Pathology and Solutions to Improve Drinking Water Treatment System in Zangalanlou Village, Dargaz city, Iran

Routine biological quality check and water safety plan at small treatment plants should be considered as a part of the control requirements due to the health deprivation and the possibility of further contamination. Zangalanlou Water Treatment Plant is often contaminated due to flood. After examining the damage, improvement was performed to remove and prevent the introduction of contamination and the system's efficiency was controlled considering some parameters. This cross-sectional study was carried out on a real scale in Zangalanlou Treatment Plant in 2017. Improvement performance and comparison of the efficiency of the treatment processes (grit removal chamber, slow sand filter and equalization pond) was statistically analyzed and calculated through measurement of turbidity, heterotrophic bacteria count (HPC), total coliform (TC), fecal coliform (FC) before and after the improvement. Cryptosperidium, Giardia and total organic carbon (TOC) were also examined after improvement. Then, the measured physicochemical parameters of water resource were analyzed for 14 years. The turbidity and HPC in the distribution network and Filter, and HPC in the equalization pond were significantly reduced compared with before improvement. FC, TC and TOC were within the standard limits and the two parasites were not observed but the presence of Blastocystis was confirmed in both raw water and filter inlet, but absent in the output. The physicochemical analysis indicated an increase in total hardness, electrical conductivity, calcium, sulfate and magnesium. Generally, improvements had a significant effect in the removal of contamination at the outlet of the treatment plant, filter and equalization pond, and the physicochemical parameters pridected the water salinity in future.