The Treatment of Sewage with Effective Microorganisms (EM) Technology for Municipal Sewerage Plants
Introduction
Many Local Authorities in Southern Africa are faced with challenges relating to the handling and treatment of sewage waste. The task becomes even greater with the need to reduce the amount of harmful chemicals and the subsequent toxic and/or carbon emissions that are released into the atmosphere.
It is the unequivocal desire of all Municipal Managers to improve the quality of their treated effluent and to reduce or eliminate the harmful contamination of our rivers, waterbodies, wetlands and the general environment. Every responsible Local Authority Manager is challenged to become a leader in responsible environmental management.
Below is a brief explanation of the effectivity of EM (Effective Microorganisms) and EM Technology in meeting these goals. EM reduce sludge accumulations (even old sludge deposits accumulated over many years) in waste streams including tanks, digester tanks, pipes, canals, lagoons, ponds, etc. and also yield numerous other environmentally sound benefits. In almost all applications the use of EM reduces the costs of treatment and disposal.
A glossary of terms used in this document is included at the end of the document.
Background
Primary and Secondary Effects in Waste Treatment of EM
Primary and secondary effects of EM-based interventions are often remarkable, where the primary target effect is gross reduction in build-up of sludge via microbial-mediated disintegration and even removal of large accumulations of old sludge. Secondary effects will usually include:
The net effect is to significantly and sometimes drastically increase the effectiveness of recycling of resources, while reducing harmful side-effects and residues.
As a cautionary note, it is important to realise that many of the above-listed results do not appear immediately upon initiation of EM usage, but rather appear progressively over a period ranging from two weeks to three months. This is due to the establishment of the beneficial microbes in mud, gravel, concrete, and on hard surfaces (rock, concrete, etc.) and in interstices, and also to the encouragement of other “wild” beneficial microbes with anti-oxidative (reducing) rather than oxidative properties, with the attendant (“competitive”) discouragement of undesirable microbes and undesirable processes.
Introduction
Many Local Authorities in Southern Africa are faced with challenges relating to the handling and treatment of sewage waste. The task becomes even greater with the need to reduce the amount of harmful chemicals and the subsequent toxic and/or carbon emissions that are released into the atmosphere.
It is the unequivocal desire of all Municipal Managers to improve the quality of their treated effluent and to reduce or eliminate the harmful contamination of our rivers, waterbodies, wetlands and the general environment. Every responsible Local Authority Manager is challenged to become a leader in responsible environmental management.
Below is a brief explanation of the effectivity of EM (Effective Microorganisms) and EM Technology in meeting these goals. EM reduce sludge accumulations (even old sludge deposits accumulated over many years) in waste streams including tanks, digester tanks, pipes, canals, lagoons, ponds, etc. and also yield numerous other environmentally sound benefits. In almost all applications the use of EM reduces the costs of treatment and disposal.
A glossary of terms used in this document is included at the end of the document.
Background
- In any waste treatment system, sludge is produced both intentionally (as an end-product for eventual use in a variety of applications, primarily to soil) and unintentionally (such as solid residue in sluiceways, on equipment surfaces, in streams, ponds and lagoons.)
- Excessive sludge from waste water treatment, as well as from industrial and agricultural waste streams, causes problems in many ways, including noxious odours, toxic off-gassing, over-limit levels of pathogenic microbes, toxic moulds, high BOD and COD, and lastly, creating a storage problem simply due to potentially massive volumes. Since much of the sludge is produced from waste facilities this may have a number of undesirable consequences.
- It is hard to find methods to easily dispose of this sludge, and even harder to find means to dispose of it in ways that are environmentally friendly and sustainable as a consequence of its odour, potential toxicity and probable presence of pathogens.
Primary and Secondary Effects in Waste Treatment of EM
Primary and secondary effects of EM-based interventions are often remarkable, where the primary target effect is gross reduction in build-up of sludge via microbial-mediated disintegration and even removal of large accumulations of old sludge. Secondary effects will usually include:
- Drastic reduction or complete elimination of odours and toxic gases from waste, including H2S, ammonia, mercaptans, sulphide gases such as methyl sulphide and dimethyl sulphide, and putrefactive off-gassing products (putrescine, cadaverine, etc.);
- Drastic reduction in pathogenic bacteria, yeasts, and protozoa, as well as drastic reduction in “toxic” moulds implicated in toxic mould syndromes;
- Reduction (often drastic) in BOD and COD of recovered water and recovered solids;
- Utility and effectiveness under both aerobic, partially-aerobic and anaerobic conditions;
- Reduction in breeding and proliferation of flies and mosquitoes in and near channels, sluiceways, ponds, lagoons and treatment facilities carrying or holding waste liquids and solids;
- Reduction in colour (aka decolorisation) and turbidity, and improvement in clarity, of waste water;
- Reduction in suspended solids (SS) and dissolved solids (DS) in end-product recovered wastewater;
- Reduction or elimination of heavy scum layers (often caused by undesirable species of actinomycetes) on surface of wastewater;
- Oftentimes the reduction in undesirable species of algae (phyto-plankton);
- In aerobic and semi-aerobic settings, an improvement (increase) in levels of DO (dissolved oxygen);
- Due to reduction in BOD and COD, a reduction in the need for aeration thus allowing frequency and duration of aeration of ponds or tanks to be reduced significantly;
- Reduction in levels of (undesirable) nitric acid, nitrous acid and sulphuric acid in wastewater. These substances result in toxicity to wildlife and livestock, and also in corrosion of plant equipment, including accelerated corrosion of metal surfaces;
- Further to the above we notice a reduction in corrosion (including rusting) of metal and other surfaces of plant and facility equipment in or near the waste stream. This is due in part to drastic reduction of the nitrogen and sulphur acids mentioned earlier, and also due to drastic reduction of oxidative free radicals, aka reactive oxygen species. Both classes of substances are responsible for most corrosion and rusting. This reduced corrosion results in lower maintenance and equipment costs;
- Reduced nitrate and nitrite levels in final recovered wastewater and solids;
- Reduced phosphate levels in final recovered wastewater and solids;
- Increase in the efficacy and speed of waste digestion, thus often allowing greater throughput or faster flow rates for a given system/plant size;
- Reduction in levels of heavy and toxic metals in waste, including cadmium (Cd), chromium (Cr), mercury (Hg, aka quicksilver), arsenic (As), copper (Cu) lead (Pb) and nickel (Ni). This is accomplished by the destruction of ionised oxidised forms of metal and reductive conversion of such oxidised forms to non-ionised forms via antioxidative (aka reductive) redox processes. Non-ionised, non-oxidised forms of metals are largely inert and are relatively harmless to plants and animals, and are also undetectable in many types of tests for harmful metals;
- Reduction in levels of particularly harmful or toxic oxidised forms of metals (e.g., hexavalent chromium, aka Cr6, Cr(VI), Cr+6 and CrVI, also the polyvalent forms of arsenic (As), such as arsenic (III) and (V) oxyanions), selenium oxyanions, and halogens (e.g., polyvalent fluoride oxyanions), along reduction of toxic metal cations in waste stream and solids. Again, as noted above, this is largely accomplished by the destruction of ionised oxidised forms of metal and reduction conversion of such oxidised form to non-ionised forms via antioxidative (aka reductive) redox processes;
- Reduction of toxic compounds such as chlorinated hydrocarbons, aldehydes, formaldehydes and nitrosamines;
- Normalisation of pH from extremes;
- Decrease in costs associated with managing waste;
- Drastic reduction in need for toxic substances in the management waste or odour management of the waste stream;
- Improvement in quality and usability of recovered water and recovered solids, rendering them far more suitable for eventual use in a variety of applications;
- Improve nutrient value, safety and (value of) microflora of recycled waste solids which will be applied to soil.
The net effect is to significantly and sometimes drastically increase the effectiveness of recycling of resources, while reducing harmful side-effects and residues.
As a cautionary note, it is important to realise that many of the above-listed results do not appear immediately upon initiation of EM usage, but rather appear progressively over a period ranging from two weeks to three months. This is due to the establishment of the beneficial microbes in mud, gravel, concrete, and on hard surfaces (rock, concrete, etc.) and in interstices, and also to the encouragement of other “wild” beneficial microbes with anti-oxidative (reducing) rather than oxidative properties, with the attendant (“competitive”) discouragement of undesirable microbes and undesirable processes.