The invention discloses a method for
dewatering sludge and detecting the
water content. The method comprises the following steps that 1, a
calibration curve is built, wherein by using a Helmholtz coiland a detection coil, a standard sample with the known
water content is obtained and subjected to low-field nuclear
magnetic testing, the standard sample and the
nuclear magnetic resonance semaphoreare subjected to primary
linear fitting, and the
calibration curve is built; 2, feeding, wherein
sludge is introduced into a filter-press chamber so as to achieve feeding; 3, filter pressing for
dewatering, wherein by using thrust of an oil cylinder and electromagnetic force between a left push plate and a right push plate, the filter-press chamber is subjected to filter pressing; 4, detection ofthe
water content, wherein by using the electromagnetic force, a detection unit is pushed to move rightwards to the detection position, an echo
attenuation curve is obtained, and a
transverse relaxation time T2 curve of samples is obtained; 5, calculation of the water content of a sample, wherein the
transverse relaxation time T2 curve, obtained in the step 4, of the samples is subjected to area integral and calculated to be substituted into the
calibration curve in the step 1, and the water content is obtained. In the method, the water content of the
sludge can be conveniently and quickly detected on line in the
dewatering process without sampling.