Research On Deep Dehydration Of Chemical-conditioning Glass Fiber Sludge

As a by-product of glass fiber industrial wastewater treatment,the glass fiber sludge is more complex than the domestic sludge,which contains the chemical components in the waste water.High moisture content of glass fiber sludge will increase the cost of transportation and the subsequent disposal and utilization of resources.Therefore,the key to solve the problem is to improve the dewatering performance of glass fiber sludge.Mechanical dewatering is the most commonly used dehydration method.It is usually necessary to regulate the sludge before mechanical dewatering,so as to improve its dewatering performance.Compared with physical conditioning and biological conditioning,chemical conditioning is widely used because of its simple operation,low investment cost and stable effect.At present,the research on the preparation and structure of the new type of conditioning agent with the domestic sewage as the main body is focused on the research of chemical conditioning.However,there are great differences in the properties and components of different kinds of sludge.Therefore,it is necessary to study the selection and optimization of the conditioning scheme for the deep dehydration of the industrial sludge such as glass fiber sludge.In this paper,the following studies were carried out to improve the dehydration performance of glass fiber sludge:using a wide soure and low cost of fly ash,phosphogypsum,gypsum gypsum,lime,bentonite,modified bentonite,respectively,alone or with FeCl₃ combined conditioning glass fiber sludge,and the screening experiments were carried out on glass fiber sludge.The response surface methodology?RSM?was used to optimize the dosage of the composite conditioning agent and the experiment of sludge dewatering by plate and frame filter was carried out.The mechanism of the effect of quicklime and FeCl₃ on the sludge was studied.The results are as follows.Chemical amendment screening test results show that:the combination of quicklime and FeCl₃ was the best and the dosage was the least.The specific resistance to filtration?SRF?was 0.8160×10¹³m/kg to 0.3438×10¹³ m/kg and the capillary suction time?CST?decreased from 106s to 66.4s,lower rates were 57.87%and 37.36%.Lime and FeCl₃ combined with glass fiber sludge conditioning mechanism research results show that:The strong alkaline of lime can destroy the floc structure of glassy sludge and reduce the organic hydrophilic substances outside the granules,and reduce the sludge viscosity;Lime and water generated by the reaction of Ca?OH?₂ floc with positive charge body surface will be negatively charged flocculant and sludge particles adsorbed together to promote FeCl₃ flocculant function,the formation of a composite system,not only the zeta potential of sludge changed from negative to positive,but also in its cohesion and netting sweep,the tiny granular sludge and other suspended material in high molecular polymer associating together,not easy to plug the filter in the filter,improve the dehydration effect;Lime can make sludge flocs by compact structure into fractal and pore structure,through the formation of sludge in porous mesh skeleton change sludge filter and compressibility,keep the permeability in the high-pressure dehydration process,provides water channels for free water.In this paper,the combination of lime and FeCl₃ for the treatment of glass fiber sludge is good,and the dosage is less.Compared with the traditional PAM method which can only get about 80%of the moisture content,the moisture content is reduced by about 36%,which has significant economic advantages and provides a basis for future industrial application.