Management of wastewater from the fertilizer industry

Abstract

Two schemes of treatment were applied to wastewater produced from a superphosphate manufacturing unit. In the first scheme the final effluent, comprising washing water from the scrubbing towers in combination with cooling water, was subjected to chemical coagulation-sedimentation using lime. In the second scheme the washing water from the scrubbing towers was chemically treated with recycling of a percentage of the treated effluent. The two treatment schemes were carried out using a continuous flow compact unit. The results obtained revealed that chemical treatment of washing water from the scrubbing towers including recycling treated effluent waste (with a ratio of 1:2) was recommended. The treatment process proved to be very efficient in removing fluoride, phosphate, silicate and suspended solids. Also, the optimum conditions required for drying the sludge using sludge drying beds were determined. Analysis of the dry sludge indicated that it can be reused with the initial raw material in the plant. A process design of the proposed treatment plant was also included.

Treatment of hazardous wastewater generated from metal finishing and electro‐coating industry via self‐coagulation: Case study

“…Treating this sludge in a sand drying bed with 36 cm filter depth and 50 cm total sludge depth at filling time, reduced its volume to 1.45 m 3 and increase its solid content to 16.6% after settling for 3 days. This is comparable to the published work by Abou-Elela et al, (1995) which indicates improvement of sludge filterability in sand bed with 20 cm depth and 32 cm maximum sludge depth. The results of this study show that 94% of water was lost from the sludge, mostly (87%) by leashing while 7% was evaporated.…”

“…This is in agreement with Metcalf and Eddy who reported that most of the water losses in the sand drying bed is via under drain pipes, while little is due to evaporation. Also, Abou-Elela et al, (1995) reported little temperature effect on the performance of the sand bed of sludge drying. On the other hand, Al-Muzaini (2003) reported that drying municipal sewage sludge in the sand drying bed increase solid content up to 40% after 9 days in summer and 15 days in winter.…”

Chemical industry wastewater treatment

“…Chemical coagulation precipitation and biological treatment via aerobic systems were investigated. -Elela et al, 1995) was operated at the optimum pH and coagulant dose. A schematic diagram and specification of the treatment unit are given in Table 2 and Fig.…”

Effect of Varying Nitrate Concentrations on Denitrifying Phosphorus Uptake by DPAOs With a Molecular Insight Into Pho Regulon Gene Expression

“…An environmental bacterium, Citrobacter freundii , was engineered for overexpression of the polyphosphate kinase gene based on a solo medium-copy plasmid strategy that resulted in 12.7% poly-P accumulation by the cells, thus overcoming the negative regulation of PhoU (Wang et al, 2017). The negative regulation of PhoU is a major limitation to PO 4 3– -P bioremediation when the soluble PO 4 3– -P level is high in waste effluents, e.g., effluents from fertilizer industry (25–308 ppm of PO 4 3– -P) (Abou-Elela et al, 1995), parboiled rice mill industry (34–143 ppm of PO 4 3– -P) (Faria et al, 2006), and rice-based distilleries (223.5 ± 27.5 ppm of PO 4 3– -P) (Bhattacharyya et al, 2014). The screening and development of phoU mutants of PAOs was considered to be a solution to overcome this limitation.…”