CIVIL ENGINEERING SEMINAR TOPICS: WATER TREATMENT USING MORINGAOLEIFERA (Page 2)

Page 2

CHAPTER 2

MATERIALS AND METHODS

2.1 MORINGA OLEIFERA

Moringaoleifera (MO), known as Moringa, is full of nutrients and vitamins and is good in your food as well as in the food of your animals. Moringa helps to clean dirty Water and is a useful source of medicines.

Fig.2.1: Moringaoleifera Tree

(Source: Eman N Ali (2009))

2.2 PREPERATION MORINGA OLEIFERA SEED POWDER

Good quality dry seeds of Moringaoleifera were selected from the pods that were collected. The pods collected were allowed to completely dry on the tree (the brown colour pods) because the green pods do not possess any coagulation activity.

The pods length ranged between (40-60) cm, and each pod contained around (20-30) seeds. The seeds coat and wings were removed manually, followed by the grinding of the seeds into a fine powder using a domestic blender, then sieving the ground powder through 250 μm sieve. Figures 2.2, 2.3, 2.4 and 2.5 shows the MO pods, MO seed, de-husked seed kernel and seed powder.

Fig.2.2: Moringaoleifera pods

(Source: Eman N Ali,(2009))

Fig.2.3: Moringaoleifera seeds

(Source: Ravikumar K and Prof. Sheeja A K (2013))

Fig.2.4:Moringaoleifera de-husked seed kernels

(Source: Ravikumar K and Prof. Sheeja A K (2013))

Fig.2.5: Moringaoleifera seed powder

(Source: Ravikumar K and Prof. Sheeja A K (2013))

2.3 AQUEOUS EXTRACT

Aqueous extract was prepared by using 200ml of tap water and 25g of MO seed powder, mixed by a magnetic stirrer for 60 minutes and settled for 20 minutes. Moringaoleifer aqueous extract is finally filtered through 20µm paper filter.

2.4 COAGULANT ACTIVITY TEST

Sedimentation Jar test were carried to determine the coagulation properties of the plant derived coagulants. Onebeaker was used as control and in other beakers varying dosage of MO coagulant was added. Jar tests were conductedon 1000 ml synthetic turbid water samples.The standard procedure was, the samples were subjected to a rapid mixing at 100 rpm for 1 minute, and a slow mixing step at 30 rpm for30 min. The stirrer was then switched off and the flock allowed to settle undisturbed for 30 minutes. The samplesfor residual turbidity measurement were withdrawn using a pipette from a height of 5cm below the surface of eachbeaker, and residual turbidity was measured. Effect of dose of natural coagulants on removal of turbidity alsostudied. Jar test also determines the effective dosage of coagulant to reduce the heavy metal of the sample.

The effect of pH on turbidity removal was also studied by varying pH of turbid water. pH of the suspension wasadjusted to the desired value by adding either 0.1 MHCl solution or 0.1M NaOH solution. Turbidity measurementwas carriedout by ‘GlobeInstrument’ Turbidity meter.pH value of the suspensionwas measured using a pH model meter.

2.5 MULTISTAGE DRINKING WATER FILTRATION

By providing roughing filter pretreatment, suspended solids are decreased. Rapid sand filtration is still a viable method of water treatment most suitable for raw water sources with turbidity and suspended solids. Multistage filtration has been shown to be an efficient and effective drinking water treatment technique for source water with high turbidity, organic matter, and suspended solids.

2.5.1 FILTRATION TEST WITH ROUGHING FILTERS

In vertical-flow roughing filters the water to be treated flows in sequence through the three filter compartments filled with coarse, medium and fine filter material. The size of the three distinct filter material fractions is generally between 25 and 3 mm, and graded, for example, into fractions of 25-16mm, 16-8mm and 8-3mm. Roughing filtration was conducted directly after the coagulation and flocculation processes with Moringaoleifera and separates the suspended solids. Vertical-flow roughing filter was operated at 0.3 to 1.0 m/h filtration rates. The separated solids, which accumulate mainly in the coarse filter fraction next to the filter bottom, can be easily flushed out with the water stored in the filter. Therefore, the use of upflow roughing filter in layers was used.

Fig.2.6: Up flow roughing filters

(Source: Ravikumar K and Prof. Sheeja A K (2013))

2.5.2 Filtration test with rapid sand filter

In rapid sand filters the water to be treated flows in sequence through the three filter compartments filled with coarse, medium and fine filter material. The size of the three distinct filter material fractions is generally between 50 and 0.5 mm, and graded, for example, into fractions of 25-50mm, 13-25mm and 0.5-1mm. Rapid sand filtration was conducted directly after the roughing filtration and separates the last remaining flocs that failed to disappear during roughing filtration. The filtration rate for a rapid filter is 5-10 m/h.

Fig.2.7: Rapid sand filter media size

(Source: Ravikumar K and Prof. Sheeja A K (2013))

2.5.3 Moringaoleifera seed coagulation and double filtration

Double filtration is an efficient and effective drinking water treatment technique for source water with high turbidity,organic matter, and suspended solids.Jar tests were carried out in the following conditions: 1 minute rapid mixing and 10 minutes slow mixing. An up-flow roughing filtration stage was chosen because it is a process with a high efficiency in the removal of light flocs. As a second stage a conventional rapid filter was adopted.

The washing of the roughing filter was carried out through lower drainage, and the washing of the rapid filter was counter current. The bed of the upflow gravel roughing filter was made up of three layers of gravel of different granule measures.