SOURCE IDENTIFICATION AND MITIGATION OF INDUSTRIAL POLLUTION

Diffuse pol lution comprises of pol lution ari s ing from a variety of dispersed, often minor, point sources . The aim of this study was to ident ify which hazardous substances that are discharged to the wastewater treatment plant (WWTP) in Eslov municipal ity from industries and bus inesses. Based on these findings control actions was suggested in order to improve the qual ity of the s ludge produced in the WWTP. Here, 43 industries and businesses connected to the municipal sewer system in Eslov municipal ity reported commodities and activ itiesa: industr ial process and maintenance products, cleaning detergents and other chemicals discharged to the sewer system, including composition of indiv i dual substances . Over 900 commodities and 2300 substances were recorded. Of these were 92 substances frequently used (present in c".5 commodities) . Most prominently was iso-propanol which was found in 6 1 commodities. A hazard i dent ification and ranking of 346 substances showed that 9% of the substances pose a potential hazard in the s ludge. Seven of the most frequently used substances cons i sted of petroleum based hydrocarbons. Most of the industries and bus inesses re ferred to hav ing an oi l separator instal led on the premises . However. recent studies have shown that effluents from oi l separators in many cases have a hydrocarbon oi l index >50 mg/L, which indicates that the efficiency should be questioned. Among the pest icides and preservatives ident ified were i sothiazol ines, B ronopol and several parabens . The i sothiazol ines and Bronopol originated from industrial appl ications, whereas the parabens derived from the personal care products used for staff wel lbeing . Noteworthy is that both the isothiazol ines and Bronopol were present in different brands of car shampoo. General ly, this study was hampered by incomplete data prov ided by the industries and businesses as wel l as the lack of inherent data, primari ly biodegradation. used in the hazard identification and ranking of the organic substances .


I INTRODUCTION
D i ffuse pol lution comprises of pollution ansmg from a variety of dispersed. often minor, point sources. Although they as individuals often are considered as minor contributors, their col lective contribution may be a significant sourcea . No single solution to tackle diffuse pol lution has been put forward. Among reliable measures are changes in the handling and house keeping of substances, in order to reduce impacts from di ffuse pollution. For example as a waste discharge charge system ( WDCS ) in South Africa [ 1 ]. In Sweden, some municipalities, the farmerso ' organisations (LRF), the food industry, the commercial trade organization and non-governmental environmental and consumer focussed organisations are collaborating in a project called ReY AQ, with the purpose to enhance the quality of municipal sludge to be applied on agricultural land in a sustainable manor [2]. Sludge is not used on agricultural land today due to the fear for pollution of the soil and consequently pollution of the crops. One of the participants, Esliiv municipality, located in the south of Sweden, aims to mitigate hazardous pollutants from their sludge and treated wastewater. The focus, has up to now, been on heavy metals (with a special emphasis on cadm ium ) and PBT (persistent, bioaccumulating and toxic) organic substances.
The aim of this study was to identi fy which hazardous substances that are discharged to the wastewater treatment plant in Esliiv municipality, and to clari fy from which industries and businesses these are em itted. Based on these findings, further control actions will be suggested. Possible actions are, e.g .. implementat ion of source control options, such as changing one commodity into another and thereby reducing the discharges of a non-wanted substance, or changing the handling strategy, e.g., collect spills and treat them as solid waste instead of discharge them to the sewer systems. Other possibilities are implementation of local treatment at the industry/business.

MATERIALS AND METHODS
The project started by launching an information campaign including a questionnaire to industries and businesses connected to the municipal sewer system in Esliiv, see Figure I .
The questionnaire included an Excel sheet in which the businesses were asked to report trade name and chemical composition of the com modities used in their operation and maintenance. They should also report CAS registry numbers for indiv idual substances included in the com modities as well as estimation on how much that is discharged into the sewer system in kg or litres on an annual basis. Additionally, any risk phrases and ecotoxicity data listed on the commodities· Material safety data sheet ( MSDS) should also be included.
The reported substances were subjected to a hazard identification according the RICH-tool (ranking and identification of chemicals hazards) procedure described by Baun et al. [3], where the substances are ranked based on their inherent properties (solubility, sorption. evaporation), effects ( acute and long-term toxicity) and environmental fate (degradation and bioaccumulation). The methodology consists of a decision tree in which hazardous and problematic compounds are identified. To visualize the sort ing of XOC the decision tree can be described as a funnel fitted with several filters. The filters have been set according to specified criteria based on sorption, volatility, persistence to biodegradation, potential for bioaccumulation and aquatic toxicity. There are also one on/of f filter for technical/aesthetical problems and a long-term chronic effects-filter considering cancer, mutagenic and reproduction hazards, endocrine disruption e ffects and allergenic effects. The output is a classi fication of the compounds in three categories (white, grey and black) depending on their priority as possible pollutants. White compounds are considered as non-hazards. which mean that these compounds will be excluded from the continuing evaluation with CHlAT. Grey compounds are passed on to the next filter. These compounds may or may not be potential hazards depending on the outcome of the following filtration. Black compounds are considered as potential hazards.
Primari ly inherent data col lected in a project focussing on domestic wastewater were, due to the limited time frame, used for the ranking procedure [4]. S ince the industrial commodities and substances generally are not present in this waste flow, toxicity data originating from the MSDS were applied and supported by inherent data on sorption and volatilization based on measured data ( PhysProp) and estimated data (EPI Suite) [5].
Commodities containing substances identified as hazardous were in the next step evaluated in order to find possible act ions, e.g .. implementation of source control options.

RESllL TS A N D DISCUSSION
Feedback was obtained from 42 industries/businesses in the munic ipal ity of Eslov. These range from food industry to a cemetery administration, with a high representation of car and farming machines styl ing and maintenance. Nine hundred and one commodities have been reported to be in use. These inc lude process and industry chemicals; equipment and office cleaning detergents; laundry detergents and personal care products. These commodities were reported to contain at least 2382 substances of which 2007 were reported with CAS and 375 were reported by name. The actual number of substances ( I 09 1) is; however, lower as gross number includes duplicates, i.e. present in more then one commodity.
The highly prioritized substance cadmium (Cd) was found not to be reported by any of the industries and businesses participating in this study. In a previous study five industries and businesses had Cd concentrations > I mg/L in their wastewater [2] indicating that Cd may originate from indirect sources such as tear and wear of industrial appliances and vehicles.

. 1 Frequently present substances
A total of 92 substances were present in 5 or more commodities, see Table I. Most frequently present were iso-propanol, butane and propane which were found in 6 1 , 42 and 46 com modities, respectively. Thereafter were the surfactants alcohol ethoxylates and the solvent acetone present in 35 and 3 1 commodities. Ten substances were found in 20-29 commodities, 2 1 in the range of I 0-1 9 and a total of 55 were present in 5-9 commodit ies.
Other substances as for example, the Bisphenol A derivate Bisphenol-A-diglycidether was present in 5 commodities related to mending paste and noor paint. Three sil icates (Sodium sil icate, Disodium metasil icate and Sodium metasil icate pentahydrate) were also found among the most frequently used substances. These were present in various cleaning and surface treatment commodities such as degreasing products, vehicle wax, vehicle shampoos, protective cream, cleaning detergent and carousel cleaners.

Inorganic ac ids and bases
Phosphoric acid, hydrochloric acid and sulphuric acid were present in 1 7, 6 and 5 commodities, respectively. Using the substance presence in com modities (%), the volume used by each business and the business estimated discharge to wastewater (%) it was found that on an annual basis 1 . 1 -1 . 7 m 1 of phosphoric acid, 1 .9 m 1 of hydrochloric acid ( of which 98.8% is reported to neutral ized or protolyzed before discharge) and 0.3-0. 7 nl sulphuric acid are enter ing the wastewater.
Sim ilarly for the bases it was found that sodium hydroxide and potassium hydroxide were present in 29 and 1 8 commodities, respectively. It was calculated, from the reported annual use of various com modities, that at least 1 5.2 tons of sodium hydroxide and 0.4-1 . 1 tons of potassium hydroxide are discharge to Eslov WWTP annually. Their appl ications were primarily cleaning, de-greasing and ion exchange.   Additionally, both some acids and based were reported to be neutral ised with Magnodol (dolom ite rock) before discharge, but no information on how much Magnodol that are used on an annual basis was reported. Other pH affecting inorgan ic substances that are among the most frequently used are ammonium hydroxide, sodium carbonate and l imestone present i n 7, 7 and 5 commodities. respect ively.

BETXs (benzene, ethyl benzene, tolu ene and xylenes)
Several of the aromatic organic solvents. the BETXs. were found among the frequently used substances ethyl benzene, toluene and xylenes. in 5, 1 2 and 25 commodities, respectively. Benzene was present in only two commodities and reported in the concentration of < 1 %. Benzene is a priority substance in the field of water policy [6] and as such it i s subjected to progressive reduction of discharges, emissions and losses [7].

Oil and grease
Many of the participating industries and businesses were connected with operation and maintained of vehicles with combustion engines or vehicle parts. and consequently there is a strong correlation with the lubricants used. Seven of the most frequently used substances were petroleum based oil or grease related substances; Distillate (petroleum) hydrotreated light present in 29 commodities, Hydrotreated heavy naphtha (28). Naphtha petroleum hydrotreated light ( 1 7), Hydrodesulfurized heavy naphtha ( 1 5), Fisherbrand vacuum pump oil ( 1 1 ), and Paraffins (petroleum) normal C5-20 (9) as well as Naphtha (petroleum) hydrodesulfurized light dearomatized (7).

Pesticides and preservatives
Three pesticides were among the most frequently used substances. These were 2-Bromo-2nitropropane-1 ,3-diol (Bronopol) which was present in 5 commodities and two isothiazolines (2-Methyl-4-isothiazolin-3-one and 5-Chloro-2-methyl-4-isothiazolin-3 -one) both present in 9 commodities. Bronopol was found to be present in wall paint, boiler water and car shampoo whereas the i sothiazolines were present in wall and floor paints, glue for wood applications, car shampoo and sanitary cleaning products. The applicability for using pesticides in car shampoo is unclear. Other isothiazolines and methyl and propyl parabens (personal care products preservatives) were used in less than five each. No agricultural or garden related facilities participated in this study and accordingly no herbicides were found. Though it cannot be excluded that the food industry indirectly may contribute with herbicides from processing of vegetable materials containing herbicide residues.

Hazard identification by RI CH ranking
A total of 346 organic substances were selected to be subjected to the RICH-tool ranking, corresponding to those with CAS included and inherent data availablea . It was noted that 69 lacked some i nherent data making them not possible to fully evaluate. Of the remaining were 2 1 8 listed as non-hazards ("white"), 3 as possible hazards ("grey") and 53 as potential hazards ("black") in the sludge phase. In the aqueous/dissolved phase were 24 1 ranked as "white", 4 as '·grey" and 37 as "black", see Figure 2.
Some of the ''black'' substances overlapped between the solid/sludge and the aqueous phase . thus a total of 76 substances were all in all identified as potential hazards. Among the "black" substances were three isothiazolines. one phthalate, the medium-chained chlorinated paraffins �. ?] , , . . . , . , .�.

Mitigation
Procedures for handling of petroleum based hydrocarbons and an efficiently review of the oil separators is suggested based on the findings presented above. Also, a discussion of substitution to rape methyl ester (RME) used by one industry as wel l as other bio-fuels and lubricates is recommended. The use of car shampoo containing pesticides in questionable both with respect to applicabi lity and further dispersal i n the environment and should be discussed w ith the bus inesses in question.
Most of the industries and bus inesses reported to use eco-labelled cleaning detergents but some commodities were found to contain linear alkylbenzene sulphonates (LAS) which has been discussed in the scientific com munity due to its low biodegradabia l ity during anaerobic conditions and toxicity to anaerobic 111 icro-organisms (9, I 0 . 1 1 ] .
The hazard identification showed that the chlorinated paraffins ( C 1 4-1 7) may pose a potential hazard to sludge and subsequently sludge amended soi l . These are closely rel ated to the short chain chlorinated paraffins ( SCCP; C I 0-1 3) which are classified as priority hazardous substances [6] and as such are subjected to the cessation or phasing-out of discharges, emissions and losses [7]. Additional ly, a few dyes and pigments were classified as potentially hazardous by the RICH-tool and as these primarily are used to beauti fy various personal care products and industrial cleaners it should be re latively easy to substitute these commodities to other commodities contain more eco-friendly colours or uncoloured ibidem. Further, mitigation options w i l l be discussed w ith the industries and businesses in the close future, especially addressing the substances also listed as problematic by the Swedish Chemicals Agency (8].