Aysenur Ugurlu

Phosphorus removal by fly ash

The aim of this work was to investigate the possible use of fly ash generated from thermic power stations in the removal of phosphorus contained in aqueous solutions. A series of batch tests were conducted and the influence of temperature, phosphate concentration, and fly ash dosage on phosphate removal were investigated. The effect of adsorption dosage was not significant at any temperature applied. Phosphate removal in excess of 99% was obtained in these studies. Maximum removals were achieved at 40°C. The tests were also carried out on a continuous basis in an adsorption column. It was found that fly ash is an efficient adsorbent for phosphate removal. This was expected due to the high concentration of calcite present in the fly ash (338 g/kg). The phosphate removal decreased to 80.4% at the end of 72 h.

Comparison of horizontal and vertical constructed wetland systems for landfill leachate treatment

The main purpose of this study was to treat organic pollution, ammonia and heavy metals present in landfill leachate by the use of constructed wetland systems and to quantify the effect of feeding mode. The effect of different bedding material (gravel and zeolite surface) was also investigated. A pilot-scale study was conducted on subsurface flow constructed wetland systems operated in vertical and horizontal mode. Two vertical systems differed from each other with their bedding material. The systems were planted with cattail (Typha latifolia) and operated identically at a flow rate of 10 l/day and hydraulic retention times of 11.8 and 12.5 day in vertical 1, vertical 2 and horizontal systems, respectively. Concentration based average removal efficiencies for VF1, VF2 and HF were NH(4)-N, 62.3%, 48.9% and 38.3%; COD, 27.3%, 30.6% and 35.7%; PO(4)-P, 52.6%, 51.9% and 46.7%; Fe(III), 21%, 40% and 17%, respectively. Better NH(4)-N removal performance was observed in the vertical system with zeolite layer than that of the vertical 2 and horizontal system. In contrast, horizontal system was more effective in COD removal.

Biological removal of carbon, nitrogen, and phosphorus in a sequencing batch reactor.

Abstract In this research the process performance of enhanced biological phosphorus removal was investigated in a sequencing batch reactor (SBR) having a new operational mode. The SBR system used in this study had simultaneous feeding and decanting conditions. The laboratory scale reactor (10 L) was operated for 392 days. The system was operated under 4 different sets each having 2 cycles per day. In each cycle, fill (4 h), anoxic (0.5 h), aerobic (7 h) and settling phases were present. In the fill phase, wastewater was fed from the bottom and the anoxic/anaerobic conditions were established in the settled sludge. During filling, the water left the system by water displacement. The system provided nitrification, denitrification as well as phosphorus and organic removal. High COD (90–98%), PO4-P (77–100%), and NH4-N (90–95%) removals were achieved by this system.

ENHANCED PHOSPHORUS REMOVAL BY GLUCOSE FED SEQUENCING BATCH REACTOR

In this study an anaerobic/aerobic sequencing batch reactor was used for an enhanced biological phosphorus removal. These conditions were tested by a laboratory scale reactor (14 liter) with a synthetic feed, glucose being the sole carbon source. However, enhanced biological phosphorus removal (EBPR) was not achieved during this study. A series of batch tests were conducted with various substrates; acetic acid, glucose and the mixture of acetic acid and glucose. High phosphate removal was obtained when acetate was the substrate (68.7%). It was observed that when the acetic acid was used as a sole substrate, the bacteria growing in the alternating anaerobic/aerobic system removed the organic substrate under anaerobic conditions. However, in case of the glucose feed most of the COD removal took place under not truly anaerobic conditions. This also coincides with low phosphate removal (37.8%). These results are in consistent with the results of the continuous operation. When the acetic acid–glucose mixture was used, the phosphate removal decreased down to 60.8%. This was thought to be due to the glucose that reduced the dependency on poly-P as an energy source.

The impact of shock loadings on the performance of thermophilic anaerobic filters with porous and non-porous packings

Abstract Two thermophilic filters, one with an open porous packing, the other packed with a non-porous medium, were subjected to a series of different shocks. These were hydraulic, organic and thermal. The filters were also stressed by changing the feed from a readily degradable waste to one which contained biocides. The performance of the filters was monitored during and after the application of each shock. The results show that, in general, the filter with the porous packing had the greater stability, although both filters recovered quickly from all but the change in feed-stock. It was also noted that the filters were less tolerant of organic shocks that were applied at a constant hydraulic retention time than to those in which the hydraulic retention time was also varied.

Comparative evaluation of biogas production from dairy manure and co-digestion with maize silage by CSTR and new anaerobic hybrid reactor

This study aimed to investigate potential methane production through anaerobic digestion of dairy manure and co‐digestion with maize silage. Two different anaerobic reactor configurations (single‐stage continuously stirred tank reactor [CSTR] and hybrid anaerobic digester) were used and biogas production performances for each reactor were compared. The HR was planned to enable phase separation in order to improve process stability and biogas production under higher total solids loadings (≥4%). The systems were tested under six different organic loading rates increased steadily from 1.1 to 5.4 g VS/L.d. The CSTR exhibited lower system stability and biomass conversion efficiency than the HR. The specific biogas production of the hybrid system was between 440 and 320 mL/gVS with 81–65% volatile solids (VS) destruction. The hybrid system provided 116% increase in specific biogas production and VS destruction improved by more than 14%. When MS was co‐digested together with dairy manure, specific biogas production rates increased about 1.2‐fold. Co‐digestion was more beneficial than mono‐material digestion. The hybrid system allowed for generating methane enriched biogas (>75% methane) by enabling phase separation in the reactor. It was observed that acidogenic conditions prevailed in the first two compartments and the following two segments as methanogenic conditions were observed. The pH of the acidogenic part ranged between 4.7 and 5.5 and the methanogenic part was between 6.8 and 7.2.