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Query: UNIPROT:A7KAX9 (grit)
 1,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Biological nutrient removal (BNR) in municipal wastewater treatment to remove carbonaceous substrates and nutrients, has recently become increasingly popular worldwide due to increasingly stringent regulations. Biological fluidized bed (BFB) technology, which could be potentially used for BNR, can provide some advantages such as high efficiency and a compact structure. This work shows the results of simultaneous elimination of organic carbon and nitrogen using a circulating fluidized bed biological reactor (CFBBR, which has been developed recently for chemical engineering processes. The CFBBR has two fluidized beds, running as anoxic and aerobic processes to accomplish simultaneous nitrification and denitrification, with continuous liquid recirculation through the anoxic bed and the aerobic bed. Soluble COD concentrations in the effluent ranging from 4 to 20 mg l(-1) were obtained at varying COD loading rates; ammonia nitrogen removal efficiencies averaged in excess of 99% at a minimum total hydraulic retention time (HRT) of 2.0 hours over a temperature range of 25 degrees C to 28 degrees C. Effluent nitrate nitrogen concentration of less than 5 mg l(-1) was achieved by increasing effluent recycle rate. No nitrite accumulation was observed either in the anoxic bed or in the aerobic bed. The system was able to treat grit chamber effluent wastewater at a HRT of 2.0 hours while achieving average effluent BOD, COD, NH3-N, TKN, nitrates, total phosphate, TSS and VSS concentrations of 10 mg l(-1), 18 mg l(-1), 1.3 mg l(-1), 1.5 mg l(-1), 7 mg l(-1), 2.0 mg l(-1), 10 mg l(-1) and 8 mg l(-1) respectively. The CFBBR appears to be not only an excellent alternative for conventional activated sludge type BNR technologies but also capable of processing much higher loadings that are suitable for industrial applications.
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PMID:Simultaneous carbon and nitrogen removal in anoxic-aerobic circulating fluidized bed biological reactor (CFBBR). 1536 90

New Borg Al-Arab city includes 9 residential areas and 4 industrial zones. The four industrial zones are occupied by 266 running factories belonging to different industrial sectors. All the domestic sewage as well as the industrial wastewater is treated at an oxidation pond treatment plant and the plant effluent is used in irrigation of silviculture areas. The plant consists of 2 pond complexes. Each complex comprises 9 facultative ponds, arranged in 3 parallel series. Raw wastewater is pre-treated through screens and grit removal before entering the primary ponds. The study aims at assessment of the performance of the waste stabilization ponds. The results revealed that pre-treatment units were not functioning properly. The retention time was calculated to be 6 days in each pond of the first complex and 3 days in each pond of the second complex. The mean BOD surface loading rate was calculated to be 676 kg/ha/d for the first complex and 1584 kg/ha/d for the second. The plant was hydraulically and organically overloaded. The percentage removal of BOD, COD, SS, and NH3-N had an annual mean of 57%, 56%, 44%, and 39%, respectively for the first complex and 21%, 42%, 39%, and 25%, respectively for the second. Faecal coliforms were reduced by about 1 log10 unit in both complexes. The final pond effluent was not complying with the Egyptian law for reuse in irrigation. The study proposed some recommendations which can improve the efficiency of the plant as well as the effluent quality.
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PMID:Assessment of the waste stabilization pond performance, New Borg El-Arab City. 1692 46