Characteristics Of Suspended Solids Research Articles

Effects of Small-Size Suspended Solids on the Emission of Escherichia coli from the Aeration Process of Wastewater Treatment

ABSTRACTThe concentrations of bioaerosols near pretreatment facilities are often higher than those near activated-sludge aeration tanks in wastewater treatment plants (WWTP). The reason for this difference is not yet clear and the differences between the characteristics of suspended solids (SS) in these two processes might play a critical role. In this study, a lab-scale wastewater treatment system was tested with Escherichia coli (E. coli) in order to investigate the effects of the type and concentration of SS on the concentration and size distribution of emitted bioaerosols. Two types of SS, activated sludge from a hospital WWTP and kaolin clay, were selected to represent floc-type mixed-liquor SS (MLSS) and non-floc-type SS, respectively. An Andersen six-stage sampler was used to analyze the size distribution of the airborne E. coli aerosols. When the tested aeration rate was as low as 0.5 L min–1, it was found that the presence of bioaerosols slightly decreased in air/water ratio (AWR, CFU m–3 air/CFU 100 mL–1 water) when the SS increased from 500 to 2000 mg L–1 for both floc and non-floc SS. However when the aeration rates went up to 5–15 L min–1, the pattern of AWR vs. SS curve was different with an increase trend for non-floc SS and a decrease trend for floc SS, with an exception of increase trend for floc SS as the MLSS increased from 0 to 500 mg L–1. The major sizes of emitted bioaerosols ranged from 0.65 to 1.1 µm. A peak was observed at an aerodynamic diameter greater than 7 µm when the aeration rate was 15 L min–1. In conclusion, floc-type activated sludge can inhibit the emission of E. coli from an aeration tank. In contrast, the non-floc-type small-size kaolin clay can enhance the emission of E. coli from the pretreatment process.

전기응고법을 이용한 오염 수 정화

수중에서 인, 질소의 함유농도는 부유고형물의 농도에 비례하여 증가하기 때문에 부유고형물의 제거는 유기물과 함께 질소, 인을 동시에 제거할 수 있다. 부유고형물은 수중에 미분체를 투입하면 투입된 미분체와 부유고형물 사이에는 반데르발스 힘과 같은 인력이 작용하여 응집이 형성되고 이 응집덩어리는 자성을 띠게 된다. 이와 같은 자성응집덩어리를 자력에 의해 형성된 자성 매트릭스에 직접 부착시켜 분리 제거함으로써 오수를 세정할 수 있다. 본 자료는 자성분리기술과 관련하여 오수 내의 부유고형물의 제거특성에 대한 것을 실험적으로 평가하고 부유물의 제거효율에 대하여 규명하고자 한다. A magnetic fluid separation technology was confirmed to be very effective to remove the suspended solids from contaminated water. We have surveyed on the effects of operating variables on the characteristics of suspended solids(SS) removal investigated through the test runs using magnetic powder. Magnetic flocculation here formed by adsorbing fine magnetites on the surface of suspended solid was observed. The strength of magnet was of significance in determining the SS removal efficiency.

Behaviour and Characteristics of Suspended Solids in Hinuma Lake

The behaviour and characteristics of suspended solids were examined using a sediment trap method at Hinuma Lake, a shallow estuarine lake, from November of 2007 to January of 2008. In a vertically well-mixed period, phytoplankton accounted for 17% in suspended solids. Hence, particulate organic carbon, nitrogen and phosphorus in suspended solids derived largely from phytoplankton. In contrast, only 4-6% of phytoplankton occupied in suspended solid in a stratification period. Fluid muds, resuspended due to wind, were likely to be a contributor for particulate organic carbon in suspended solids.

濃縮倍率とエネルギー効率を考慮したハチミツ限外ろ過

In the ultrafiltration of honey, filtration efficiency can not be expressed by permeate flux because it is necessary to dilute raw honey with water. Instead, rate of recovered sugar (RRS) which considers permeate flux and sugar content, was employed as an indicator of the filtration efficiency in this study.The effect of dilution on filtration efficiency was that RRS increased with a decrease in sugar content at initial stage of filtration. However, at concentration factor (CF) above 1.5, RRS at sugar content of 40% was higher than that at sugar content of 30%. This result was probably caused by changes in characteristics of suspended solids in raw honey due to dilution. In this case, the changes were small when the sugar content was 50%.The effect of operation temperature on filtration efficiency was shown that high RRS was observed at 50°C rather than 20°C and 30°C, however, temperature influenced cake resistance less than sugar content during filtration.The effects of operation pressure and cross-flow velocity on filtration efficiency were that when cross-flow velocity was 1.07-1.6 m/s, RRS increased as pressure increased. Whereas influence of cross-flow velocity on RRS decreased as pressure became decreased.Furthermore, total operation energy was easily calculated using inlet pressure under several filtration conditions to obtain a constant volume of permeate.At constant pressure, the cross-flow velocity was proportional to the energy. At constant cross-flow velocity, there were optimum pressures at each cross-flow velocity for useful filtration.

RNA Coliphage Qβ as a Bioindicator of the Ultraviolet Disinfection Efficiency

F-specific RNA coliphage Qβ was used for evaluating the factors (UV absorbents and suspended solids) affecting UV disinfection efficiency. Qβ was an adequate bioindicator for measuring actual UV intensity profiles because of its high consistency and reproducibility. The effect of suspended solids (kaolin and activated sludge) on UV disinfection efficiency depended on the UV reflection characteristics of suspended solids.

EFFECTS OF SUSPENDED SOLIDS ON THE ACUTE TOXICITY OF ZINC TO DAPHNIA MAGNA AND PIMEPHALES PROMELAS1

ABSTRACT: Current procedures for setting site‐specific water quality criteria consider abiotic and biotic factors. Suspended solids were shown to be important in reducing zinc toxicity to water column organisms. At zinc concentrations of ∼ 1 mg/L in solutions with < 100 mg/L of all suspended solids tested, zinc toxicity to D. magna was reduced. Sorption of zinc to suspended solids and/or changes in water chemistry due to the addition of suspended solids appear to have been the factors causing reductions in zinc toxicity to D. magna. Only suspended solids levels of 483–734 mg/L of a type that increased total alkalinity, total hardness, and total dissolved carbon clearly reduced the toxicity of ∼ 20 mg/L zinc to P. promelas. The toxic form of zinc to these organisms appears to reside in the aqueous phase. Characteristics of suspended solids did not influence the partition coefficient of zinc in sorption experiments of 96 h. The slopes of dose‐response curves proved to be useful for assessing the potential of an organism to respond to changes in aqueous phase zinc concentrations, and may be a useful biological parameter when considering site‐specific water quality criteria for chemicals.

Physical and geochemical characteristics of suspended solids, Wilton Creek, Ontario

Physical and geochemical characteristics of suspended solids, Wilton Creek, Ontario

Physical and geochemical characteristics of suspended solids, Wilton Creek, Ontario

Physical and geochemical characteristics of suspended solids, Wilton Creek, Ontario

A new optical method for measuring suspended solids in pulp and paper mill effluents

A new optical method, the so-called TP-method, has been developed at the Swedish Forest Products Research Laboratory for measuring the amount of suspended solids. The great advantage of this method compared to other existing optical methods is that the result is independent of particle size. This is an important feature, since the characteristics of suspended solids from pulp and paper mills can vary significantly. The TP-method also provides a first order measure on the size distribution of the particles in the suspension. Furthermore, the TP-method is independent of the flow rate of the measuring medium and by compensation insensitive to variation in colour.The TP-method has been extensively tested in the laboratory and in mills with different kinds of production. The results show that the TP-method is well suited for quantitative measurement of suspended solids.Several years of experience with TP-instruments in different on-line positions is also very good. The instruments have shown to provide valuable and relevant information on both variations in concentration and variations in particle size distribution, with the result that it has been possible to indicate and to explain disturbances within the process - system. Several instruments have been used in an in-mill pollution control system, which was installed in a sulphate pulp mill in Sweden.

A New Optical Method for Measuring Suspended Solids in Pulp and Paper Mill Effluents

A new optical method, the so-called TP-method, has been developed at the Swedish Forest Products Research Laboratory for measuring the amount of suspended solids. The great advantage of this method compared to other existing optical methods is that the result is independent of particle size. This is an important feature, since the characteristics of suspended solids from pulp and paper mills can vary significantly. The TP-method also provides a first order measure on the size distribution of the particles in the suspension. Furthermore, the TP-method is independent of the flow rate of the measuring medium and by compensation insensitive to variation in colour.The TP-method has been extensively tested in the laboratory and in mills with different kinds of production. The results show that the TP-method is well suited for quantitative measurement of suspended solids.Several years of experience with TP-instruments in different on-line positions is also very good. The instruments have shown to provide valuable and relevant information on both variations in concentration and variations in particle size distribution, with the result that it has been possible to indicate and to explain disturbances within the process - system. Several instruments have been used in an in-mill pollution control system, which was installed in a sulphate pulp mill in Sweden.