DIRTY WATER FROM DAIRY FARMS, I - BIOCHEMICAL CHARACTERISTICS

The quality of dirty water arising on 20 dairy farms in England and Wa les was investigated. Farms were selected where existing pumped dirty irrigation systems allowed for appropriate sampling. Each farm was vis ited on three occasions during the year, in March, June and September, to sample dirty water. Considerable variations were found in total so lids (TS) with concentrations ranging from 0.08% to 4.64%. Marked seas onal variations were observed with the highest concentrations in June and the lowest in March. The biochemical characteristics of dirty wate r showed fairly good correlations between the following parameters and TS: 5-day Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (C OD), Kjeldahl nitrogen, potassium and phosphate. No corresponding corr elation was found for ammoniacal nitrogen concentrations. These findin gs indicated that effective biological treatment for dirty water was f easible. (C) 1998 Elsevier Science Ltd. All rights reserved.