Application of Municipal Refuse and Liquid Sewage Sludge to Agricultural Land: II. Lysimeter Study

Abstract

AbstractTo determine if agricultural land could be used simultaneously for crop production and waste disposal‐utilization, a lysimeter study was conducted using liquid sewage sludge and unsorted, pulverized municipal refuse. Refuse (R) at 188 metric tons/ha and a 2.3‐cm depth of sewage sludge (S) were applied separately and in combination (RS). A double refuse‐sludge rate [2(RS)] and a control treatment (C) receiving no additions were also used. Treatments were applied in the fall of 1971 and 1973. The cropping sequence was wintdr fallow—corn (Zea mays L.)—winter fallow—spring barley (Hordeum vulgare L.)—winter rye (Secale cereale L.)—corn.There was no effect of treatment on corn grain yields in 1972 but all treatments containing refuse increased grain yields in 1974. Treatments had little effect on levels of Cr, Fe, Mn, Ni, and Pb in the corn grain and stover. Levels of Zn, Cu, and Cd were increased mainly by treatments containing refuse. The 2(RS) treatment resulted in stover Cd levels greater than the acceptable level for foodstuffs.Nitrate leaching losses were greater for S and RS than C. Although NO3‐N leached from 2(RS) was low, the chemical oxygen demand (COD) concentrations were high (> 1,000 ppm) and cumulative COD loss was 120 times that of the loss from C. The effect of treatment C/N was inconclusive, i.e., mixing sludge (C/N = 4.9) with refuse (C/N = 63) resulted in reduced NO3‐N leaching from RS (C/N = 41) as compared to that from S. However, refuse alone did not cause immobilization because NO3‐N losses from R were identical to those from C.