298 94 307/02 Untersuchungen zum Stand der Umsetzung des ...

Teil 3 Seite 4-48
To optimise the microbiological environmental conditions, to free ammonia from the or-
ganic nitrogen compounds, acidification dosage may be required, e.g. by the addition of
hydrochloric acid or phosphoric acid. Depending on the effluent to be treated an addi-
tional dose of nutrients, e.g. phosphorus, may be required. A COD:N:P:S ratio of
800:5:1:0.5 is considered optimal. Toxicity problems may arise if there are higher ammo-
nia and hydrogen sulphide contents. The inhibiting effects are determined by the pH, the
substrate composition and the adaptation time of the micro-organisms.
Table 4-13 shows the results of anaerobic pretreatment. Data are given for 2 months:
February and July. It is not known to what extent the results of the treatment are due to
the temperature of the anaerobic treatment or the difference in storage conditions of the
raw material. The results are summarised in terms of the percentage change in each pa-
rameter. The starting loads were different.
Table 4-13 Influent and effluent data from an anaerobic waste water pretreatment plant
Parameter
February July
Influent Effluent % in-
crease/
decrease
pH value 7.5 7.8 7.9 8.2
Specific
conductivity
(mS/cm)
Filterable solids
(mg/l)
6.67 6.89 7.54 7.66
Influent Effluent % in-
crease/
1115 532 - 61.8 2642 1011 - 62
decrease
COD total (mg/l) 4311 1156 - 73.2 9414 2208 - 76.5
BOD5 total (mg/l) 3433 534 - 84.5 5890 1154 - 80.4
Fat (mg/l) 370 90.8 - 75.5 717 265 - 63
NH4-N (mg/l) 126 145 + 15.1 185 208 + 12.4
org.-N (mg/l) 57.6 30.4 - 47.2 80.2 59.4 - 25.9
P total (mg/l) 8.7 8.6 - 0.7 14.5 12.8 - 12.1
Sulphide (mg/l) 24.1 8 - 66.8 8.1 13.5 + 65.2
Sulphate (mg/l) 39.5 11 - 72.2 65.5 22.8 - 65.2
Applicability
Applicable as a pretreatment in slaughterhouses and rendering plants, prior to aerobic
treatment.
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