Chapter 2. Water Quality System of Puerto Berrío

Drinking water and wastewater management in Puerto Berrío

Section keywords: water supply, sewage system, coverage, wastewater treatment plants, DENARIO

Related documents: PBOT de Puerto Berrío, Plan de Desarrollo de Puerto Berrío 2008-2011, Plan Maestro de Saneamiento de Puerto Berrío.

Expected product: flow diagrams for three different scenarios

Drinking water supply system

The water supply service in Puerto Berrío varies from the urban to the rural area in coverage as well as in quality, being the urban area the most favoured thanks to the concentration of the population. Currently, the company Aguas del Puerto S.A. provides the urban area with drinking water, taking it from the Magdalena River and giving it a conventional treatment to reach the desired and required quality for human consumption. In the urban area 96,3% (Info Basica P.B.) of the population is covered with the service, with a supply of 140 l/s. However the coverage seems high, the distribution system presents a lot of deficiencies such as cracks, illegal connections, leaking, insufficient pressure, inadequate pipe diameters and inadequate storage capacity of the tank, causing losses of around 50%. On the other side the water quality is very good and monitored continuously in the outlet of the treatment plant. The individual houses and spread settlements in the rural area make it difficult to provide a centralized water supply service and usually every settlement or group of settlements has different drinking water sources with inadequate distribution networks or none at all. In the rural area, only 64,8% (Info Basica P.B.) of the population is connected to a water supply system, and the drinking water doesn’t receive any kind of treatment before its consumption in almost all cases. Fortunately, the region is very reach in water resources and therefore there is good availability, but the quality is not always adequate for consumption due to unprotected (deforestation) or affected watersheds by anthropogenic activities. In analysis performed to analyse the drinking water quality in the rural area, coliform bacteria have been found, which results in health problems of the population such as skin infections, diarrhoea and gastroenteritis, especially in children under 5 years.

Sewer system

The coverage in the sewer system presents a similar behaviour to the drinking water system. The urban area is prioritised with a coverage of 57,6% (Plan de Desarrollo), while in the rural area only very few settlements some kind of sewer system. The sewer system of Puerto Berrío was built 50 years ago, initially for the collection of rainwater but later, the wastewater was connected too making it a combined sewer system, with many hydraulic deficiencies due to under dimensioning. All discharges of the system flow into the Magdalena River or one of its tributaries without any treatment, except for a 10% of the wastewaters that are treated in a small plant called El Pensil. The current sewer system network is divided in four sectors: La Malena, Barrio Milla No. 2, Puerto Colombia and Centro. As for the rural area, the wastewater doesn’t receive any treatment and is disposed into the nearest water body, usually a tributary of the Magdalena River or the river itself depending on the location of the settlement. Discharge of total wastewater of the municipality?

Wastewater treatment plants

In Puerto Berrío there are three wastewater treatment plants. At the time of the field visit to the study area, one of them was operating correctly, one had just been finished and was still being prepared for the commencement of operations, and the last one was built but not completely and has never been operated. The wastewater treatment plant being operated since February 2007 is called “El Pensil” and treats 12 L/s with an removal efficiency of around 84% for BOD and 75% for COD and total solids. The new wastewater treatment plant called “Lagunas” was finished in April 2008. Besides a primary treatment, the system provides a biological treatment through three oxidation ponds, one anaerobic and two facultative with an expected efficiencies of 80% BOD and total solids removal. This plant was built to treat around 80% of the municipal wastewater connected to sewer system, discharged currently untreated into the Magdalena River using a pumping station.

Identification of point sources

Section keywords: Treated wastewater, untreated waste water, location, distances, amount.

Related documents: Plan de Vertimientos de Puerto Berrío, PBOT Puerto Berrío.

Expected product: Sketch of the municipality and the river with the identified point sources. Map or aereal photograph with the river stretch delimitation and the identification of the wastewater discharge point sources.

According to the definition given by the U.S.A. Environmental Protection Agency, E.P.A., a point source is a stationary location or fixed facility from which pollutants are discharged or any single identifiable source of pollution; e.g. a pipe, ditch, ship, ore pit, factory smokestack. Tomado de EPA Terms of Environment.

As mentioned in the previous section, the wastewater network of Puerto Berrío can be divided in four sectors. The Land Use Plan (2000), identifies the wastewater discharges into the Magdalena River or one of its tributaries as follows:

a. The main discharge comes from the sector Centro, where around 80% of the urban population is found. This wastewater doesn’t receive any treatment and flows first into a pumping station from which it is pumped to guarantee the adequate evacuation into the Magdalena River.

b. From the sector Barrio La Milla No. 2, there are 4 direct discharges into the river.

c. In Puerto Colombia there are three wastewater collectors, all of them flowing directly into the Magdalena River. Besides, due to the location of the neighborhood, there are some houses on riverside, which discharge the wastewater individually and directly into the river.

(Section to be completed)

Description of the receiving water body

Section keywords: river stretch, flow discharge, water quality, seasonal variations, POEM

As has been mentioned already, Puerto Berrío is located on the riverside of the Magdalena River, and it has grown to the interior as well as along the river, which is used as receiving water body for most of the wastewater discharges of the municipality. This sections will give a brief presentation of some characteristics of the Magdalena watershed, of the river and specially of the river stretch affected particularly by the discharges of Puerto Berrío, which need to be taken into account and will serve as a base later on for the analysis of the system city-river.

The Magdalena River Basin

The size of the Magdalena River Basin is 199.294 Km2, occupying 17% of the whole national territory. As mentioned previously, the length of the river is 1.528 Km, from which 886 Km are navigable making it an important communication and transport route, both of them relevant aspects for the economy of the country. It rises in the south, at a height of 5.617 m above sea level and flows to the North, flowing into the Caribbean Sea (see Figure 2). The population in the river basin is 20.8 million, which represents 49% of the country’s population (census 2006). 17 departments and 557 municipalities are settled on the river basin, making its management quiet a challenge (See Figure 3). (PMC, 2007).

Figuras 2 y 3

The climate in the region is warm, with temperatures that go over the 24°C and with two dry periods, one between January and March and the other one between June and August. The rainy seasons are also two, one in May and April and one from September till December. The dry periods are usually short or interrupted by the rain [http://www.colombiamulticolor.net Colombia Multicolor). According to the bimodal distribution of the rain and the dry periods, clearly influenced by the Intertropical Convergence Front, the river discharge also presents two low water seasons. Though a natural behavior of the river, the low water seasons entail a series of problems such as limited availability in the reservoirs and drinking water intakes, restricted navigability due to very low water levels and erosion of the river bed and bank (PMC). In the middle Magdalena region, the morphology of the river is mainly flat, with smooth undulations, meandered to the south and braided to the north. Some formations found here are flood plains and terraces, islets, swamps and abandoned channels. The islands, some of them very large, and spread channels are the more significant formations (Ingeominas, 1999).

Water quality of the Magdalena River

Water quality is defined by several physical, chemical and biological variables, whose limiting values may be set differently according to the scope for which they are defined. According to these variables and the established limiting values, water quality can be considered good or bad or, adequate or inadequate, for example as habitat for some species or for human consumption. An environmental indicator is a quantifiable variable that can be measured and gives information about the state of the resource under study, in this case, about the quality of the water body. In Colombia, the entity that carries out monitoring activities of the quality of the water resources at the national level is the IDEAM (see Chapter 1. Background). At the present, the entity uses four environmental indicators to determine the state of the national surface water resources, namely temperature, pH, chemical oxygen demand and oxygen deficit.

Particularly for the Magdalena River, during the past two years (2006 and 2007), exhaustive water quality monitoring activities were carried out by the IDEAM together with Cormagdalena. Several variables where measured both in the high and low water seasons, some of them no site like pH, temperature, conductivity and dissolved oxygen, and the rest through laboratory procedures. Some of the measured variables were the biochemical oxygen demand, turbidity, total suspended solids, chemical oxygen demand, nitrogen compounds, phosphorus compounds, E-Coli, total coliform bacteria and metals in water and sediments. For the analysis of the measurements, the General Quality Index was estimated according to guidelines of the IDEAM. This index referred to as ICAg (from its name in Spanish) is calculated based on two other indexes, namely the Aggregated Index of Physico-chemical and Bacteriological quality, and the Lotic Index of General Environmental Capacity, directly related to the river flow, which plays a significant role in the assimilation of pollutants and the self-recovery (self-purification?) processes of the river. According to this last index, the environmental capacity of a stream varies from very low, for flows less than 1 m3/s, to very high, for flows higher than 1.000 m3/s. The Magdalena River flow could be classified in the category of 100 to 1000 m3/s, which puts it in the category of high environmental capacity. For the ICAg, the values range from 0 to 1, distributed as follows:

• Very bad: 0-0,25
• Bad: 0,26-0,50
• Middle: 0,51-0,70
• Good: 0,71-0,90
• Excellent: 0,91-1,00

The results obtained for the Magdalena River reflect that 47% of the river has a good water quality, while the rest has a middle water quality. Also no heavy metals were detected. (Campaña Monitoreo IDEAM, 2007)

Clasification of the river stretch according to existing water quality data

Section keywords: physical and chemical water quality parameters, monitoring, measurements, updated data.

Expected product: Map with the classified river stretch

Related documents: Leitfaden zur typspezifischen Bewertung der allgemeinen chemisch/physikalischen Parameter in Fließgewässern [Lebensministerium Österreich, 2005], Gewässergütekarte Baden-Württemberg [Landesanstalt für Umweltschutz Baden-Württemberg, 1998]; Gütebericht 2002: Entwicklung der Fließgewässerbeschaffenheit in Baden-Württemberg - chemisch-biologisch-morphologisch - [Landesanstalt für Umweltschutz Baden-Württemberg, 2002]; Gütezustand der Fließgewässer Neckar-Einzugsgebiet [Gewässerdirektion Neckar, Besigheim,2005], Nueva medición de la calidad de agua en los rios Magdalena, y Cauca [IDEAM, Cormagdalena y ONF Andina, 2007], Datos de programa de monitoreo de ISAGEN.

Interrelation community-river

Section keywords: water withdrawal, drinking water treatment plant, raw water supply (informal), sand and other material extraction, recreation, fishing, navigation, public health.

Volver