Factors Regulating Environmental Transformation of

Organic P – Nutrient Resource Ratio By Sayantani Ghosh (51444937)

MSc Environmental MicrobiologySupervised by Professor Graeme Paton

Introduction

• Phosphorus is the basis of all living forms which cannot be replaced and is a non-renewable resource.• 90% of global demand for phosphorus is directed to agriculture for its use as fertilizer in food production.

• The P present in the wastewater is a major threat to the environment. • Therefore, P recovery from wastewater system is likely to become a sustainable option to meet current and future P demands in agriculture.

Establish the relationship between P transformation andnutrient resource ratio. The main objective of the work was manipulation of nutrient resource ratio expecting to notice a change in P mineralization capacities.

The C:N:P ratio was manipulated to measure the difference of aryl – phosphatase activity and its effect on the biomass and pH .

Methods

Samples were taken each time to determine the effect of the varied ratio on the aryl-phosphatase activity. The phosphatase assay was used but in a microtiter plate so that a large number of samples could be analysed over a short period of time.

Skimmed milk was used as the source of organic P where the inoculum was added and C:N ratio was varied and placed on the shaker incubator to carry on the experiment.

The samples were also digested by acetic acid and analysed using FIA (flow injection analysis) to determine the production of PO4

3- .

The cfu and the pH was also calculated to determine its effect.

Results

Fig. 1 • C:N 9.2:.5; • C:N 18.4:.5; • C:N 23:.5; • 46:.5

7.4 7.6 7.8 8 8.2 8.4 8.6 8.8 90

1000000000

2000000000

3000000000

4000000000

5000000000

6000000000

7000000000

mM pnp /hr

colo

ny fo

rmin

g un

its/m

l

7.4 7.6 7.8 8 8.2 8.4 8.6 8.8 947

48

49

50

51

52

53

54

55

56

mM PNP/HR

PO43

-

Fig. 1 • C:N 9.2:.5; • C:N 18.4:.5; • C:N 23:.5; • 46:.5

Results

11.5 12.5 13.5 14.5 15.5 16.5 17.5 18.50.00E+00

1.00E+09

2.00E+09

3.00E+09

4.00E+09

5.00E+09

6.00E+09

7.00E+09

mM pnp/hr

colo

ny fo

rmin

g un

its/m

l

10 11 12 13 14 15 16 17 18 19 2046

48

50

52

54

56

58

60

62

mM PNP/HR

PO43

-

Fig. 1 • C:N 4.6:1; • C:N 4.6:2 • C:N 4.6:2.5; • 4.6:5

Fig. 1 • C:N 4.6:1; • C:N 4.6:2 • C:N 4.6:2.5; • 4.6:5

Future prospects

It was seen that the assay could be performed in a microtiter plate if possible modifications are done accordingly.In the future, the efficiency of the microtiter plate method can be tested at commercial level and with wastewater samples.Comparing the results of different C:N ratios, the appropriate ratio for the maximum activity will be challenging to determine as the wastewater will have highly varied C:N ratios.

ASHLEY, K., CORDELL, D. and MAVINIC, D., 2011. A brief history of phosphorus: From the philosopher’s stone to nutrient recovery and reuse. Chemosphere, 84(6), pp. 737-746.

References

KARUNANITHI, R., SZOGI, A.A., BOLAN, N., NAIDU, R., LOGANATHAN, P., HUNT, P.G., VANOTTI, M.B., SAINT, C.P., OK, Y.S. and KRISHNAMOORTHY, S., Phosphorus Recovery and Reuse from Waste Streams. Advances in Agronomy, (0).

GATERELL, M., GAY, R., WILSON, R., GOCHIN, R. and LESTER, J., 2000. An economic and environmental evaluation of the opportunities for substituting phosphorus recovered from wastewater treatment works in existing UK fertiliser markets. Environmental technology, 21(9), pp. 1067-1084.

TABATABAI, M.A. and BREMNER, J.M., 1969. Use of p-nitrophenyl phosphate for assay of soil phosphatase activity. Soil Biology and Biochemistry, 1(4), pp. 301-307.

Thank you