Solids refer to matter suspended or dissolved in water or waste water.Solids may affect water or effluent quality adversely in number of ways.Waters with high dissolved solids generally are of inferior palatability and may induce an unfavorable physiolog ical reaction in the transient consumer .For these reasons,a limit of 500 mg dissolved solids/L is desirable ofr dring waters.Highly mineralized waters also are unsuitable for many industrial applications. Waters high in suspended solids may be esthetically unsatisfactory for such purposes as bathing.Solids analyses are important in the control of biological and physical wasterwater treatment processes and assessing compling compliance with regulatory agency wastewater effluent limitations