Treatment of potato farm wastewater with sand filtration

Denitrification process and suspended solids separation in deep-bed two-media down-flow filters

A denitrification process with simultaneous suspended solids separation and denitrification was studied in pilot-scale filters. Denitrification rates for the total, upper, middle, and lower layer of the filter bed were 21.3, 79.0, 27.8, and 21.9 g (NO₃+NO₂)-N m^-3 filter bed h^-1 (g NO_x-N m^-3 h^-1), respectively. The biofilm on the grains showed denitrification rates for not backwashed grains and grains backwashed once of 8.8 and 7.8 g NO_x-N m^-3 h^-1, respectively, indicating a robust biofilm. Construction and operation strategies of full-scale filters were done based on the pilot-scale study results. For further optimization of the denitrification process, 1 of 60 filters in operation was chosen for a full-scale study. The denitrification rates for the total layer, upper layer, middle layers, and lower layer of the filter bed were 12.7, 15.6, 27.3, 27.9, 27.8, and 14.0 g NO_x-N m^-3 h^-1, respectively. The rate of 27.8 g NO_x-N m^-3 h^-1 was obtained for a middle layer in both filters. The amount of nitrogen possible to reduce in the full-scale filters was calculated to 8.8 mg N L^-1 or 2403 kg N d^-1. This paper presents results of denitrification rates, reaction orders, rate constants, and suspended solids separation.

Preparation of affordable and multifunctional clay-based ceramic filter matrix for treatment of drinking water

Affordable clay-based ceramic filters with multifunctional properties were prepared using low-cost and active ingredients. The characterization results clearly revealed well crystallinity, structural elucidation, extensive porosity, higher surface area, higher stability, and durability which apparently enhance the treatment efficiency. The filtration rates of ceramic filter were evaluated under gravity and the results obtained were compared with a typical gravity slow sand filter (GSSF). All ceramic filters showed significant filtration rates of about 50-180 m/h, which is comparatively higher than the typical GSSF. Further, purification efficiency of clay-based ceramic filters was evaluated by considering important drinking water parameters and contaminants. A significant removal potential was achieved by the clay-based ceramic filter with 25% and 30% activated carbon along with active agents. Desired drinking water quality parameters were achieved by potential removal of nitrite (98.5%), nitrate (80.5%), total dissolved solids (62%), total hardness (55%), total organic pollutants (89%), and pathogenic microorganisms (100%) using ceramic filters within a short duration. The remarkable purification and disinfection efficiencies were attributed to the extensive porosity (0.202 cm³ g^-1), surface area (124.61 m² g^-1), stability, and presence of active nanoparticles such as Cu, TiO₂, and Ag within the porous matrix of the ceramic filter.