In　order　to　verify　whether　a　conventional　wastewater　treatment　process　can　provide　sufficient　protective　screen　of　heavy　metals,　a　longterm　regular　monitoring　of　different　stages　of　a　wastewater　treatment　plant　was　conducted.　Through　a　series　of　adsorption　experiments　using　quartz　sand,　kaolin　of　known　size　distribution　as　inorganic　adsorbents　and　laboratory-cultured　activated　sludge　as　organic　adsorbent　for　adsorbing　model　of　the　Cu　and　Zn,　it　was　found　that　the　adsorption　of　heavy　metals　by　the　inorganic　adsorbents　well　followed　by　the　Langmuir　isotherm　with　the　saturation　capacity　proportional　to　the　specific　surface　area　of　the　solid　particles,　indicating　a　single-layer　adsorption　property.　However　for　the　activated　sludge,　its　adsorption　isotherm　showed　a　property　of　multilayer　adsorption　and　the　adsorption　capacity　was　one　order　higher　than　the　inorganic　particles.　Models　obtained　from　the　adsorption　experiment　were　practical　and　can　provide　an　approach　to　predicting　the　contents　of　heavy　metals　in　the　wastewater　treatment　plant＇s　effluent.