The Effects of Wastewater Treatment in the Wendling Beck on Water Quality - Essay Example

Evaluate the effects of wastewater treatment in the Wendling Beck on water quality by biological and physical assessment Introduction: Water is the key element for life and makes up the majority of most organisms. For human being water make of 60% of the human body. It plays a role in regulating the temperature of the human body and acts as a solvent for most of the substance. Hence, we need to maintain the balance of body fluids every day.( http://curiosity.discovery.com/question/why-people-need-water). There are various sources f water that include groundwater, river, lake, and desalination. moreover, the most use of water are for drinking, irrigation and industry. So river is one of the common sources of water but before we use it for any purpose, we need to check the quality of water to avoid any effect in the human body. Hence, we choose wending duck to determine the effect of Dereham sewage treatment works(STW) on both water quality and quantity. wending duck is a side channel of the river Wensum in the United Kingdom, and the water comes from Chalk rocks. there is also east Dereham treatment works next to it. East Dereham treatment works releases water straight into wending duck (see figure 1).(booklet). There are two types of measurement to check water quality; chemical and biological samplings. 1-Chemical sampling: by taking sample to a laboratory and measuring the quality of water. 2-Biological sampling: by measuring the macroinvertebrate animal community over a period of time, and with this method water quality is assessed by two measurements: 1) Biological Monitoring Working Party (BMWP); this method measure the biological quality of the river using a different type of macroinvertebrates as indicators. (booklet). The principle of this method is different macroinvertebrate have different potential of pollution. http://en.wikipedia.org/wiki/Biological_monitoring_working_party. 2) The average score per taxon(ASPT): the average of pollution sensitivity of all macroinvertebrate families found. The main function of sewage work is to treat and recycle wastewater, and this involves four steps: preliminary, primary, secondary and tertiary. Preliminary treatment: in this step, we prepare Sewage for the main treatment, and this process include removing oil and grease and screening from the Sewage. Primary treatment: after the sewerage has been treated with a previous step we use this step to remove the solids in the wastewater and keep it in a storage tank for the next treatment. secondary treatment(biological treatment): this step describes how to move organic material by two main ways: biological filtration and activated sludge. Tertiary treatment: this is the final step, ultra violet and a thin membrane are used to remove bacteria and virus from the treatment process, and this water made for another purpose than drinking such as washing clothes,irrigation and toilets.(https://learn.uea.ac.uk/bbcswebdav/pid-1226628-dt-content-rid-1544301_1/courses/INTO-PSE-JUN14_E/wastewater-web--2-.pdf). The aim of the fieldwork was to investigate the impact of wastewater treatment on the river Wensum and evaluate water pollution and quantity Fig. 1. Location of Wendling Beck and the East Dereham Sewage Treatment Works Methodology: First, clarity of water, substratum, vegetation and obvious pollutants were assessed. A measure of the width of the river: By using a measurement tape across the River to find out the width of the river that has been divided into four sections. After dividing the river, a meter stick was used to find out the depth of the river in each section. All of the results were recorded in the results section. Dissolved oxygen and temperature were measured by oxygen meter "Do2 meter." The stick method to find out the volumetric flow: A rope of 5 meters was placed on the surface of the river to calculate the velocity of the stream. A stick was thrown into the river from the beginning of the 5 meters rope while the stopwatch was turned on to calculate the time when the stick was traveling next to the rope till the end of the 5 meters rope. This method have been done twice Kick sample method to assess the biological sampling: We used benthic kick sample to measure biological sampling. We hold the benthos net firmly on the bottom of the river across the flow.Then river was vigorously disturbed by heel, so removed material is washed into the net and kept it in a white tray. Finally, the species were counted in the white tray. Result: Table (1) shows explanations of subjective assessment. Upstream Downstream Clarity Clear unclear Substratum Stone,silt and sand Muddy-silt vegetation sparse Water reed iris Obvious pollutants Nothing Cans and leather From table 1 the clarity of upstream is more the downstream,also the substratum of upstream contain less silt and sand ,while downstream has muddy silt,also there is different vegetation between both side of the river,also upstream the river has no obvious pollution as downstream has. Table (2) summarize the average of Dissolved oxygen, Temperature , Volumetric flow rate, Biotic index BMWP and Biotic index ASPT. upstream downstream Dissloved Oxygen 114 % 65% Temperature 18.325 Co 18.675 Co Volumetric flow rate 0.0911 M3 S-1 0.19 M3 S-1 Biotic index (BMWP) 88 63 Biotic index (ASPT) 5.5 4.5 Table 2 shows the difference between upstream and downstream of the river in many aspects. Dissolved oxygen almost doubled in upstream of the river at 114 %. Also, there is a slight difference in temperature between upstream and downstream for 0.35 Co, and according to the flow rate upstream has half the speed than downstream. Furthermore the difference between upstream and downstream of the river in BMWP score is 25 points. Also, there is one-point difference between the up and down streams of the river in ASPT. Formials: BMWP = number of how many different types of macroinvertebrates ASPT = number of total BMWP score /number of Taxa identified. The pie chart shows the data of affluent of the river. Formials: Effluent(STW)= volumetric flow downstream - volumetric flow upstream =0.19 -0.0911= 0.0989 M3 S-1 STW % = STW/ volumetric flow downstream *100 =0.0989 M3 S-1/0.19 M3 S-1*100 = 52 % Results from a pie chart show 52 per cent or 0.0989 M3 S-1 of effluent in the river come from STW, and the rest come from upstream of the river. Discussion: The purpose of this study is to invistagte if wedling duck was polluted or not from the STW. From subjective assessment table we can see the water in upstream is clear and unpolluted from that of downstream of the river and might be the reason of The amount of organisms that lived in downstream. Table 2 shows the difference between upstream and downstream in many aspects. Dissolved oxygen almost doubled in upstream at 114 % and the flow rate upstream has half the speed than downstream. This may be due to the discharge from STW. Furthermore the BMWP of upstream is 88 and 64 in the downstream. According to BMWP table its mean the water is clean but slightly impacted and in downstream the water is moderately impacted. The study was limited by lack of proper tools for analysis. The data could also have been more accurate if we used proper tools such as flow meter, oxygen meter and advanced thermometer. Moreover, we did not do any laboratory test to get more data to make sure there was contamination or not in the river. In addition, we could not measure the flow rate in the downstream because of plants, and hence we took data from previous years and assumed the condition could be the same. In conclusion, it is possible that the discharge from Sewage Treatment Works led to contamination of the river and we need more lab test to confirm it. Read More