Conventional flocculation method poses several disadvantages: (1) high dosage of multivalent slat is required to achieve satisfactory result, (2) it produces large quantity of sludge that increases the difficulty to dehydrate the biomass, and (3) flocculation efficiency is highly dependent on pH level [169,177].
Besides, the disadvantages of water-soluble chemicals are poor effect of viscosity reduction, a large quantity of sewage to deal with and difficulty in water-in-oil emulsion demulsification.
These difficulties have been, the large quantity of wear media required, noise from the re-circulating wear media, dust generation and poor reliability.
Although good understanding on this protein is of critical importance to drug design, studies on the structure and functions of CCR3 are still limited, mainly due to the difficulties to obtain a large quantity of pure and functional protein.
The previously reported technique [ 22] for imprinting the grating pattern on the tip of polished glass rods had numerous difficulties in aligning a large quantity of miniature angled optical substrates as well as in detaching the gratings from their fixture.
The phenol chloroform method had many disadvantages including time consumption, difficulty and demanding of large quantity of samples which is not always available in real forensic investigations.
Pure subtractive methodologies are of limited use due to the need for a large quantity of mRNA to drive hybridization to completion as well as the difficulty in cloning the tiny amount of cDNA remaining after hybridization.
Problems such as the difficulty of the selection of technical parameters and the large quantity of experimental work, exist in the forming of composite tubes or bars by the semi-solid extrusion process.
Selling a large quantity of diluted cocaine powder, or a small quantity of pure cocaine?
He illustrated the difficulty by describing a recent incident in which border guards scouring a suspicious passenger bus found a large quantity of heroin concealed in the compressor for the air brakes.
He also provides a large quantity of fascinating background information.
