Definitions (nfm: from various sources)
- "Black water: Heavily contaminated wastewater, e.g., toiletwastewater. Black water is also known as ‘brown water’, black wateris heavily polluted and difficult to treat because of high concentrations ofmostly organic pollution.
- Grey water Household wastewater without input of human and /or animal excreta, including sources from baths, showers, hand basins, washing machines, dishwashers, laundries and kitchen sinks (also called ‘sullage’). Eventually kitchen waste water may also be treated separately, or together with black water, as it may contain larger concentrations of organic matter, oil, etc.
- Irrigation Water artificially supplied (by, e.g., pipes, ditchesor streams) for the purpose of watering grass, trees, and other plants.
- Waste: any material (solid materials such as process residues as well as liquid and gaseous effluents) that has been or willbe discarded as being of no further use.
- Sanitation Interventions to reduce people’s exposure to diseases by providing a clean environment in which to live; measures to break down the cycle of disease. Sanitation involves both behaviours and facilities, which work together to form a hygienic environment.
- Leachate Liquids draining from sewers, pits or waste collection chambers.
- Sewage sludge Sludge resulting from the treatment of raw wastewater.
- Dry sanitation: on-site disposal of human urine and faeces without the use of water as a carrier. It includes many of the most popular options forlowcost sanitation including pit latrines, Ventilated Improved Pits, SanPlats, etc.".
Bellagio Principles (et. al.) on Sanitation and Waste Management : "1) Human dignity, quality of life and environmental security at household level should be at the centre, responsive and accountable to needs and demands in the local and national setting. 2) Solutions should be tailored to the full spectrum of social, economic, health and environmental (Identify appropriate simple, affordable decentralised sanitation systems and promote their adoption). 3) The household and community environment should be protected the economic opportunities of waste recovery and use should be harnessed. 4) In line with good governance principles, decision making should involve participation of all stakeholders, informed choices incentives (care health and hygiene education so that physical facilities would be properly used and maintained, and that hygienic behaviour would support the improvements). 5) Facilities should be consistent and be balanced by responsibilities (Implement appropriate technologies with the participation of the communities to be served). 6) Waste should be considered a resource, and its management should be holistic and form part of integrated water resources, nutrient flow and sanitation. 7) Inputs should be reduced. 8) Waste should be minimised to reduce the spread of pollution (destruction of pathogens through flow stream separation, containment and specific treatment). 9) Wastewater should be recycled and added to the water budget 10) Solutions should be kept to the minimum practical size (household, community, town, district, catchment, city) and wastes diluted as little as possible. 11) Waste should be managed as close as possible to the source (need to close the resource loops through the productive use of the nutrients contained in excreta). 12) Water should be minimally used to transport (elimination or minimisation of wastewater discharges to the environment)13) Waste additional technologies for waste sanitisation and 14) reuse should be developed (resource conservation through a reduced use of potable water as a transport medium for human waste and by recovering wastewater for irrigation)".
There is a wide range of technologies for disposing of human excreta, from simple improved traditional latrines, to complex sewerage systems: 1) Bucket collection of excreta 2) basic improved traditional latrine; 3) ventilated improved pit latrine; 4 ) double-vault compost latrine; 5) bored hole latrine; 6) pour-flush latrine with leaching pit; 7) septic tank and aqua privy; 8) vacuum tanker; 9) manual latrine-pit emptying technology (MAPET); 10) soakaway; 11) drainage field; 12) small-bore or settled sewerage. 13) sewer 14) sludge 15) effluent treatment technologies (stabilization ponds, aeration) ponds.
“Modern” water-borne sewer systems are a relatively new technology, which began to spread around the end of the 19th century, when piped water supplies and the use of flush toilets lead to an increased water consumption, and wastewater production. This led to streams and stagnant pools of wastewater in city streets, causing outbreaks of cholera and other diseases. Seen serious water pollution; step by step mechanical wastewater treatment plants, biological treatment for the degradation of organic substances, and tertiary treatment for the removal of nutrients were added to reduce the pollution and eutrophication of the receiving water bodies. These represented the present state-of-the-art in wastewater treatment. However conventional centralized systems require a huge financial investment, and have relatively high maintenance and operation costs. So the current sanitation paradigm is failing the world, with the poor suffering most, threatening the integrity of fresh water supplies, and in general creating unsustainable linear flows that can ultimately make life on earth difficult or no longer feasible".
Sanitary Sewer: "1) Local Sewer Authority: the regulations of the local sewer authority should be followed. 2) Discharge in Remote Rural Areas: in areas where no public sewers exist, septic tanks and leach fields should be used for sewage discharge. Cesspools are not permitted. 3) Septic systems sould have additional land area (in accordance with local and State code requirements) for future expansion of the discharge system. 4) Locating Sewer Pipes: all sewer lines should be located below unpaved areas if at all possible. 5) Manholes: pipe runs between manholes should be straight lines. 6) Manholes: must not be located in the main pedestrian route in walkways; the placement of manholes in other pedestrian areas such as plazas and entry courts should be avoided, particularly in the primary traffic routes across plazas and entry courts. 6) Cleanouts: should be provided on all service lines, approximately 1.5 m away from the building, and at all line bends where manholes are not used. 7) Storm Drainage: systems should always use gravity flow. 8) Location of Storm Drainage Pipes: should be located in unpaved areas wherever possible. It is desirable to offset inlets from main trunk lines to prevent clogging. 9) Rainwater Harvesting: strategies may be considered where appropriate, including filtering and retaining rainwater in cisterns for irrigation or flushing of toilets; and must comply with all local codes and standards".
"Drainage infrastructure systems are like: culverts, storm sewers, outfall and related drainage elements. The variety in material types, shapes, backfill materials, types of roads located above and environmental conditions make every single culvert unique in terms of its behavior and durability. Wide geospatial distribution of drainage infrastructure assets further complicates the management of these assets".
Projects and Treatments Types
- Sludge care aspects are: 1) Anaerobic Sludge Digestion, 2) Aerobic Sludge Digestion, 3) Sludge Handling, 4) Sludge Disposal 5) Regulations,
- Small Wastewater Treatment Systems: 1) Septic Tank System, 2) Grease and OilInterception Tanks, 3) Imhoff Tanks, 4) Intermittent SandFilter, 5) Absorption (Disposal) Fields, 6) Mound System, 7) Pit Privy, 8) Vault Toilets and Aerated Vault Latrines, 9) Composting Toilets, 10) Contact Stabilization, 11) Wastewater Collection Systems Effluent Treatment, 12) Pressure Sewers, 13) Vacuum Sewers, 14) Small Diameter Gravity Sewers, 15) Physical-Chemical Treatment, 16) Package Plants, 17) Lagoons (Ponds), 18) Land Treatment Methods, 19) Submerged Bed Constructed Wetlands, 20) Septage Holding Tank or Station, 21) Septage and Septage Disposal, 22) Effluent Disposal Options, 23) Sludge Treatment, 24) Effluent treatment.
- Natural Systems Wastewater Treatment examples:1) Constructed Wetlands Aquatic - Plant Systems - Subsurface Flow - Wetland Types, 2) Floating Aquatic Plant Treatment, 3) Land Application - Overland Flow - Rapid Infiltration - Slow Rate , 4) Stabilization Ponds - Aerobic Lagoons or Anaerobic Lagoons or Facultative Lagoons- , 5) Subsurface Wastewater Infiltration System.
- Effluent Disinfection: 1) Chlorination, 2) Ozonation, 3) Effluent Disinfection-Ultraviolet, 4) Others.
Basically 4 types of projects: 1) Rural upgrading, 2) Urban upgrading, 3) New development areas, 4) Non-residential (schools, offices etc.)
"Non-Monetary Evaluation Criteria:
- Operability: 1) Ease of operation Minimizes operator attention/expertise required to ensure successful process performance 2) Ease Maintenance requirements not excessive and do not require special expertise facilities and equipment readily accessible 3) Operator familiarity Staff familiarity and ability to usestaff experience from existingfacilities
- Reliability: 1) Demonstrated performance - Proven process/technology to meet permit limits reliably, 2) Hydraulic sensitivity Capability to handle variations in hydraulic loads with minimal process impacts, 3) Waste loading sensitivity - Capability to handle variations in waste loads with minimal process impacts, 4) Process control stability - Not subject to upset from inadvertent operational changes, toxic slugs, 5) Flexibility Capability for changes in process operations to handle differing waste load conditions and to meet differing treatment objectives for different effluent requirements
- Environmental Effects: 1) Odor Minimizes potential for odors, 2) Noise Minimizes potential for noise 3) Visual impacts Minimizes negative visual impact of facility, 4) Effects on floodplain Minimizes changes to floodplain, 5) Effects on wetlands Minimizes changes to wetlands, 6) Footprint Minimizes footprint and disruption to site, including removal of trees, etc.
- Expandability; 1) Footprint Maximizes area available for expansion, 2) Flexibility: Easily modified to meet differing future loads, effluent requirements, and/or treatment objectives".
Final disposal Criteria
Type of receiving water: 1) Small lakes and rivers are usually easier to model. 2) Large lakes, estuaries, and large (river, lake, or estuary) river systems are more complex. 3) Water quality parameters: Dissolved oxygen Usually decreases as discharge increases. Used as a water quality indicator in most water quality models - Biochemical oxygen: a measure of oxygen-reducing potential for waterborne discharges. Used in most demand (BOD) water quality models. 4) Temperature is often increased by discharges, especially from electric power plants. 5) Ammonia nitrogen reduces dissolved oxygen concentrations and adds nitrate to water. 6). Algal concentration Increases with pollution, especially nitrates and phosphates: predicted by moderately complex models. 7) Coliform bacteria is an indicator of contamination from sewage and animal waste. 8) Nitrates are nutrients for algal growth and a health hazard at very high concentrations in drinking water: they are predicted by moderately complex models. 9) Phosphates are nutrients for algal growthand predicted by moderately complex models. 10) Toxic organic compounds: there isa wide variety of organic (carbon-based) compounds can affect aquatic life and may be directly hazardous to humans. Usually they are very difficult to model. 11) Heavy metals Substances containing lead, mercury, cadmium, and other metals can cause both ecological and human health problems, difficult to model in detail".
Nitrates have a special relations to 'modern' agriculture's pollution. "Possible causes of nitrate contamination of drinking water include: 1) Cultivation of crops for which high doses of nitrogen fertilizers are applied: e.g. tobacco, vegetables, flowers, etc. It must be emphasized that organic farming does not ensure freedom from nitrate problems. 2) Surface disposal of sewage without treatment to remove nitrogen. 3) Use of sewage water for irrigation of crops is commonly practiced in India and this may lead to nitrate contamination of groundwater. 4) Disposal of industrial effluents containing nitrogen. 5) Landfilling: Quarry pits are often filled with municipal wastes which contain large quantities of nitrogen. 6)Deforestation: If the foliage is allowed to mineralize in situ, nitrate contamination is possible. 7) Dairy industry: If large amounts of animal excreta are disposed off on land both ammonia volatilization and nitrification will be rapid. Ammonia may contaminate surface waters and it may get converted to nitrate by the process of nitrification. Nitrate in soil may contaminate surface waters through run off or it may percolate to the groundwater with rain or irrigation water. 8) Since the recoveries of nitrogen fertilizers are, in general, below 50%, nitrate contamination of groundwater can take place if water percolating from a large area converges to a point beneath the soil due to hydrological or other reasons".