Water Quality Analysis Of Deep Sludge Dehydrated From Surplus Sludge And Its Treatment Of Water Quality

At present,the problem of sludge utilization in urban sewage treatment plants is becoming more and more prominent.Many cities construct sludge treatment plants for sludge dewatering to achieve resource utilization.However,they are generally far away from the original sewage treatment plants and water of dehydration requires separate treatment before it can be discharged.The sludge from the three sewage treatment plants was selected.After multiple sampling and conditioning,deep dewatering was carried out.The water quality of the dewatered water was analyzed.It was found that its ammonia nitrogen and phosphate content were higher and the design was removed using a two-step process.The first step is to use modified vermiculite to study the adsorption and regeneration characteristics of ammonia nitrogen through static and dynamic adsorption;In the second step,chemical precipitation is used to remove phosphate,and struvite is produced by adjusting pH and using Ca²⁺and Mg²⁺in seawater to react with NH₄⁺and PO₄^3-in the dewatering of Surplus sludge.Research indicates:?1?The COD,ammonia nitrogen,phosphate,color,and suspended matter in the water with deep sludge excretion exceed the emission standards,but the ammonia nitrogen and phosphate are higher,which are 100 mg/L and 20 mg/L,respectively.?2?The optimum temperature for the modification of vermiculite at high temperature is 500?.After the modified vermiculite is further modified with H₂SO₄,NaOH,NaCl,NaCl+ultrasound,these modifications are used to adsorb ammonia nitrogen and phosphate.The adsorption effects are NaCl+ultrasonic>NaOH>NaCl>H₂SO₄>high temperature.The adsorption properties of the above methods are in line with Langmuir adsorption model,and also meet the pseudo-second-order kinetics.Analysis of dynamic bed penetration curves at different bed heights and flow rates,dynamic bed penetration consistent with logistic models.The best selection of NaCl for the regeneration process.?3?The seawater of Qinhuangdao the Bohai Sea was selected as the source of calcium and magnesium.Ca²⁺and Mg²⁺were measured at 375 mg/L and 1180 mg/L,respectively,and they were occured chemical precipitation reaction with wastewater which Contains ammonia nitrogen and phosphate concentrations of 20mg/L and 15 mg/L,respectively.At 30?,when the pH is10 and the optimal mixing ratio of sewage and seawater is 0.5:10,the removal rates of ammonia nitrogen and phosphate are 90%and 95%respectively.?4?Sludge is added with chemicals to perform high-pressure pressure filtration to obtain dehydrated water for two-step reaction.The removal rates of ammonia nitrogen and phosphate are all over90%.The subject can fully remove the ammonia nitrogen and phosphate from the tapped water,and the struvite produced can also be used as a fertilizer.The technology provides certain research ideas for the technical study of the discharge of the dewatered water from the deep compression process of the excess sludge in the sludge treatment plant.