A Study Of Removal Phosphorus And Severa Stages Treatment Process On CRI

Constructed rapid infiltration(CRI) system is a whole new biology treatmentsystem, developing step by step from the base of traditional land treatment byZHONG Zuo-shen of China University of Geosciences BeiJing, currently CRI iscommonly used to treat domestic wastewater and slight concentration of river. mostpeople research about COD,LAS,BOD,NH4-N and so on, but there are few researchabout treat T-P and T-N by CRI, therefore in this paper we study CRI in detail ,basingon the treatment of T-P and several stages treatment system.The special infiltration medium adsorption experiment by means of marble,zeolite, coke, haydite and sponge iron shows that the sponge iron adsorption quantityto phosphorus in 50mg/l KH2PO4 solution is maximum and reaches 0.47mgT-P/gsponge iron. Besides, the sponge iron adsorption quantity to phosphorus in 10mg/lKH2PO4 solution is also maximum and reaches 0.095 mgT-P/g sponge iron.Dynamic simulation experiment of 300 mm high sponge iron shows that theeffluent concentration is 0.65mg/l, the average removal rate is 90% and the totaladsorption quantity is 51.2mg, under the condition of the average hydraulic being notless than 1m/d and the total flooding being 9070ml. The results of experiment ofmixture of sponge iron and sand (in the volume proportion of 5 to 1) and experimentof a stratum of sponge iron being laid separately show that the effect ofphosphorus-removal of experiment mixture of sponge iron and sand (in the volumeproportion of 5 to 1) is better than sponge iron being laid separately. However, layinga stratum of sponge iron separately can raise COD-removal rate and reducechromairance of effluentThe result of middle experiment shows that it will produce good effect ofphosphorus-removal when sponge iron is added to. Under the condition of totalflooding concentration being 6.43mg/l, the average effluent concentration is 0.07mg/land the phosphorus-removal ratio reaches 98.7%. The system also produces goodeffect to remove other pollutant. The average concentration of COD in treated water is36mg/l and the average concentration of ammonia nitrogen in treated water is 2.3mg/l.All the effluent meets the sewage discharge standard and recycled water standard.The result of experiment of three stages series system shows that if averageflooding concentration of COD is 1017mg/l, the average effluent concentration ofCOD in first stage is 390mg/l and the removal rate is 61%;second stage is 301mg/land the total removal rate is 70%;third stages is 200mg/l and the total removal rate is81%. average flooding concentration of ammonia nitrogen is 96.5mg/l, the averageeffluent concentration of ammonia nitrogen in first stage is 18.8 mg/l and the removalratio is 81%;the average effluent concentration of ammonia nitrogen in second stageis 10.7mg/l and the total removal ratio is 89%;the average effluent concentration ofammonia nitrogen in third stage is 5.3 mg/l and the total removal rate is94.5%. Theeffluent concentration of every stage meets the sewage discharge standard of industry.In the meantime, three stages series system can also prevent a clogging in the systemeffectively.