Papers by Keyword: Flocculants

Abstract: Study on the pretreatment of printing and dyeing wastewater with PAC、Fe₂(SO₄)₃ and FeCl₃ was carried out. Effects of the flocculants dosage, pH on the treatment efficiency were studied. The results showed that with PAC, Fe₂(SO₄)₃ and the FeCl₃ dosage rising, the treatment effect first decreased and then increased and when the addition amount was 300 mg.L^-1、300mg.L^-1and 250 mg.L^-1,the COD removal efficiency achieved 69%、78%、74% , respectively. With the rising of pH, the treatment effects of the three types of flocculants increased first and then decreased, the optimum pH of PAC and Fe₂(SO₄)₃ was 7and the best pH of FeCl₃ was 6. At last, the settle ability and the amount of the producing floc were studied, the results showed that the settle ability was the best and the least amount of sludge produced by FeCl₃ flocculation. Keywords: printing and dyeing wastewater, pretreatment, flocculants, screening.

Abstract: Artificial organic polymer flocculants has been widely applied in water treatment; however, disadvantages of nonbiodegradable and poisonous may cause another environmental problem. This paper established an effective water treatment technique using Abelmoschus moschatu (Okra) in combining of glue extraction process and flocculating process, with fully consideration of factors such as treating time, cost, and efficiency. Results showed that ethanol extraction was an effective method for extraction of glue form Okra. After being soaked in distilled water overnight with ratios of material to solvent, and was extracted by ethanol with volume percentage of 50% at stable temperature of 70 °C for one hour, the extraction rate of Okra glue could be as high as 18.38%. The glue usage of 0.015-0.020 g.L^-1 and flocculating time of five minutes could be the optimal usage in treating suspending liquid of kaolin, with the turbidity of 3.0 g.L^-1. The processes are low cost, simple, efficient, and low pollution, having broad application prospects.

Abstract: In this paper, the paste tailing preparation and stacking technology were applied in Wunugetushan Copper-molybdenum ore where in high latitude cold area of our country, the paste tailing preparation and stacking technology, Deep-cone thickener, Diaphragm pump and flocculating agent adding device were introduced. The production practice has proved that the paste tailing technology in high latitude cold area of our country obtained successful application, and had effected on the development of tailing disposal technology of our country.

Abstract: Drinking water is contaminated from the chemicals and biological impurities around the world mostly in rural area. These contaminations may come from natural sources and leaching of waste deposits which cause a major human health hazard in many parts of the world. There has been very little scientific research work into the use of natural flocculants to purify raw water. Most of the research studies that have been done on conventional water purification in developing countries have focussed on conventional water purification systems using inorganic and poly-electrolyte flocculants. Such systems are very expensive for rural communities in these developing countries as our objective is to provide water that is safe for human consumption by using facilities which can be constructed and operated at a reasonable cost. There is a need to evaluate natural flocculants for conventional water treatment in order to develop inexpensive ways for developing countries to purify their water. In this study, the natural flocculants such as Moringa seeds powder, Guar Gum seeds powder, aluminium sulphate and polyelectrolyte were tested in a jar test apparatus to determine the optimum operating conditions for water or wastewater treatment plants. The results showed that the addition of Moringa Oleifera seeds powder, Guar Gum seeds powder, aluminium sulphate and polyelectrolyte flocculants improved the quality of raw water. The raw water samples from all treatment plants showed a reduction in turbidity that was more than 70% when all the four flocculants applied synergistically.

Abstract: For heavy oil wastewater from Henan oilfield, removal of silica has been investigated under the condition of different flocculants and reaction time when magnesia has been used as a desilica agent. An optimum method has been determined by conditional experiments, 63% of silica could be removed.

Abstract: Based on the concept of “waste control by waste”, a kind of inorganic polymeric flocculants which was called Polysilicate Aluminium Ferric (PSFA) was made from bentonite, wastewater containing Al3+, wastewater containing Fe3+ and sulfuric acid under normal temperature conditions, and it was adopted to treat banknote printing wastewater. The experiment results revealed that the maximal Chemical Oxygen Demand (COD) removal efficiency of 95.52% with residual COD of 3571mg/L and color removal efficiency of 96% with residual color of 40 times could be achieved at the optimal dosage of 48g/L wastewater, a number of big and dense alum flocs appeared quite fast, the flocs and water could be obviously separated in a short time, the pH of coagulating effluent of which color was light green was about 4.01, the effects of coagulation were very well.