alum dosage calculation in water treatment

{"cid":"91224806","title":"Fs Coagulant Ferric Sulphate for Waste Water Treatment Water Clarification","imgUrl":"https:\/\/img.chinax.com\/nimg\/64\/7a\/49d08219e94d1af2502b71d9ab07-200x200-1.jpg","attrs":{"Price":"USD320","Brand Name":"OYI","Model Number":"FS-98","Minimum Order Quantity":"5TONS","Delivery Time":"5-15DAYS","Applications":"Water treatment, paper making, sludge dewatering, oildrilling, mining etc","Supply Ability":"2000T\/M","Content":"21%min","Appearance":"Solid yellow powder","Certification":"ISO","Payment Terms":"T\/T,L\/C,Western Union","Place of Origin":"CHINA","Packaging Details":"25KG, 750KG BAG","SOLID CONTENT":"98%"}}

{"cid":"91148437","title":"Polyaluminium Chloride Water Treatment For Drinking Water PAC Polymer coagulants","imgUrl":"https:\/\/img.chinax.com\/nimg\/d5\/e3\/82a8de78f01841a1ee5b69192b49-200x200-1.jpg","attrs":{"Price":"negotiable","Brand Name":"BLUWAT","Model Number":"PAC-01","Minimum Order Quantity":"23 tons","Delivery Time":"10 work days","Certification":"SGS ISO","Place of Origin":"China","Payment Terms":"L\/C, T\/T","Supply Ability":"3000 tons per month","Packaging Details":"25kg pp woven bags","Chemical name":"Polyaluminium Chloride","Short name":"PAC for drinking water treatment","Color":"white","Al2O3 %":"30%min","Basicity %":"45-55%","Insoluble % :":"\u22640.1%"}}