13. Bespoke waste assessment
Inhibition values for aerobic and anaerobic processes.
Waste you accept must be suitable for biological treatment. This section applies to bespoke waste types which are more novel, for example chemical process waste and sets out inhibition values.
Table A: general inhibitors for anaerobic processes
| Determinant | Threshold |
|---|---|
| pH hydrolysis and fermentation acido and aceto genesis | Optimal pH 5 to 7 |
| Methanogenesis | Optimal pH 7 to 8, Operational 6.5 to 8.5 |
| Temperature below optimum (mesophillic optimum temperature 37°C, thermophillic optimum temperature 55°C) | The rate of activity will drop by approximately 50% for every 10 degrees below the respective optimum temperature (Caine, 1990). |
| Temperature above optimum (mesophillic optimum temperature 37°C) | Where the temperature is raised gradually above the mesophillic optimum, the cultures will adapt and thermophiles will become established. During this period performance will be reduced. Where temperature is raised suddenly by 10°C performance may reduce significantly. |
| Temperature above optimum (thermophilic optimum temperature 55°C) | Performance of thermophiles will drop if temperature is raised above the optimum values but will survive extreme increase up to 100°C |
| Ammonium inhibition | Ammonium build up may inhibit the anaerobic process. |
Table B: general inhibitors for aerobic processes
| Determinant | Threshold |
|---|---|
| Moisture content | Optimal range of 50 to 70% |
| pH | Optimal range of 6 to 8 |
| C/N | Optimal range of 25:1 to 40:1 |
Table C: specific guideline inhibitors for aerobic treatment
The following table contains indicative inhibitive concentrations for a range of substances for aerobic treatment processes.
Blanks mean that no data is available in literature.
The first column of data for aerobic treatment is based on the inhibition of respirometric activity, the second is based on the inhibition of nitrification.
You must show that where you receive waste that falls within these inhibition ranges you can manage and maintain a stable process.
The waste must be capable of being treated and recovered by the aerobic process.
This table does not list every substance which may be inhibitory to aerobic or anaerobic organisms. You must also consider the potential inhibitory effect of other substances used or generated at your facility.
| Parameter | Aerobic treatment threshold mg/L | |
|---|---|---|
| Activated sludge | Nitrification | |
| Anthracene ug/l | 500 | |
| Arsenic (As) | 0.1 | 1.5 |
| Cadmium (Cd) | 1 to 10 | 5.2 |
| Chloride mg/kg | 180 | |
| Chromium (Cr) III | 10 to 50 | |
| Chromium (Cr) total | 1 to 100 | 0.25 to 1.9 |
| Chromium (Cr) VI | 1 | 1 to 10 (as chromate) |
| Copper (Cu) | 1 | 0.05 to 0.48 |
| Cyanide | 0.1 to 5 | 0.34 to 0.5 |
| Iodine (I) | 10 | |
| Lead (Pb) | 1 to 5 or 10 to 100 | 0.5 |
| Mercury (Hg) | 0.1 to 1; 2.5 as Hg(II) | |
| Naphthalene | 500 (EPA); 29 to 670 | IC50 (mg/L) for Nitrosomonas and aerobic heterotrphs respectively |
| Nickel (Ni) | 1.0 to 2.5; 5 | 0.25 to 0.5; 5 |
| Phenantherene ug/l | 500 | |
| Sulphide | 25 to 30 | |
| Total ammonia nitrogen | 480 | |
| Zinc (Zn) | 0.3 to 5; 5 to 10 | 0.08 to 0.5 |
Table D: specific inhibitors for anaerobic treatment
The following table contains guideline indicative inhibitive concentrations for a range of substances for anaerobic treatment processes. Blanks mean that no data is available in literature. You must show that where you receive waste that falls within these inhibition ranges you can manage and maintain a stable process. The waste must be capable of being treated and recovered by the anaerobic process. This table does not list every substance which may be inhibitory to aerobic or anaerobic organisms. You must also consider the potential inhibitory effect of other substances used or generated at your facility.
| Parameter | Anaerobic treatment threshold g/l |
|---|---|
| Acrylates | 62 to 150 mg/l |
| Alcohols | 22 to 43000 mg/l |
| Alkylbenzenes | 160 to 580 mg/l |
| Aluminium (Al) | 1 (2% inhibition of methane production after 59 days) |
| Amines | 13000 1-methylpyrrolidine mg/l |
| Arsenic (As) | 0.0016 |
| Cadmium (Cd) | 0.15 to 0.33 |
| Calcium (Ca) | 2.5 to 4 |
| Chlorinated aliphatics | 0.5 to 600 mg/l |
| Chromium (Cr) total | 0.2 |
| Copper (Cu) | 0.009 |
| Fluoride (F) | 0.018 |
| Halobenzenes | 20 to 750 mg/l |
| Halogenated alcohols | 0.3 to 630 mg/l |
| Halogenated carboxylic acids | < 0.001 to 0.01 mg/l |
| Halogenated phenols | 2-300 for mono,-di and trichloros; 0.04 and 0.13 for penta and tetra mg/l |
| Ketones | 6000 to 50000 mg/l |
| Lead (Pb) | 3.2 to 8 |
| Magnesium (Mg) | 12 |
| Nickel (Ni) | 0.1 to 1.6 |
| Nitriles | 90 to 28000 Acrylonitrile and Acetonitrile respectively mg/l |
| Nitrobenzenes | 13 nitrobenzene |
| Nitrophenols | 4 to 12 mg/l |
| Phenol and alkylphenols | phenol 1850; o,m,and p-cresol 850, 925, 975 mg/l |
| Potassium (K) | 2.8 to 14 |
| Silver (Ag) | 0.1 |
| Sodium (Na) | 5.6 to 53 |
| Sulphate | Methane production is reduced by one mole for every mole of sulphate added due to sulphate reduction dominating over methanogenesis |
| Sulphide | 100 to 800 |
| Surfactants | For example, alkyl dimethylbenzylammonium chloride: 6.7; sodium alkyl ethersulfate: 11 mg/l |
| TiO2 (mg/gTS) | 150 |
| Total ammonia nitrogen | 1.7 to 14 |
| Zinc (Zn)m as ZnO nanno particles | 0.03 |
(Inhibitory values are under review. Subject to that review, substances may be added or removed, or values amended).