Akademik Veri Yönetim Sistemi
TMMOB–ÇMO, XIII. Ulusal- I. Uluslararası Çevre Mühendisliği Kongresi, Kocaeli, Türkiye, 10 - 12 Ekim 2019
Wastewaters with a complex structure such as leachate and slaughterhouse waters contain oil
and surfactants in addition to high ammonia content. Hence, the use of biological treatments in
the treatment of these wastewaters causes some difficulties. In particular, wastewaters with high
ammonia concentrations need to have ammonia contents decreased before biological treatment.
Methods such as aeration at high pH, ion exchange, and MAP precipitation are used to decrease
the ammonia concentration.
Hydrodynamic cavitation (HDC) is a process that creates cavities in water by creating sudden
pressure changes and leads to high turbulence conditions due to the collapse of cavities. Various
studies in the literature stated that due to the advantages of high turbulence and enhanced
transition between phases, advanced oxidation techniques operate more efficiently with less
chemical consumption. In this study, ammonia stripping efficiency in a continuously-operated
HDC reactor was investigated at different hydraulic retention times (HRT).
Firstly, the synthetic wastewater prepared from NH4Cl was used, afterwards, leachate was used.
Parameters of pH 11, 30°C temperature, 2500 mg/L initial concentration, 25 L/min air flow
rate, 7 mm venturi cavitation tube, and 0.12 cavitation number were used for a reactor operating
for at least 24 hours with varying HRTs. For all HRTs, the reactor reached equilibrium in 10
hours. Equilibrium concentrations were calculated as 1232, 705, 424, and 322 mg/L for 6, 12,
24, and 36 hours and ammonia removal efficiencies were 51%, 72%, 83%, and 87%,
respectively. The operating parameters of the continuous reactor for leachate are all the same as for
synthetic wastewater studies except for 0.17 cavitation number, 24 h HRT, and absence of aeration.
Ammonia stripping efficiency of 68% was obtained for leachate at equilibrium concentration.
In all experimental studies, the reactor temperature was kept constant at 30 °C by the controller
and the proportional valve connected to it. However, another advantage of HDC is that it
increases the temperature of water in the reactor. Ammonia stripping can be completed in
shorter periods when performed at high temperatures. As a result, when HDC is used for
stripping ammonia, it eliminates the cost of additional heaters to achieve high temperatures.
This innovative system offers an alternative for reducing the ammonia content of wastewater
to the desired concentration before biological treatment.