Relative Coagulation Effectiveness of Jatropha curcas Press Cake ( Physic Nut ) and Aluminium Sulphate in Purifying Domestic Sewage

An investigation was conducted on the relative effectiveness of using press cake of dried Jatropha curcas (Physic nut) seed and alum (Aluminium sulphate) for the purification of domestic sewage. The experimental design used was Completely Randomized Design (CRD) replicated three times. Physical and chemical properties of domestic sewage were investigated before and after the purification exercise. Treatments imposed included: the control culture (no alum and Jatropha), 10 mg/l of Aluminium Sulphate (alum) treatment, 80 mg/l of J. curcas treatment, 100 mg/l of J. curcas treatment and 120 mg/l of J. curcas treatment. The results showed that for the total dissolved solids, cultured tanks treated with 80 mg/l of J. curcas reduced the sewage concentration from 30.1 mg/l to 23.20 mg/l, Biological Oxygen Demand (BOD) was reduced from 30.55 mg/l to 30.10 mg/l, increased acidity from 5.33 mg/l to 5.66 mg/l, reduced alkalinity from 6.35 mg/l to 6.0 mg/l, reduced pH from 7.6 to 6.55, and likewise 10 mg/l of alum also reduced pH from 7.6 to 6.55. The cultured tanks treated with 120 mg/l of J. curcas performed best in reducing turbidity and Chemical Oxygen Demand (COD) of the sewage. The turbidity was reduced from 5.99 NTU to 5.6 NTU; 120 mg/l of J. curcas also reduced total hardness from 9.6 mg/l to 7.15 mg/l, total solids from 55.6 mg/l to 55.17 mg/l. Cultured tanks treated with 10 mg/l of alum reduced total dissolved solids from 30.1 mg/l to 24.30 mg/l, while those treated with 80 mg/l of J. curcas reduced it from 30.1 mg/l to 23.20 mg/l, 100 mg/l and 120 mg/l of J. curcas reduced it to 25.20 mg/l. Total suspended solids increased from 25.5 mg/l to 30.96 mg/l for 10 mg/l of alum, to 30.22 mg/l for 80 mg/l of J. curcas, 30.26 mg/l for 100 mg/l of J. curcas and 30.38 mg/l for 120 mg/l of J. curcas. Conductivity increased withion the study period from 525 μS/cm to 830 μS/cm for 10 mg/l of alum, to 590 μS/cm for 80 mg/l of J. curcas, 634 μS/cm for 100 mg/l of J. curcas and finally to 662 μS/cm for 120 mg/l of J. curcas. The results show that, within the reduction of BOD, pH, alkalinity and total solids, 80 mg/l of J. curcas performed best, while for reduction of COD and turbidity, 120 mg/l of J. curcas gave the best results. The study showed that Jatropha curcas was effective in purifying domestic sewage with little or no harmful effect on the ecology.


Introduction
In most parts of sub-Saharan Africa, water demand far outstrips supply.In Nigeria, rural water supply and sanitation projects implemented in several rural districts in the country by the Community Water and Sanitation Agency (CWSA) are currently facing certain drawbacks due to poor management and financial constraints (WaterAid, 2007).The outcome of this is that the few installed water facilities for these communities are unable to suffice the needs of the population.Rural communities most often rely greatly on ground water provided that it is available in sufficient quantities, and also on surface water which may be contaminated in most cases.
Most of the diseases causing death in the country are related to poor water and sanitation, with malaria, diarrhea and cholera being the main causes of mortality.
Two major epidemics were recorded in 1991 and in 1999, with fatality ranging from 2.2 to 3.4% (WHO, 2005).
Water collection and storage practices, especially the choice of water collection and storage containers, are fundamental in determining household water quality (Sobsey, 2002).Murcott (2006) identified three broad areas of water quality: physical, chemical and microbiological, that can be improved by household water treatment.Physical removal technologies include ceramic and bio-sand filters, cloth filters, coagulation and flocculation practices.Boiling, solar disinfection (SODIS) and chlorination are examples of technologies that improve microbial quality of water (WHO, 2004).
One of the goals in water treatment is the removal of turbidity and other contaminants including natural organic materials and organisms.Previous studies has shown that the application of alum in water may be related with the Alzheimer disease (Kawahara, 2005;Shcherbatykh and Carpenter, 2007;Kawahara and Kato-Negishi, 2011) and that is why the use of coagulants from sources such as plants, animal and microorganisms has attracted interest in finding replacement for alum and also to reduce dependency on alum usage.Ali et al. (2010) reported that Moringa oleifera seeds are an efficient and cost effective natural coagulant that can be used as an alternative to aluminium sulphate and other coagulants for water treatment.Yongabi (2004Yongabi ( , 2010) ) reported that the seed powder of physic nut (Jatropha curcas) is very useful in wastewater treatment.
The objective of this study was to investigate the relative effectiveness of using Jatropha curcas and aluminium sulphate (alum) in the purification of domestic sewage.

Experimental design
The sewage sample was cultured in a 16 liter capacity container for a period of seven weeks.Physical and chemical tests were carried out daily at the point of collection, for a period of seven weeks.The experiment was designed based on Completely Randomized Design (CRD); the design was replicated three times.
Treatments imposed included: the control culture (no alum and J. curcas), 10 mg/l of Aluminium sulphate (alum) treatment, 80 mg/l of J. curcas treatment, 100 mg/l of J. curcas treatment and 120 mg/l of J. curcas treatment.

Physical and chemical analyses
Physical parameters of sewage samples such as pH, conductivity, total dissolved solids and hardness were determined using EDTA titration, while electrical conductivity was done using conductivity meter.Turbidity was determined using the Jackson's turbidimeter.Total dissolved solids, total solids, total suspended solids, dissolved solids were determined using the gravimetric method.
All the analyses were carried out using standard procedures recommended by the American Public Health Association (APHA, 2006;AWWA, 2012).Chemical properties such as total hardness were determined using the complexometric titration (EDTA), dissolved oxygen by the Winkler method, biochemical oxygen demand and chemical oxygen demand using standard procedure (APHA, 2006;AWWA, 2012); the chloride ion was determined by the Mohr method, nitrate by the colorimetric method and phosphate using the spectrophotometric method of determination (APHA, 2006;AWWA, 2012).

Statistical analysis
Analysis of variance (ANOVA) was performed on the results obtained from water analysis.Mean separation was done where significant difference existed using Duncan multiple range test procedure as described in the SAS 8.3 software.Significant difference was accepted at P < 0.05 (SAS, 2002).

Results and Discussion
The results of the physical and chemical analyses performed on the sewage samples collected are as shown in Figs.1-10, while statistical analyses are as shown in Tables 1-10.Fig. 1 shows the variations in the values of pH.The pH of the domestic sewage at the point of collection was 7.6 and at the end of the test pH was finally reduced to 6.65 for the control culture, 6.55 for the 10 mg/l of Aluminium sulphate (alum), 6.55 for the 80 mg/l of J. curcas, 7.0 for the 100 mg/l of J. curcas and finally 7.1 for 120 mg/l of J. curcas.The results show that samples cultured with 80 mg/l of Jatropha was more effective than those treated with 100 mg/l and 120 mg/l of J. curcas respectively, in reducing the pH of sewage.The final result for the containers treated with 80 mg/l of Jatropha (6.55) was comparable with those treated with 10 mg/l of alum (6.55).Using the Nigeria Industrial Standard for drinking water (NIS 2007) ranges 6.5 -8.5 show that all the treatments imposed effectively reduced the pH of sewage.Table 1 shows the ANOVA test results for pH for the tested he concentration (Fcal = 24.779)and with significant difference (P = 0.000).Fig. 2 shows the variations in the values of hardness.Total hardness of the domestic sewage at the point of collection was 9.6 mg/l whereas at the end of the test total hardness was finally reduced to 9.6 mg/l for the control culture, 9.2 mg/l for the 10 mg/l of Aluminium sulphate (alum), 7.2 mg/l for the 80 mg/l of J. curcas, 7.3 mg/l for the 100 mg/l of J. curcas and finally 7.15 mg/l for 120 mg/l of J. curcas.In comparison with NIS (2007), the permissible amount is 150 mg/l; therefore, the values obtained at the point of collection, control culture and the treatments imposed are all safe and minimal.
The ANOVA test results for total solids are given in Table 2, (the concentration Fcal = 22.246 and with significant difference P = 0.000).As evidenced in Fig. 3, the value of total solids at the point of collection was 55.6 mg/l and this indicated a low presence of solid particles in the domestic sewage.The average drop of total solid for the control culture, after the seventh week of the experiment, was 55.30 mg/l, 55.26 mg/l for the 10 mg/l of alum, 55.19 mg/l for the 80 mg/l of J. curcas, 55.18 mg/l for the 100 mg/l of Jatropha and 55.17 mg/l for the 120 mg/l of J. curcas.From these results, it can be deduced that 120 mg/l of J. curcas were more effective than the other treatments imposed as compare to the values of point of collection.ANOVA test results are shown in Table 3, the concentration (Fcal = 0.850), with significant difference (P = 0.505).
Fig. 4 shows the variations in the values of dissolved oxygen, which at the point of collection was 96.3 mg/l; after the periods of study, it later drop to 93.90 mg/l for control culture, 82.20 mg/l for the 10 mg/l of alum, 81.60 mg/l for the 80 mg/l of J. curcas, 60 mg/l for the 100 mg/l of J. curcas and finally 89.70 mg/l for the 120 mg/l of J. curcas.There was formation of small organism in the water during the course of the experiment.It was observed that the water was favorable to these organisms and also aid in the formation of dissolved oxygen.The Fig. 9 shows the variations in the values of Biological Oxygen Demand (BOD); at the point of collection, the BOD level of the domestic sewage was 30.55 mg/l, along the line of the analysis, and the average BOD removed for the period of seven weeks for control culture (no J. curcas), 10 mg/l of alum, 80 mg/l of J. curcas, 100 mg/l of J. curcas and lastly 120 mg/l of J. curcas were 30.25 mg/l, 20.08 mg/l, 30.10 mg/l, 30.18 mg/l and 30.20 mg/l.respectively.When compared to that of point of collection, 10 mg/l of alum were more effective and 80 mg/l of J. curcas also reduced BOD as compared with other ranges of Jatropha.Consequently, increasing the ranges of J. curcas may lead to wastage of coagulant material without sufficient increase in the removal of BOD.The ANOVA test results are given in Table 9, the concentration Fcal = 0.979 and with significant difference (P = 0.433).
The turbidity at the point of collection was 5.99 NTU (Fig. 10).The reduced turbidity level for the control culture, 10 mg/l of alum, 80 mg/l of J. curcas, 100 mg/l of J. curcas and 120 mg/l of J. curcas during the process of the experiment were 5.75 NTU, 5.78 NTU, 5.73 NTU, 5.70 NTU and 5.60 NTU.Also, in comparison to NIS (2007) with the permissible amount of 5 NTU, all the values for the treatments imposed were higher.The ANOVA test results are given in Table 10, the concentration Fcal = 1.799 and with significant difference (P = 0.154).
Fig. 11 shows the variations in the values of acidity; at the point of collection, the domestic sewage was 5.33 mg/l; along the line of the test, the increase in the level of acidity for the period of seven weeks for control culture (no J. curcas), 10 mg/l of alum, 80 mg/l of J. curcas, 100 mg/l of J. curcas and lastly 120 mg/l of J. curcas were 6.35 mg/l, 6.88 mg/l, 6.37 mg/l, 5.66 mg/l and 5.65 mg/l respectively.When compared to that of point of 308 suitability of the water to the organisms also proved that the water was conducive for them to live and since the water was not harmful to their sustenance, that show it cannot be harmful to plants or human after treatment.The ANOVA test results are given in Table 4, the concentration Fcal = 20.458 and significant difference determined for (P = 0.000).
Fig. 5 shows the variation in the values of total dissolved solids.From Fig. 4 and 5, it can be noted that the total dissolved solid at the point of collection was 30.1 mg/l and this shows that even though pollution level was minimal, there was a significant reduction in its level at the end of the experiment to 29.90 mg/l for the control culture at the end of the seventh week, 24.30 mg/l for the 10 mg/l of alum, 23.20 mg/l for the 80 mg/l of J. curcas, 25.20 mg/l for the 100 mg/l of J. curcas and 25.20 mg/l for the 120 mg/l of J. curcas respectively.For the experiment, it was observed that the 80 mg/l of J. curcas was more effective in the treatment of the domestic sewage.The ANOVA test results are summarised in Table 5, the concentration (Fcal =1.624) and with significant difference (P = 0.193).These are solid particles (organic and inorganic) suspended within the sewage, but are undissolved.
Fig. 6 shows the variations in the values of total suspended solids (TSS); at the point of collection, the domestic sewage was 25.5 mg/l, whereas along the line of the analysis, average TSS for the period of seven weeks for control culture (no J. curcas), 10 mg/l of alum, 80 mg/l of J. curcas, 100 mg/l of J. curcas and lastly 120 mg/l of J. curcas were 25.54 mg/l, 30.96 mg/l, 30.22 mg/l, 30.26 mg/l and 30.38 mg/l respectively.The ANOVA test results are given in Table 6, with the concentration (Fcal = 0.626) and significant difference (P = 0.647).
Fig. 7 shows that the alkalinity at the collection point was 6.35 mg/l for all treatments.By comparing control culture value and the values of treatments imposed to point of collection, it can be observed that alkalinity decreased to average value of 5.5 mg/l for the control culture, it decreased to 5.1 mg/l for the 10 mg/l of alum, it decreased to 5.2 mg/l for the 80 mg/l of J. curcas, it decreased to 5.3 mg/l for the 100 mg/l of J. curcas and lastly, it decreased to 5.4 mg/l for the 120 mg/l of J. curcas.This implied that 80 mg/l of J. curcas was more effective among the ranges of Jatropha use.The ANOVA test results are given in Tables 4 and 7, with the concentration Fcal = 0.844 and significant difference (P = 0.508) Fig. 8 shows that the conductivity at the point of collection was 525 μS/cm (microsiemens per centimeter) and increased during the experiment period at room temperature (25 o C).The average increments after seven weeks of test for control culture, 10 mg/l of alum, 80 mg/l of J. curcas, 100 mg/l of J. curcas and 120 mg/l of J. curcas were 597 μS/cm, 830 μS/cm, 590 μS/cm, 634 μS/cm and 662 μS/cm respectively.In comparison with NIS (2007), the permissible amount is 1,000 μS/cm, which implies that all treatments imposed were safe and conductivity was minimal.From the ANOVA test, it resulted data summarised in Table 8, with the concentration Fcal = 5.036 and with significant difference (P = 0.003).collection, 10 mg/l of alum were more effective; 80 mg/l of J. curcas also increased the acidity as compared with other ranges of Jatropha.Consequently, increasing the ranges of J. curcas may leads to wastage of coagulant material without sufficient results.From the ANOVA test results Table 11, with the concentration Fcal = 1.439 and with significant difference (P = 0.245).Fig. 12 shows the variations in the values of Chemical Oxygen Demand (COD); at the point of collection, the domestic sewage was 8.45 mg/l; during the periods of study, COD removed for the period of seven weeks for control culture (no J. curcas), 10 mg/l of alum, 80 mg/l of J. curcas, 100 mg/l of J. curcas and lastly 120 mg/l of J. curcas were 8.4 mg/l, 8.2 mg/l, 8.17 mg/l, 8.05 mg/l and 7.8 mg/l respectively.The ANOVA test results are given in Table 12, the concentration Fcal = 10.224 and with significant difference (P = 0.000).
The obtained data prove that J. curcasis can be an effective natural coagulant.Water coagulation with alum are usually very acidic and thus dangerous for human consumption, as it is liable to harming the gastrointestinal tract.J. curcas can be cultivated very cheaply at the household level or in small communal nurseries, which is to be encouraged among the rural populations.

Conclusions
The study showed that Jatropha curcas was effective in purifying domestic sewage with little or no harmful effect on the ecology.The study showed the reduction in BOD, which brings about aerobic decomposition of organic matter in sewage.J. curcasis can be an effective natural coagulant, which can be used in improving the physicochemical characteristics of water in terms of pH, turbidity, total dissolved solids, suspended solids, alkalinity and conductivity etc.In coagulation, Jatropha seeds hardly affect pH of water as compared to alum which requires pH adjustment after treatment.This is likely to reduce the high cost of the current water treatment systems.Thus, J. curcas seeds present a viable alternative coagulant to alum in treating water for rural dwellers, since alum has side effects like Alzheimer's disease while J. curcas is environmentally friendly, cheap to cultivate and without side effects.

Table 1 .
Statistical analysis of pH

Table 3 .
Statistical analysis of total solids

Table 2 .
Statistical analysis of total hardness

Table 4 .
Statistical analysis of dissolved oxygen

Table 5 .
Statistical analysis of total dissolved solid

Table 6 .
Statistical analysis of TSS

Table 8 .
Statistical analysis of conductivity

Table 7 .
Statistical analysis of alkalinity

Table 10 .
Statistical analysis of turbidity

Table 9 .
Statistical analysis of BOD

Table 12 .
Statistical analysis of COD

Table 11 .
Statistical analysis of acidity