Overloading, hydraulic

Shock load The arrival at a plant of a waste which is toxic to organisms in sufficient quantity or strength to cause operating problems. Possible problems include odors and sloughing off of the growth or slime on a trickling-filter media. Organic or hydraulic overloads also can cause a shock load. 

Rising sludge can also be caused by internal solids overloading and hydraulic overloading to the secondary sedimentation. Poor sedimentation clarifier design and operation in terms of flow-through velocity, weir design, and so on are also possible causes. 

As it can be seen, the fuzzy module Qi -pH detects well the hydraulic overloads (ie., HO) from 10 to 25 and from 40 to 120 hours Cf. Figure 15.c). Then, it cannot differentiate among organic overload and toxicity i.e., OOUTox) between 120 and 150 hours Cf. Figure 15.e). Addition of the toxic is well detected between 150 and 155 hours Cf Figure 15.d) while after that, underload i.e., UL) is the main fault detected Cf. Figure 15.b). 

The validity of the model can be tested by subjecting it to simulation conditions which cause failure in field digesters, seeing if the model also predicts failure, and comparing the response of the operational variables given by the simulation with those observed in the field. Simulations of both organic and hydraulic overloading have therefore been made. In both instances the reactor was initially at steady state see Table I) for an input substrate concentration (acetic acid). So, of 167 mmoles/liter, influent net cation concentration, Zo, of 50 meq/liter, and a residence time of 10 days. The liquid volume, V, was 10 liters, and the gas volume, Vcr, was 2.0 liters. 

Blockage or hydraulic overloading of sewers leading to foul flooding of property or pollution of watercourses via network overflows. 

Hydraulic cylindrical tank classifier Om tp (M-F) Hydraulic form of overloaded thickener. Siphon-Sizer (N-F) uses siphon to discharge underflow instead of rotating rake. 1.0 to 40 1.4 mm to 45 im (25 mm) 1 to 150 Not critical 0.4 to 15 20 to 35 0.75 to 11 Two-product device giving very clean underflow. Requires relatively little hydraulic water (2 t/t solids feed). Used for washing, desliming, and closed circuit grinding. 

This new concept is applied for improving the operation of an existing overloaded activated sludge plant, or for the expansion of the hydraulic capacity to handle additional wastewater flow. 

Figure 27.12 shows the improved activated sludge process in which a new secondary flotation is applied in series between the aeration basin and the final sedimentation clarifier for increasing the overall treatment performance and hydraulic capacity of an originally overloaded existing plant. 

The hydraulic detention time of the secondary sedimentation of the original overloaded conventional system can be calculated as... 

Because of the coalescing action, these separators can separate oil droplets as small as 0.006 mm (6 microns) in diameter and produce effluent-free oil concentrations as low as 10 mg/L [27], There is a broad range of applications for tilted-plate separators. As little space is required, they can be installed to polish the effluent from existing API separators that are either overloaded or improperly designed, or they can be installed parallel with existing separators, reducing the hydraulic load and enhancing the oil removal capacity of the system. 

Kadlec, R.H. (1990) Overload flow in wetlands vegetation resistance. J. Hydraul. Eng. 116, 691-706. 

The economics of powdered carhon addition are difficult to assess. While the use of carhon might appear to increase material cost, reduction in total expense may, in some cases, be realized through savings on coagulants, sludge handhng chemicals, and so on. In other cases, the cost of carhon can he justified if it provides treatment protection from hydraulic or toxic overloads. 

The only reliable means to overcome these problems in punch-and-die presses is to employ hydraulic actuation of the punch(es) (Fig. 8.95b). The timing of the punch strokes as well as the rate of increasing or decreasing pressure and the dwell time can be easily adjusted. In addition, hydraulic presses typically feature overload protection by gas filled accumulators and, because there is no physical limit to the length of the stroke, densification ratios can be very high, thus allowing successful compaction of large amounts of feed even if its initial bulk density is low. 

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