Ubeyde Ipek

Stripping/flocculation/membrane bioreactor/reverse osmosis treatment of municipal landfill leachate

This study presents a configuration for the complete treatment of landfill leachate with high organic and ammonium concentrations. Ammonia stripping is performed to overcome the ammonia toxicity to aerobic microorganisms. By coagulation-flocculation process, COD and suspended solids (SS) were removed 36 and 46%, respectively. After pretreatment, an aerobic/anoxic membrane bioreactor (Aer/An MBR) accomplished the COD and total inorganic nitrogen (total-N(i)) removals above 90 and 92%, respectively, at SRT of 30 days. Concentrations of COD and total-N(i) (not considering organic nitrogen) in the Aer/An MBR effluent decreased to 450 and 40 mg/l, respectively, by significant organic oxidation and nitrification/denitrification processes. As an advanced treatment for the leachate, the reverse osmosis (RO) was applied to the collected Aer/An MBR effluents. Reverse osmosis provided high quality effluent by reducing the effluent COD from MBR to less than 4.0mg/l at SRT of 30 days.

Role of intermittent aeration in domestic wastewater treatment by submerged membrane activated sludge system

Abstract In this study, the treatment of domestic wastewater in a lab-scale submerged membrane activated sludge system (sMBR) was investigated under different aeration intervals. The COD concentration of the system effluent varied generally between 5 and 25 mg/l and the COD removal at the organic loads of 0.6–0.8 kg COD/m3.d was observed to be above 98%. The total phosphorus content of the filtrate was decreased to a level that was less than 1 mg/l under the aerobic conditions in which the aeration was continuously made. A dramatic increase in the total phosphorus content of filtrate was observed under the aerobic + anoxic conditions in which the aeration was made at differential intervals. The filtrate was free of suspended solid (SS) and total coliform bacteria and a percent removal of 100 was achieved in terms of these parameters. The influent turbidity removal was 97–99.8%. Generally, the removal of total Kjeldahl nitrogen (TKN) and ammonium nitrogen varied in the ranges of 87.8–99.1% and in the ranges of 89.4–99.8%, respectively. While the nitrate concentrations in the filtrate increased to 26.8 mg/l under the aerobic conditions, it was determined that this value was decreased to 2.4 mg/l under the aerobic + anoxic conditions.

Physico-chemical treatment of marble processing wastewater and the recycling of its sludge

In the first part of this study, the treatability of marble processing wastewater by the coagulation-flocculation process was investigated. Optimum coagulant-flocculant doses for turbidity removal in wastewater from the cutting, faience and equalization processes were determined as 500, 200 and 500 ppm of Al2(SO4)3; 300, 500 and 300 ppm of FeCl3 and 600, 400 and 200 ppm of Agrofloc 100 (AGRON Water Treatment Technologies and Chemical Marketing Industry and Trade Limited Company, İzmir, Turkey), respectively. It was found that the removal of total solids from cutting and equalization process wastewaters was highest for the 100 ppm dosage of all chemicals used. The amount of total solids removed from faience process wastewater by Agrofloc 100 was higher than that removed by the other chemicals used. The removals of suspended solids from cutting, faience and equalization process wastewaters were similar to each other for each of the chemicals. The pH values after treatment by Agrofloc 100 were higher than the values determined after treatment by other chemicals for all process wastewater. Electrical conductivity values, however, were lower for Agrofloc 100 than for the others. Settled sludge volume experiments showed that settled sludge volumes decreased with time. The results of the quiescent settling experiment showed that the settling type could be termed flocculent settling. In the second part of the study, the usage of waste sludge from marble processing as an additive material in cement was investigated. The waste sludge originated from the wastewaters of different steps of the marble processing plant. Waste sludge was replaced with cement at various percentages by weight to prepare the mixtures of mortar. The specimens poured into the moulds were held for 24 h, removed from the moulds and held again for 28 days in lime-saturated water at 23°C. Compressive and flexural strengths were evaluated with respect to percentages of waste sludge replaced with cement. The maximum compressive and flexural strengths were observed for specimens containing a 6% waste sludge when compared with control and it was also found that waste sludge up to 9% could effectively be used as an additive material in cement.

Determination of degradation of radioactivity and its kinetics in aerobic composting

In this study, the kinetics of disappearance of radioactivity in aerobic composting was investigated. For this purpose, compost materials were prepared by mixing sugar beet wastes, wine factory wastes (grape wastes), straw and biological treatment sludge in different amounts. While alpha-radioactivity was not initially detected in all composting materials, the composting materials had some beta-radioactivity. In the mixtures of sugar beet wastes--straw-biological treatment sludge (1), sugar beet wastes-wine factory wastes (grape wastes)-biological treatment sludge (II) and wine factory wastes (grape wastes)-biological treatment sludge (III), the beta-radioactivity reduced by 82%, 58%, 85% respectively of initial values after 52 d. The beta-radioactivity degradation in the composting process could be represented by first-order kinetics and reaction rate constants of mixtures of I, II and III were k = 0.0693 d(-1) (R2 - 0.84), k = 0.0453 d(-1) (R2 = 0.98), k = 0.0234 d(-1) (R2 = 0.97), respectively.

Phenol removal capacity of RO with and without pre-treatment

The effect of traditional pre-treatment methods, such as depth filtration and granular activated carbon (GAC), on the phenol removal capacity of reverse osmosis (RO) was investigated. Two experimental series were performed in the pH range of 4-9. Firstly, a phenol- containing water sample was passed through a RO membrane alone. A sample was then passed through a depth filter and a GAC unit prior to it being passed through the RO membrane. The results indicate that the best RO phenol removal efficiency occurs with GAC pre-treatment. The phenol concentration in the RO effluent was reduced to less than 0.25 mg/l.