, as provided by Bishop and Cross (2015), the method of grass filtration (as shown in figure 1) was later adopted in the 1930s and used mainly during winter. The method involved a pre-treatment stage and a filtration stage. Initially, sewage is directed into large tanks where sedimentation is done to do away with rubbish. It was then trickled over sloping-grass covered bay which has a high tolerance for constant flooding. At the bay’s end the filtered effluent was directed to port Philip bay. Treatment lagoons were first constructed in 1936. Lagoon facilities have undergone continuous upgrade over time and today, the sewage at the Werribee plant is treated in modernized lagoons. Modern lagoons have the capacity to filter out huge amounts of nitrogen. The lagoons are usable all seasons.
Figure 2: Grass Filtrations
Source: Bishop and Cross (2015).
Describe the method of treatment currently used as Warribee. What are the recent improvements? Why were they introduced?
As aforementioned, while the use of management lagoons date back to the 1930s, lagoons are still used as the method of treatment at the Western Treatment Plant. However, the current lagoon facilities have been upgraded to very high standards. The current lagoons are in the form of large ponds which can hold up to six hundred million liters of water. The whole water treatment process at Werribee currently takes up to about thirty-five days. The lagoons have been upgraded and specified in order to encourage the growth of different types of bacteria. There are anaerobic lagoons and aerobic lagoons. The anaerobic lagoons are the first lagoons and have large plastic covers designed to keep out oxygen. Anaerobic bacteria can then thrive in this environment and help with the breakdown of organic material. As the process of decomposition proceeds, odors and gases such as methane are produced. The methane produced is then captured under the covers. The odor is thus reduced, and so is the greenhouse emission of methane. The trapped methane can instead be used to power engines and generate electricity.
The filtrate from the anaerobic lagoons then streams into the aerobic ponds or lagoons. Oxygen is propelled into the water, which makes aerobic bacteria to remove the presence of nitrogen (Warry, Reich, Woodland, Thomson, MacNally, and Cook, 2016: 25). The process also makes solids clump together allowing wastewater to flow easily into clarifiers, settling tanks. The solids are then dried and kept in piles or later reused as bio-solids. The leftover nutrients also provide birds with plenty of food (Loyn, Swindley, and Stamation, 2014: 147). By the time water reaches the final pond, it is extremely clean and can now be released into Port Philip Bay while some of the clean water is further treated and recycled (Loyn et al., 2014: 147). While a lot of improvements have been made already in relation to water and sewage treatment, more improvements are on the way to enhance the environmental performance in the treatment field of wastewater.
Describe the treatment method currently used as Carrum. How do they differ from Warribee?
On the other hand, it is quite clear that the management or treatment methods at the Carrum front is different from those used at Werribee. In 2012, the sewage/water treatment plant at Carrum was upgraded to treat water to more advanced (tertiary) level, further (Dow, Milne, Zhu, Gray, Duke, Murphy, Solomon, Mieog, Blackbeard, Currie, and Ho, 2014). Currently, sewage/water treatment at Carrum is done through three intensive stages which takes a total of only twenty-four hours (Dow et al., 2014). These steps include the primary, secondary, and secondary management or treatment stages. In the primary stage, rubbish or pollutants are physically removed from the sewage. In order to filter the cotton buds, rags, and other rubbish forms, fine screens are used. Oxygen is also added to the water/sewage to make fine particle float. Sedimentation occurs as heavy particles or substances descend to the lowest to form sludge. The deposit of sludge is then propelled to the adjacent tanks called digesters, where they are decomposed.
In the second treatment stage, tanks with different oxygen concentrations are used to in order to provide suitable environments for both aerobic and anaerobic bacteria which further breakdown organic material. The rest of the sewage is then passed into the clarifiers where sedimentation takes place leaving clear water to flow into large basins. This clean, treated water is referred to as secondary effluent (Dow et al., 2014). In the tertiary treatment stage, the main operation involves disinfection of the water. The color and odor of water are also reduced at this stage. Biological filters and bacteria are further used to break down any possibly remaining organic material in the water. Ultraviolet light is also used at this stage to disinfect the effluent further. Final disinfection is done using chlorine. Some of the water from the treatment plant is supplied to nearby customers as reused water whereas the rest is pumped into the ocean at the Boags Rocks.
What are the major problems that arise in the treatment of the sewage from the major city such as Melbourne? What measures could be introduced to deal with these problems? Include in your discussion issues related to the re-use of water.
Sewage and waste water treatment benefits the inhabitants in within and around the Melbourne area in a lot of ways. At the same time, there are various problems associated with the process of water and sewage treatment and the re-use of water. Workers at the water treatment are the most affected by some of these problems. The major problems and hazards associated with the water treatment process in Melbourne are health effects and odor. The health concerns here include inhalation of harmful gases such as hydrogen sulphide and methane, infections of hepatitis and leptospirosis, skin and respiratory diseases, and musculoskeletal disorders. While a gas like hydrogen sulphide is harmful, it also has quite a bad smell. Workers at the water plants are most at risk of developing some of the infections or disorders highlighted above. Those who live close to the water plants may also suffer some of these problems. The odor that comes out of the treatment plant can make living around the area quite uncomfortable.
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Problems associated with the re-use of water are mainly those that affect the soil and crops grown on it. It is calculated that continued use of recycled water for irrigation may interfere with the salinity of the soil, thereby, interfering with plant growth. While the two major water plants discussed here produce clean and reusable water, other water plants elsewhere may not have sufficient facilities to provide clean water. Water which has not been treated properly may cause serious infections in individuals when used domestically.
Efforts have been made in the current day to curb some of the serious problems and hazards which emanate from the treatment plants (Rogers, Brown, de Haan, and Deletic, 2015: 42-64). Through engineering, odor in the treatment plants has been reduced to a considerable level. More legislative and engineering measures are to be taken in order to protect against possible exposers. Medical measures will also help detect the effects of the exposers at early stages making it easy to protect against them.
Why is Warribee area an ideal location for the sewage facility? What are the major environmental impacts of the facility at Warribee? Are there problems with the locations of the site as Carrum?
The treatment plant at Werribee is about eleven thousand hectares in size and serves to treat over half of Melbourne’s sewage. The location of plants is ideal for its operations. The plant lies on an extensive plain-land west of the Melbourne city. The plant’s location at Werribee is appropriate for its operations as it a good distance away from the city center. Surrounding the plant are agricultural lands, originally dry lands, mainly used for irrigation and cultivation of various crops. Other than treating wastewater the plant also provides the local irrigators with clean recycled water (Radcliffe, 2015). The plant has impacted the environment at Werribee quite positively in a lot of ways. The availability of the fresh recycled water from Werribee plant has made it possible for people to venture into crop cultivation and irrigation in areas adjacent or close to the plant (Low, Grant, Hamilton, Gan, Saphores, Arora, and Feldman, 2015: 315-328). The Mason Brothers Vegetable Farms is an example of the farms around the area, which benefit from the treatment plant (Alcantara, Doronila, Nicolas, Ebbs, and Kolev, 2015: 25-32).
The Carrum Plant, on the other hand, is smaller in size, roughly about a tenth of the Werribee plant. Unlike the Western Plant, the Eastern Plant has not created significant environmental impacts other than treating and recycling water. Excess treated water or effluent is released into the ocean while some get into a valley near Boags Rocks.
In conclusion, as presented above, the two water treatment plants in Melbourne are of very high standards. As mentioned above, while the water plants have been greatly upgraded over the years, more developments are still on the way, and the goal of each water plant is to become the best in the world and make Melbourne the greatest city in terms of water conservation. While the eastern treatment plant was constructed recently in the late twentieth century, the western plant has been around since the 1800s. Also, the size of the Western Treatment Plant is almost ten times that of the eastern treatment plant at Carrum. As seen in the report, the wastewater treatment methods used in each of the two treatment plants are not similar. In Carrum, treatment undergoes three stages, namely, primary, secondary and tertiary treatments. At Werribee treatment is done by use of pond-like structures called lagoons.
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