Water Treatment Plant - Case Study Example

Water Treatment Plant Introduction Clean water is important for the most basic hygiene need and for sustaining our survival. However, clean water isinadequate and keeping it clean is difficult. Recycling dirty water is one of the best ways to preserve this important resource. The process used to clean water is known as waste water treatment. This essay focuses on St Mary’s waste water treatment plant that is located in Sydney’s western suburb that is approximately thirty five kilometers from the coast. The treated water from this plant is distributed to St Mary’s recycled water plant or to Ropes Creek as stipulated in the environmental plant license. The treatment plant plays an imperative role in improving the levels of water recycling in the region to nearly 70 billion liters of water annually by the year 2015 (Yudelson, 2013: 14). The plant boasts of an annual production of nearly 18 billion liters. This is mainly used to maintain the water levels in Hawkesbury-Nepean River. Additionally, the water from the treatment plan will aid in the reduction of the nutrient levels in the river and this will translate into an increase in the drinking water available from Warragamba Dam. History of the Treatment Plant and Future Plans The history of the plant can be dates back in 1939 when it served government facilities using a traditional filter plant (Yudelson, 2013: 15). This was updated to a modern treatment plant in the 1960s. These changes were conducted in1993 and 1998 owing to mounting pressure caused by population growth (Yudelson, 2013: 17). Currently, the plant treats approximately 35 million litres of dirty water on a daily basis. It functions through a license that has been issued by the NSW Department of Environment, Climate Change and Water (DECCW) (Yudelson, 2013: 22). The processes at the treatment plant are managed by a manager and seven subordinate staff. They are in charge of servicing the machine and equipment in the plant, conducting laboratory tests and ensuring that all operations within the plant are being managed efficiently and safely. The plant generates 20, 000 tonnes of biosolids that have a high nutrient content and are utilized in agriculture, land rehabilitation and composting (Yudelson, 2013: 133). The treatment plant has future plans that are aimed at expanding its production of clean water. The plant is a component of the Replacement Flows Project. Water that is not fully treated at St Mary’s and Penrith, Quakers Hill treatment plants is treated more at the St Marys Recycled Water Plant. Approximately 18 billion litres of clean water will be channeled to Perinth in a move to maintain the water levels in Hawkesbury Nepean River (Yudelson, 2013: 25). The history can be summarized as: Stage 1 was constructed in 1964, Stage 2 was constructed in 1974, Stage 3 was constructed in 1998, the plant was expanded to serve a population of 138, 000 individuals, its area is 84 square kilometres, it has nine pumping stations and 881 kilometres of pipes (Yudelson, 2013: 45). Wastewater Collection The collection system is made up of an underground grid system that pipes channels industrial and domestic sewage to pump station where the pump channels the sewage to the treatment plant for cleansing. The pump system handles over 10, 000, 000 gallons of dirty water daily (Yudelson, 2013: 45). The conditions in the major pump stations are managed through a control and monitoring system. Flow Equalization Equipment at the start of the treatment process regulate the amount of wastewater that can be daily. In instances where the flow is high that is over 9, 000, 000 gallons daily, the plant cannot deal with these volumes and an electric gate has been installed to divert the excess flow of wastewater to a 2, 700, 000 gallon storage basin (Yudelson, 2013: 53). The water that has been captured in the equalization basin is pumped back to the treatment plan when the water levels revert back to normal. A computerized system regulates all the equalization functions. Wastewater Treatment Procedure The process of purifying waste water is complex, takes time (22 hours) and goes through numerous stages (Yudelson, 2013: 63). This process uses chemical, biological and physical processes to remove waste from the dirty water. It is highly automated and can be monitored outside normal working hours. The wastewater channeled into the plant is divided into sections that are aimed for primary and secondary treatment. The processes are Intermittently Decanted Aerated Lagoon (IDAL) and biological reactor. Following this, treated water is pumped from each processes and collected so that it can be finally be pumped for tertiary treatment. Stage 1 and 2 Procedures Primary Treatment This step involves remove of waste materials from the dirty water. In this stage, the operation involves removal of solid waste (Yudelson, 2013: 77). Three key procedures are important within the primary treatment, screening, grit removal and sedimentation. Secondary Treatment: Biological and Chemical Processes In spite of the fact that the primary stage involves that removal of solid waste, some dissolved ant tiny sediments remain. The biological and chemical procedures provide varying environments for microorganisms in the water. At this level, there is a minimized level of Biological Oxygen Demand abbreviated as (BOD) and nutrients are removed. The secondary treatment of waste water is made up of Anoxic zone 1, Aeration zone 1, Anoxic zone 2 with methanol, Aeration zone 2 and Secondary Clarifiers (Yudelson, 2013: 88). Stage 3 Process Line 1. Primary Treatment This is made up of three major stages including screening, grit removal and pre-fermentation. 2. Secondary Treatment: Biological and Chemical This involves provision of biological environments that remove pollutants and nutrients from waste water. These include Anaerobic Zone, Anoxic Zone, Aerobic Zone and Secondary Clarifiers (Yudelson, 2013: 101). 3. Tertiary Treatment This is the final stage of treatment that is made up of processes including phosphorus reduction, filtering, disinfection and filtering (Yudelson, 2013: 55). Recycled Water Productions After adding chlorine at the tertiary stage to achieve better disinfection and to ensure that the treated water pipes is free of bacteria. This ensures that the Australian Guidelines for Water Recycling standards are met. Finally, the treated water goes into a system where the purified water can be used at homes and industries for various purposes such as cleaning, flushing toilets and washing cars and equipment. Present Design Flow and Expected Future Flow This project connects St Mary’s, Penrith and Quakers Hill recycling plant to the modern recycling plant at St Mary’s (Yudelson, 2013: 124). The new recycling plant was designed to treat tertiary dirty water from the three recycling plant to higher volumes before it is let to flow into Hawkesbury-Nepean River. Nearly 65 million litres of waste water that have gone through tertiary treatment are pumped into the new recycling plant (Yudelson, 2013: 143). This waste water has already passed through numerous treatment stages including filtering to eliminate all nutrients and biodegradable organic wastes before being channeled to the St Mary Water Recycling Plant. This water has also been disinfected at this stage. The tertiary treated waste water is directed into a balance tank that ensures a steady supply for the plant during normal operation. The waste water then goes through a mechanical strainer before it passes through an ultra-filtration process. This removes any particles that are organic in nature that may have remained. The next stage is ultra-filtration whereby the wastewater is channeled into a tank that is full of ultra filtration membranes. At this point, a vacuum is applied so that the water can be drawn through the semi-permeable membranes. Bacteria, suspended solids and some viruses are blocked as well. Wastewater that has gone through ultra-filtration is afterwards forced at high pressure into a compartment with numerous reverse osmosis membranes. These membranes are fine sieves that absorb water and leave behind a concentration of waste water. The water that is obtained from this reverse process is then channeled to the de-carbonators. De-carbonators are aimed at minimizing the carbon dioxide levels in the water. The water is stored on a temporary basis in the balanced tank before it is channeled to Penrith (Yudelson, 2013: 145). Before this water reaches the Boundary Creek in Penrith, the pH level is regulated and the recycled water is disinfected. Present Maintenance and Operation Process The treatment plant runs round the clock but its employees have a working program of 7 am to 5pm (Yudelson, 2013: 5). This is because it is an automatic plant and only minimal operations are carried out during the day. The maintenance of the plant is carried out by private contractors. On the other hand, sedimentation tanks are run continuously and their maintenance involves monitoring inlet channels and overflow weirs. At times rages and other forms of debris are not screened and can block the inlet pipes in these tanks. Outlet and inlet tanks should be kept clean at all times. In a move to achieve an effective maintenance level, there is an adequate access to tools and equipment needed to complete the work and services (Yudelson, 2013: 135). Basic maintenance for screens is attained through a visual inspection for malfunctions. When some important observations are present, fast maintenance should be carried out. Finally, maintenance should be recorded and regulated for future purposes. New Concepts Processing Bio-solids for Re-use Wastewater contains bio-solids that have nutrient rich solids that can be treated and used in the agricultural sector. These solids are collected from sedimentation tanks. The sludge is channeled into air floatation tanks to thicken it before it goes through an aerobic digestion process. After this, open air sludge is thickened further before it is dewatered. Excess water is later removed using two belt processes. The bio-solids can be utilized in landscaping, rehabilitation, forestry and agriculture. The plant produces approximately 190,000 tonnes of bio-solids annually (Yudelson, 2013: 143). Importance of Reducing Biological Oxygen Demand (BOD) Organic material breaks down oxygen that is present in water ways. Adding huge volumes of organic material minimizes the oxygen that is available to the aquatic life. BOD levels are measure in milligrams of oxygen in a litre of water (Yudelson, 2013: 97). Rising BOD can be caused by materials including dirty water, dumped grass pieces and nutrients from agricultural land. The treatment plant breaks down the organic elements in waste water in the environments that are maintained in treatment tanks. This increases the oxygen supply for marine life and facilitates the quality of treated water. Recommendations Improvements should be made in the following areas: replacement of chemical feed systems, main electrical components and pumping systems, structural additions to process tanks, improvement of the pumping capacity and renovation of the building and structures. There is a wide array of approaches that can be adopted to improve the quality of water. Therefore, infrastructure and technologies used to treat water should be employed across the world. This can be done through coming up with new technologies whenever they are needed and offering financing to execute the needed infrastructure projects and technologies, connecting businesses, governments and communities. Environmental Factor Objectives are said to preserve the environment by undertaking operation according to the policies of Ecologically Sustainable Development (ESD). The precautionary policy reduces the opportunities of grave environmental issues even though they are not sure whether the problems will take place. Better valuation and pricing of environmental resources ensures improved valuation and this information is used for making decisions (Yudelson, 2013: 17). Conservation of ecological integrity and biodiversity promotes the range of indigenous plants and animals. Intra-generational equity and inter-generational equity mitigates the impact of human activities on the environment. In conclusion St Mary’s treatment plant helps in reduction of environmental pollution by minimizing wastes that are released to the environment. Reference Yudelson, J. (2013) Dry run: preventing the next urban water crisis, New Society Publishers. Read More