Research On The Biological Treatment Of High Salinity Wastewater By SBR Process

In this paper, the organics degradation rate and NH₄⁺-N removal efficiency are studied in high salinity wastewater (the wastewater contain 50% seawater) by SBR process. The researches include the comparison of two different modes of sludge acclimation, and the effects of influent concentration of CODcr and NH₄⁺-N, temperature, the value of pH and stock salinity on the whole activate sludge system are also studied.1, In the organic degradation, when the influent CODcr concentration is 300mg/L, the mode of acclimation directly and the mode of acclimation with salinity grads both can reach 85%CODcr removal efficiency. But the former need 28 acclimation periods (every periods includes 10h), and the latter need 42 acclimation periods. When sludge acclimation accomplished, microorganism phase is abundance, except Zoogloea bacteria and Filamentous bacteria, few Protozoa are exit in activate sludge, the sludge settling performance improved, and sludge volume index (SVI) decreased with the increase of salinity.In the steady high salinity sludge system, with the influent concentration CODcr increasing, the degradation rate drops. When the influent CODcr concentration is 1100mg/L, the effluent is 184mg/L. The salinity stock effect of 30%propotion seawater on CODcr removal efficiency in the steady system is light. The salinity stock of 70%proportin seawater need 3 cycles to come back the initialization, and no seawater need 5 cycles.2, In NH₄⁺-N removal, when the influent concentration is 45mg/L, the removal efficiency of two acclimation modes both can reach above 97%. But the period of acclimation with salinity grads mode is longer than another one. The former need 35 acclimation periods and the latter need 28 acclimation periods.In the steady high salinity sludge system, with the influent NH₄⁺-N concentration increasing, the removal efficiency drops. When the influent NH₄⁺-N concentration is 105mg/L, the removal efficiency fall to 45%. Under the high NH₄⁺-N load, increasing the value of pH, the efficiency is improved. When the value of pH is 8.3, the ammonianitrogen removal efficiency can reach to 76.6%. With the temperature range from 20 °Cto30 "C, with the temperature increasing the removal efficiency of NH/-N is improved. The salinity stock effect of 30%propotion seawater on NH/-N removal efficiency in the steady system is light. The salinity stock of 70%proportin seawater need 4 cycles to come back the initialization, and no seawater need 5 cycles.3> The paper also studied the new CODcr determination method —potassium iodine alkaline potassium permanganate determination, and research different The value of K, viz. CODoh?ki /CODcr? The result shows that the value of K is decreased with the increasing of the concentration of CODoh-ki- When the concentration of CODoh-ki above 100 mg/L, the value of K is level off to 1.5.