CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="120"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "publications.waset.org",cType: 'non-interactive',cRay: '914c2670ca59f938',cH: 'CjhHq2VqvR918rQrOWLB1UsZ1HHNprCfHKLGXzwkFj4-1740029903-1.2.1.1-U.bBa2dwF.4R5ZJrxZVGE7VG_0bucdTJ25ooNpsXP_UV4TTYFDn4M3gu4Ts9Gbvg',cUPMDTk: "\/abstracts\/search?q=alum%20sludge&page=5&__cf_chl_tk=4Nx.nmWxgzk5bJ72N4oa26cnL2JTk6qw3y8EdR65As0-1740029903-1.0.1.1-5ijMVMYjkj_3mPeR03ZHoakXTWfuu1nvr8PHoFKUuig",cFPWv: 'g',cITimeS: '1740029903',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported-browser",fa: "\/abstracts\/search?q=alum%20sludge&page=5&__cf_chl_f_tk=4Nx.nmWxgzk5bJ72N4oa26cnL2JTk6qw3y8EdR65As0-1740029903-1.0.1.1-5ijMVMYjkj_3mPeR03ZHoakXTWfuu1nvr8PHoFKUuig",md: "QeFXRiyx.gcX6gtP.bLf8a4hj._XdMqt6UahgNPM1ZY-1740029903-1.2.1.1-br8v_ipnQSnNnGRbM9oq3xl2X.n1Cf_pDusUIo7oJWCAWvpAMnja80.I_PFSMfrIELlCahVq7KBmcGozvDyebPEBnPP9p55kupUCZTUpvz6N_nn5jQmxj_Sy3AgBEdmevuo2jTOZi6vTB4OKSHi4ipnFEMklNACj7hdm7XlwDg7cG1mfbIsdi2h_kjp9p5s6foL6Ijcu0GN2zq5BjM2rvwZNPdQ4UnEbYeUoztLL0vUkRZo_NqekZHPEKbrRdamfivo0oQjH9NIgH8FNIR9VAUHD5k37ORv6oVvkv.WRwsrvfswB_LB1hkCrJ2SmZNXNLgkCTVMkwbtjARMfyB1woRmtz2Ugey3qB1vfulglOecPVLaMJVOg7SEl86g1k7h.ppnBok2ESZI7Myd2VQ184GnacFpA1QtaEr.7ky73JsxGRLYGExH3UAx..iEk8SPXjVs964s6s8F3GFDNCeAmhaTDImrI3sJ0Lb9UvrtAf1wYfREGm2qet6SZBxTIm4vexDGxLHUfwMtuxvl1XBDHnWyHG46xPGx4l5A0_Gsg_Na5kbzkcVDSTvA2_n5BxV2AOB9Iwdn4UXVoXOEp_RqjzwCcCH.qFdJmn5Q6VGFGGtnOicWn8pxQjbMU4aE_oznq2Hqa6VHMZ5YV7AogNSwcr0RjMi_k_1ZRpqDqKjFBGf8KVp71hteJyJeIrt8GEgZlb0Pf9fqVxT9O9rAG6rhHgyjKw808vU.65YfsC7ZXUFmUkR1821Wys5L6Hu.XN2jv7_UhTbhJ9XIsqByh0VFvChJyW8J3qGRZWe5rVxWqERuNGcjq3sT5tTYvHKAjMgtiAORuRvXW1OsVhv_Hdue8AoQFuARQHR4tjQD06jsAy7QDs2NuxHbR6hy7hGJFkW.TCszwfcC7IjbmOab2_Ukq1BlXOuwdxJxtpqllxCksya34NG98eCrvsEcZ71HsY2hXgZ9bZI.WqWLXK4OvOM3FZGJQpgrcBC7gQopDLNrav_FN9UPD5Rr5nv3AXHzrvjCI0KyTZawGXAG4hAejhICfPJ2heB_6zvwdndH2dQCviYPCzatVaoI5CWG33HBXlMM3.nJ_R6xfcKLTVpCJvc24t2pMUhEFo8or6NJmViszAototptq4FajETzfpO_OARCdhNV.KZH57aZXxjIldBskz2Yzxt25smR6o9JP.NQXo8SYVp0oTyjK0bXxTrx9BPz72JoQp__ZnKBGy..E2rLotPOwUiusYKF8kXEIXk.PsxpExJHU5JkzJAZlR_csCUaGYx2n2femSQJaLgU8TXm_hFfOS3t2dEAAY7pGtIo8h_8Lmu7ewEi0XJGhRzxT0ZWxjtqt8BcpwgnHxPLK7gr6h0G5H5wfkxDdI_cY6R1aVQJPl8c9ONvGLqOaaWq5o_dMIpOw2GQnMzEaVn07TUgH8Ovlx1KwYC2vD4jCXGaQckOzb423sztM2J8yVVojSyE5EuQlaFbh3FTgzUHQcZjEn.Hd65erF8.N4JVkH4TfImjwBhRIdsV33JxuT389i0Q4aOy7lkM9WtT6L51eLREKc1N9ECdrYSx3f.DerJ7AECxMnL81cQVlHYS3.8lYJlzHyN432DT7SXfyKLcWsjJYseihzgj6.Hz7O.Jk6MVFEVvwgIUwsiuJ7o9PWsCdMih9sA7JsujAcz4MP2P97d9ho4Ut7EK0R89CUxfejTG_kjZaaUqG80g.9mN2pMHsIrRTJEbbdvACKVfg044KQILCQyNxg7Wxl78XZZjZiGlydfIw8iw3Pn20Soh_WzxPtZcxS3XOr6n.ePwLM7dDoi.OO.0lSuO2jb..OxvAkD.RbLyvZsImkM7io0hNsRtRzyv5JbJhCmIjRhPmjwNbe5x5OEWMJrd6hQtDfrux56iKYsy83eU2RZpeoARWi.qDbaSFE7O0WhS3jUoWqXM2TMH9R1aeg87SAXbfwQOdS1hiRPY",mdrd: ".asvCgBX_nEKCdhrJaKByG.HvPRts4Z3hqRP3h8XOjQ-1740029903-1.2.1.1-3r0AqMh.axcZCrLd14mSvCML05VC0wN1wOPkyfv0f2l6QN0dcolFQV6c694qlAk49KTSJwxIs0G7OgKjV0R562L47K6IjfsU1lmtDRjAH2YF9QfGXzJ7JwaZTZ3ZINJtvxbdPcRgxnLx0bl.91nMCvsbP8nhL9JO5R1aAqRqcOakr1fqMjOiTFB9s3Sm7ldlQHRHJNEjUjNq5SYHicBD2kafM76XsoJcE.vqo_SJfi9UnLhR49zdefh_KMYk6dejLMc21sJa3ZRjg8eCE1O9OgtPCzbMxLq8OruyTkN_sjcPW8CbdWkHU9165Aor_XYh7p4Xt6rWpyL2QU2g3TRdRxAFNL0FMhkfBb0EtIpiDs7HPL_lCQ1_J9jGAhuxdzwC.lwjoN3KG7h3QzvQhuevj3pEg8yOR_NctXsTmIGUGwUoe6Fh0FqN7MdSPFBmx5BC15F6o.Ef3BhSIHo9wauvdq5UEDndVH3eR6MlR1wGoUxglAPXxoVPGYr_BGTAFi5IXRpPKINU8TMvbjSlmTovDJteF2EKoB.zTSTzCZq1gU7IV7fuv9CQPxbm2d_DKYnC0k9pJdj7LArOL0hp5kOXsqdbMWqaU8kLzxncpPveCgx7iYqS.VoZzkOIgOzFns5vXJs21KVpT_WrwrnuLVWhJBQtApW.LcN822a7u8Ai0Qia8Z6F4d30og6kLXUISFqoq42GmZfojHP27fBlO.ZtBdS_dcej0MrILVEhx2cVxF2duAr20sL02r56oYxrB8Iw0C5y0iZi2E9hwI_zf69cw0lWuFTc6u24AdrpyQhyLiQUB57KHqpScQB1p.uyPEJJhTUF1Y4IRYRPTPqV4KKtBlq2o396Tn.9Acl5hH2KbaZULzaPOjVeEdYPXp826zv1pQnkPv4yYPsY5V2Q1oyKXnaQc1eV1t2.NaAuPDlwY8aoQqLf0gM4aA_HmO8WVTVs3N36nQQYcalZmxrlAANCQBYOzoquUGyDX.vTTMW1NbW16hoFYKjx7y0u1KZZ3kszE7eW3t.0WOsyQXwhFmyAlu7tx5DD3lQ6Qu9yVlHuwG0JxIBJu59mjgN2DyZpOib80bcrbwwyyGii04JYmfnDPn2lFn0UVwHtCS7zabJ1FyXIlIQ8TsaDnQQDU._PezQUlJGRnF_U9EbC5w2q6ooFk1c_UnoGuna823xkUUg8IH6eYS8Eb54vxWHMaEZO3WQgAzg0qNsoK61ViQJ9NDdkA31bwI4rRWuqOufnaI1UZ.omUjAwb4AK6pE.Wlyo9isKoQyyn.Hd9Zet0pTrdDTpqKHegU7QvQMSGHxS40pUufmicdu.gYimWlMaoP3qdt37aCuV1h1qSb_GFBfqON5Kbyr8b.aooLPibFKjYa1jBuRddIVEPDrg02BKYpvwhdz.5irRT069RXLjqNkEQIBnKEandW7Mumhfghe8SF4VZCk4vELhK1cn8jDGQJ0RfJOi8lAiHnxocx0gt1kAyjH0gIkAEYDdJIiuTGwYuHroGWuhEXg0DR1txZxcLbO_VuRc._OdBHg0F7nE.euM9fBqyoZmylM6zIu0JwuW7KRY5KZAnew3l3JfQVISFk_yHy981xXA0H9pXO4HS5Uq1HqqXIgcbddCGpLEZbk7puNimJpRTzgGnQMEbYi0V_5a3LibUUIwvAyzVPyAZDKt7s.Qs5Y6ROcn3nT2SsmTWDhM_6BClpIkSZAGwmuV_eZuiKTLwv6JMNToQBjx76ouifGyAwILY4Koi9VJzQq7qX.9SqYbme_coUIP4rmyyEGgGNcOE7vASF04MLjvmKg7FYarZVKPeT4FgB3JuIhnNGQMhQyqgs5CXkBA3uawkmmfBEGctDD7bqisZBNvegQGzzBdMADJdPR0VF_x6b.wSxi2tGVr3Sf97yklA7hUsLGh0rkWLZr1CtEH2XJeVSDAO9ed.a1F4uym5afPBXHDzqA6p9pDvA4U.e6t7MUsh4yf_R5eep7rv7tqNnelbPVLKz2Dpg"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=914c2670ca59f938';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/abstracts\/search?q=alum%20sludge&page=5&__cf_chl_rt_tk=4Nx.nmWxgzk5bJ72N4oa26cnL2JTk6qw3y8EdR65As0-1740029903-1.0.1.1-5ijMVMYjkj_3mPeR03ZHoakXTWfuu1nvr8PHoFKUuig" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>