Quality requirements 3.1 Appearance: liquid, no visible impurities. 3.2 Physical and chemical indicators The physical and chemical indicators should meet the requirements of Table 1. Table 1 Physical and chemical index project requirements Content of organic matter, g/L ≥ 100 pH value (1:250 times dilution) 5.7-10.0 Content of water-insoluble matter, g/L 50.0 Number of fecal coliforms, individuals/mL ≤ 100 Death of roundworm eggs Rate, % ≥ 95 Total arsenic (As) content, mg/kg ≤ 10 Total mercury (Hg) content, mg/kg ≤ 2 Total lead (Pb) content, mg/kg ≤ 50 Total cadmium (Cd) content, mg/ kg ≤ 3 Total chromium (Cr) content, mg/kg ≤ 50 Total thallium (Tl) content, mg/kg ≤ 2.5