EXPERIMENT 2: SUSPENDED SOLIDS 1. 0 OBJECTIVE This objective of this experiment is to determine the quantity of suspended solids in polluted water samples. 2. 0 INTRODUCTION Water quality is vitally important in our daily life. However, due to water pollution, the quality of water is questionable for safe usage. In order to determine water quality, one of the indicator and measurement that can be used is by suspended solids (SS). Suspended solids is one type of physical water-quality measurement.

Suspended solids refer to small particles which remain in suspension in water as a colloid or due to the motion of the water, with sizes larger than 0. 01mm. Suspended solids may consist of organic particles such as vegetation fibres, alga, bacteria and micro-organisms and non-organic suspended solids such as clay, silt and other soil materials. Wastewater is water that has been affected in quality by human activities on the environment such as liquid discharged from industry, domestic residences, commercial and others. In wastewater, materials other than water are considered as solid.

The definition for solid is the residue of water evaporation from 103? C (slightly more than boiling point). Solids can be classified into dissolved solids and suspended solid. Suspended solid can be obtained from filtration method. Solid that remains on the filter paper after drying at 103? C is suspended solid. Concentration of the suspended solid can be calculated as below: Concentration of suspended solid = ( A ? B) ? 1000 Volume of sample (mL) A = weight of suspended solid + filter paper (mg) B = weight of filter paper (mg) 1 3. 0 LITERATURE REVIEW

When there is no adequate water sources to meet needs of a community, it is necessary to use surface water to meet the community water needs. Surface waters require more treatment than groundwater. Part of the problems lies in the fact that no two surface waters have exactly the same chemical and microbial characteristics. Even two surface water supplies, located on the same river will have slightly different characteristics as a result of different drainage between the two water intakes. Surface waters have both suspended solids and dissolved solids.

The suspended solid (nonfilterable residue) content of wastewater is of direct water quality significance in terms of turbidity in receiving waters, and indirectly in relation to the associated transport of other waste constituents such as nitrogen, phosphorus, and BOD. Suspended solid are very finely divided particles that are kept in suspension by the turbulent action of the moving water; they are insoluble in water but are filterable. The suspended solids are normally organic solids combined with organic solids but may be entirely inorganic solids.

Some of the suspended solids consist readily biodegradable organic compounds together with some organic compounds that are non-biodegrable in the aqueous environment. [1] Microorganisms are part of the suspended solid. The higher plants and animals found in surface waters are not considered as part of the suspended solids. The dissolved solids are mostly inorganic with some soluble organic compounds. The soluble organic compounds may be biodegradable, non-biodegradable or a combination of the two relationship. Colloidal suspended solids are also found in surface waters.

Colloids are very tiny particles that act like soluble solids and are often measured as part of the soluble solids. Time, temperature and other environmental factors determine microbial response in the surface water supplies. [2] 2 After the measurement of BOD, the suspended solid content is probably the next most tests for both crude sewage and treated effluents. The amount of suspended and soluble solids in sewage will govern the design details of both the sedimentation tanks and the sludge drying treatment process.

The determination of the concentration of suspended solids is indicative of the contaminating strength of the sewage. It is normal to distinguish between organic (fixed) and organic (volatile) suspended solids as it is the latter that are putrescible. The quantity of volatile solids is measured by the loss on ignition at 600°C and it will normally be found that the mineral content of a domestic sewage is quite small. The tests call for the use of laboratory equipments and hence, are unsuitable for smaller works.

The quantity of total suspended solid (fixed and volatile) will be indicative of the insoluble content of the sewage (both organic and mineral) while the quantity of settle able solid is an indicator of the quantity of sludge to be treated and the amount of solids which may be carried forward to the secondary (biological) process. Average strength of domestic sewage will consist of 300-400 mg/l suspended solids before the settling process is affected. various solids shows in the Figure 1 below. [3] The classification of the Total solids, TS Total suspended solids, TSS Total dissolved solids, TDS

Volatile suspended solids, VSS Total fixed solids, TFS Volatile dissolved solids, VDS Fixed dissolved solids, FDS Total volatile solids, TVS Total fixed solids, TFS Figure 1: Types of suspended solids in water and wastewater. 3 Total solids are obtained by evaporating a sample of wastewater to dryness at 103? C -105? C. Total solids (TSS) are the sum of the dissolved and suspended solids in the water sample. The total solids and the total dissolved solids (TDS) are determined directly; the suspended solids are assumed to be the difference since Total suspended solids (TSS) = total solids (TS) – total dissolved solids (TDS)

A filtration steps separates the total suspended solids (TSS), which remain on the filter, from the total dissolves solids (TDS), which pass in the filtrate. The residue that remains after TS are ignited at 500? C is called the total fixed solids (TFS) and they represent the inorganic slats in the sample. The solids that are volatilized are burned off the total volatile (TVS) and they represence the organic matter including microorganisms. The suspended solids content of wastewater is not usually a limiting factor design, but the improper management of solids within the system can result in process failure.

The amount of suspended matter in wastewater increases with the degree of pollution. Sludges represent an extreme case in which most of the solid matter is suspended. The determination of suspended solids therefore valuable in the analysis of polluted waters. It is one of the major parameters for evaluating the strength of domestic wastewater and for determining the efficiency of treatment units. One critical concern for both aquatic and terrestrial systems is the attainment of proper distribution of solids within the treatment reactor.

The removal of suspended solids in ponds systems depends primarily on gravity sedimentation and algae can be a concern in some situations. Sedimentation and entrapment in the microbial growths are both contributing factors in hyacinth, wetland, and the overland-flow process. [4] 4 4. 0 MATERIALS AND APPARATUS 1. Three water samples are collected from three sources: (i) Pond at Kampung E Hostel (ii) Pond at School of Science and Technology (SST) (iii) Concrete curing tank at School of Engineering and Information Technology (SEIT) Figure 2: Water Samples . Filter papers and Glass Plate 3. Drying Oven Figure 3: Filter papers and Glass Plate Figure 4: Drying Oven 5 4. Analytical Balance 5. Measuring Cylinder Figure 5: Analytical Balance Figure 6: Measuring Cylinder 6. Forceps 7. Filtering Apparatus and Vacuum Pump Figure 7: Forceps Figure 8: Filtering Apparatus and Vacuum Pump 6 5. 0 METHOD / PROCEDURES 1. Three water samples from nearby water sources which is from pond at Kampung E hostel, concrete curing tank of SEIT and pond at SST are collected. Figure 9: Water Sample from Pond at Kampung E Hostel.

Figure 10: Water Sample from Concrete Curing Tank at SEIT. 7 Figure 11: Water Sample from Pond at SST. 2. The filtering apparatus such as membrane filter, filter holder, filter flask and aspirator are assembled. Figure 12: Filtering Apparatus is Assembled. 3. The filter is rinsed by pouring about 50mL of deionized water through the filter. The rinse water is discarded. 4. Another 50mL of deionized water is poured through the filter. 8 5. After setting up the apparatus, the filter papers are cleaned with 60mL deionized water with every time 20mL for three times. . The filter papers are dried in the oven at temperature 103-105°C for 1 hour. Figure 13: Filter Papers are Dried in Drying Oven. 7. The filter papers are put in the drying machine before use. 8. The filter papers are weighed before use. Figure 14: Filter papers are Weighed with Analytical Balance. 9 9. 250mL water sample (more if content of the suspended solid is low) is filtered with a vacuum pump. Figure 15: Water Sample is Filtered with Filtering Apparatus and Vacuum Pump. 10. The filter paper is cleaned with deionized water to wash the remaining waste.

Figure 16: Filter Paper Cleaned with Deionized Water. 10 11. The filter paper is dried in the oven at temperature 103-105°C and is weighed until constant weight is obtained. Figure 17: Filter Paper with Suspended Solids to be Dried in Oven. 12. Step 5 to 12 is repeated for another water samples. 11 6. 0 RESULTS Weight of Filter Sample Paper + Suspended Solid, A (mg) Weight of Filter Paper, B (mg) Suspended Solids Content, SS (mg/L) (a) Pond at Kampung E hostel 251. 2 240. 2 44. 0 (b) Pond at SST 259. 7 240. 3 77. 6 (c) Concrete Curing Tank at SEIT 257. 8 32. 6 100. 8 12 7. 0 DISCUSSION/ ANALYSIS 1. The calculation to obtain the Suspended Solids Content of water samples are shown as follow by using the formula as below ( A ? B) ? 1000 Volume of sample (mL) Concentration of suspended solid, SS = A = Weight of Suspended Solid + Filter Paper (mg) B = Weight of Filter Paper (mg) (a) Sample from Pond at Kampung E Hostel: Concentration of suspended solid, SS = (251. 2 ? 240. 2) ? 1000 250 = 44. 0 mg/L (b) Sample from Pond at SST: Concentration of suspended solid, SS = (259. 7 ? 240. 3) ? 1000 250 = 77. 6 mg/L c) Sample from Concrete Curing Tank at SEIT: Concentration of suspended solid, SS = (257. 8 ? 232. 6) ? 1000 250 = 100. 8 mg/L 13 2. From the results obtained from the three samples, the sample with the highest amount of suspended solids content is the sample from concrete curing tank at SEIT with a value of 100. 8 mg/L. Followed by next is sample from the pond at SST with amount of suspended solids content at 77. 6 mg/L. Among all three, water sample from the pond at Kampung E Hostel has the lowest amount of suspended solids content with a value of 44. 0 mg/L. 3.

The concentration of suspended solids obtained is in the unit of mg/L. This indicates that concentration of suspended solids is the amount of suspended solids in every 1L of water. 4. The high value of concentration of suspended solids at concrete curing tank at SEIT can be explained in the sense that the main components contributor to suspended solid are the sand particle, cement and aggregate from the concrete cube. The concrete cube is placed in water tank for curing purposes. From time to time, the amount of residues that are the sand, cement and aggregate particles collect in the tank.

Apart from that, the curing tank is located at an exposed area which is subjected to contamination by leaves, sand or any materials that is blown by wind. Thus, the water quality is greatly influenced. 5. As for the water sample collected at the pond at SST, the value of concentration of suspended solids is also considered high. The result can be explained where by the pond at SST is exposed to direct sunlight and it may have high biological activity due to the availability of light and oxygen. The upper layer of water through which sunlight can penetrate through is called euphotic zone.

This zone encourages the growth of plants such as algae and phytoplankton. Since the water sample was collected at the littoral zone, which was near to the shore and euphotic zone, rooted water plants and pondweeds can be seen floating on the water surface of the pond. Thus, this brings to the explanation that the suspended solid in this case may refer to organic particles such as vegetation fibers and micro-organisms. 14 6. The pond at Kampung E hostel is surrounded by trees, stone and vegetation plants.

However, the concentration of suspended solid of the pond is much lower compared to the pond at SST might be due to the location of the pond which is shaded under the sunlight. Thus, it can be observed that no plant growth on the water surface due to the limited sunlight penetration. Nonetheless, there is still existence of suspended solids and the value obtained most likely due to the organic particles such as vegetation fibers and micro-organisms as well as nonorganic particles such as clay and silt. 7. From eye observation, the concentration of small solid particles which retained on filter papers can be seen clearly.

The filter paper of water sample from concrete curing tank at SEIT has the darkest colour of layer of suspension solid compared to the water samples collected at the ponds of Kampung E and SST. Thus, this also explains the higher amount of concentration of suspended solids at concrete curing tank compared to the rest. 8. The results obtained might not reflect the actual amount of suspended solids in the water sources. This is due to the process when collecting the water samples. While collecting the samples, water is not agitated first so that the water is evenly distributed.

Usually, major and heavier particles or suspended solids such as clay, silt and sand tend to sink to the bottom of tank or bed of the pond. Thus, water that obtained directly from the top surface of the water source does not represent the actual amount of suspended solids in the water. 9. Comparing the results obtained from the water samples with the Water Quality Index, water quality index for pond at Kampung E Hostel is 86, water quality for pond at SST is 85 and the water quality for concrete curing tank at SEIT is 83.

The water quality index for all three samples show that they falls in the Class II (WQI 76. 5 – 92. 7) where water supply needs conventional treatment but fit for fishery and recreational activities. 15 10. While conducting the experiment, precautionary measures should be taken in order to obtain result that is more accurate. The precautionary measures are: (a) All reading must be observed at the meniscus level in order to avoid parallax error. (b) Make sure that the filter papers dry for an hour and weighted until constant weight to obtained the accurate value. c) Vibrations should be avoided when using the analytical balance as the apparatus is sensitive to air-conditioning and table movement. This affects the accuracy of the result. (d) The filter papers must clean with deionized water to wash the remaining waste. The set of vacuum pump must wash by deionized water before repeating the steps for other samples. 8. 0 CONCLUSION In conclusion, suspended solids test was conducted on the three water samples collected from the pond at Kampung E hostel, pond at SST and the concrete curing tank at SEIT.

The highest value of concentration of suspended solids obtained is from the concrete curing tank with the value of 100. 8 mg/L, followed by sample from the pond at SST, 77. 6 mg/L and the lowest amount of suspended solids content from the pond at Kampung E hostel at 44. 0 mg/L. Therefore, the objective of the experiment is achieved. 16 9. 0 REFERENCES [1] J. R. Backhurst, J. F. Richardson, J. H. Harker. 2001. Chemical Engineering: Solutions to the Problems in Volume 1 (Coulson and Richardsons Chemical Engineering). Butterworth-Heinemann: pg68. [2] Jo Allan Beran. 2010.

Laboratory Manual for Principles of General Chemistry. John Wiley and Sons: pg61. [3] Srinivasan. 2009. Environmental Engineering. PHI Learning Pvt. Ltd. : pg29. [4] Sherwood C. Reed, Ronald W. Crites, E. Joe Middlebrooks. 1998. Natural Systems for Waste Management and Treatment. McGraw-Hill Professional: pg62 [5] Mackenzine L. Davis and David A. Cornwell. 2008. Introduction to Environmental Engineering, 4th edition. Mc Graw Hill: pg 357, 391-400. [6] Citing internet sources: Retrieved on 17 October 2011: http://www. waterresearch. net/watrqualindex/index. htm 17