Comparison of lime treatment plants in an emergency situation (Bangladesh)

The focus was specifically on the Kutupalong refugee camp in Cox’s Bazar, Bangladesh. Two different lime treatment plan have been evaluated by their pathogens, COD and nutrient removal. The treatment plants have been evaluated for their removal efficiency per treatment step and overall removal, measuring pH, EC, TS (TSS), VS, coliform, E. coli, helminth eggs, TCOD, TN, NH4-N, NO3-N. The results indicated that both treatment plants were not compliant with the Bangladesh standard. One of them did not did not meet the standards for coliform, COD and TN, and the other one did not meet the standards for pH, COD, TN and TS. The efficiency of each treatment step of each plant was then analysed and it was concluded that some of the treatment processes need to be improved to comply with the standards, or that the standards FS treatment are indeed set at too low concentrations and it is almost impossible to meet. Upon completion of the field experiments, further laboratory analyses were performed to investigate the possibility of regrowth of pathogens and the long term effect of hydrated lime on FS (simulants were used as a substitute of real FS). During these laboratory experiments it was found that regrowth of pathogen did not take place for E. coli, and the long-term effect of hydrated lime was demonstrated by the measured concentration of TDN (total dissolved nitrogen), DOC (dissolved organic matter), EC (electrical conductivity) and pH. The laboratory experiments also showed the influence of hydrated lime on metal concentration of Na, K, Ca and Mg.